// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Simplified MAC Kernel (smack) security module
 *
 *  This file contains the smack hook function implementations.
 *
 *  Authors:
 *      Casey Schaufler <casey@schaufler-ca.com>
 *      Jarkko Sakkinen <jarkko.sakkinen@intel.com>
 *
 *  Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
 *  Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
 *                Paul Moore <paul@paul-moore.com>
 *  Copyright (C) 2010 Nokia Corporation
 *  Copyright (C) 2011 Intel Corporation.
 */

#include <linux/xattr.h>
#include <linux/pagemap.h>
#include <linux/mount.h>
#include <linux/stat.h>
#include <linux/kd.h>
#include <asm/ioctls.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/icmpv6.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <net/cipso_ipv4.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <linux/audit.h>
#include <linux/magic.h>
#include <linux/dcache.h>
#include <linux/personality.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <uapi/linux/shm.h>
#include <linux/binfmts.h>
#include <linux/parser.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/watch_queue.h>
#include <linux/io_uring/cmd.h>
#include <uapi/linux/lsm.h>
#include "smack.h"

#define TRANS_TRUE      "TRUE"
#define TRANS_TRUE_SIZE 4

#define SMK_CONNECTING  0
#define SMK_RECEIVING   1
#define SMK_SENDING     2

/*
 * Smack uses multiple xattrs.
 * SMACK64 - for access control,
 * SMACK64TRANSMUTE - label initialization,
 * Not saved on files - SMACK64IPIN and SMACK64IPOUT,
 * Must be set explicitly - SMACK64EXEC and SMACK64MMAP
 */
#define SMACK_INODE_INIT_XATTRS 2

#ifdef SMACK_IPV6_PORT_LABELING
static DEFINE_MUTEX(smack_ipv6_lock);
static LIST_HEAD(smk_ipv6_port_list);
#endif
struct kmem_cache *smack_rule_cache;
int smack_enabled __initdata;

#define A(s) {"smack"#s, sizeof("smack"#s) - 1, Opt_##s}
static struct {
        const char *name;
        int len;
        int opt;
} smk_mount_opts[] = {
        {"smackfsdef", sizeof("smackfsdef") - 1, Opt_fsdefault},
        A(fsdefault), A(fsfloor), A(fshat), A(fsroot), A(fstransmute)
};
#undef A

static int match_opt_prefix(char *s, int l, char **arg)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(smk_mount_opts); i++) {
                size_t len = smk_mount_opts[i].len;
                if (len > l || memcmp(s, smk_mount_opts[i].name, len))
                        continue;
                if (len == l || s[len] != '=')
                        continue;
                *arg = s + len + 1;
                return smk_mount_opts[i].opt;
        }
        return Opt_error;
}

#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static char *smk_bu_mess[] = {
        "Bringup Error",        /* Unused */
        "Bringup",              /* SMACK_BRINGUP_ALLOW */
        "Unconfined Subject",   /* SMACK_UNCONFINED_SUBJECT */
        "Unconfined Object",    /* SMACK_UNCONFINED_OBJECT */
};

static void smk_bu_mode(int mode, char *s)
{
        smack_str_from_perm(s, mode);
}
#endif

#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_note(char *note, struct smack_known *sskp,
                       struct smack_known *oskp, int mode, int rc)
{
        char acc[SMK_NUM_ACCESS_TYPE + 1];

        if (rc <= 0)
                return rc;
        if (rc > SMACK_UNCONFINED_OBJECT)
                rc = 0;

        smk_bu_mode(mode, acc);
        pr_info("Smack %s: (%s %s %s) %s\n", smk_bu_mess[rc],
                sskp->smk_known, oskp->smk_known, acc, note);
        return 0;
}
#else
#define smk_bu_note(note, sskp, oskp, mode, RC) (RC)
#endif

#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_current(char *note, struct smack_known *oskp,
                          int mode, int rc)
{
        struct task_smack *tsp = smack_cred(current_cred());
        char acc[SMK_NUM_ACCESS_TYPE + 1];

        if (rc <= 0)
                return rc;
        if (rc > SMACK_UNCONFINED_OBJECT)
                rc = 0;

        smk_bu_mode(mode, acc);
        pr_info("Smack %s: (%s %s %s) %s %s\n", smk_bu_mess[rc],
                tsp->smk_task->smk_known, oskp->smk_known,
                acc, current->comm, note);
        return 0;
}
#else
#define smk_bu_current(note, oskp, mode, RC) (RC)
#endif

#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_task(struct task_struct *otp, int mode, int rc)
{
        struct task_smack *tsp = smack_cred(current_cred());
        struct smack_known *smk_task = smk_of_task_struct_obj(otp);
        char acc[SMK_NUM_ACCESS_TYPE + 1];

        if (rc <= 0)
                return rc;
        if (rc > SMACK_UNCONFINED_OBJECT)
                rc = 0;

        smk_bu_mode(mode, acc);
        pr_info("Smack %s: (%s %s %s) %s to %s\n", smk_bu_mess[rc],
                tsp->smk_task->smk_known, smk_task->smk_known, acc,
                current->comm, otp->comm);
        return 0;
}
#else
#define smk_bu_task(otp, mode, RC) (RC)
#endif

#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_inode(struct inode *inode, int mode, int rc)
{
        struct task_smack *tsp = smack_cred(current_cred());
        struct inode_smack *isp = smack_inode(inode);
        char acc[SMK_NUM_ACCESS_TYPE + 1];

        if (isp->smk_flags & SMK_INODE_IMPURE)
                pr_info("Smack Unconfined Corruption: inode=(%s %ld) %s\n",
                        inode->i_sb->s_id, inode->i_ino, current->comm);

        if (rc <= 0)
                return rc;
        if (rc > SMACK_UNCONFINED_OBJECT)
                rc = 0;
        if (rc == SMACK_UNCONFINED_SUBJECT &&
            (mode & (MAY_WRITE | MAY_APPEND)))
                isp->smk_flags |= SMK_INODE_IMPURE;

        smk_bu_mode(mode, acc);

        pr_info("Smack %s: (%s %s %s) inode=(%s %ld) %s\n", smk_bu_mess[rc],
                tsp->smk_task->smk_known, isp->smk_inode->smk_known, acc,
                inode->i_sb->s_id, inode->i_ino, current->comm);
        return 0;
}
#else
#define smk_bu_inode(inode, mode, RC) (RC)
#endif

#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_file(struct file *file, int mode, int rc)
{
        struct task_smack *tsp = smack_cred(current_cred());
        struct smack_known *sskp = tsp->smk_task;
        struct inode *inode = file_inode(file);
        struct inode_smack *isp = smack_inode(inode);
        char acc[SMK_NUM_ACCESS_TYPE + 1];

        if (isp->smk_flags & SMK_INODE_IMPURE)
                pr_info("Smack Unconfined Corruption: inode=(%s %ld) %s\n",
                        inode->i_sb->s_id, inode->i_ino, current->comm);

        if (rc <= 0)
                return rc;
        if (rc > SMACK_UNCONFINED_OBJECT)
                rc = 0;

        smk_bu_mode(mode, acc);
        pr_info("Smack %s: (%s %s %s) file=(%s %ld %pD) %s\n", smk_bu_mess[rc],
                sskp->smk_known, smk_of_inode(inode)->smk_known, acc,
                inode->i_sb->s_id, inode->i_ino, file,
                current->comm);
        return 0;
}
#else
#define smk_bu_file(file, mode, RC) (RC)
#endif

#ifdef CONFIG_SECURITY_SMACK_BRINGUP
static int smk_bu_credfile(const struct cred *cred, struct file *file,
                                int mode, int rc)
{
        struct task_smack *tsp = smack_cred(cred);
        struct smack_known *sskp = tsp->smk_task;
        struct inode *inode = file_inode(file);
        struct inode_smack *isp = smack_inode(inode);
        char acc[SMK_NUM_ACCESS_TYPE + 1];

        if (isp->smk_flags & SMK_INODE_IMPURE)
                pr_info("Smack Unconfined Corruption: inode=(%s %ld) %s\n",
                        inode->i_sb->s_id, inode->i_ino, current->comm);

        if (rc <= 0)
                return rc;
        if (rc > SMACK_UNCONFINED_OBJECT)
                rc = 0;

        smk_bu_mode(mode, acc);
        pr_info("Smack %s: (%s %s %s) file=(%s %ld %pD) %s\n", smk_bu_mess[rc],
                sskp->smk_known, smk_of_inode(inode)->smk_known, acc,
                inode->i_sb->s_id, inode->i_ino, file,
                current->comm);
        return 0;
}
#else
#define smk_bu_credfile(cred, file, mode, RC) (RC)
#endif

/**
 * smk_fetch - Fetch the smack label from a file.
 * @name: type of the label (attribute)
 * @ip: a pointer to the inode
 * @dp: a pointer to the dentry
 *
 * Returns a pointer to the master list entry for the Smack label,
 * NULL if there was no label to fetch, or an error code.
 */
static struct smack_known *smk_fetch(const char *name, struct inode *ip,
                                        struct dentry *dp)
{
        int rc;
        char *buffer;
        struct smack_known *skp = NULL;

        if (!(ip->i_opflags & IOP_XATTR))
                return ERR_PTR(-EOPNOTSUPP);

        buffer = kzalloc(SMK_LONGLABEL, GFP_NOFS);
        if (buffer == NULL)
                return ERR_PTR(-ENOMEM);

        rc = __vfs_getxattr(dp, ip, name, buffer, SMK_LONGLABEL);
        if (rc < 0)
                skp = ERR_PTR(rc);
        else if (rc == 0)
                skp = NULL;
        else
                skp = smk_import_entry(buffer, rc);

        kfree(buffer);

        return skp;
}

/**
 * init_inode_smack - initialize an inode security blob
 * @inode: inode to extract the info from
 * @skp: a pointer to the Smack label entry to use in the blob
 *
 */
static void init_inode_smack(struct inode *inode, struct smack_known *skp)
{
        struct inode_smack *isp = smack_inode(inode);

        isp->smk_inode = skp;
        isp->smk_flags = 0;
}

/**
 * init_task_smack - initialize a task security blob
 * @tsp: blob to initialize
 * @task: a pointer to the Smack label for the running task
 * @forked: a pointer to the Smack label for the forked task
 *
 */
static void init_task_smack(struct task_smack *tsp, struct smack_known *task,
                                        struct smack_known *forked)
{
        tsp->smk_task = task;
        tsp->smk_forked = forked;
        INIT_LIST_HEAD(&tsp->smk_rules);
        INIT_LIST_HEAD(&tsp->smk_relabel);
        mutex_init(&tsp->smk_rules_lock);
}

/**
 * smk_copy_rules - copy a rule set
 * @nhead: new rules header pointer
 * @ohead: old rules header pointer
 * @gfp: type of the memory for the allocation
 *
 * Returns 0 on success, -ENOMEM on error
 */
static int smk_copy_rules(struct list_head *nhead, struct list_head *ohead,
                                gfp_t gfp)
{
        struct smack_rule *nrp;
        struct smack_rule *orp;
        int rc = 0;

        list_for_each_entry_rcu(orp, ohead, list) {
                nrp = kmem_cache_zalloc(smack_rule_cache, gfp);
                if (nrp == NULL) {
                        rc = -ENOMEM;
                        break;
                }
                *nrp = *orp;
                list_add_rcu(&nrp->list, nhead);
        }
        return rc;
}

/**
 * smk_copy_relabel - copy smk_relabel labels list
 * @nhead: new rules header pointer
 * @ohead: old rules header pointer
 * @gfp: type of the memory for the allocation
 *
 * Returns 0 on success, -ENOMEM on error
 */
static int smk_copy_relabel(struct list_head *nhead, struct list_head *ohead,
                                gfp_t gfp)
{
        struct smack_known_list_elem *nklep;
        struct smack_known_list_elem *oklep;

        list_for_each_entry(oklep, ohead, list) {
                nklep = kzalloc_obj(struct smack_known_list_elem, gfp);
                if (nklep == NULL) {
                        smk_destroy_label_list(nhead);
                        return -ENOMEM;
                }
                nklep->smk_label = oklep->smk_label;
                list_add(&nklep->list, nhead);
        }

        return 0;
}

/**
 * smk_ptrace_mode - helper function for converting PTRACE_MODE_* into MAY_*
 * @mode: input mode in form of PTRACE_MODE_*
 *
 * Returns a converted MAY_* mode usable by smack rules
 */
static inline unsigned int smk_ptrace_mode(unsigned int mode)
{
        if (mode & PTRACE_MODE_ATTACH)
                return MAY_READWRITE;
        if (mode & PTRACE_MODE_READ)
                return MAY_READ;

        return 0;
}

/**
 * smk_ptrace_rule_check - helper for ptrace access
 * @tracer: tracer process
 * @tracee_known: label entry of the process that's about to be traced
 * @mode: ptrace attachment mode (PTRACE_MODE_*)
 * @func: name of the function that called us, used for audit
 *
 * Returns 0 on access granted, -error on error
 */
static int smk_ptrace_rule_check(struct task_struct *tracer,
                                 struct smack_known *tracee_known,
                                 unsigned int mode, const char *func)
{
        int rc;
        struct smk_audit_info ad, *saip = NULL;
        struct task_smack *tsp;
        struct smack_known *tracer_known;
        const struct cred *tracercred;

        if ((mode & PTRACE_MODE_NOAUDIT) == 0) {
                smk_ad_init(&ad, func, LSM_AUDIT_DATA_TASK);
                smk_ad_setfield_u_tsk(&ad, tracer);
                saip = &ad;
        }

        rcu_read_lock();
        tracercred = __task_cred(tracer);
        tsp = smack_cred(tracercred);
        tracer_known = smk_of_task(tsp);

        if ((mode & PTRACE_MODE_ATTACH) &&
            (smack_ptrace_rule == SMACK_PTRACE_EXACT ||
             smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)) {
                if (tracer_known->smk_known == tracee_known->smk_known)
                        rc = 0;
                else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)
                        rc = -EACCES;
                else if (smack_privileged_cred(CAP_SYS_PTRACE, tracercred))
                        rc = 0;
                else
                        rc = -EACCES;

                if (saip)
                        smack_log(tracer_known->smk_known,
                                  tracee_known->smk_known,
                                  0, rc, saip);

                rcu_read_unlock();
                return rc;
        }

        /* In case of rule==SMACK_PTRACE_DEFAULT or mode==PTRACE_MODE_READ */
        rc = smk_tskacc(tsp, tracee_known, smk_ptrace_mode(mode), saip);

        rcu_read_unlock();
        return rc;
}

/*
 * LSM hooks.
 * We he, that is fun!
 */

/**
 * smack_ptrace_access_check - Smack approval on PTRACE_ATTACH
 * @ctp: child task pointer
 * @mode: ptrace attachment mode (PTRACE_MODE_*)
 *
 * Returns 0 if access is OK, an error code otherwise
 *
 * Do the capability checks.
 */
static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
{
        struct smack_known *skp;

        skp = smk_of_task_struct_obj(ctp);

        return smk_ptrace_rule_check(current, skp, mode, __func__);
}

/**
 * smack_ptrace_traceme - Smack approval on PTRACE_TRACEME
 * @ptp: parent task pointer
 *
 * Returns 0 if access is OK, an error code otherwise
 *
 * Do the capability checks, and require PTRACE_MODE_ATTACH.
 */
static int smack_ptrace_traceme(struct task_struct *ptp)
{
        struct smack_known *skp;

        skp = smk_of_task(smack_cred(current_cred()));

        return smk_ptrace_rule_check(ptp, skp, PTRACE_MODE_ATTACH, __func__);
}

/**
 * smack_syslog - Smack approval on syslog
 * @typefrom_file: unused
 *
 * Returns 0 on success, error code otherwise.
 */
static int smack_syslog(int typefrom_file)
{
        int rc = 0;
        struct smack_known *skp = smk_of_current();

        if (smack_privileged(CAP_MAC_OVERRIDE))
                return 0;

        if (smack_syslog_label != NULL && smack_syslog_label != skp)
                rc = -EACCES;

        return rc;
}

/*
 * Superblock Hooks.
 */

/**
 * smack_sb_alloc_security - allocate a superblock blob
 * @sb: the superblock getting the blob
 *
 * Returns 0 on success or -ENOMEM on error.
 */
static int smack_sb_alloc_security(struct super_block *sb)
{
        struct superblock_smack *sbsp = smack_superblock(sb);

        sbsp->smk_root = &smack_known_floor;
        sbsp->smk_default = &smack_known_floor;
        sbsp->smk_floor = &smack_known_floor;
        sbsp->smk_hat = &smack_known_hat;
        /*
         * SMK_SB_INITIALIZED will be zero from kzalloc.
         */

        return 0;
}

struct smack_mnt_opts {
        const char *fsdefault;
        const char *fsfloor;
        const char *fshat;
        const char *fsroot;
        const char *fstransmute;
};

static void smack_free_mnt_opts(void *mnt_opts)
{
        kfree(mnt_opts);
}

static int smack_add_opt(int token, const char *s, void **mnt_opts)
{
        struct smack_mnt_opts *opts = *mnt_opts;
        struct smack_known *skp;

        if (!opts) {
                opts = kzalloc_obj(struct smack_mnt_opts);
                if (!opts)
                        return -ENOMEM;
                *mnt_opts = opts;
        }
        if (!s)
                return -ENOMEM;

        skp = smk_import_entry(s, 0);
        if (IS_ERR(skp))
                return PTR_ERR(skp);

        switch (token) {
        case Opt_fsdefault:
                if (opts->fsdefault)
                        goto out_opt_err;
                opts->fsdefault = skp->smk_known;
                break;
        case Opt_fsfloor:
                if (opts->fsfloor)
                        goto out_opt_err;
                opts->fsfloor = skp->smk_known;
                break;
        case Opt_fshat:
                if (opts->fshat)
                        goto out_opt_err;
                opts->fshat = skp->smk_known;
                break;
        case Opt_fsroot:
                if (opts->fsroot)
                        goto out_opt_err;
                opts->fsroot = skp->smk_known;
                break;
        case Opt_fstransmute:
                if (opts->fstransmute)
                        goto out_opt_err;
                opts->fstransmute = skp->smk_known;
                break;
        }
        return 0;

out_opt_err:
        pr_warn("Smack: duplicate mount options\n");
        return -EINVAL;
}

/**
 * smack_fs_context_submount - Initialise security data for a filesystem context
 * @fc: The filesystem context.
 * @reference: reference superblock
 *
 * Returns 0 on success or -ENOMEM on error.
 */
static int smack_fs_context_submount(struct fs_context *fc,
                                 struct super_block *reference)
{
        struct superblock_smack *sbsp;
        struct smack_mnt_opts *ctx;
        struct inode_smack *isp;

        ctx = kzalloc_obj(*ctx);
        if (!ctx)
                return -ENOMEM;
        fc->security = ctx;

        sbsp = smack_superblock(reference);
        isp = smack_inode(reference->s_root->d_inode);

        if (sbsp->smk_default) {
                ctx->fsdefault = kstrdup(sbsp->smk_default->smk_known, GFP_KERNEL);
                if (!ctx->fsdefault)
                        return -ENOMEM;
        }

        if (sbsp->smk_floor) {
                ctx->fsfloor = kstrdup(sbsp->smk_floor->smk_known, GFP_KERNEL);
                if (!ctx->fsfloor)
                        return -ENOMEM;
        }

        if (sbsp->smk_hat) {
                ctx->fshat = kstrdup(sbsp->smk_hat->smk_known, GFP_KERNEL);
                if (!ctx->fshat)
                        return -ENOMEM;
        }

        if (isp->smk_flags & SMK_INODE_TRANSMUTE) {
                if (sbsp->smk_root) {
                        ctx->fstransmute = kstrdup(sbsp->smk_root->smk_known, GFP_KERNEL);
                        if (!ctx->fstransmute)
                                return -ENOMEM;
                }
        }
        return 0;
}

/**
 * smack_fs_context_dup - Duplicate the security data on fs_context duplication
 * @fc: The new filesystem context.
 * @src_fc: The source filesystem context being duplicated.
 *
 * Returns 0 on success or -ENOMEM on error.
 */
static int smack_fs_context_dup(struct fs_context *fc,
                                struct fs_context *src_fc)
{
        struct smack_mnt_opts *dst, *src = src_fc->security;

        if (!src)
                return 0;

        fc->security = kzalloc_obj(struct smack_mnt_opts);
        if (!fc->security)
                return -ENOMEM;

        dst = fc->security;
        dst->fsdefault = src->fsdefault;
        dst->fsfloor = src->fsfloor;
        dst->fshat = src->fshat;
        dst->fsroot = src->fsroot;
        dst->fstransmute = src->fstransmute;

        return 0;
}

static const struct fs_parameter_spec smack_fs_parameters[] = {
        fsparam_string("smackfsdef",            Opt_fsdefault),
        fsparam_string("smackfsdefault",        Opt_fsdefault),
        fsparam_string("smackfsfloor",          Opt_fsfloor),
        fsparam_string("smackfshat",            Opt_fshat),
        fsparam_string("smackfsroot",           Opt_fsroot),
        fsparam_string("smackfstransmute",      Opt_fstransmute),
        {}
};

/**
 * smack_fs_context_parse_param - Parse a single mount parameter
 * @fc: The new filesystem context being constructed.
 * @param: The parameter.
 *
 * Returns 0 on success, -ENOPARAM to pass the parameter on or anything else on
 * error.
 */
static int smack_fs_context_parse_param(struct fs_context *fc,
                                        struct fs_parameter *param)
{
        struct fs_parse_result result;
        int opt, rc;

        opt = fs_parse(fc, smack_fs_parameters, param, &result);
        if (opt < 0)
                return opt;

        rc = smack_add_opt(opt, param->string, &fc->security);
        if (!rc)
                param->string = NULL;
        return rc;
}

static int smack_sb_eat_lsm_opts(char *options, void **mnt_opts)
{
        char *from = options, *to = options;
        bool first = true;

        while (1) {
                char *next = strchr(from, ',');
                int token, len, rc;
                char *arg = NULL;

                if (next)
                        len = next - from;
                else
                        len = strlen(from);

                token = match_opt_prefix(from, len, &arg);
                if (token != Opt_error) {
                        arg = kmemdup_nul(arg, from + len - arg, GFP_KERNEL);
                        rc = smack_add_opt(token, arg, mnt_opts);
                        kfree(arg);
                        if (unlikely(rc)) {
                                if (*mnt_opts)
                                        smack_free_mnt_opts(*mnt_opts);
                                *mnt_opts = NULL;
                                return rc;
                        }
                } else {
                        if (!first) {   // copy with preceding comma
                                from--;
                                len++;
                        }
                        if (to != from)
                                memmove(to, from, len);
                        to += len;
                        first = false;
                }
                if (!from[len])
                        break;
                from += len + 1;
        }
        *to = '\0';
        return 0;
}

/**
 * smack_set_mnt_opts - set Smack specific mount options
 * @sb: the file system superblock
 * @mnt_opts: Smack mount options
 * @kern_flags: mount option from kernel space or user space
 * @set_kern_flags: where to store converted mount opts
 *
 * Returns 0 on success, an error code on failure
 *
 * Allow filesystems with binary mount data to explicitly set Smack mount
 * labels.
 */
static int smack_set_mnt_opts(struct super_block *sb,
                void *mnt_opts,
                unsigned long kern_flags,
                unsigned long *set_kern_flags)
{
        struct dentry *root = sb->s_root;
        struct inode *inode = d_backing_inode(root);
        struct superblock_smack *sp = smack_superblock(sb);
        struct inode_smack *isp;
        struct smack_known *skp;
        struct smack_mnt_opts *opts = mnt_opts;
        bool transmute = false;

        if (sp->smk_flags & SMK_SB_INITIALIZED)
                return 0;

        if (!smack_privileged(CAP_MAC_ADMIN)) {
                /*
                 * Unprivileged mounts don't get to specify Smack values.
                 */
                if (opts)
                        return -EPERM;
                /*
                 * Unprivileged mounts get root and default from the caller.
                 */
                skp = smk_of_current();
                sp->smk_root = skp;
                sp->smk_default = skp;
                /*
                 * For a handful of fs types with no user-controlled
                 * backing store it's okay to trust security labels
                 * in the filesystem. The rest are untrusted.
                 */
                if (sb->s_user_ns != &init_user_ns &&
                    sb->s_magic != SYSFS_MAGIC && sb->s_magic != TMPFS_MAGIC &&
                    sb->s_magic != RAMFS_MAGIC) {
                        transmute = true;
                        sp->smk_flags |= SMK_SB_UNTRUSTED;
                }
        }

        sp->smk_flags |= SMK_SB_INITIALIZED;

        if (opts) {
                if (opts->fsdefault) {
                        skp = smk_import_entry(opts->fsdefault, 0);
                        if (IS_ERR(skp))
                                return PTR_ERR(skp);
                        sp->smk_default = skp;
                }
                if (opts->fsfloor) {
                        skp = smk_import_entry(opts->fsfloor, 0);
                        if (IS_ERR(skp))
                                return PTR_ERR(skp);
                        sp->smk_floor = skp;
                }
                if (opts->fshat) {
                        skp = smk_import_entry(opts->fshat, 0);
                        if (IS_ERR(skp))
                                return PTR_ERR(skp);
                        sp->smk_hat = skp;
                }
                if (opts->fsroot) {
                        skp = smk_import_entry(opts->fsroot, 0);
                        if (IS_ERR(skp))
                                return PTR_ERR(skp);
                        sp->smk_root = skp;
                }
                if (opts->fstransmute) {
                        skp = smk_import_entry(opts->fstransmute, 0);
                        if (IS_ERR(skp))
                                return PTR_ERR(skp);
                        sp->smk_root = skp;
                        transmute = true;
                }
        }

        /*
         * Initialize the root inode.
         */
        init_inode_smack(inode, sp->smk_root);

        if (transmute) {
                isp = smack_inode(inode);
                isp->smk_flags |= SMK_INODE_TRANSMUTE;
        }

        return 0;
}

/**
 * smack_sb_statfs - Smack check on statfs
 * @dentry: identifies the file system in question
 *
 * Returns 0 if current can read the floor of the filesystem,
 * and error code otherwise
 */
static int smack_sb_statfs(struct dentry *dentry)
{
        struct superblock_smack *sbp = smack_superblock(dentry->d_sb);
        int rc;
        struct smk_audit_info ad;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

        rc = smk_curacc(sbp->smk_floor, MAY_READ, &ad);
        rc = smk_bu_current("statfs", sbp->smk_floor, MAY_READ, rc);
        return rc;
}

/*
 * BPRM hooks
 */

/**
 * smack_bprm_creds_for_exec - Update bprm->cred if needed for exec
 * @bprm: the exec information
 *
 * Returns 0 if it gets a blob, -EPERM if exec forbidden and -ENOMEM otherwise
 */
static int smack_bprm_creds_for_exec(struct linux_binprm *bprm)
{
        struct inode *inode = file_inode(bprm->file);
        struct task_smack *bsp = smack_cred(bprm->cred);
        struct inode_smack *isp;
        struct superblock_smack *sbsp;
        int rc;

        isp = smack_inode(inode);
        if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task)
                return 0;

        sbsp = smack_superblock(inode->i_sb);
        if ((sbsp->smk_flags & SMK_SB_UNTRUSTED) &&
            isp->smk_task != sbsp->smk_root)
                return 0;

        if (bprm->unsafe & LSM_UNSAFE_PTRACE) {
                struct task_struct *tracer;
                rc = 0;

                rcu_read_lock();
                tracer = ptrace_parent(current);
                if (likely(tracer != NULL))
                        rc = smk_ptrace_rule_check(tracer,
                                                   isp->smk_task,
                                                   PTRACE_MODE_ATTACH,
                                                   __func__);
                rcu_read_unlock();

                if (rc != 0)
                        return rc;
        }
        if (bprm->unsafe & ~LSM_UNSAFE_PTRACE)
                return -EPERM;

        bsp->smk_task = isp->smk_task;
        bprm->per_clear |= PER_CLEAR_ON_SETID;

        /* Decide if this is a secure exec. */
        if (bsp->smk_task != bsp->smk_forked)
                bprm->secureexec = 1;

        return 0;
}

/*
 * Inode hooks
 */

/**
 * smack_inode_alloc_security - allocate an inode blob
 * @inode: the inode in need of a blob
 *
 * Returns 0
 */
static int smack_inode_alloc_security(struct inode *inode)
{
        struct smack_known *skp = smk_of_current();

        init_inode_smack(inode, skp);
        return 0;
}

/**
 * smk_rule_transmutes - does access rule for (subject,object) contain 't'?
 * @subject: a pointer to the subject's Smack label entry
 * @object: a pointer to the object's Smack label entry
 */
static bool
smk_rule_transmutes(struct smack_known *subject,
              const struct smack_known *object)
{
        int may;

        rcu_read_lock();
        may = smk_access_entry(subject->smk_known, object->smk_known,
                               &subject->smk_rules);
        rcu_read_unlock();
        return (may > 0) && (may & MAY_TRANSMUTE);
}

static int
xattr_dupval(struct xattr *xattrs, int *xattr_count,
             const char *name, const void *value, unsigned int vallen)
{
        struct xattr * const xattr = lsm_get_xattr_slot(xattrs, xattr_count);

        if (!xattr)
                return 0;

        xattr->value = kmemdup(value, vallen, GFP_NOFS);
        if (!xattr->value)
                return -ENOMEM;

        xattr->value_len = vallen;
        xattr->name = name;
        return 0;
}

/**
 * smack_inode_init_security - copy out the smack from an inode
 * @inode: the newly created inode
 * @dir: containing directory object
 * @qstr: unused
 * @xattrs: where to put the attributes
 * @xattr_count: current number of LSM-provided xattrs (updated)
 *
 * Returns 0 if it all works out, -ENOMEM if there's no memory
 */
static int smack_inode_init_security(struct inode *inode, struct inode *dir,
                                     const struct qstr *qstr,
                                     struct xattr *xattrs, int *xattr_count)
{
        struct task_smack *tsp = smack_cred(current_cred());
        struct inode_smack * const issp = smack_inode(inode);
        struct smack_known *dsp = smk_of_inode(dir);
        int rc = 0;
        int transflag = 0;
        bool trans_cred;
        bool trans_rule;

        /*
         * UNIX domain sockets use lower level socket data. Let
         * UDS inode have fixed * label to keep smack_inode_permission() calm
         * when called from unix_find_bsd()
         */
        if (S_ISSOCK(inode->i_mode)) {
                /* forced label, no need to save to xattrs */
                issp->smk_inode = &smack_known_star;
                goto instant_inode;
        }
        /*
         * If equal, transmuting already occurred in
         * smack_dentry_create_files_as(). No need to check again.
         */
        trans_cred = (tsp->smk_task == tsp->smk_transmuted);
        if (!trans_cred)
                trans_rule = smk_rule_transmutes(smk_of_task(tsp), dsp);

        /*
         * In addition to having smk_task equal to smk_transmuted,
         * if the access rule allows transmutation and the directory
         * requests transmutation then by all means transmute.
         * Mark the inode as changed.
         */
        if (trans_cred || (trans_rule && smk_inode_transmutable(dir))) {
                /*
                 * The caller of smack_dentry_create_files_as()
                 * should have overridden the current cred, so the
                 * inode label was already set correctly in
                 * smack_inode_alloc_security().
                 */
                if (!trans_cred)
                        issp->smk_inode = dsp;

                if (S_ISDIR(inode->i_mode)) {
                        transflag = SMK_INODE_TRANSMUTE;

                        if (xattr_dupval(xattrs, xattr_count,
                                XATTR_SMACK_TRANSMUTE,
                                TRANS_TRUE,
                                TRANS_TRUE_SIZE
                        ))
                                rc = -ENOMEM;
                }
        }

        if (rc == 0)
                if (xattr_dupval(xattrs, xattr_count,
                            XATTR_SMACK_SUFFIX,
                            issp->smk_inode->smk_known,
                     strlen(issp->smk_inode->smk_known)
                ))
                        rc = -ENOMEM;
instant_inode:
        issp->smk_flags |= (SMK_INODE_INSTANT | transflag);
        return rc;
}

/**
 * smack_inode_link - Smack check on link
 * @old_dentry: the existing object
 * @dir: unused
 * @new_dentry: the new object
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
                            struct dentry *new_dentry)
{
        struct smack_known *isp;
        struct smk_audit_info ad;
        int rc;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);

        isp = smk_of_inode(d_backing_inode(old_dentry));
        rc = smk_curacc(isp, MAY_WRITE, &ad);
        rc = smk_bu_inode(d_backing_inode(old_dentry), MAY_WRITE, rc);

        if (rc == 0 && d_is_positive(new_dentry)) {
                isp = smk_of_inode(d_backing_inode(new_dentry));
                smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
                rc = smk_curacc(isp, MAY_WRITE, &ad);
                rc = smk_bu_inode(d_backing_inode(new_dentry), MAY_WRITE, rc);
        }

        return rc;
}

/**
 * smack_inode_unlink - Smack check on inode deletion
 * @dir: containing directory object
 * @dentry: file to unlink
 *
 * Returns 0 if current can write the containing directory
 * and the object, error code otherwise
 */
static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
{
        struct inode *ip = d_backing_inode(dentry);
        struct smk_audit_info ad;
        int rc;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

        /*
         * You need write access to the thing you're unlinking
         */
        rc = smk_curacc(smk_of_inode(ip), MAY_WRITE, &ad);
        rc = smk_bu_inode(ip, MAY_WRITE, rc);
        if (rc == 0) {
                /*
                 * You also need write access to the containing directory
                 */
                smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
                smk_ad_setfield_u_fs_inode(&ad, dir);
                rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
                rc = smk_bu_inode(dir, MAY_WRITE, rc);
        }
        return rc;
}

/**
 * smack_inode_rmdir - Smack check on directory deletion
 * @dir: containing directory object
 * @dentry: directory to unlink
 *
 * Returns 0 if current can write the containing directory
 * and the directory, error code otherwise
 */
static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
{
        struct smk_audit_info ad;
        int rc;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

        /*
         * You need write access to the thing you're removing
         */
        rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
        rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
        if (rc == 0) {
                /*
                 * You also need write access to the containing directory
                 */
                smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
                smk_ad_setfield_u_fs_inode(&ad, dir);
                rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
                rc = smk_bu_inode(dir, MAY_WRITE, rc);
        }

        return rc;
}

/**
 * smack_inode_rename - Smack check on rename
 * @old_inode: unused
 * @old_dentry: the old object
 * @new_inode: unused
 * @new_dentry: the new object
 *
 * Read and write access is required on both the old and
 * new directories.
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_rename(struct inode *old_inode,
                              struct dentry *old_dentry,
                              struct inode *new_inode,
                              struct dentry *new_dentry)
{
        int rc;
        struct smack_known *isp;
        struct smk_audit_info ad;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);

        isp = smk_of_inode(d_backing_inode(old_dentry));
        rc = smk_curacc(isp, MAY_READWRITE, &ad);
        rc = smk_bu_inode(d_backing_inode(old_dentry), MAY_READWRITE, rc);

        if (rc == 0 && d_is_positive(new_dentry)) {
                isp = smk_of_inode(d_backing_inode(new_dentry));
                smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
                rc = smk_curacc(isp, MAY_READWRITE, &ad);
                rc = smk_bu_inode(d_backing_inode(new_dentry), MAY_READWRITE, rc);
        }
        return rc;
}

/**
 * smack_inode_permission - Smack version of permission()
 * @inode: the inode in question
 * @mask: the access requested
 *
 * This is the important Smack hook.
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_permission(struct inode *inode, int mask)
{
        struct superblock_smack *sbsp = smack_superblock(inode->i_sb);
        struct smk_audit_info ad;
        int no_block = mask & MAY_NOT_BLOCK;
        int rc;

        mask &= (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND);
        /*
         * No permission to check. Existence test. Yup, it's there.
         */
        if (mask == 0)
                return 0;

        if (sbsp->smk_flags & SMK_SB_UNTRUSTED) {
                if (smk_of_inode(inode) != sbsp->smk_root)
                        return -EACCES;
        }

        /* May be droppable after audit */
        if (no_block)
                return -ECHILD;
        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
        smk_ad_setfield_u_fs_inode(&ad, inode);
        rc = smk_curacc(smk_of_inode(inode), mask, &ad);
        rc = smk_bu_inode(inode, mask, rc);
        return rc;
}

/**
 * smack_inode_setattr - Smack check for setting attributes
 * @idmap: idmap of the mount
 * @dentry: the object
 * @iattr: for the force flag
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
                               struct iattr *iattr)
{
        struct smk_audit_info ad;
        int rc;

        /*
         * Need to allow for clearing the setuid bit.
         */
        if (iattr->ia_valid & ATTR_FORCE)
                return 0;
        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

        rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
        rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
        return rc;
}

/**
 * smack_inode_getattr - Smack check for getting attributes
 * @path: path to extract the info from
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_getattr(const struct path *path)
{
        struct smk_audit_info ad;
        struct inode *inode = d_backing_inode(path->dentry);
        int rc;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
        smk_ad_setfield_u_fs_path(&ad, *path);
        rc = smk_curacc(smk_of_inode(inode), MAY_READ, &ad);
        rc = smk_bu_inode(inode, MAY_READ, rc);
        return rc;
}

/**
 * smack_inode_xattr_skipcap - Skip the xattr capability checks?
 * @name: name of the xattr
 *
 * Returns 1 to indicate that Smack "owns" the access control rights to xattrs
 * named @name; the LSM layer should avoid enforcing any traditional
 * capability based access controls on this xattr.  Returns 0 to indicate that
 * Smack does not "own" the access control rights to xattrs named @name and is
 * deferring to the LSM layer for further access controls, including capability
 * based controls.
 */
static int smack_inode_xattr_skipcap(const char *name)
{
        if (strncmp(name, XATTR_SMACK_SUFFIX, strlen(XATTR_SMACK_SUFFIX)))
                return 0;

        if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
            strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
            strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 ||
            strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
            strcmp(name, XATTR_NAME_SMACKMMAP) == 0 ||
            strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0)
                return 1;

        return 0;
}

/**
 * smack_inode_setxattr - Smack check for setting xattrs
 * @idmap: idmap of the mount
 * @dentry: the object
 * @name: name of the attribute
 * @value: value of the attribute
 * @size: size of the value
 * @flags: unused
 *
 * This protects the Smack attribute explicitly.
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_setxattr(struct mnt_idmap *idmap,
                                struct dentry *dentry, const char *name,
                                const void *value, size_t size, int flags)
{
        struct smk_audit_info ad;
        struct smack_known *skp;
        int check_priv = 0;
        int check_import = 0;
        int check_star = 0;
        int rc = 0;
        umode_t const i_mode = d_backing_inode(dentry)->i_mode;

        /*
         * Check label validity here so import won't fail in post_setxattr
         */
        if (strcmp(name, XATTR_NAME_SMACK) == 0) {
                /*
                 * UDS inode has fixed label
                 */
                if (S_ISSOCK(i_mode)) {
                        rc = -EINVAL;
                } else {
                        check_priv = 1;
                        check_import = 1;
                }
        } else if (strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
                   strcmp(name, XATTR_NAME_SMACKIPOUT) == 0) {
                check_priv = 1;
                check_import = 1;
        } else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
                   strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
                check_priv = 1;
                check_import = 1;
                check_star = 1;
        } else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
                check_priv = 1;
                if (!S_ISDIR(i_mode) ||
                    size != TRANS_TRUE_SIZE ||
                    strncmp(value, TRANS_TRUE, TRANS_TRUE_SIZE) != 0)
                        rc = -EINVAL;
        }

        if (check_priv && !smack_privileged(CAP_MAC_ADMIN))
                rc = -EPERM;

        if (rc == 0 && check_import) {
                skp = size ? smk_import_entry(value, size) : NULL;
                if (IS_ERR(skp))
                        rc = PTR_ERR(skp);
                else if (skp == NULL || (check_star &&
                    (skp == &smack_known_star || skp == &smack_known_web)))
                        rc = -EINVAL;
        }

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

        if (rc == 0) {
                rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
                rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
        }

        return rc;
}

/**
 * smack_inode_post_setxattr - Apply the Smack update approved above
 * @dentry: object
 * @name: attribute name
 * @value: attribute value
 * @size: attribute size
 * @flags: unused
 *
 * Set the pointer in the inode blob to the entry found
 * in the master label list.
 */
static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
                                      const void *value, size_t size, int flags)
{
        struct smack_known *skp;
        struct inode_smack *isp = smack_inode(d_backing_inode(dentry));

        if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
                isp->smk_flags |= SMK_INODE_TRANSMUTE;
                return;
        }

        if (strcmp(name, XATTR_NAME_SMACK) == 0) {
                skp = smk_import_entry(value, size);
                if (!IS_ERR(skp))
                        isp->smk_inode = skp;
        } else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0) {
                skp = smk_import_entry(value, size);
                if (!IS_ERR(skp))
                        isp->smk_task = skp;
        } else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
                skp = smk_import_entry(value, size);
                if (!IS_ERR(skp))
                        isp->smk_mmap = skp;
        }

        return;
}

/**
 * smack_inode_getxattr - Smack check on getxattr
 * @dentry: the object
 * @name: unused
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_getxattr(struct dentry *dentry, const char *name)
{
        struct smk_audit_info ad;
        int rc;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

        rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_READ, &ad);
        rc = smk_bu_inode(d_backing_inode(dentry), MAY_READ, rc);
        return rc;
}

/**
 * smack_inode_removexattr - Smack check on removexattr
 * @idmap: idmap of the mount
 * @dentry: the object
 * @name: name of the attribute
 *
 * Removing the Smack attribute requires CAP_MAC_ADMIN
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_removexattr(struct mnt_idmap *idmap,
                                   struct dentry *dentry, const char *name)
{
        struct inode_smack *isp;
        struct smk_audit_info ad;
        int rc = 0;

        if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
            strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
            strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 ||
            strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
            strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0 ||
            strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
                if (!smack_privileged(CAP_MAC_ADMIN))
                        rc = -EPERM;
        }

        if (rc != 0)
                return rc;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

        rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
        rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
        if (rc != 0)
                return rc;

        isp = smack_inode(d_backing_inode(dentry));
        /*
         * Don't do anything special for these.
         *      XATTR_NAME_SMACKIPIN
         *      XATTR_NAME_SMACKIPOUT
         *      XATTR_NAME_SMACK if S_ISSOCK (UDS inode has fixed label)
         */
        if (strcmp(name, XATTR_NAME_SMACK) == 0) {
                if (!S_ISSOCK(d_backing_inode(dentry)->i_mode)) {
                        struct super_block *sbp = dentry->d_sb;
                        struct superblock_smack *sbsp = smack_superblock(sbp);

                        isp->smk_inode = sbsp->smk_default;
                }
        } else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0)
                isp->smk_task = NULL;
        else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0)
                isp->smk_mmap = NULL;
        else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0)
                isp->smk_flags &= ~SMK_INODE_TRANSMUTE;

        return 0;
}

/**
 * smack_inode_set_acl - Smack check for setting posix acls
 * @idmap: idmap of the mnt this request came from
 * @dentry: the object
 * @acl_name: name of the posix acl
 * @kacl: the posix acls
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_set_acl(struct mnt_idmap *idmap,
                               struct dentry *dentry, const char *acl_name,
                               struct posix_acl *kacl)
{
        struct smk_audit_info ad;
        int rc;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

        rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
        rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
        return rc;
}

/**
 * smack_inode_get_acl - Smack check for getting posix acls
 * @idmap: idmap of the mnt this request came from
 * @dentry: the object
 * @acl_name: name of the posix acl
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_get_acl(struct mnt_idmap *idmap,
                               struct dentry *dentry, const char *acl_name)
{
        struct smk_audit_info ad;
        int rc;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

        rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_READ, &ad);
        rc = smk_bu_inode(d_backing_inode(dentry), MAY_READ, rc);
        return rc;
}

/**
 * smack_inode_remove_acl - Smack check for getting posix acls
 * @idmap: idmap of the mnt this request came from
 * @dentry: the object
 * @acl_name: name of the posix acl
 *
 * Returns 0 if access is permitted, an error code otherwise
 */
static int smack_inode_remove_acl(struct mnt_idmap *idmap,
                                  struct dentry *dentry, const char *acl_name)
{
        struct smk_audit_info ad;
        int rc;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
        smk_ad_setfield_u_fs_path_dentry(&ad, dentry);

        rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
        rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
        return rc;
}

/**
 * smack_inode_getsecurity - get smack xattrs
 * @idmap: idmap of the mount
 * @inode: the object
 * @name: attribute name
 * @buffer: where to put the result
 * @alloc: duplicate memory
 *
 * Returns the size of the attribute or an error code
 */
static int smack_inode_getsecurity(struct mnt_idmap *idmap,
                                   struct inode *inode, const char *name,
                                   void **buffer, bool alloc)
{
        struct socket_smack *ssp;
        struct socket *sock;
        struct super_block *sbp;
        struct inode *ip = inode;
        struct smack_known *isp;
        struct inode_smack *ispp;
        size_t label_len;
        char *label = NULL;

        if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
                isp = smk_of_inode(inode);
        } else if (strcmp(name, XATTR_SMACK_TRANSMUTE) == 0) {
                ispp = smack_inode(inode);
                if (ispp->smk_flags & SMK_INODE_TRANSMUTE)
                        label = TRANS_TRUE;
                else
                        label = "";
        } else {
                /*
                 * The rest of the Smack xattrs are only on sockets.
                 */
                sbp = ip->i_sb;
                if (sbp->s_magic != SOCKFS_MAGIC)
                        return -EOPNOTSUPP;

                sock = SOCKET_I(ip);
                if (sock == NULL || sock->sk == NULL)
                        return -EOPNOTSUPP;

                ssp = smack_sock(sock->sk);

                if (strcmp(name, XATTR_SMACK_IPIN) == 0)
                        isp = ssp->smk_in;
                else if (strcmp(name, XATTR_SMACK_IPOUT) == 0)
                        isp = ssp->smk_out;
                else
                        return -EOPNOTSUPP;
        }

        if (!label)
                label = isp->smk_known;

        label_len = strlen(label);

        if (alloc) {
                *buffer = kstrdup(label, GFP_KERNEL);
                if (*buffer == NULL)
                        return -ENOMEM;
        }

        return label_len;
}


/**
 * smack_inode_listsecurity - list the Smack attributes
 * @inode: the object
 * @buffer: where they go
 * @buffer_size: size of buffer
 */
static int smack_inode_listsecurity(struct inode *inode, char *buffer,
                                    size_t buffer_size)
{
        int len = sizeof(XATTR_NAME_SMACK);

        if (buffer != NULL && len <= buffer_size)
                memcpy(buffer, XATTR_NAME_SMACK, len);

        return len;
}

/**
 * smack_inode_getlsmprop - Extract inode's security id
 * @inode: inode to extract the info from
 * @prop: where result will be saved
 */
static void smack_inode_getlsmprop(struct inode *inode, struct lsm_prop *prop)
{
        prop->smack.skp = smk_of_inode(inode);
}

/*
 * File Hooks
 */

/*
 * There is no smack_file_permission hook
 *
 * Should access checks be done on each read or write?
 * UNICOS and SELinux say yes.
 * Trusted Solaris, Trusted Irix, and just about everyone else says no.
 *
 * I'll say no for now. Smack does not do the frequent
 * label changing that SELinux does.
 */

/**
 * smack_file_alloc_security - assign a file security blob
 * @file: the object
 *
 * The security blob for a file is a pointer to the master
 * label list, so no allocation is done.
 *
 * f_security is the owner security information. It
 * isn't used on file access checks, it's for send_sigio.
 *
 * Returns 0
 */
static int smack_file_alloc_security(struct file *file)
{
        struct smack_known **blob = smack_file(file);

        *blob = smk_of_current();
        return 0;
}

/**
 * smack_file_ioctl - Smack check on ioctls
 * @file: the object
 * @cmd: what to do
 * @arg: unused
 *
 * Relies heavily on the correct use of the ioctl command conventions.
 *
 * Returns 0 if allowed, error code otherwise
 */
static int smack_file_ioctl(struct file *file, unsigned int cmd,
                            unsigned long arg)
{
        int rc = 0;
        struct smk_audit_info ad;
        struct inode *inode = file_inode(file);

        if (unlikely(IS_PRIVATE(inode)))
                return 0;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
        smk_ad_setfield_u_fs_path(&ad, file->f_path);

        if (_IOC_DIR(cmd) & _IOC_WRITE) {
                rc = smk_curacc(smk_of_inode(inode), MAY_WRITE, &ad);
                rc = smk_bu_file(file, MAY_WRITE, rc);
        }

        if (rc == 0 && (_IOC_DIR(cmd) & _IOC_READ)) {
                rc = smk_curacc(smk_of_inode(inode), MAY_READ, &ad);
                rc = smk_bu_file(file, MAY_READ, rc);
        }

        return rc;
}

/**
 * smack_file_lock - Smack check on file locking
 * @file: the object
 * @cmd: unused
 *
 * Returns 0 if current has lock access, error code otherwise
 */
static int smack_file_lock(struct file *file, unsigned int cmd)
{
        struct smk_audit_info ad;
        int rc;
        struct inode *inode = file_inode(file);

        if (unlikely(IS_PRIVATE(inode)))
                return 0;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
        smk_ad_setfield_u_fs_path(&ad, file->f_path);
        rc = smk_curacc(smk_of_inode(inode), MAY_LOCK, &ad);
        rc = smk_bu_file(file, MAY_LOCK, rc);
        return rc;
}

/**
 * smack_file_fcntl - Smack check on fcntl
 * @file: the object
 * @cmd: what action to check
 * @arg: unused
 *
 * Generally these operations are harmless.
 * File locking operations present an obvious mechanism
 * for passing information, so they require write access.
 *
 * Returns 0 if current has access, error code otherwise
 */
static int smack_file_fcntl(struct file *file, unsigned int cmd,
                            unsigned long arg)
{
        struct smk_audit_info ad;
        int rc = 0;
        struct inode *inode = file_inode(file);

        if (unlikely(IS_PRIVATE(inode)))
                return 0;

        switch (cmd) {
        case F_GETLK:
                break;
        case F_SETLK:
        case F_SETLKW:
                smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
                smk_ad_setfield_u_fs_path(&ad, file->f_path);
                rc = smk_curacc(smk_of_inode(inode), MAY_LOCK, &ad);
                rc = smk_bu_file(file, MAY_LOCK, rc);
                break;
        case F_SETOWN:
        case F_SETSIG:
                smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
                smk_ad_setfield_u_fs_path(&ad, file->f_path);
                rc = smk_curacc(smk_of_inode(inode), MAY_WRITE, &ad);
                rc = smk_bu_file(file, MAY_WRITE, rc);
                break;
        default:
                break;
        }

        return rc;
}

/**
 * smack_mmap_file - Check permissions for a mmap operation.
 * @file: contains the file structure for file to map (may be NULL).
 * @reqprot: contains the protection requested by the application.
 * @prot: contains the protection that will be applied by the kernel.
 * @flags: contains the operational flags.
 *
 * The @file may be NULL, e.g. if mapping anonymous memory.
 *
 * Return 0 if permission is granted.
 */
static int smack_mmap_file(struct file *file,
                           unsigned long reqprot, unsigned long prot,
                           unsigned long flags)
{
        struct smack_known *skp;
        struct smack_known *mkp;
        struct smack_rule *srp;
        struct task_smack *tsp;
        struct smack_known *okp;
        struct inode_smack *isp;
        struct superblock_smack *sbsp;
        int may;
        int mmay;
        int tmay;
        int rc;

        if (file == NULL)
                return 0;

        if (unlikely(IS_PRIVATE(file_inode(file))))
                return 0;

        isp = smack_inode(file_inode(file));
        if (isp->smk_mmap == NULL)
                return 0;
        sbsp = smack_superblock(file_inode(file)->i_sb);
        if (sbsp->smk_flags & SMK_SB_UNTRUSTED &&
            isp->smk_mmap != sbsp->smk_root)
                return -EACCES;
        mkp = isp->smk_mmap;

        tsp = smack_cred(current_cred());
        skp = smk_of_current();
        rc = 0;

        rcu_read_lock();
        /*
         * For each Smack rule associated with the subject
         * label verify that the SMACK64MMAP also has access
         * to that rule's object label.
         */
        list_for_each_entry_rcu(srp, &skp->smk_rules, list) {
                okp = srp->smk_object;
                /*
                 * Matching labels always allows access.
                 */
                if (mkp->smk_known == okp->smk_known)
                        continue;
                /*
                 * If there is a matching local rule take
                 * that into account as well.
                 */
                may = smk_access_entry(srp->smk_subject->smk_known,
                                       okp->smk_known,
                                       &tsp->smk_rules);
                if (may == -ENOENT)
                        may = srp->smk_access;
                else
                        may &= srp->smk_access;
                /*
                 * If may is zero the SMACK64MMAP subject can't
                 * possibly have less access.
                 */
                if (may == 0)
                        continue;

                /*
                 * Fetch the global list entry.
                 * If there isn't one a SMACK64MMAP subject
                 * can't have as much access as current.
                 */
                mmay = smk_access_entry(mkp->smk_known, okp->smk_known,
                                        &mkp->smk_rules);
                if (mmay == -ENOENT) {
                        rc = -EACCES;
                        break;
                }
                /*
                 * If there is a local entry it modifies the
                 * potential access, too.
                 */
                tmay = smk_access_entry(mkp->smk_known, okp->smk_known,
                                        &tsp->smk_rules);
                if (tmay != -ENOENT)
                        mmay &= tmay;

                /*
                 * If there is any access available to current that is
                 * not available to a SMACK64MMAP subject
                 * deny access.
                 */
                if ((may | mmay) != mmay) {
                        rc = -EACCES;
                        break;
                }
        }

        rcu_read_unlock();

        return rc;
}

/**
 * smack_file_set_fowner - set the file security blob value
 * @file: object in question
 *
 */
static void smack_file_set_fowner(struct file *file)
{
        struct smack_known **blob = smack_file(file);

        *blob = smk_of_current();
}

/**
 * smack_file_send_sigiotask - Smack on sigio
 * @tsk: The target task
 * @fown: the object the signal come from
 * @signum: unused
 *
 * Allow a privileged task to get signals even if it shouldn't
 *
 * Returns 0 if a subject with the object's smack could
 * write to the task, an error code otherwise.
 */
static int smack_file_send_sigiotask(struct task_struct *tsk,
                                     struct fown_struct *fown, int signum)
{
        struct smack_known **blob;
        struct smack_known *skp;
        struct smack_known *tkp = smk_of_task(smack_cred(tsk->cred));
        const struct cred *tcred;
        struct file *file;
        int rc;
        struct smk_audit_info ad;

        /*
         * struct fown_struct is never outside the context of a struct file
         */
        file = fown->file;

        /* we don't log here as rc can be overridden */
        blob = smack_file(file);
        skp = *blob;
        rc = smk_access(skp, tkp, MAY_DELIVER, NULL);
        rc = smk_bu_note("sigiotask", skp, tkp, MAY_DELIVER, rc);

        rcu_read_lock();
        tcred = __task_cred(tsk);
        if (rc != 0 && smack_privileged_cred(CAP_MAC_OVERRIDE, tcred))
                rc = 0;
        rcu_read_unlock();

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
        smk_ad_setfield_u_tsk(&ad, tsk);
        smack_log(skp->smk_known, tkp->smk_known, MAY_DELIVER, rc, &ad);
        return rc;
}

/**
 * smack_file_receive - Smack file receive check
 * @file: the object
 *
 * Returns 0 if current has access, error code otherwise
 */
static int smack_file_receive(struct file *file)
{
        int rc;
        int may = 0;
        struct smk_audit_info ad;
        struct inode *inode = file_inode(file);
        struct socket *sock;
        struct task_smack *tsp;
        struct socket_smack *ssp;

        if (unlikely(IS_PRIVATE(inode)))
                return 0;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
        smk_ad_setfield_u_fs_path(&ad, file->f_path);

        if (inode->i_sb->s_magic == SOCKFS_MAGIC) {
                sock = SOCKET_I(inode);
                ssp = smack_sock(sock->sk);
                tsp = smack_cred(current_cred());
                /*
                 * If the receiving process can't write to the
                 * passed socket or if the passed socket can't
                 * write to the receiving process don't accept
                 * the passed socket.
                 */
                rc = smk_access(tsp->smk_task, ssp->smk_out, MAY_WRITE, &ad);
                rc = smk_bu_file(file, may, rc);
                if (rc < 0)
                        return rc;
                rc = smk_access(ssp->smk_in, tsp->smk_task, MAY_WRITE, &ad);
                rc = smk_bu_file(file, may, rc);
                return rc;
        }
        /*
         * This code relies on bitmasks.
         */
        if (file->f_mode & FMODE_READ)
                may = MAY_READ;
        if (file->f_mode & FMODE_WRITE)
                may |= MAY_WRITE;

        rc = smk_curacc(smk_of_inode(inode), may, &ad);
        rc = smk_bu_file(file, may, rc);
        return rc;
}

/**
 * smack_file_open - Smack dentry open processing
 * @file: the object
 *
 * Set the security blob in the file structure.
 * Allow the open only if the task has read access. There are
 * many read operations (e.g. fstat) that you can do with an
 * fd even if you have the file open write-only.
 *
 * Returns 0 if current has access, error code otherwise
 */
static int smack_file_open(struct file *file)
{
        struct task_smack *tsp = smack_cred(file->f_cred);
        struct inode *inode = file_inode(file);
        struct smk_audit_info ad;
        int rc;

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
        smk_ad_setfield_u_fs_path(&ad, file->f_path);
        rc = smk_tskacc(tsp, smk_of_inode(inode), MAY_READ, &ad);
        rc = smk_bu_credfile(file->f_cred, file, MAY_READ, rc);

        return rc;
}

/*
 * Task hooks
 */

/**
 * smack_cred_alloc_blank - "allocate" blank task-level security credentials
 * @cred: the new credentials
 * @gfp: the atomicity of any memory allocations
 *
 * Prepare a blank set of credentials for modification.  This must allocate all
 * the memory the LSM module might require such that cred_transfer() can
 * complete without error.
 */
static int smack_cred_alloc_blank(struct cred *cred, gfp_t gfp)
{
        init_task_smack(smack_cred(cred), NULL, NULL);
        return 0;
}


/**
 * smack_cred_free - "free" task-level security credentials
 * @cred: the credentials in question
 *
 */
static void smack_cred_free(struct cred *cred)
{
        struct task_smack *tsp = smack_cred(cred);
        struct smack_rule *rp;
        struct list_head *l;
        struct list_head *n;

        smk_destroy_label_list(&tsp->smk_relabel);

        list_for_each_safe(l, n, &tsp->smk_rules) {
                rp = list_entry(l, struct smack_rule, list);
                list_del(&rp->list);
                kmem_cache_free(smack_rule_cache, rp);
        }
}

/**
 * smack_cred_prepare - prepare new set of credentials for modification
 * @new: the new credentials
 * @old: the original credentials
 * @gfp: the atomicity of any memory allocations
 *
 * Prepare a new set of credentials for modification.
 */
static int smack_cred_prepare(struct cred *new, const struct cred *old,
                              gfp_t gfp)
{
        struct task_smack *old_tsp = smack_cred(old);
        struct task_smack *new_tsp = smack_cred(new);
        int rc;

        init_task_smack(new_tsp, old_tsp->smk_task, old_tsp->smk_task);

        rc = smk_copy_rules(&new_tsp->smk_rules, &old_tsp->smk_rules, gfp);
        if (rc != 0)
                return rc;

        rc = smk_copy_relabel(&new_tsp->smk_relabel, &old_tsp->smk_relabel,
                                gfp);
        return rc;
}

/**
 * smack_cred_transfer - Transfer the old credentials to the new credentials
 * @new: the new credentials
 * @old: the original credentials
 *
 * Fill in a set of blank credentials from another set of credentials.
 */
static void smack_cred_transfer(struct cred *new, const struct cred *old)
{
        struct task_smack *old_tsp = smack_cred(old);
        struct task_smack *new_tsp = smack_cred(new);

        init_task_smack(new_tsp, old_tsp->smk_task, old_tsp->smk_task);
}

/**
 * smack_cred_getsecid - get the secid corresponding to a creds structure
 * @cred: the object creds
 * @secid: where to put the result
 *
 * Sets the secid to contain a u32 version of the smack label.
 */
static void smack_cred_getsecid(const struct cred *cred, u32 *secid)
{
        struct smack_known *skp;

        rcu_read_lock();
        skp = smk_of_task(smack_cred(cred));
        *secid = skp->smk_secid;
        rcu_read_unlock();
}

/**
 * smack_cred_getlsmprop - get the Smack label for a creds structure
 * @cred: the object creds
 * @prop: where to put the data
 *
 * Sets the Smack part of the ref
 */
static void smack_cred_getlsmprop(const struct cred *cred,
                                  struct lsm_prop *prop)
{
        rcu_read_lock();
        prop->smack.skp = smk_of_task(smack_cred(cred));
        rcu_read_unlock();
}

/**
 * smack_kernel_act_as - Set the subjective context in a set of credentials
 * @new: points to the set of credentials to be modified.
 * @secid: specifies the security ID to be set
 *
 * Set the security data for a kernel service.
 */
static int smack_kernel_act_as(struct cred *new, u32 secid)
{
        struct task_smack *new_tsp = smack_cred(new);

        new_tsp->smk_task = smack_from_secid(secid);
        return 0;
}

/**
 * smack_kernel_create_files_as - Set the file creation label in a set of creds
 * @new: points to the set of credentials to be modified
 * @inode: points to the inode to use as a reference
 *
 * Set the file creation context in a set of credentials to the same
 * as the objective context of the specified inode
 */
static int smack_kernel_create_files_as(struct cred *new,
                                        struct inode *inode)
{
        struct inode_smack *isp = smack_inode(inode);
        struct task_smack *tsp = smack_cred(new);

        tsp->smk_forked = isp->smk_inode;
        tsp->smk_task = tsp->smk_forked;
        return 0;
}

/**
 * smk_curacc_on_task - helper to log task related access
 * @p: the task object
 * @access: the access requested
 * @caller: name of the calling function for audit
 *
 * Return 0 if access is permitted
 */
static int smk_curacc_on_task(struct task_struct *p, int access,
                                const char *caller)
{
        struct smk_audit_info ad;
        struct smack_known *skp = smk_of_task_struct_obj(p);
        int rc;

        smk_ad_init(&ad, caller, LSM_AUDIT_DATA_TASK);
        smk_ad_setfield_u_tsk(&ad, p);
        rc = smk_curacc(skp, access, &ad);
        rc = smk_bu_task(p, access, rc);
        return rc;
}

/**
 * smack_task_setpgid - Smack check on setting pgid
 * @p: the task object
 * @pgid: unused
 *
 * Return 0 if write access is permitted
 */
static int smack_task_setpgid(struct task_struct *p, pid_t pgid)
{
        return smk_curacc_on_task(p, MAY_WRITE, __func__);
}

/**
 * smack_task_getpgid - Smack access check for getpgid
 * @p: the object task
 *
 * Returns 0 if current can read the object task, error code otherwise
 */
static int smack_task_getpgid(struct task_struct *p)
{
        return smk_curacc_on_task(p, MAY_READ, __func__);
}

/**
 * smack_task_getsid - Smack access check for getsid
 * @p: the object task
 *
 * Returns 0 if current can read the object task, error code otherwise
 */
static int smack_task_getsid(struct task_struct *p)
{
        return smk_curacc_on_task(p, MAY_READ, __func__);
}

/**
 * smack_current_getlsmprop_subj - get the subjective secid of the current task
 * @prop: where to put the result
 *
 * Sets the secid to contain a u32 version of the task's subjective smack label.
 */
static void smack_current_getlsmprop_subj(struct lsm_prop *prop)
{
        prop->smack.skp = smk_of_current();
}

/**
 * smack_task_getlsmprop_obj - get the objective data of the task
 * @p: the task
 * @prop: where to put the result
 *
 * Sets the secid to contain a u32 version of the task's objective smack label.
 */
static void smack_task_getlsmprop_obj(struct task_struct *p,
                                      struct lsm_prop *prop)
{
        prop->smack.skp = smk_of_task_struct_obj(p);
}

/**
 * smack_task_setnice - Smack check on setting nice
 * @p: the task object
 * @nice: unused
 *
 * Return 0 if write access is permitted
 */
static int smack_task_setnice(struct task_struct *p, int nice)
{
        return smk_curacc_on_task(p, MAY_WRITE, __func__);
}

/**
 * smack_task_setioprio - Smack check on setting ioprio
 * @p: the task object
 * @ioprio: unused
 *
 * Return 0 if write access is permitted
 */
static int smack_task_setioprio(struct task_struct *p, int ioprio)
{
        return smk_curacc_on_task(p, MAY_WRITE, __func__);
}

/**
 * smack_task_getioprio - Smack check on reading ioprio
 * @p: the task object
 *
 * Return 0 if read access is permitted
 */
static int smack_task_getioprio(struct task_struct *p)
{
        return smk_curacc_on_task(p, MAY_READ, __func__);
}

/**
 * smack_task_setscheduler - Smack check on setting scheduler
 * @p: the task object
 *
 * Return 0 if read access is permitted
 */
static int smack_task_setscheduler(struct task_struct *p)
{
        return smk_curacc_on_task(p, MAY_WRITE, __func__);
}

/**
 * smack_task_getscheduler - Smack check on reading scheduler
 * @p: the task object
 *
 * Return 0 if read access is permitted
 */
static int smack_task_getscheduler(struct task_struct *p)
{
        return smk_curacc_on_task(p, MAY_READ, __func__);
}

/**
 * smack_task_movememory - Smack check on moving memory
 * @p: the task object
 *
 * Return 0 if write access is permitted
 */
static int smack_task_movememory(struct task_struct *p)
{
        return smk_curacc_on_task(p, MAY_WRITE, __func__);
}

/**
 * smack_task_kill - Smack check on signal delivery
 * @p: the task object
 * @info: unused
 * @sig: unused
 * @cred: identifies the cred to use in lieu of current's
 *
 * Return 0 if write access is permitted
 *
 */
static int smack_task_kill(struct task_struct *p, struct kernel_siginfo *info,
                           int sig, const struct cred *cred)
{
        struct smk_audit_info ad;
        struct smack_known *skp;
        struct smack_known *tkp = smk_of_task_struct_obj(p);
        int rc;

        if (!sig)
                return 0; /* null signal; existence test */

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
        smk_ad_setfield_u_tsk(&ad, p);
        /*
         * Sending a signal requires that the sender
         * can write the receiver.
         */
        if (cred == NULL) {
                rc = smk_curacc(tkp, MAY_DELIVER, &ad);
                rc = smk_bu_task(p, MAY_DELIVER, rc);
                return rc;
        }
        /*
         * If the cred isn't NULL we're dealing with some USB IO
         * specific behavior. This is not clean. For one thing
         * we can't take privilege into account.
         */
        skp = smk_of_task(smack_cred(cred));
        rc = smk_access(skp, tkp, MAY_DELIVER, &ad);
        rc = smk_bu_note("USB signal", skp, tkp, MAY_DELIVER, rc);
        return rc;
}

/**
 * smack_task_to_inode - copy task smack into the inode blob
 * @p: task to copy from
 * @inode: inode to copy to
 *
 * Sets the smack pointer in the inode security blob
 */
static void smack_task_to_inode(struct task_struct *p, struct inode *inode)
{
        struct inode_smack *isp = smack_inode(inode);
        struct smack_known *skp = smk_of_task_struct_obj(p);

        isp->smk_inode = skp;
        isp->smk_flags |= SMK_INODE_INSTANT;
}

/*
 * Socket hooks.
 */

/**
 * smack_sk_alloc_security - Allocate a socket blob
 * @sk: the socket
 * @family: unused
 * @gfp_flags: memory allocation flags
 *
 * Assign Smack pointers to current
 *
 * Returns 0 on success, -ENOMEM is there's no memory
 */
static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
{
        struct smack_known *skp = smk_of_current();
        struct socket_smack *ssp = smack_sock(sk);

        /*
         * Sockets created by kernel threads receive web label.
         */
        if (unlikely(current->flags & PF_KTHREAD)) {
                ssp->smk_in = &smack_known_web;
                ssp->smk_out = &smack_known_web;
        } else {
                ssp->smk_in = skp;
                ssp->smk_out = skp;
        }
        ssp->smk_packet = NULL;

        return 0;
}

#ifdef SMACK_IPV6_PORT_LABELING
/**
 * smack_sk_free_security - Free a socket blob
 * @sk: the socket
 *
 * Clears the blob pointer
 */
static void smack_sk_free_security(struct sock *sk)
{
        struct smk_port_label *spp;

        if (sk->sk_family == PF_INET6) {
                rcu_read_lock();
                list_for_each_entry_rcu(spp, &smk_ipv6_port_list, list) {
                        if (spp->smk_sock != sk)
                                continue;
                        spp->smk_can_reuse = 1;
                        break;
                }
                rcu_read_unlock();
        }
}
#endif

/**
 * smack_sk_clone_security - Copy security context
 * @sk: the old socket
 * @newsk: the new socket
 *
 * Copy the security context of the old socket pointer to the cloned
 */
static void smack_sk_clone_security(const struct sock *sk, struct sock *newsk)
{
        struct socket_smack *ssp_old = smack_sock(sk);
        struct socket_smack *ssp_new = smack_sock(newsk);

        *ssp_new = *ssp_old;
}

/**
* smack_ipv4host_label - check host based restrictions
* @sip: the object end
*
* looks for host based access restrictions
*
* This version will only be appropriate for really small sets of single label
* hosts.  The caller is responsible for ensuring that the RCU read lock is
* taken before calling this function.
*
* Returns the label of the far end or NULL if it's not special.
*/
static struct smack_known *smack_ipv4host_label(struct sockaddr_in *sip)
{
        struct smk_net4addr *snp;
        struct in_addr *siap = &sip->sin_addr;

        if (siap->s_addr == 0)
                return NULL;

        list_for_each_entry_rcu(snp, &smk_net4addr_list, list)
                /*
                 * we break after finding the first match because
                 * the list is sorted from longest to shortest mask
                 * so we have found the most specific match
                 */
                if (snp->smk_host.s_addr ==
                    (siap->s_addr & snp->smk_mask.s_addr))
                        return snp->smk_label;

        return NULL;
}

#if IS_ENABLED(CONFIG_IPV6)
/*
 * smk_ipv6_localhost - Check for local ipv6 host address
 * @sip: the address
 *
 * Returns boolean true if this is the localhost address
 */
static bool smk_ipv6_localhost(struct sockaddr_in6 *sip)
{
        __be16 *be16p = (__be16 *)&sip->sin6_addr;
        __be32 *be32p = (__be32 *)&sip->sin6_addr;

        if (be32p[0] == 0 && be32p[1] == 0 && be32p[2] == 0 && be16p[6] == 0 &&
            ntohs(be16p[7]) == 1)
                return true;
        return false;
}

/**
* smack_ipv6host_label - check host based restrictions
* @sip: the object end
*
* looks for host based access restrictions
*
* This version will only be appropriate for really small sets of single label
* hosts.  The caller is responsible for ensuring that the RCU read lock is
* taken before calling this function.
*
* Returns the label of the far end or NULL if it's not special.
*/
static struct smack_known *smack_ipv6host_label(struct sockaddr_in6 *sip)
{
        struct smk_net6addr *snp;
        struct in6_addr *sap = &sip->sin6_addr;
        int i;
        int found = 0;

        /*
         * It's local. Don't look for a host label.
         */
        if (smk_ipv6_localhost(sip))
                return NULL;

        list_for_each_entry_rcu(snp, &smk_net6addr_list, list) {
                /*
                 * If the label is NULL the entry has
                 * been renounced. Ignore it.
                 */
                if (snp->smk_label == NULL)
                        continue;
                /*
                * we break after finding the first match because
                * the list is sorted from longest to shortest mask
                * so we have found the most specific match
                */
                for (found = 1, i = 0; i < 8; i++) {
                        if ((sap->s6_addr16[i] & snp->smk_mask.s6_addr16[i]) !=
                            snp->smk_host.s6_addr16[i]) {
                                found = 0;
                                break;
                        }
                }
                if (found)
                        return snp->smk_label;
        }

        return NULL;
}
#endif /* CONFIG_IPV6 */

/**
 * smack_netlbl_add - Set the secattr on a socket
 * @sk: the socket
 *
 * Attach the outbound smack value (smk_out) to the socket.
 *
 * Returns 0 on success or an error code
 */
static int smack_netlbl_add(struct sock *sk)
{
        struct socket_smack *ssp = smack_sock(sk);
        struct smack_known *skp = ssp->smk_out;
        int rc;

        local_bh_disable();
        bh_lock_sock_nested(sk);

        rc = netlbl_sock_setattr(sk, sk->sk_family, &skp->smk_netlabel,
                                 netlbl_sk_lock_check(sk));
        switch (rc) {
        case 0:
                ssp->smk_state = SMK_NETLBL_LABELED;
                break;
        case -EDESTADDRREQ:
                ssp->smk_state = SMK_NETLBL_REQSKB;
                rc = 0;
                break;
        }

        bh_unlock_sock(sk);
        local_bh_enable();

        return rc;
}

/**
 * smack_netlbl_delete - Remove the secattr from a socket
 * @sk: the socket
 *
 * Remove the outbound smack value from a socket
 */
static void smack_netlbl_delete(struct sock *sk)
{
        struct socket_smack *ssp = smack_sock(sk);

        /*
         * Take the label off the socket if one is set.
         */
        if (ssp->smk_state != SMK_NETLBL_LABELED)
                return;

        local_bh_disable();
        bh_lock_sock_nested(sk);
        netlbl_sock_delattr(sk);
        bh_unlock_sock(sk);
        local_bh_enable();
        ssp->smk_state = SMK_NETLBL_UNLABELED;
}

/**
 * smk_ipv4_check - Perform IPv4 host access checks
 * @sk: the socket
 * @sap: the destination address
 *
 * Set the correct secattr for the given socket based on the destination
 * address and perform any outbound access checks needed.
 *
 * Returns 0 on success or an error code.
 *
 */
static int smk_ipv4_check(struct sock *sk, struct sockaddr_in *sap)
{
        struct smack_known *skp;
        int rc = 0;
        struct smack_known *hkp;
        struct socket_smack *ssp = smack_sock(sk);
        struct smk_audit_info ad;

        rcu_read_lock();
        hkp = smack_ipv4host_label(sap);
        if (hkp != NULL) {
#ifdef CONFIG_AUDIT
                struct lsm_network_audit net;

                smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
                ad.a.u.net->family = sap->sin_family;
                ad.a.u.net->dport = sap->sin_port;
                ad.a.u.net->v4info.daddr = sap->sin_addr.s_addr;
#endif
                skp = ssp->smk_out;
                rc = smk_access(skp, hkp, MAY_WRITE, &ad);
                rc = smk_bu_note("IPv4 host check", skp, hkp, MAY_WRITE, rc);
                /*
                 * Clear the socket netlabel if it's set.
                 */
                if (!rc)
                        smack_netlbl_delete(sk);
        }
        rcu_read_unlock();

        return rc;
}

#if IS_ENABLED(CONFIG_IPV6)
/**
 * smk_ipv6_check - check Smack access
 * @subject: subject Smack label
 * @object: object Smack label
 * @address: address
 * @act: the action being taken
 *
 * Check an IPv6 access
 */
static int smk_ipv6_check(struct smack_known *subject,
                                struct smack_known *object,
                                struct sockaddr_in6 *address, int act)
{
#ifdef CONFIG_AUDIT
        struct lsm_network_audit net;
#endif
        struct smk_audit_info ad;
        int rc;

#ifdef CONFIG_AUDIT
        smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
        ad.a.u.net->family = PF_INET6;
        ad.a.u.net->dport = address->sin6_port;
        if (act == SMK_RECEIVING)
                ad.a.u.net->v6info.saddr = address->sin6_addr;
        else
                ad.a.u.net->v6info.daddr = address->sin6_addr;
#endif
        rc = smk_access(subject, object, MAY_WRITE, &ad);
        rc = smk_bu_note("IPv6 check", subject, object, MAY_WRITE, rc);
        return rc;
}
#endif /* CONFIG_IPV6 */

#ifdef SMACK_IPV6_PORT_LABELING
/**
 * smk_ipv6_port_label - Smack port access table management
 * @sock: socket
 * @address: address
 *
 * Create or update the port list entry
 */
static void smk_ipv6_port_label(struct socket *sock, struct sockaddr *address)
{
        struct sock *sk = sock->sk;
        struct sockaddr_in6 *addr6;
        struct socket_smack *ssp = smack_sock(sock->sk);
        struct smk_port_label *spp;
        unsigned short port = 0;

        if (address == NULL) {
                /*
                 * This operation is changing the Smack information
                 * on the bound socket. Take the changes to the port
                 * as well.
                 */
                rcu_read_lock();
                list_for_each_entry_rcu(spp, &smk_ipv6_port_list, list) {
                        if (sk != spp->smk_sock)
                                continue;
                        spp->smk_in = ssp->smk_in;
                        spp->smk_out = ssp->smk_out;
                        rcu_read_unlock();
                        return;
                }
                /*
                 * A NULL address is only used for updating existing
                 * bound entries. If there isn't one, it's OK.
                 */
                rcu_read_unlock();
                return;
        }

        addr6 = (struct sockaddr_in6 *)address;
        port = ntohs(addr6->sin6_port);
        /*
         * This is a special case that is safely ignored.
         */
        if (port == 0)
                return;

        /*
         * Look for an existing port list entry.
         * This is an indication that a port is getting reused.
         */
        rcu_read_lock();
        list_for_each_entry_rcu(spp, &smk_ipv6_port_list, list) {
                if (spp->smk_port != port || spp->smk_sock_type != sock->type)
                        continue;
                if (spp->smk_can_reuse != 1) {
                        rcu_read_unlock();
                        return;
                }
                spp->smk_port = port;
                spp->smk_sock = sk;
                spp->smk_in = ssp->smk_in;
                spp->smk_out = ssp->smk_out;
                spp->smk_can_reuse = 0;
                rcu_read_unlock();
                return;
        }
        rcu_read_unlock();
        /*
         * A new port entry is required.
         */
        spp = kzalloc_obj(*spp);
        if (spp == NULL)
                return;

        spp->smk_port = port;
        spp->smk_sock = sk;
        spp->smk_in = ssp->smk_in;
        spp->smk_out = ssp->smk_out;
        spp->smk_sock_type = sock->type;
        spp->smk_can_reuse = 0;

        mutex_lock(&smack_ipv6_lock);
        list_add_rcu(&spp->list, &smk_ipv6_port_list);
        mutex_unlock(&smack_ipv6_lock);
        return;
}

/**
 * smk_ipv6_port_check - check Smack port access
 * @sk: socket
 * @address: address
 * @act: the action being taken
 *
 * Create or update the port list entry
 */
static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address,
                                int act)
{
        struct smk_port_label *spp;
        struct socket_smack *ssp = smack_sock(sk);
        struct smack_known *skp = NULL;
        unsigned short port;
        struct smack_known *object;

        if (act == SMK_RECEIVING) {
                skp = smack_ipv6host_label(address);
                object = ssp->smk_in;
        } else {
                skp = ssp->smk_out;
                object = smack_ipv6host_label(address);
        }

        /*
         * The other end is a single label host.
         */
        if (skp != NULL && object != NULL)
                return smk_ipv6_check(skp, object, address, act);
        if (skp == NULL)
                skp = smack_net_ambient;
        if (object == NULL)
                object = smack_net_ambient;

        /*
         * It's remote, so port lookup does no good.
         */
        if (!smk_ipv6_localhost(address))
                return smk_ipv6_check(skp, object, address, act);

        /*
         * It's local so the send check has to have passed.
         */
        if (act == SMK_RECEIVING)
                return 0;

        port = ntohs(address->sin6_port);
        rcu_read_lock();
        list_for_each_entry_rcu(spp, &smk_ipv6_port_list, list) {
                if (spp->smk_port != port || spp->smk_sock_type != sk->sk_type)
                        continue;
                object = spp->smk_in;
                if (act == SMK_CONNECTING)
                        ssp->smk_packet = spp->smk_out;
                break;
        }
        rcu_read_unlock();

        return smk_ipv6_check(skp, object, address, act);
}
#endif

/**
 * smack_inode_setsecurity - set smack xattrs
 * @inode: the object
 * @name: attribute name
 * @value: attribute value
 * @size: size of the attribute
 * @flags: unused
 *
 * Sets the named attribute in the appropriate blob
 *
 * Returns 0 on success, or an error code
 */
static int smack_inode_setsecurity(struct inode *inode, const char *name,
                                   const void *value, size_t size, int flags)
{
        struct smack_known *skp;
        struct inode_smack *nsp = smack_inode(inode);
        struct socket_smack *ssp;
        struct socket *sock;
        int rc = 0;

        if (value == NULL || size > SMK_LONGLABEL || size == 0)
                return -EINVAL;

        if (strcmp(name, XATTR_SMACK_TRANSMUTE) == 0) {
                if (!S_ISDIR(inode->i_mode) || size != TRANS_TRUE_SIZE ||
                    strncmp(value, TRANS_TRUE, TRANS_TRUE_SIZE) != 0)
                        return -EINVAL;

                nsp->smk_flags |= SMK_INODE_TRANSMUTE;
                return 0;
        }

        skp = smk_import_entry(value, size);
        if (IS_ERR(skp))
                return PTR_ERR(skp);

        if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
                nsp->smk_inode = skp;
                nsp->smk_flags |= SMK_INODE_INSTANT;
                return 0;
        }
        /*
         * The rest of the Smack xattrs are only on sockets.
         */
        if (inode->i_sb->s_magic != SOCKFS_MAGIC)
                return -EOPNOTSUPP;

        sock = SOCKET_I(inode);
        if (sock == NULL || sock->sk == NULL)
                return -EOPNOTSUPP;

        ssp = smack_sock(sock->sk);

        if (strcmp(name, XATTR_SMACK_IPIN) == 0)
                ssp->smk_in = skp;
        else if (strcmp(name, XATTR_SMACK_IPOUT) == 0) {
                ssp->smk_out = skp;
                if (sock->sk->sk_family == PF_INET) {
                        rc = smack_netlbl_add(sock->sk);
                        if (rc != 0)
                                printk(KERN_WARNING
                                        "Smack: \"%s\" netlbl error %d.\n",
                                        __func__, -rc);
                }
        } else
                return -EOPNOTSUPP;

#ifdef SMACK_IPV6_PORT_LABELING
        if (sock->sk->sk_family == PF_INET6)
                smk_ipv6_port_label(sock, NULL);
#endif

        return 0;
}

/**
 * smack_socket_post_create - finish socket setup
 * @sock: the socket
 * @family: protocol family
 * @type: unused
 * @protocol: unused
 * @kern: unused
 *
 * Sets the netlabel information on the socket
 *
 * Returns 0 on success, and error code otherwise
 */
static int smack_socket_post_create(struct socket *sock, int family,
                                    int type, int protocol, int kern)
{
        struct socket_smack *ssp;

        if (sock->sk == NULL)
                return 0;

        /*
         * Sockets created by kernel threads receive web label.
         */
        if (unlikely(current->flags & PF_KTHREAD)) {
                ssp = smack_sock(sock->sk);
                ssp->smk_in = &smack_known_web;
                ssp->smk_out = &smack_known_web;
        }

        if (family != PF_INET)
                return 0;
        /*
         * Set the outbound netlbl.
         */
        return smack_netlbl_add(sock->sk);
}

/**
 * smack_socket_socketpair - create socket pair
 * @socka: one socket
 * @sockb: another socket
 *
 * Cross reference the peer labels for SO_PEERSEC
 *
 * Returns 0
 */
static int smack_socket_socketpair(struct socket *socka,
                                   struct socket *sockb)
{
        struct socket_smack *asp = smack_sock(socka->sk);
        struct socket_smack *bsp = smack_sock(sockb->sk);

        asp->smk_packet = bsp->smk_out;
        bsp->smk_packet = asp->smk_out;

        return 0;
}

#ifdef SMACK_IPV6_PORT_LABELING
/**
 * smack_socket_bind - record port binding information.
 * @sock: the socket
 * @address: the port address
 * @addrlen: size of the address
 *
 * Records the label bound to a port.
 *
 * Returns 0 on success, and error code otherwise
 */
static int smack_socket_bind(struct socket *sock, struct sockaddr *address,
                                int addrlen)
{
        if (sock->sk != NULL && sock->sk->sk_family == PF_INET6) {
                if (addrlen < SIN6_LEN_RFC2133 ||
                    address->sa_family != AF_INET6)
                        return -EINVAL;
                smk_ipv6_port_label(sock, address);
        }
        return 0;
}
#endif /* SMACK_IPV6_PORT_LABELING */

/**
 * smack_socket_connect - connect access check
 * @sock: the socket
 * @sap: the other end
 * @addrlen: size of sap
 *
 * Verifies that a connection may be possible
 *
 * Returns 0 on success, and error code otherwise
 */
static int smack_socket_connect(struct socket *sock, struct sockaddr *sap,
                                int addrlen)
{
        int rc = 0;

        if (sock->sk == NULL)
                return 0;
        if (sock->sk->sk_family != PF_INET &&
            (!IS_ENABLED(CONFIG_IPV6) || sock->sk->sk_family != PF_INET6))
                return 0;
        if (addrlen < offsetofend(struct sockaddr, sa_family))
                return 0;

#if IS_ENABLED(CONFIG_IPV6)
        if (sap->sa_family == AF_INET6) {
                struct sockaddr_in6 *sip = (struct sockaddr_in6 *)sap;
                struct smack_known *rsp = NULL;

                if (addrlen < SIN6_LEN_RFC2133)
                        return 0;
                if (__is_defined(SMACK_IPV6_SECMARK_LABELING))
                        rsp = smack_ipv6host_label(sip);
                if (rsp != NULL) {
                        struct socket_smack *ssp = smack_sock(sock->sk);

                        rc = smk_ipv6_check(ssp->smk_out, rsp, sip,
                                            SMK_CONNECTING);
                }
#ifdef SMACK_IPV6_PORT_LABELING
                rc = smk_ipv6_port_check(sock->sk, sip, SMK_CONNECTING);
#endif

                return rc;
        }
#endif /* CONFIG_IPV6 */

        if (sap->sa_family != AF_INET || addrlen < sizeof(struct sockaddr_in))
                return 0;
        rc = smk_ipv4_check(sock->sk, (struct sockaddr_in *)sap);
        return rc;
}

/**
 * smack_flags_to_may - convert S_ to MAY_ values
 * @flags: the S_ value
 *
 * Returns the equivalent MAY_ value
 */
static int smack_flags_to_may(int flags)
{
        int may = 0;

        if (flags & S_IRUGO)
                may |= MAY_READ;
        if (flags & S_IWUGO)
                may |= MAY_WRITE;
        if (flags & S_IXUGO)
                may |= MAY_EXEC;

        return may;
}

/**
 * smack_msg_msg_alloc_security - Set the security blob for msg_msg
 * @msg: the object
 *
 * Returns 0
 */
static int smack_msg_msg_alloc_security(struct msg_msg *msg)
{
        struct smack_known **blob = smack_msg_msg(msg);

        *blob = smk_of_current();
        return 0;
}

/**
 * smack_of_ipc - the smack pointer for the ipc
 * @isp: the object
 *
 * Returns a pointer to the smack value
 */
static struct smack_known *smack_of_ipc(struct kern_ipc_perm *isp)
{
        struct smack_known **blob = smack_ipc(isp);

        return *blob;
}

/**
 * smack_ipc_alloc_security - Set the security blob for ipc
 * @isp: the object
 *
 * Returns 0
 */
static int smack_ipc_alloc_security(struct kern_ipc_perm *isp)
{
        struct smack_known **blob = smack_ipc(isp);

        *blob = smk_of_current();
        return 0;
}

/**
 * smk_curacc_shm : check if current has access on shm
 * @isp : the object
 * @access : access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smk_curacc_shm(struct kern_ipc_perm *isp, int access)
{
        struct smack_known *ssp = smack_of_ipc(isp);
        struct smk_audit_info ad;
        int rc;

#ifdef CONFIG_AUDIT
        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
        ad.a.u.ipc_id = isp->id;
#endif
        rc = smk_curacc(ssp, access, &ad);
        rc = smk_bu_current("shm", ssp, access, rc);
        return rc;
}

/**
 * smack_shm_associate - Smack access check for shm
 * @isp: the object
 * @shmflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_shm_associate(struct kern_ipc_perm *isp, int shmflg)
{
        int may;

        may = smack_flags_to_may(shmflg);
        return smk_curacc_shm(isp, may);
}

/**
 * smack_shm_shmctl - Smack access check for shm
 * @isp: the object
 * @cmd: what it wants to do
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_shm_shmctl(struct kern_ipc_perm *isp, int cmd)
{
        int may;

        switch (cmd) {
        case IPC_STAT:
        case SHM_STAT:
        case SHM_STAT_ANY:
                may = MAY_READ;
                break;
        case IPC_SET:
        case SHM_LOCK:
        case SHM_UNLOCK:
        case IPC_RMID:
                may = MAY_READWRITE;
                break;
        case IPC_INFO:
        case SHM_INFO:
                /*
                 * System level information.
                 */
                return 0;
        default:
                return -EINVAL;
        }
        return smk_curacc_shm(isp, may);
}

/**
 * smack_shm_shmat - Smack access for shmat
 * @isp: the object
 * @shmaddr: unused
 * @shmflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_shm_shmat(struct kern_ipc_perm *isp, char __user *shmaddr,
                           int shmflg)
{
        int may;

        may = smack_flags_to_may(shmflg);
        return smk_curacc_shm(isp, may);
}

/**
 * smk_curacc_sem : check if current has access on sem
 * @isp : the object
 * @access : access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smk_curacc_sem(struct kern_ipc_perm *isp, int access)
{
        struct smack_known *ssp = smack_of_ipc(isp);
        struct smk_audit_info ad;
        int rc;

#ifdef CONFIG_AUDIT
        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
        ad.a.u.ipc_id = isp->id;
#endif
        rc = smk_curacc(ssp, access, &ad);
        rc = smk_bu_current("sem", ssp, access, rc);
        return rc;
}

/**
 * smack_sem_associate - Smack access check for sem
 * @isp: the object
 * @semflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_sem_associate(struct kern_ipc_perm *isp, int semflg)
{
        int may;

        may = smack_flags_to_may(semflg);
        return smk_curacc_sem(isp, may);
}

/**
 * smack_sem_semctl - Smack access check for sem
 * @isp: the object
 * @cmd: what it wants to do
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_sem_semctl(struct kern_ipc_perm *isp, int cmd)
{
        int may;

        switch (cmd) {
        case GETPID:
        case GETNCNT:
        case GETZCNT:
        case GETVAL:
        case GETALL:
        case IPC_STAT:
        case SEM_STAT:
        case SEM_STAT_ANY:
                may = MAY_READ;
                break;
        case SETVAL:
        case SETALL:
        case IPC_RMID:
        case IPC_SET:
                may = MAY_READWRITE;
                break;
        case IPC_INFO:
        case SEM_INFO:
                /*
                 * System level information
                 */
                return 0;
        default:
                return -EINVAL;
        }

        return smk_curacc_sem(isp, may);
}

/**
 * smack_sem_semop - Smack checks of semaphore operations
 * @isp: the object
 * @sops: unused
 * @nsops: unused
 * @alter: unused
 *
 * Treated as read and write in all cases.
 *
 * Returns 0 if access is allowed, error code otherwise
 */
static int smack_sem_semop(struct kern_ipc_perm *isp, struct sembuf *sops,
                           unsigned nsops, int alter)
{
        return smk_curacc_sem(isp, MAY_READWRITE);
}

/**
 * smk_curacc_msq : helper to check if current has access on msq
 * @isp : the msq
 * @access : access requested
 *
 * return 0 if current has access, error otherwise
 */
static int smk_curacc_msq(struct kern_ipc_perm *isp, int access)
{
        struct smack_known *msp = smack_of_ipc(isp);
        struct smk_audit_info ad;
        int rc;

#ifdef CONFIG_AUDIT
        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
        ad.a.u.ipc_id = isp->id;
#endif
        rc = smk_curacc(msp, access, &ad);
        rc = smk_bu_current("msq", msp, access, rc);
        return rc;
}

/**
 * smack_msg_queue_associate - Smack access check for msg_queue
 * @isp: the object
 * @msqflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_msg_queue_associate(struct kern_ipc_perm *isp, int msqflg)
{
        int may;

        may = smack_flags_to_may(msqflg);
        return smk_curacc_msq(isp, may);
}

/**
 * smack_msg_queue_msgctl - Smack access check for msg_queue
 * @isp: the object
 * @cmd: what it wants to do
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_msg_queue_msgctl(struct kern_ipc_perm *isp, int cmd)
{
        int may;

        switch (cmd) {
        case IPC_STAT:
        case MSG_STAT:
        case MSG_STAT_ANY:
                may = MAY_READ;
                break;
        case IPC_SET:
        case IPC_RMID:
                may = MAY_READWRITE;
                break;
        case IPC_INFO:
        case MSG_INFO:
                /*
                 * System level information
                 */
                return 0;
        default:
                return -EINVAL;
        }

        return smk_curacc_msq(isp, may);
}

/**
 * smack_msg_queue_msgsnd - Smack access check for msg_queue
 * @isp: the object
 * @msg: unused
 * @msqflg: access requested
 *
 * Returns 0 if current has the requested access, error code otherwise
 */
static int smack_msg_queue_msgsnd(struct kern_ipc_perm *isp, struct msg_msg *msg,
                                  int msqflg)
{
        int may;

        may = smack_flags_to_may(msqflg);
        return smk_curacc_msq(isp, may);
}

/**
 * smack_msg_queue_msgrcv - Smack access check for msg_queue
 * @isp: the object
 * @msg: unused
 * @target: unused
 * @type: unused
 * @mode: unused
 *
 * Returns 0 if current has read and write access, error code otherwise
 */
static int smack_msg_queue_msgrcv(struct kern_ipc_perm *isp,
                                  struct msg_msg *msg,
                                  struct task_struct *target, long type,
                                  int mode)
{
        return smk_curacc_msq(isp, MAY_READWRITE);
}

/**
 * smack_ipc_permission - Smack access for ipc_permission()
 * @ipp: the object permissions
 * @flag: access requested
 *
 * Returns 0 if current has read and write access, error code otherwise
 */
static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
{
        struct smack_known **blob = smack_ipc(ipp);
        struct smack_known *iskp = *blob;
        int may = smack_flags_to_may(flag);
        struct smk_audit_info ad;
        int rc;

#ifdef CONFIG_AUDIT
        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
        ad.a.u.ipc_id = ipp->id;
#endif
        rc = smk_curacc(iskp, may, &ad);
        rc = smk_bu_current("svipc", iskp, may, rc);
        return rc;
}

/**
 * smack_ipc_getlsmprop - Extract smack security data
 * @ipp: the object permissions
 * @prop: where result will be saved
 */
static void smack_ipc_getlsmprop(struct kern_ipc_perm *ipp, struct lsm_prop *prop)
{
        struct smack_known **iskpp = smack_ipc(ipp);

        prop->smack.skp = *iskpp;
}

/**
 * smack_d_instantiate - Make sure the blob is correct on an inode
 * @opt_dentry: dentry where inode will be attached
 * @inode: the object
 *
 * Set the inode's security blob if it hasn't been done already.
 */
static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
{
        struct super_block *sbp;
        struct superblock_smack *sbsp;
        struct inode_smack *isp;
        struct smack_known *skp;
        struct smack_known *ckp = smk_of_current();
        struct smack_known *final;
        char trattr[TRANS_TRUE_SIZE];
        int transflag = 0;
        int rc;
        struct dentry *dp;

        if (inode == NULL)
                return;

        isp = smack_inode(inode);

        /*
         * If the inode is already instantiated
         * take the quick way out
         */
        if (isp->smk_flags & SMK_INODE_INSTANT)
                return;

        sbp = inode->i_sb;
        sbsp = smack_superblock(sbp);
        /*
         * We're going to use the superblock default label
         * if there's no label on the file.
         */
        final = sbsp->smk_default;

        /*
         * If this is the root inode the superblock
         * may be in the process of initialization.
         * If that is the case use the root value out
         * of the superblock.
         */
        if (opt_dentry->d_parent == opt_dentry) {
                switch (sbp->s_magic) {
                case CGROUP_SUPER_MAGIC:
                case CGROUP2_SUPER_MAGIC:
                        /*
                         * The cgroup filesystem is never mounted,
                         * so there's no opportunity to set the mount
                         * options.
                         */
                        sbsp->smk_root = &smack_known_star;
                        sbsp->smk_default = &smack_known_star;
                        isp->smk_inode = sbsp->smk_root;
                        break;
                case TMPFS_MAGIC:
                        /*
                         * What about shmem/tmpfs anonymous files with dentry
                         * obtained from d_alloc_pseudo()?
                         */
                        isp->smk_inode = smk_of_current();
                        break;
                case PIPEFS_MAGIC:
                        isp->smk_inode = smk_of_current();
                        break;
                case SOCKFS_MAGIC:
                        /*
                         * Socket access is controlled by the socket
                         * structures associated with the task involved.
                         */
                        isp->smk_inode = &smack_known_star;
                        break;
                default:
                        isp->smk_inode = sbsp->smk_root;
                        break;
                }
                isp->smk_flags |= SMK_INODE_INSTANT;
                return;
        }

        /*
         * This is pretty hackish.
         * Casey says that we shouldn't have to do
         * file system specific code, but it does help
         * with keeping it simple.
         */
        switch (sbp->s_magic) {
        case SMACK_MAGIC:
        case CGROUP_SUPER_MAGIC:
        case CGROUP2_SUPER_MAGIC:
                /*
                 * Casey says that it's a little embarrassing
                 * that the smack file system doesn't do
                 * extended attributes.
                 *
                 * Cgroupfs is special
                 */
                final = &smack_known_star;
                break;
        case DEVPTS_SUPER_MAGIC:
                /*
                 * devpts seems content with the label of the task.
                 * Programs that change smack have to treat the
                 * pty with respect.
                 */
                final = ckp;
                break;
        case PROC_SUPER_MAGIC:
                /*
                 * Casey says procfs appears not to care.
                 * The superblock default suffices.
                 */
                break;
        case TMPFS_MAGIC:
                /*
                 * Device labels should come from the filesystem,
                 * but watch out, because they're volitile,
                 * getting recreated on every reboot.
                 */
                final = &smack_known_star;
                /*
                 * If a smack value has been set we want to use it,
                 * but since tmpfs isn't giving us the opportunity
                 * to set mount options simulate setting the
                 * superblock default.
                 */
                fallthrough;
        default:
                /*
                 * This isn't an understood special case.
                 * Get the value from the xattr.
                 */

                /*
                 * UDS inode has fixed label (*)
                 */
                if (S_ISSOCK(inode->i_mode)) {
                        final = &smack_known_star;
                        break;
                }
                /*
                 * No xattr support means, alas, no SMACK label.
                 * Use the aforeapplied default.
                 * It would be curious if the label of the task
                 * does not match that assigned.
                 */
                if (!(inode->i_opflags & IOP_XATTR))
                        break;
                /*
                 * Get the dentry for xattr.
                 */
                dp = dget(opt_dentry);
                skp = smk_fetch(XATTR_NAME_SMACK, inode, dp);
                if (!IS_ERR_OR_NULL(skp))
                        final = skp;

                /*
                 * Transmuting directory
                 */
                if (S_ISDIR(inode->i_mode)) {
                        /*
                         * If this is a new directory and the label was
                         * transmuted when the inode was initialized
                         * set the transmute attribute on the directory
                         * and mark the inode.
                         *
                         * If there is a transmute attribute on the
                         * directory mark the inode.
                         */
                        rc = __vfs_getxattr(dp, inode,
                                            XATTR_NAME_SMACKTRANSMUTE, trattr,
                                            TRANS_TRUE_SIZE);
                        if (rc >= 0 && strncmp(trattr, TRANS_TRUE,
                                               TRANS_TRUE_SIZE) != 0)
                                rc = -EINVAL;
                        if (rc >= 0)
                                transflag = SMK_INODE_TRANSMUTE;
                }
                /*
                 * Don't let the exec or mmap label be "*" or "@".
                 */
                skp = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp);
                if (IS_ERR(skp) || skp == &smack_known_star ||
                    skp == &smack_known_web)
                        skp = NULL;
                isp->smk_task = skp;

                skp = smk_fetch(XATTR_NAME_SMACKMMAP, inode, dp);
                if (IS_ERR(skp) || skp == &smack_known_star ||
                    skp == &smack_known_web)
                        skp = NULL;
                isp->smk_mmap = skp;

                dput(dp);
                break;
        }

        if (final == NULL)
                isp->smk_inode = ckp;
        else
                isp->smk_inode = final;

        isp->smk_flags |= (SMK_INODE_INSTANT | transflag);

        return;
}

/**
 * smack_getselfattr - Smack current process attribute
 * @attr: which attribute to fetch
 * @ctx: buffer to receive the result
 * @size: available size in, actual size out
 * @flags: reserved, currently zero
 *
 * Fill the passed user space @ctx with the details of the requested
 * attribute.
 *
 * Returns the number of attributes on success, an error code otherwise.
 * There will only ever be one attribute.
 */
static int smack_getselfattr(unsigned int attr, struct lsm_ctx __user *ctx,
                             u32 *size, u32 flags)
{
        int rc;
        struct smack_known *skp;

        if (attr != LSM_ATTR_CURRENT)
                return -EOPNOTSUPP;

        skp = smk_of_current();
        rc = lsm_fill_user_ctx(ctx, size,
                               skp->smk_known, strlen(skp->smk_known) + 1,
                               LSM_ID_SMACK, 0);
        return (!rc ? 1 : rc);
}

/**
 * smack_getprocattr - Smack process attribute access
 * @p: the object task
 * @name: the name of the attribute in /proc/.../attr
 * @value: where to put the result
 *
 * Places a copy of the task Smack into value
 *
 * Returns the length of the smack label or an error code
 */
static int smack_getprocattr(struct task_struct *p, const char *name, char **value)
{
        struct smack_known *skp = smk_of_task_struct_obj(p);
        char *cp;
        int slen;

        if (strcmp(name, "current") != 0)
                return -EINVAL;

        cp = kstrdup(skp->smk_known, GFP_KERNEL);
        if (cp == NULL)
                return -ENOMEM;

        slen = strlen(cp);
        *value = cp;
        return slen;
}

/**
 * do_setattr - Smack process attribute setting
 * @attr: the ID of the attribute
 * @value: the value to set
 * @size: the size of the value
 *
 * Sets the Smack value of the task. Only setting self
 * is permitted and only with privilege
 *
 * Returns zero on success or an error code
 */
static int do_setattr(unsigned int attr, void *value, size_t size)
{
        struct task_smack *tsp = smack_cred(current_cred());
        struct cred *new;
        struct smack_known *skp;
        int label_len;

        /*
         * let unprivileged user validate input, check permissions later
         */
        if (value == NULL || size == 0 || size >= SMK_LONGLABEL)
                return -EINVAL;

        label_len = smk_parse_label_len(value, size);
        if (label_len < 0 || label_len != size)
                return -EINVAL;

        /*
         * No process is ever allowed the web ("@") label
         * and the star ("*") label.
         */
        if (label_len == 1 /* '@', '*' */) {
                const char c = *(const char *)value;

                if (c == *smack_known_web.smk_known ||
                    c == *smack_known_star.smk_known)
                        return -EPERM;
        }

        if (!smack_privileged(CAP_MAC_ADMIN)) {
                const struct smack_known_list_elem *sklep;
                list_for_each_entry(sklep, &tsp->smk_relabel, list) {
                        const char *cp = sklep->smk_label->smk_known;

                        if (strlen(cp) == label_len &&
                            strncmp(cp, value, label_len) == 0)
                                goto in_relabel;
                }
                return -EPERM;
in_relabel:
                ;
        }

        skp = smk_import_valid_label(value, label_len, GFP_KERNEL);
        if (IS_ERR(skp))
                return PTR_ERR(skp);

        new = prepare_creds();
        if (new == NULL)
                return -ENOMEM;

        tsp = smack_cred(new);
        tsp->smk_task = skp;
        /*
         * process can change its label only once
         */
        smk_destroy_label_list(&tsp->smk_relabel);

        commit_creds(new);
        return 0;
}

/**
 * smack_setselfattr - Set a Smack process attribute
 * @attr: which attribute to set
 * @ctx: buffer containing the data
 * @size: size of @ctx
 * @flags: reserved, must be zero
 *
 * Fill the passed user space @ctx with the details of the requested
 * attribute.
 *
 * Returns 0 on success, an error code otherwise.
 */
static int smack_setselfattr(unsigned int attr, struct lsm_ctx *ctx,
                             u32 size, u32 flags)
{
        if (attr != LSM_ATTR_CURRENT)
                return -EOPNOTSUPP;

        if (ctx->flags)
                return -EINVAL;
        /*
         * string must have \0 terminator, included in ctx->ctx
         * (see description of struct lsm_ctx)
         */
        if (ctx->ctx_len == 0)
                return -EINVAL;

        if (ctx->ctx[ctx->ctx_len - 1] != '\0')
                return -EINVAL;
        /*
         * other do_setattr() caller, smack_setprocattr(),
         * does not count \0 into size, so
         * decreasing length by 1 to accommodate the divergence.
         */
        return do_setattr(attr, ctx->ctx, ctx->ctx_len - 1);
}

/**
 * smack_setprocattr - Smack process attribute setting
 * @name: the name of the attribute in /proc/.../attr
 * @value: the value to set
 * @size: the size of the value
 *
 * Sets the Smack value of the task. Only setting self
 * is permitted and only with privilege
 *
 * Returns the size of the input value or an error code
 */
static int smack_setprocattr(const char *name, void *value, size_t size)
{
        size_t realsize = size;
        unsigned int attr = lsm_name_to_attr(name);

        switch (attr) {
        case LSM_ATTR_UNDEF:   return -EINVAL;
        default:               return -EOPNOTSUPP;
        case LSM_ATTR_CURRENT:
                ;
        }

        /*
         * The value for the "current" attribute is the label
         * followed by one of the 4 trailers: none, \0, \n, \n\0
         *
         * I.e. following inputs are accepted as 3-characters long label "foo":
         *
         *   "foo"     (3 characters)
         *   "foo\0"   (4 characters)
         *   "foo\n"   (4 characters)
         *   "foo\n\0" (5 characters)
         */

        if (realsize && (((const char *)value)[realsize - 1] == '\0'))
                --realsize;

        if (realsize && (((const char *)value)[realsize - 1] == '\n'))
                --realsize;

        return do_setattr(attr, value, realsize) ? : size;
}

/**
 * smack_unix_stream_connect - Smack access on UDS
 * @sock: one sock
 * @other: the other sock
 * @newsk: unused
 *
 * Return 0 if a subject with the smack of sock could access
 * an object with the smack of other, otherwise an error code
 */
static int smack_unix_stream_connect(struct sock *sock,
                                     struct sock *other, struct sock *newsk)
{
        struct smack_known *skp;
        struct smack_known *okp;
        struct socket_smack *ssp = smack_sock(sock);
        struct socket_smack *osp = smack_sock(other);
        struct socket_smack *nsp = smack_sock(newsk);
        struct smk_audit_info ad;
        int rc = 0;
#ifdef CONFIG_AUDIT
        struct lsm_network_audit net;
#endif

        if (!smack_privileged(CAP_MAC_OVERRIDE)) {
                skp = ssp->smk_out;
                okp = osp->smk_in;
#ifdef CONFIG_AUDIT
                smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
                smk_ad_setfield_u_net_sk(&ad, other);
#endif
                rc = smk_access(skp, okp, MAY_WRITE, &ad);
                rc = smk_bu_note("UDS connect", skp, okp, MAY_WRITE, rc);
                if (rc == 0) {
                        okp = osp->smk_out;
                        skp = ssp->smk_in;
                        rc = smk_access(okp, skp, MAY_WRITE, &ad);
                        rc = smk_bu_note("UDS connect", okp, skp,
                                                MAY_WRITE, rc);
                }
        }

        if (rc == 0) {
                /*
                 * Cross reference the peer labels for SO_PEERSEC.
                 */
                nsp->smk_packet = ssp->smk_out;
                ssp->smk_packet = osp->smk_out;

                /*
                 * new/child/established socket must inherit listening socket labels
                 */
                nsp->smk_out = osp->smk_out;
                nsp->smk_in  = osp->smk_in;
        }

        return rc;
}

/**
 * smack_unix_may_send - Smack access on UDS
 * @sock: one socket
 * @other: the other socket
 *
 * Return 0 if a subject with the smack of sock could access
 * an object with the smack of other, otherwise an error code
 */
static int smack_unix_may_send(struct socket *sock, struct socket *other)
{
        struct socket_smack *ssp = smack_sock(sock->sk);
        struct socket_smack *osp = smack_sock(other->sk);
        struct smk_audit_info ad;
        int rc;

#ifdef CONFIG_AUDIT
        struct lsm_network_audit net;

        smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
        smk_ad_setfield_u_net_sk(&ad, other->sk);
#endif

        if (smack_privileged(CAP_MAC_OVERRIDE))
                return 0;

        rc = smk_access(ssp->smk_out, osp->smk_in, MAY_WRITE, &ad);
        rc = smk_bu_note("UDS send", ssp->smk_out, osp->smk_in, MAY_WRITE, rc);
        return rc;
}

/**
 * smack_socket_sendmsg - Smack check based on destination host
 * @sock: the socket
 * @msg: the message
 * @size: the size of the message
 *
 * Return 0 if the current subject can write to the destination host.
 * For IPv4 this is only a question if the destination is a single label host.
 * For IPv6 this is a check against the label of the port.
 */
static int smack_socket_sendmsg(struct socket *sock, struct msghdr *msg,
                                int size)
{
        struct sockaddr_in *sip = (struct sockaddr_in *) msg->msg_name;
#if IS_ENABLED(CONFIG_IPV6)
        struct sockaddr_in6 *sap = (struct sockaddr_in6 *) msg->msg_name;
#endif
#ifdef SMACK_IPV6_SECMARK_LABELING
        struct socket_smack *ssp = smack_sock(sock->sk);
        struct smack_known *rsp;
#endif
        int rc = 0;

        /*
         * Perfectly reasonable for this to be NULL
         */
        if (sip == NULL)
                return 0;

        switch (sock->sk->sk_family) {
        case AF_INET:
                if (msg->msg_namelen < sizeof(struct sockaddr_in) ||
                    sip->sin_family != AF_INET)
                        return -EINVAL;
                rc = smk_ipv4_check(sock->sk, sip);
                break;
#if IS_ENABLED(CONFIG_IPV6)
        case AF_INET6:
                if (msg->msg_namelen < SIN6_LEN_RFC2133 ||
                    sap->sin6_family != AF_INET6)
                        return -EINVAL;
#ifdef SMACK_IPV6_SECMARK_LABELING
                rsp = smack_ipv6host_label(sap);
                if (rsp != NULL)
                        rc = smk_ipv6_check(ssp->smk_out, rsp, sap,
                                                SMK_CONNECTING);
#endif
#ifdef SMACK_IPV6_PORT_LABELING
                rc = smk_ipv6_port_check(sock->sk, sap, SMK_SENDING);
#endif
#endif /* IS_ENABLED(CONFIG_IPV6) */
                break;
        }
        return rc;
}

/**
 * smack_from_secattr - Convert a netlabel attr.mls.lvl/attr.mls.cat pair to smack
 * @sap: netlabel secattr
 * @ssp: socket security information
 *
 * Returns a pointer to a Smack label entry found on the label list.
 */
static struct smack_known *smack_from_secattr(struct netlbl_lsm_secattr *sap,
                                                struct socket_smack *ssp)
{
        struct smack_known *skp;
        int found = 0;
        int acat;
        int kcat;

        /*
         * Netlabel found it in the cache.
         */
        if ((sap->flags & NETLBL_SECATTR_CACHE) != 0)
                return (struct smack_known *)sap->cache->data;

        if ((sap->flags & NETLBL_SECATTR_SECID) != 0)
                /*
                 * Looks like a fallback, which gives us a secid.
                 */
                return smack_from_secid(sap->attr.secid);

        if ((sap->flags & NETLBL_SECATTR_MLS_LVL) != 0) {
                /*
                 * Looks like a CIPSO packet.
                 * If there are flags but no level netlabel isn't
                 * behaving the way we expect it to.
                 *
                 * Look it up in the label table
                 * Without guidance regarding the smack value
                 * for the packet fall back on the network
                 * ambient value.
                 */
                rcu_read_lock();
                list_for_each_entry_rcu(skp, &smack_known_list, list) {
                        if (sap->attr.mls.lvl != skp->smk_netlabel.attr.mls.lvl)
                                continue;
                        /*
                         * Compare the catsets. Use the netlbl APIs.
                         */
                        if ((sap->flags & NETLBL_SECATTR_MLS_CAT) == 0) {
                                if ((skp->smk_netlabel.flags &
                                     NETLBL_SECATTR_MLS_CAT) == 0)
                                        found = 1;
                                break;
                        }
                        for (acat = -1, kcat = -1; acat == kcat; ) {
                                acat = netlbl_catmap_walk(sap->attr.mls.cat,
                                                          acat + 1);
                                kcat = netlbl_catmap_walk(
                                        skp->smk_netlabel.attr.mls.cat,
                                        kcat + 1);
                                if (acat < 0 || kcat < 0)
                                        break;
                        }
                        if (acat == kcat) {
                                found = 1;
                                break;
                        }
                }
                rcu_read_unlock();

                if (found)
                        return skp;

                if (ssp != NULL && ssp->smk_in == &smack_known_star)
                        return &smack_known_web;
                return &smack_known_star;
        }
        /*
         * Without guidance regarding the smack value
         * for the packet fall back on the network
         * ambient value.
         */
        return smack_net_ambient;
}

#if IS_ENABLED(CONFIG_IPV6)
static int smk_skb_to_addr_ipv6(struct sk_buff *skb, struct sockaddr_in6 *sip)
{
        u8 nexthdr;
        int offset;
        int proto = -EINVAL;
        struct ipv6hdr _ipv6h;
        struct ipv6hdr *ip6;
        __be16 frag_off;
        struct tcphdr _tcph, *th;
        struct udphdr _udph, *uh;

        sip->sin6_port = 0;

        offset = skb_network_offset(skb);
        ip6 = skb_header_pointer(skb, offset, sizeof(_ipv6h), &_ipv6h);
        if (ip6 == NULL)
                return -EINVAL;
        sip->sin6_addr = ip6->saddr;

        nexthdr = ip6->nexthdr;
        offset += sizeof(_ipv6h);
        offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
        if (offset < 0)
                return -EINVAL;

        proto = nexthdr;
        switch (proto) {
        case IPPROTO_TCP:
                th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph);
                if (th != NULL)
                        sip->sin6_port = th->source;
                break;
        case IPPROTO_UDP:
        case IPPROTO_UDPLITE:
                uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph);
                if (uh != NULL)
                        sip->sin6_port = uh->source;
                break;
        }
        return proto;
}
#endif /* CONFIG_IPV6 */

/**
 * smack_from_skb - Smack data from the secmark in an skb
 * @skb: packet
 *
 * Returns smack_known of the secmark or NULL if that won't work.
 */
#ifdef CONFIG_NETWORK_SECMARK
static struct smack_known *smack_from_skb(struct sk_buff *skb)
{
        if (skb == NULL || skb->secmark == 0)
                return NULL;

        return smack_from_secid(skb->secmark);
}
#else
static inline struct smack_known *smack_from_skb(struct sk_buff *skb)
{
        return NULL;
}
#endif

/**
 * smack_from_netlbl - Smack data from the IP options in an skb
 * @sk: socket data came in on
 * @family: address family
 * @skb: packet
 *
 * Find the Smack label in the IP options. If it hasn't been
 * added to the netlabel cache, add it here.
 *
 * Returns smack_known of the IP options or NULL if that won't work.
 */
static struct smack_known *smack_from_netlbl(const struct sock *sk, u16 family,
                                             struct sk_buff *skb)
{
        struct netlbl_lsm_secattr secattr;
        struct socket_smack *ssp = NULL;
        struct smack_known *skp = NULL;

        netlbl_secattr_init(&secattr);

        if (sk)
                ssp = smack_sock(sk);

        if (netlbl_skbuff_getattr(skb, family, &secattr) == 0) {
                skp = smack_from_secattr(&secattr, ssp);
                if (secattr.flags & NETLBL_SECATTR_CACHEABLE)
                        netlbl_cache_add(skb, family, &skp->smk_netlabel);
        }

        netlbl_secattr_destroy(&secattr);

        return skp;
}

/**
 * smack_socket_sock_rcv_skb - Smack packet delivery access check
 * @sk: socket
 * @skb: packet
 *
 * Returns 0 if the packet should be delivered, an error code otherwise
 */
static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
        struct socket_smack *ssp = smack_sock(sk);
        struct smack_known *skp = NULL;
        int rc = 0;
        struct smk_audit_info ad;
        u16 family = sk->sk_family;
#ifdef CONFIG_AUDIT
        struct lsm_network_audit net;
#endif
#if IS_ENABLED(CONFIG_IPV6)
        struct sockaddr_in6 sadd;
        int proto;

        if (family == PF_INET6 && skb->protocol == htons(ETH_P_IP))
                family = PF_INET;
#endif /* CONFIG_IPV6 */

        switch (family) {
        case PF_INET:
                /*
                 * If there is a secmark use it rather than the CIPSO label.
                 * If there is no secmark fall back to CIPSO.
                 * The secmark is assumed to reflect policy better.
                 */
                skp = smack_from_skb(skb);
                if (skp == NULL) {
                        skp = smack_from_netlbl(sk, family, skb);
                        if (skp == NULL)
                                skp = smack_net_ambient;
                }

#ifdef CONFIG_AUDIT
                smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
                ad.a.u.net->family = family;
                ad.a.u.net->netif = skb->skb_iif;
                ipv4_skb_to_auditdata(skb, &ad.a, NULL);
#endif
                /*
                 * Receiving a packet requires that the other end
                 * be able to write here. Read access is not required.
                 * This is the simplest possible security model
                 * for networking.
                 */
                rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
                rc = smk_bu_note("IPv4 delivery", skp, ssp->smk_in,
                                        MAY_WRITE, rc);
                if (rc != 0)
                        netlbl_skbuff_err(skb, family, rc, 0);
                break;
#if IS_ENABLED(CONFIG_IPV6)
        case PF_INET6:
                proto = smk_skb_to_addr_ipv6(skb, &sadd);
                if (proto != IPPROTO_UDP && proto != IPPROTO_UDPLITE &&
                    proto != IPPROTO_TCP)
                        break;
#ifdef SMACK_IPV6_SECMARK_LABELING
                skp = smack_from_skb(skb);
                if (skp == NULL) {
                        if (smk_ipv6_localhost(&sadd))
                                break;
                        skp = smack_ipv6host_label(&sadd);
                        if (skp == NULL)
                                skp = smack_net_ambient;
                }
#ifdef CONFIG_AUDIT
                smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
                ad.a.u.net->family = family;
                ad.a.u.net->netif = skb->skb_iif;
                ipv6_skb_to_auditdata(skb, &ad.a, NULL);
#endif /* CONFIG_AUDIT */
                rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
                rc = smk_bu_note("IPv6 delivery", skp, ssp->smk_in,
                                        MAY_WRITE, rc);
#endif /* SMACK_IPV6_SECMARK_LABELING */
#ifdef SMACK_IPV6_PORT_LABELING
                rc = smk_ipv6_port_check(sk, &sadd, SMK_RECEIVING);
#endif /* SMACK_IPV6_PORT_LABELING */
                if (rc != 0)
                        icmpv6_send(skb, ICMPV6_DEST_UNREACH,
                                        ICMPV6_ADM_PROHIBITED, 0);
                break;
#endif /* CONFIG_IPV6 */
        }

        return rc;
}

/**
 * smack_socket_getpeersec_stream - pull in packet label
 * @sock: the socket
 * @optval: user's destination
 * @optlen: size thereof
 * @len: max thereof
 *
 * returns zero on success, an error code otherwise
 */
static int smack_socket_getpeersec_stream(struct socket *sock,
                                          sockptr_t optval, sockptr_t optlen,
                                          unsigned int len)
{
        struct socket_smack *ssp;
        char *rcp = "";
        u32 slen = 1;
        int rc = 0;

        ssp = smack_sock(sock->sk);
        if (ssp->smk_packet != NULL) {
                rcp = ssp->smk_packet->smk_known;
                slen = strlen(rcp) + 1;
        }
        if (slen > len) {
                rc = -ERANGE;
                goto out_len;
        }

        if (copy_to_sockptr(optval, rcp, slen))
                rc = -EFAULT;
out_len:
        if (copy_to_sockptr(optlen, &slen, sizeof(slen)))
                rc = -EFAULT;
        return rc;
}


/**
 * smack_socket_getpeersec_dgram - pull in packet label
 * @sock: the peer socket
 * @skb: packet data
 * @secid: pointer to where to put the secid of the packet
 *
 * Sets the netlabel socket state on sk from parent
 */
static int smack_socket_getpeersec_dgram(struct socket *sock,
                                         struct sk_buff *skb, u32 *secid)

{
        struct socket_smack *ssp = NULL;
        struct smack_known *skp;
        struct sock *sk = NULL;
        int family = PF_UNSPEC;
        u32 s = 0;      /* 0 is the invalid secid */

        if (skb != NULL) {
                if (skb->protocol == htons(ETH_P_IP))
                        family = PF_INET;
#if IS_ENABLED(CONFIG_IPV6)
                else if (skb->protocol == htons(ETH_P_IPV6))
                        family = PF_INET6;
#endif /* CONFIG_IPV6 */
        }
        if (family == PF_UNSPEC && sock != NULL)
                family = sock->sk->sk_family;

        switch (family) {
        case PF_UNIX:
                ssp = smack_sock(sock->sk);
                s = ssp->smk_out->smk_secid;
                break;
        case PF_INET:
                skp = smack_from_skb(skb);
                if (skp) {
                        s = skp->smk_secid;
                        break;
                }
                /*
                 * Translate what netlabel gave us.
                 */
                if (sock != NULL)
                        sk = sock->sk;
                skp = smack_from_netlbl(sk, family, skb);
                if (skp != NULL)
                        s = skp->smk_secid;
                break;
        case PF_INET6:
#ifdef SMACK_IPV6_SECMARK_LABELING
                skp = smack_from_skb(skb);
                if (skp)
                        s = skp->smk_secid;
#endif
                break;
        }
        *secid = s;
        if (s == 0)
                return -EINVAL;
        return 0;
}

/**
 * smack_inet_conn_request - Smack access check on connect
 * @sk: socket involved
 * @skb: packet
 * @req: unused
 *
 * Returns 0 if a task with the packet label could write to
 * the socket, otherwise an error code
 */
static int smack_inet_conn_request(const struct sock *sk, struct sk_buff *skb,
                                   struct request_sock *req)
{
        u16 family = sk->sk_family;
        struct smack_known *skp;
        struct socket_smack *ssp = smack_sock(sk);
        struct sockaddr_in addr;
        struct iphdr *hdr;
        struct smack_known *hskp;
        int rc;
        struct smk_audit_info ad;
#ifdef CONFIG_AUDIT
        struct lsm_network_audit net;
#endif

#if IS_ENABLED(CONFIG_IPV6)
        if (family == PF_INET6) {
                /*
                 * Handle mapped IPv4 packets arriving
                 * via IPv6 sockets. Don't set up netlabel
                 * processing on IPv6.
                 */
                if (skb->protocol == htons(ETH_P_IP))
                        family = PF_INET;
                else
                        return 0;
        }
#endif /* CONFIG_IPV6 */

        /*
         * If there is a secmark use it rather than the CIPSO label.
         * If there is no secmark fall back to CIPSO.
         * The secmark is assumed to reflect policy better.
         */
        skp = smack_from_skb(skb);
        if (skp == NULL) {
                skp = smack_from_netlbl(sk, family, skb);
                if (skp == NULL)
                        skp = &smack_known_huh;
        }

#ifdef CONFIG_AUDIT
        smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
        ad.a.u.net->family = family;
        ad.a.u.net->netif = skb->skb_iif;
        ipv4_skb_to_auditdata(skb, &ad.a, NULL);
#endif
        /*
         * Receiving a packet requires that the other end be able to write
         * here. Read access is not required.
         */
        rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
        rc = smk_bu_note("IPv4 connect", skp, ssp->smk_in, MAY_WRITE, rc);
        if (rc != 0)
                return rc;

        /*
         * Save the peer's label in the request_sock so we can later setup
         * smk_packet in the child socket so that SO_PEERCRED can report it.
         */
        req->peer_secid = skp->smk_secid;

        /*
         * We need to decide if we want to label the incoming connection here
         * if we do we only need to label the request_sock and the stack will
         * propagate the wire-label to the sock when it is created.
         */
        hdr = ip_hdr(skb);
        addr.sin_addr.s_addr = hdr->saddr;
        rcu_read_lock();
        hskp = smack_ipv4host_label(&addr);
        rcu_read_unlock();

        if (hskp == NULL)
                rc = netlbl_req_setattr(req, &ssp->smk_out->smk_netlabel);
        else
                netlbl_req_delattr(req);

        return rc;
}

/**
 * smack_inet_csk_clone - Copy the connection information to the new socket
 * @sk: the new socket
 * @req: the connection's request_sock
 *
 * Transfer the connection's peer label to the newly created socket.
 */
static void smack_inet_csk_clone(struct sock *sk,
                                 const struct request_sock *req)
{
        struct socket_smack *ssp = smack_sock(sk);
        struct smack_known *skp;

        if (req->peer_secid != 0) {
                skp = smack_from_secid(req->peer_secid);
                ssp->smk_packet = skp;
        } else
                ssp->smk_packet = NULL;
}

/*
 * Key management security hooks
 *
 * Casey has not tested key support very heavily.
 * The permission check is most likely too restrictive.
 * If you care about keys please have a look.
 */
#ifdef CONFIG_KEYS

/**
 * smack_key_alloc - Set the key security blob
 * @key: object
 * @cred: the credentials to use
 * @flags: unused
 *
 * No allocation required
 *
 * Returns 0
 */
static int smack_key_alloc(struct key *key, const struct cred *cred,
                           unsigned long flags)
{
        struct smack_known **blob = smack_key(key);
        struct smack_known *skp = smk_of_task(smack_cred(cred));

        *blob = skp;
        return 0;
}

/**
 * smack_key_permission - Smack access on a key
 * @key_ref: gets to the object
 * @cred: the credentials to use
 * @need_perm: requested key permission
 *
 * Return 0 if the task has read and write to the object,
 * an error code otherwise
 */
static int smack_key_permission(key_ref_t key_ref,
                                const struct cred *cred,
                                enum key_need_perm need_perm)
{
        struct smack_known **blob;
        struct smack_known *skp;
        struct key *keyp;
        struct smk_audit_info ad;
        struct smack_known *tkp = smk_of_task(smack_cred(cred));
        int request = 0;
        int rc;

        /*
         * Validate requested permissions
         */
        switch (need_perm) {
        case KEY_NEED_READ:
        case KEY_NEED_SEARCH:
        case KEY_NEED_VIEW:
                request |= MAY_READ;
                break;
        case KEY_NEED_WRITE:
        case KEY_NEED_LINK:
        case KEY_NEED_SETATTR:
                request |= MAY_WRITE;
                break;
        case KEY_NEED_UNSPECIFIED:
        case KEY_NEED_UNLINK:
        case KEY_SYSADMIN_OVERRIDE:
        case KEY_AUTHTOKEN_OVERRIDE:
        case KEY_DEFER_PERM_CHECK:
                return 0;
        default:
                return -EINVAL;
        }

        keyp = key_ref_to_ptr(key_ref);
        if (keyp == NULL)
                return -EINVAL;
        /*
         * If the key hasn't been initialized give it access so that
         * it may do so.
         */
        blob = smack_key(keyp);
        skp = *blob;
        if (skp == NULL)
                return 0;
        /*
         * This should not occur
         */
        if (tkp == NULL)
                return -EACCES;

        if (smack_privileged(CAP_MAC_OVERRIDE))
                return 0;

#ifdef CONFIG_AUDIT
        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_KEY);
        ad.a.u.key_struct.key = keyp->serial;
        ad.a.u.key_struct.key_desc = keyp->description;
#endif
        rc = smk_access(tkp, skp, request, &ad);
        rc = smk_bu_note("key access", tkp, skp, request, rc);
        return rc;
}

/*
 * smack_key_getsecurity - Smack label tagging the key
 * @key points to the key to be queried
 * @_buffer points to a pointer that should be set to point to the
 * resulting string (if no label or an error occurs).
 * Return the length of the string (including terminating NUL) or -ve if
 * an error.
 * May also return 0 (and a NULL buffer pointer) if there is no label.
 */
static int smack_key_getsecurity(struct key *key, char **_buffer)
{
        struct smack_known **blob = smack_key(key);
        struct smack_known *skp = *blob;
        size_t length;
        char *copy;

        if (skp == NULL) {
                *_buffer = NULL;
                return 0;
        }

        copy = kstrdup(skp->smk_known, GFP_KERNEL);
        if (copy == NULL)
                return -ENOMEM;
        length = strlen(copy) + 1;

        *_buffer = copy;
        return length;
}


#ifdef CONFIG_KEY_NOTIFICATIONS
/**
 * smack_watch_key - Smack access to watch a key for notifications.
 * @key: The key to be watched
 *
 * Return 0 if the @watch->cred has permission to read from the key object and
 * an error otherwise.
 */
static int smack_watch_key(struct key *key)
{
        struct smk_audit_info ad;
        struct smack_known *tkp = smk_of_current();
        struct smack_known **blob = smack_key(key);
        int rc;

        /*
         * This should not occur
         */
        if (tkp == NULL)
                return -EACCES;

        if (smack_privileged_cred(CAP_MAC_OVERRIDE, current_cred()))
                return 0;

#ifdef CONFIG_AUDIT
        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_KEY);
        ad.a.u.key_struct.key = key->serial;
        ad.a.u.key_struct.key_desc = key->description;
#endif
        rc = smk_access(tkp, *blob, MAY_READ, &ad);
        rc = smk_bu_note("key watch", tkp, *blob, MAY_READ, rc);
        return rc;
}
#endif /* CONFIG_KEY_NOTIFICATIONS */
#endif /* CONFIG_KEYS */

#ifdef CONFIG_WATCH_QUEUE
/**
 * smack_post_notification - Smack access to post a notification to a queue
 * @w_cred: The credentials of the watcher.
 * @cred: The credentials of the event source (may be NULL).
 * @n: The notification message to be posted.
 */
static int smack_post_notification(const struct cred *w_cred,
                                   const struct cred *cred,
                                   struct watch_notification *n)
{
        struct smk_audit_info ad;
        struct smack_known *subj, *obj;
        int rc;

        /* Always let maintenance notifications through. */
        if (n->type == WATCH_TYPE_META)
                return 0;

        if (!cred)
                return 0;
        subj = smk_of_task(smack_cred(cred));
        obj = smk_of_task(smack_cred(w_cred));

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_NOTIFICATION);
        rc = smk_access(subj, obj, MAY_WRITE, &ad);
        rc = smk_bu_note("notification", subj, obj, MAY_WRITE, rc);
        return rc;
}
#endif /* CONFIG_WATCH_QUEUE */

/*
 * Smack Audit hooks
 *
 * Audit requires a unique representation of each Smack specific
 * rule. This unique representation is used to distinguish the
 * object to be audited from remaining kernel objects and also
 * works as a glue between the audit hooks.
 *
 * Since repository entries are added but never deleted, we'll use
 * the smack_known label address related to the given audit rule as
 * the needed unique representation. This also better fits the smack
 * model where nearly everything is a label.
 */
#ifdef CONFIG_AUDIT

/**
 * smack_audit_rule_init - Initialize a smack audit rule
 * @field: audit rule fields given from user-space (audit.h)
 * @op: required testing operator (=, !=, >, <, ...)
 * @rulestr: smack label to be audited
 * @vrule: pointer to save our own audit rule representation
 * @gfp: type of the memory for the allocation
 *
 * Prepare to audit cases where (@field @op @rulestr) is true.
 * The label to be audited is created if necessary.
 */
static int smack_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule,
                                 gfp_t gfp)
{
        struct smack_known *skp;
        char **rule = (char **)vrule;
        *rule = NULL;

        if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
                return -EINVAL;

        if (op != Audit_equal && op != Audit_not_equal)
                return -EINVAL;

        skp = smk_import_entry(rulestr, 0);
        if (IS_ERR(skp))
                return PTR_ERR(skp);

        *rule = skp->smk_known;

        return 0;
}

/**
 * smack_audit_rule_known - Distinguish Smack audit rules
 * @krule: rule of interest, in Audit kernel representation format
 *
 * This is used to filter Smack rules from remaining Audit ones.
 * If it's proved that this rule belongs to us, the
 * audit_rule_match hook will be called to do the final judgement.
 */
static int smack_audit_rule_known(struct audit_krule *krule)
{
        struct audit_field *f;
        int i;

        for (i = 0; i < krule->field_count; i++) {
                f = &krule->fields[i];

                if (f->type == AUDIT_SUBJ_USER || f->type == AUDIT_OBJ_USER)
                        return 1;
        }

        return 0;
}

/**
 * smack_audit_rule_match - Audit given object ?
 * @prop: security id for identifying the object to test
 * @field: audit rule flags given from user-space
 * @op: required testing operator
 * @vrule: smack internal rule presentation
 *
 * The core Audit hook. It's used to take the decision of
 * whether to audit or not to audit a given object.
 */
static int smack_audit_rule_match(struct lsm_prop *prop, u32 field, u32 op,
                                  void *vrule)
{
        struct smack_known *skp = prop->smack.skp;
        char *rule = vrule;

        if (unlikely(!rule)) {
                WARN_ONCE(1, "Smack: missing rule\n");
                return -ENOENT;
        }

        if (field != AUDIT_SUBJ_USER && field != AUDIT_OBJ_USER)
                return 0;

        /*
         * No need to do string comparisons. If a match occurs,
         * both pointers will point to the same smack_known
         * label.
         */
        if (op == Audit_equal)
                return (rule == skp->smk_known);
        if (op == Audit_not_equal)
                return (rule != skp->smk_known);

        return 0;
}

/*
 * There is no need for a smack_audit_rule_free hook.
 * No memory was allocated.
 */

#endif /* CONFIG_AUDIT */

/**
 * smack_ismaclabel - check if xattr @name references a smack MAC label
 * @name: Full xattr name to check.
 */
static int smack_ismaclabel(const char *name)
{
        return (strcmp(name, XATTR_SMACK_SUFFIX) == 0);
}

/**
 * smack_to_secctx - fill a lsm_context
 * @skp: Smack label
 * @cp: destination
 *
 * Fill the passed @cp and return the length of the string
 */
static int smack_to_secctx(struct smack_known *skp, struct lsm_context *cp)
{
        int len = strlen(skp->smk_known);

        if (cp) {
                cp->context = skp->smk_known;
                cp->len = len;
                cp->id = LSM_ID_SMACK;
        }
        return len;
}

/**
 * smack_secid_to_secctx - return the smack label for a secid
 * @secid: incoming integer
 * @cp: destination
 *
 * Exists for networking code.
 */
static int smack_secid_to_secctx(u32 secid, struct lsm_context *cp)
{
        return smack_to_secctx(smack_from_secid(secid), cp);
}

/**
 * smack_lsmprop_to_secctx - return the smack label
 * @prop: includes incoming Smack data
 * @cp: destination
 *
 * Exists for audit code.
 */
static int smack_lsmprop_to_secctx(struct lsm_prop *prop,
                                   struct lsm_context *cp)
{
        return smack_to_secctx(prop->smack.skp, cp);
}

/**
 * smack_secctx_to_secid - return the secid for a smack label
 * @secdata: smack label
 * @seclen: how long result is
 * @secid: outgoing integer
 *
 * Exists for audit and networking code.
 */
static int smack_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
{
        struct smack_known *skp = smk_find_entry(secdata);

        if (skp)
                *secid = skp->smk_secid;
        else
                *secid = 0;
        return 0;
}

/*
 * There used to be a smack_release_secctx hook
 * that did nothing back when hooks were in a vector.
 * Now that there's a list such a hook adds cost.
 */

static int smack_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen)
{
        /*
         * UDS inode has fixed label. Ignore nfs label.
         */
        if (S_ISSOCK(inode->i_mode))
                return 0;
        return smack_inode_setsecurity(inode, XATTR_SMACK_SUFFIX, ctx,
                                       ctxlen, 0);
}

static int smack_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
{
        return __vfs_setxattr_locked(&nop_mnt_idmap, dentry, XATTR_NAME_SMACK,
                                     ctx, ctxlen, 0, NULL);
}

static int smack_inode_getsecctx(struct inode *inode, struct lsm_context *cp)
{
        struct smack_known *skp = smk_of_inode(inode);

        cp->context = skp->smk_known;
        cp->len = strlen(skp->smk_known);
        cp->id = LSM_ID_SMACK;
        return 0;
}

static int smack_inode_copy_up(struct dentry *dentry, struct cred **new)
{

        struct task_smack *tsp;
        struct smack_known *skp;
        struct inode_smack *isp;
        struct cred *new_creds = *new;

        if (new_creds == NULL) {
                new_creds = prepare_creds();
                if (new_creds == NULL)
                        return -ENOMEM;
        }

        tsp = smack_cred(new_creds);

        /*
         * Get label from overlay inode and set it in create_sid
         */
        isp = smack_inode(d_inode(dentry));
        skp = isp->smk_inode;
        tsp->smk_task = skp;
        *new = new_creds;
        return 0;
}

static int smack_inode_copy_up_xattr(struct dentry *src, const char *name)
{
        /*
         * Return -ECANCELED if this is the smack access Smack attribute.
         */
        if (!strcmp(name, XATTR_NAME_SMACK))
                return -ECANCELED;

        return -EOPNOTSUPP;
}

static int smack_dentry_create_files_as(struct dentry *dentry, int mode,
                                        const struct qstr *name,
                                        const struct cred *old,
                                        struct cred *new)
{
        struct task_smack *otsp = smack_cred(old);
        struct task_smack *ntsp = smack_cred(new);
        struct inode_smack *isp;

        /*
         * Use the process credential unless all of
         * the transmuting criteria are met
         */
        ntsp->smk_task = otsp->smk_task;

        /*
         * the attribute of the containing directory
         */
        isp = smack_inode(d_inode(dentry->d_parent));

        if (isp->smk_flags & SMK_INODE_TRANSMUTE) {
                /*
                 * If the directory is transmuting and the rule
                 * providing access is transmuting use the containing
                 * directory label instead of the process label.
                 */
                if (smk_rule_transmutes(otsp->smk_task, isp->smk_inode)) {
                        ntsp->smk_task = isp->smk_inode;
                        ntsp->smk_transmuted = ntsp->smk_task;
                }
        }
        return 0;
}

#ifdef CONFIG_IO_URING
/**
 * smack_uring_override_creds - Is io_uring cred override allowed?
 * @new: the target creds
 *
 * Check to see if the current task is allowed to override it's credentials
 * to service an io_uring operation.
 */
static int smack_uring_override_creds(const struct cred *new)
{
        struct task_smack *tsp = smack_cred(current_cred());
        struct task_smack *nsp = smack_cred(new);

        /*
         * Allow the degenerate case where the new Smack value is
         * the same as the current Smack value.
         */
        if (tsp->smk_task == nsp->smk_task)
                return 0;

        if (smack_privileged_cred(CAP_MAC_OVERRIDE, current_cred()))
                return 0;

        return -EPERM;
}

/**
 * smack_uring_sqpoll - check if a io_uring polling thread can be created
 *
 * Check to see if the current task is allowed to create a new io_uring
 * kernel polling thread.
 */
static int smack_uring_sqpoll(void)
{
        if (smack_privileged_cred(CAP_MAC_ADMIN, current_cred()))
                return 0;

        return -EPERM;
}

/**
 * smack_uring_cmd - check on file operations for io_uring
 * @ioucmd: the command in question
 *
 * Make a best guess about whether a io_uring "command" should
 * be allowed. Use the same logic used for determining if the
 * file could be opened for read in the absence of better criteria.
 */
static int smack_uring_cmd(struct io_uring_cmd *ioucmd)
{
        struct file *file = ioucmd->file;
        struct smk_audit_info ad;
        struct task_smack *tsp;
        struct inode *inode;
        int rc;

        if (!file)
                return -EINVAL;

        tsp = smack_cred(file->f_cred);
        inode = file_inode(file);

        smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
        smk_ad_setfield_u_fs_path(&ad, file->f_path);
        rc = smk_tskacc(tsp, smk_of_inode(inode), MAY_READ, &ad);
        rc = smk_bu_credfile(file->f_cred, file, MAY_READ, rc);

        return rc;
}

#endif /* CONFIG_IO_URING */

struct lsm_blob_sizes smack_blob_sizes __ro_after_init = {
        .lbs_cred = sizeof(struct task_smack),
        .lbs_file = sizeof(struct smack_known *),
        .lbs_inode = sizeof(struct inode_smack),
        .lbs_ipc = sizeof(struct smack_known *),
        .lbs_key = sizeof(struct smack_known *),
        .lbs_msg_msg = sizeof(struct smack_known *),
        .lbs_sock = sizeof(struct socket_smack),
        .lbs_superblock = sizeof(struct superblock_smack),
        .lbs_xattr_count = SMACK_INODE_INIT_XATTRS,
};

static const struct lsm_id smack_lsmid = {
        .name = "smack",
        .id = LSM_ID_SMACK,
};

static struct security_hook_list smack_hooks[] __ro_after_init = {
        LSM_HOOK_INIT(ptrace_access_check, smack_ptrace_access_check),
        LSM_HOOK_INIT(ptrace_traceme, smack_ptrace_traceme),
        LSM_HOOK_INIT(syslog, smack_syslog),

        LSM_HOOK_INIT(fs_context_submount, smack_fs_context_submount),
        LSM_HOOK_INIT(fs_context_dup, smack_fs_context_dup),
        LSM_HOOK_INIT(fs_context_parse_param, smack_fs_context_parse_param),

        LSM_HOOK_INIT(sb_alloc_security, smack_sb_alloc_security),
        LSM_HOOK_INIT(sb_free_mnt_opts, smack_free_mnt_opts),
        LSM_HOOK_INIT(sb_eat_lsm_opts, smack_sb_eat_lsm_opts),
        LSM_HOOK_INIT(sb_statfs, smack_sb_statfs),
        LSM_HOOK_INIT(sb_set_mnt_opts, smack_set_mnt_opts),

        LSM_HOOK_INIT(bprm_creds_for_exec, smack_bprm_creds_for_exec),

        LSM_HOOK_INIT(inode_alloc_security, smack_inode_alloc_security),
        LSM_HOOK_INIT(inode_init_security, smack_inode_init_security),
        LSM_HOOK_INIT(inode_link, smack_inode_link),
        LSM_HOOK_INIT(inode_unlink, smack_inode_unlink),
        LSM_HOOK_INIT(inode_rmdir, smack_inode_rmdir),
        LSM_HOOK_INIT(inode_rename, smack_inode_rename),
        LSM_HOOK_INIT(inode_permission, smack_inode_permission),
        LSM_HOOK_INIT(inode_setattr, smack_inode_setattr),
        LSM_HOOK_INIT(inode_getattr, smack_inode_getattr),
        LSM_HOOK_INIT(inode_xattr_skipcap, smack_inode_xattr_skipcap),
        LSM_HOOK_INIT(inode_setxattr, smack_inode_setxattr),
        LSM_HOOK_INIT(inode_post_setxattr, smack_inode_post_setxattr),
        LSM_HOOK_INIT(inode_getxattr, smack_inode_getxattr),
        LSM_HOOK_INIT(inode_removexattr, smack_inode_removexattr),
        LSM_HOOK_INIT(inode_set_acl, smack_inode_set_acl),
        LSM_HOOK_INIT(inode_get_acl, smack_inode_get_acl),
        LSM_HOOK_INIT(inode_remove_acl, smack_inode_remove_acl),
        LSM_HOOK_INIT(inode_getsecurity, smack_inode_getsecurity),
        LSM_HOOK_INIT(inode_setsecurity, smack_inode_setsecurity),
        LSM_HOOK_INIT(inode_listsecurity, smack_inode_listsecurity),
        LSM_HOOK_INIT(inode_getlsmprop, smack_inode_getlsmprop),

        LSM_HOOK_INIT(file_alloc_security, smack_file_alloc_security),
        LSM_HOOK_INIT(file_ioctl, smack_file_ioctl),
        LSM_HOOK_INIT(file_ioctl_compat, smack_file_ioctl),
        LSM_HOOK_INIT(file_lock, smack_file_lock),
        LSM_HOOK_INIT(file_fcntl, smack_file_fcntl),
        LSM_HOOK_INIT(mmap_file, smack_mmap_file),
        LSM_HOOK_INIT(mmap_addr, cap_mmap_addr),
        LSM_HOOK_INIT(file_set_fowner, smack_file_set_fowner),
        LSM_HOOK_INIT(file_send_sigiotask, smack_file_send_sigiotask),
        LSM_HOOK_INIT(file_receive, smack_file_receive),

        LSM_HOOK_INIT(file_open, smack_file_open),

        LSM_HOOK_INIT(cred_alloc_blank, smack_cred_alloc_blank),
        LSM_HOOK_INIT(cred_free, smack_cred_free),
        LSM_HOOK_INIT(cred_prepare, smack_cred_prepare),
        LSM_HOOK_INIT(cred_transfer, smack_cred_transfer),
        LSM_HOOK_INIT(cred_getsecid, smack_cred_getsecid),
        LSM_HOOK_INIT(cred_getlsmprop, smack_cred_getlsmprop),
        LSM_HOOK_INIT(kernel_act_as, smack_kernel_act_as),
        LSM_HOOK_INIT(kernel_create_files_as, smack_kernel_create_files_as),
        LSM_HOOK_INIT(task_setpgid, smack_task_setpgid),
        LSM_HOOK_INIT(task_getpgid, smack_task_getpgid),
        LSM_HOOK_INIT(task_getsid, smack_task_getsid),
        LSM_HOOK_INIT(current_getlsmprop_subj, smack_current_getlsmprop_subj),
        LSM_HOOK_INIT(task_getlsmprop_obj, smack_task_getlsmprop_obj),
        LSM_HOOK_INIT(task_setnice, smack_task_setnice),
        LSM_HOOK_INIT(task_setioprio, smack_task_setioprio),
        LSM_HOOK_INIT(task_getioprio, smack_task_getioprio),
        LSM_HOOK_INIT(task_setscheduler, smack_task_setscheduler),
        LSM_HOOK_INIT(task_getscheduler, smack_task_getscheduler),
        LSM_HOOK_INIT(task_movememory, smack_task_movememory),
        LSM_HOOK_INIT(task_kill, smack_task_kill),
        LSM_HOOK_INIT(task_to_inode, smack_task_to_inode),

        LSM_HOOK_INIT(ipc_permission, smack_ipc_permission),
        LSM_HOOK_INIT(ipc_getlsmprop, smack_ipc_getlsmprop),

        LSM_HOOK_INIT(msg_msg_alloc_security, smack_msg_msg_alloc_security),

        LSM_HOOK_INIT(msg_queue_alloc_security, smack_ipc_alloc_security),
        LSM_HOOK_INIT(msg_queue_associate, smack_msg_queue_associate),
        LSM_HOOK_INIT(msg_queue_msgctl, smack_msg_queue_msgctl),
        LSM_HOOK_INIT(msg_queue_msgsnd, smack_msg_queue_msgsnd),
        LSM_HOOK_INIT(msg_queue_msgrcv, smack_msg_queue_msgrcv),

        LSM_HOOK_INIT(shm_alloc_security, smack_ipc_alloc_security),
        LSM_HOOK_INIT(shm_associate, smack_shm_associate),
        LSM_HOOK_INIT(shm_shmctl, smack_shm_shmctl),
        LSM_HOOK_INIT(shm_shmat, smack_shm_shmat),

        LSM_HOOK_INIT(sem_alloc_security, smack_ipc_alloc_security),
        LSM_HOOK_INIT(sem_associate, smack_sem_associate),
        LSM_HOOK_INIT(sem_semctl, smack_sem_semctl),
        LSM_HOOK_INIT(sem_semop, smack_sem_semop),

        LSM_HOOK_INIT(d_instantiate, smack_d_instantiate),

        LSM_HOOK_INIT(getselfattr, smack_getselfattr),
        LSM_HOOK_INIT(setselfattr, smack_setselfattr),
        LSM_HOOK_INIT(getprocattr, smack_getprocattr),
        LSM_HOOK_INIT(setprocattr, smack_setprocattr),

        LSM_HOOK_INIT(unix_stream_connect, smack_unix_stream_connect),
        LSM_HOOK_INIT(unix_may_send, smack_unix_may_send),

        LSM_HOOK_INIT(socket_post_create, smack_socket_post_create),
        LSM_HOOK_INIT(socket_socketpair, smack_socket_socketpair),
#ifdef SMACK_IPV6_PORT_LABELING
        LSM_HOOK_INIT(socket_bind, smack_socket_bind),
#endif
        LSM_HOOK_INIT(socket_connect, smack_socket_connect),
        LSM_HOOK_INIT(socket_sendmsg, smack_socket_sendmsg),
        LSM_HOOK_INIT(socket_sock_rcv_skb, smack_socket_sock_rcv_skb),
        LSM_HOOK_INIT(socket_getpeersec_stream, smack_socket_getpeersec_stream),
        LSM_HOOK_INIT(socket_getpeersec_dgram, smack_socket_getpeersec_dgram),
        LSM_HOOK_INIT(sk_alloc_security, smack_sk_alloc_security),
#ifdef SMACK_IPV6_PORT_LABELING
        LSM_HOOK_INIT(sk_free_security, smack_sk_free_security),
#endif
        LSM_HOOK_INIT(sk_clone_security, smack_sk_clone_security),
        LSM_HOOK_INIT(inet_conn_request, smack_inet_conn_request),
        LSM_HOOK_INIT(inet_csk_clone, smack_inet_csk_clone),

 /* key management security hooks */
#ifdef CONFIG_KEYS
        LSM_HOOK_INIT(key_alloc, smack_key_alloc),
        LSM_HOOK_INIT(key_permission, smack_key_permission),
        LSM_HOOK_INIT(key_getsecurity, smack_key_getsecurity),
#ifdef CONFIG_KEY_NOTIFICATIONS
        LSM_HOOK_INIT(watch_key, smack_watch_key),
#endif
#endif /* CONFIG_KEYS */

#ifdef CONFIG_WATCH_QUEUE
        LSM_HOOK_INIT(post_notification, smack_post_notification),
#endif

 /* Audit hooks */
#ifdef CONFIG_AUDIT
        LSM_HOOK_INIT(audit_rule_init, smack_audit_rule_init),
        LSM_HOOK_INIT(audit_rule_known, smack_audit_rule_known),
        LSM_HOOK_INIT(audit_rule_match, smack_audit_rule_match),
#endif /* CONFIG_AUDIT */

        LSM_HOOK_INIT(ismaclabel, smack_ismaclabel),
        LSM_HOOK_INIT(secid_to_secctx, smack_secid_to_secctx),
        LSM_HOOK_INIT(lsmprop_to_secctx, smack_lsmprop_to_secctx),
        LSM_HOOK_INIT(secctx_to_secid, smack_secctx_to_secid),
        LSM_HOOK_INIT(inode_notifysecctx, smack_inode_notifysecctx),
        LSM_HOOK_INIT(inode_setsecctx, smack_inode_setsecctx),
        LSM_HOOK_INIT(inode_getsecctx, smack_inode_getsecctx),
        LSM_HOOK_INIT(inode_copy_up, smack_inode_copy_up),
        LSM_HOOK_INIT(inode_copy_up_xattr, smack_inode_copy_up_xattr),
        LSM_HOOK_INIT(dentry_create_files_as, smack_dentry_create_files_as),
#ifdef CONFIG_IO_URING
        LSM_HOOK_INIT(uring_override_creds, smack_uring_override_creds),
        LSM_HOOK_INIT(uring_sqpoll, smack_uring_sqpoll),
        LSM_HOOK_INIT(uring_cmd, smack_uring_cmd),
#endif
};


static __init void init_smack_known_list(void)
{
        /*
         * Initialize rule list locks
         */
        mutex_init(&smack_known_huh.smk_rules_lock);
        mutex_init(&smack_known_hat.smk_rules_lock);
        mutex_init(&smack_known_floor.smk_rules_lock);
        mutex_init(&smack_known_star.smk_rules_lock);
        mutex_init(&smack_known_web.smk_rules_lock);
        /*
         * Initialize rule lists
         */
        INIT_LIST_HEAD(&smack_known_huh.smk_rules);
        INIT_LIST_HEAD(&smack_known_hat.smk_rules);
        INIT_LIST_HEAD(&smack_known_star.smk_rules);
        INIT_LIST_HEAD(&smack_known_floor.smk_rules);
        INIT_LIST_HEAD(&smack_known_web.smk_rules);
        /*
         * Create the known labels list
         */
        smk_insert_entry(&smack_known_huh);
        smk_insert_entry(&smack_known_hat);
        smk_insert_entry(&smack_known_star);
        smk_insert_entry(&smack_known_floor);
        smk_insert_entry(&smack_known_web);
}

/**
 * smack_init - initialize the smack system
 *
 * Returns 0 on success, -ENOMEM is there's no memory
 */
static __init int smack_init(void)
{
        struct cred *cred = (struct cred *) current->cred;
        struct task_smack *tsp;

        smack_rule_cache = KMEM_CACHE(smack_rule, 0);
        if (!smack_rule_cache)
                return -ENOMEM;

        /*
         * Set the security state for the initial task.
         */
        tsp = smack_cred(cred);
        init_task_smack(tsp, &smack_known_floor, &smack_known_floor);

        /*
         * Register with LSM
         */
        security_add_hooks(smack_hooks, ARRAY_SIZE(smack_hooks), &smack_lsmid);
        smack_enabled = 1;

        pr_info("Smack:  Initializing.\n");
#ifdef CONFIG_SECURITY_SMACK_NETFILTER
        pr_info("Smack:  Netfilter enabled.\n");
#endif
#ifdef SMACK_IPV6_PORT_LABELING
        pr_info("Smack:  IPv6 port labeling enabled.\n");
#endif
#ifdef SMACK_IPV6_SECMARK_LABELING
        pr_info("Smack:  IPv6 Netfilter enabled.\n");
#endif

        /* initialize the smack_known_list */
        init_smack_known_list();

        /* Inform the audit system that secctx is used */
        audit_cfg_lsm(&smack_lsmid,
                      AUDIT_CFG_LSM_SECCTX_SUBJECT |
                      AUDIT_CFG_LSM_SECCTX_OBJECT);

        return 0;
}

int __init smack_initcall(void)
{
        int rc_fs = init_smk_fs();
        int rc_nf = smack_nf_ip_init();

        return rc_fs ? rc_fs : rc_nf;
}

/*
 * Smack requires early initialization in order to label
 * all processes and objects when they are created.
 */
DEFINE_LSM(smack) = {
        .id = &smack_lsmid,
        .flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE,
        .blobs = &smack_blob_sizes,
        .init = smack_init,
        .initcall_device = smack_initcall,
};