root/fs/ocfs2/acl.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * acl.c
 *
 * Copyright (C) 2004, 2008 Oracle.  All rights reserved.
 *
 * CREDITS:
 * Lots of code in this file is copy from linux/fs/ext3/acl.c.
 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/fs_struct.h>

#include <cluster/masklog.h>

#include "ocfs2.h"
#include "alloc.h"
#include "dlmglue.h"
#include "file.h"
#include "inode.h"
#include "journal.h"
#include "ocfs2_fs.h"

#include "xattr.h"
#include "acl.h"

/*
 * Convert from xattr value to acl struct.
 */
static struct posix_acl *ocfs2_acl_from_xattr(const void *value, size_t size)
{
        int n, count;
        struct posix_acl *acl;

        if (!value)
                return NULL;
        if (size < sizeof(struct posix_acl_entry))
                return ERR_PTR(-EINVAL);

        count = size / sizeof(struct posix_acl_entry);

        acl = posix_acl_alloc(count, GFP_NOFS);
        if (!acl)
                return ERR_PTR(-ENOMEM);
        for (n = 0; n < count; n++) {
                struct ocfs2_acl_entry *entry =
                        (struct ocfs2_acl_entry *)value;

                acl->a_entries[n].e_tag  = le16_to_cpu(entry->e_tag);
                acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
                switch(acl->a_entries[n].e_tag) {
                case ACL_USER:
                        acl->a_entries[n].e_uid =
                                make_kuid(&init_user_ns,
                                          le32_to_cpu(entry->e_id));
                        break;
                case ACL_GROUP:
                        acl->a_entries[n].e_gid =
                                make_kgid(&init_user_ns,
                                          le32_to_cpu(entry->e_id));
                        break;
                default:
                        break;
                }
                value += sizeof(struct posix_acl_entry);

        }
        return acl;
}

/*
 * Convert acl struct to xattr value.
 */
static void *ocfs2_acl_to_xattr(const struct posix_acl *acl, size_t *size)
{
        struct ocfs2_acl_entry *entry = NULL;
        char *ocfs2_acl;
        size_t n;

        *size = acl->a_count * sizeof(struct posix_acl_entry);

        ocfs2_acl = kmalloc(*size, GFP_NOFS);
        if (!ocfs2_acl)
                return ERR_PTR(-ENOMEM);

        entry = (struct ocfs2_acl_entry *)ocfs2_acl;
        for (n = 0; n < acl->a_count; n++, entry++) {
                entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
                entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
                switch(acl->a_entries[n].e_tag) {
                case ACL_USER:
                        entry->e_id = cpu_to_le32(
                                from_kuid(&init_user_ns,
                                          acl->a_entries[n].e_uid));
                        break;
                case ACL_GROUP:
                        entry->e_id = cpu_to_le32(
                                from_kgid(&init_user_ns,
                                          acl->a_entries[n].e_gid));
                        break;
                default:
                        entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID);
                        break;
                }
        }
        return ocfs2_acl;
}

static struct posix_acl *ocfs2_get_acl_nolock(struct inode *inode,
                                              int type,
                                              struct buffer_head *di_bh)
{
        int name_index;
        char *value = NULL;
        struct posix_acl *acl;
        int retval;

        switch (type) {
        case ACL_TYPE_ACCESS:
                name_index = OCFS2_XATTR_INDEX_POSIX_ACL_ACCESS;
                break;
        case ACL_TYPE_DEFAULT:
                name_index = OCFS2_XATTR_INDEX_POSIX_ACL_DEFAULT;
                break;
        default:
                return ERR_PTR(-EINVAL);
        }

        retval = ocfs2_xattr_get_nolock(inode, di_bh, name_index, "", NULL, 0);
        if (retval > 0) {
                value = kmalloc(retval, GFP_NOFS);
                if (!value)
                        return ERR_PTR(-ENOMEM);
                retval = ocfs2_xattr_get_nolock(inode, di_bh, name_index,
                                                "", value, retval);
        }

        if (retval > 0)
                acl = ocfs2_acl_from_xattr(value, retval);
        else if (retval == -ENODATA || retval == 0)
                acl = NULL;
        else
                acl = ERR_PTR(retval);

        kfree(value);

        return acl;
}

/*
 * Helper function to set i_mode in memory and disk. Some call paths
 * will not have di_bh or a journal handle to pass, in which case it
 * will create it's own.
 */
static int ocfs2_acl_set_mode(struct inode *inode, struct buffer_head *di_bh,
                              handle_t *handle, umode_t new_mode)
{
        int ret, commit_handle = 0;
        struct ocfs2_dinode *di;

        if (di_bh == NULL) {
                ret = ocfs2_read_inode_block(inode, &di_bh);
                if (ret) {
                        mlog_errno(ret);
                        goto out;
                }
        } else
                get_bh(di_bh);

        if (handle == NULL) {
                handle = ocfs2_start_trans(OCFS2_SB(inode->i_sb),
                                           OCFS2_INODE_UPDATE_CREDITS);
                if (IS_ERR(handle)) {
                        ret = PTR_ERR(handle);
                        mlog_errno(ret);
                        goto out_brelse;
                }

                commit_handle = 1;
        }

        di = (struct ocfs2_dinode *)di_bh->b_data;
        ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), di_bh,
                                      OCFS2_JOURNAL_ACCESS_WRITE);
        if (ret) {
                mlog_errno(ret);
                goto out_commit;
        }

        inode->i_mode = new_mode;
        inode_set_ctime_current(inode);
        di->i_mode = cpu_to_le16(inode->i_mode);
        di->i_ctime = cpu_to_le64(inode_get_ctime_sec(inode));
        di->i_ctime_nsec = cpu_to_le32(inode_get_ctime_nsec(inode));
        ocfs2_update_inode_fsync_trans(handle, inode, 0);

        ocfs2_journal_dirty(handle, di_bh);

out_commit:
        if (commit_handle)
                ocfs2_commit_trans(OCFS2_SB(inode->i_sb), handle);
out_brelse:
        brelse(di_bh);
out:
        return ret;
}

/*
 * Set the access or default ACL of an inode.
 */
static int ocfs2_set_acl(handle_t *handle,
                         struct inode *inode,
                         struct buffer_head *di_bh,
                         int type,
                         struct posix_acl *acl,
                         struct ocfs2_alloc_context *meta_ac,
                         struct ocfs2_alloc_context *data_ac)
{
        int name_index;
        void *value = NULL;
        size_t size = 0;
        int ret;

        if (S_ISLNK(inode->i_mode))
                return -EOPNOTSUPP;

        switch (type) {
        case ACL_TYPE_ACCESS:
                name_index = OCFS2_XATTR_INDEX_POSIX_ACL_ACCESS;
                break;
        case ACL_TYPE_DEFAULT:
                name_index = OCFS2_XATTR_INDEX_POSIX_ACL_DEFAULT;
                if (!S_ISDIR(inode->i_mode))
                        return acl ? -EACCES : 0;
                break;
        default:
                return -EINVAL;
        }

        if (acl) {
                value = ocfs2_acl_to_xattr(acl, &size);
                if (IS_ERR(value))
                        return (int)PTR_ERR(value);
        }

        if (handle)
                ret = ocfs2_xattr_set_handle(handle, inode, di_bh, name_index,
                                             "", value, size, 0,
                                             meta_ac, data_ac);
        else
                ret = ocfs2_xattr_set(inode, name_index, "", value, size, 0);

        kfree(value);
        if (!ret)
                set_cached_acl(inode, type, acl);

        return ret;
}

int ocfs2_iop_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
                      struct posix_acl *acl, int type)
{
        struct buffer_head *bh = NULL;
        int status, had_lock;
        struct ocfs2_lock_holder oh;
        struct inode *inode = d_inode(dentry);

        had_lock = ocfs2_inode_lock_tracker(inode, &bh, 1, &oh);
        if (had_lock < 0)
                return had_lock;
        if (type == ACL_TYPE_ACCESS && acl) {
                umode_t mode;

                status = posix_acl_update_mode(&nop_mnt_idmap, inode, &mode,
                                               &acl);
                if (status)
                        goto unlock;

                status = ocfs2_acl_set_mode(inode, bh, NULL, mode);
                if (status)
                        goto unlock;
        }
        status = ocfs2_set_acl(NULL, inode, bh, type, acl, NULL, NULL);
unlock:
        ocfs2_inode_unlock_tracker(inode, 1, &oh, had_lock);
        brelse(bh);
        return status;
}

struct posix_acl *ocfs2_iop_get_acl(struct inode *inode, int type, bool rcu)
{
        struct ocfs2_super *osb;
        struct buffer_head *di_bh = NULL;
        struct posix_acl *acl;
        int had_lock;
        struct ocfs2_lock_holder oh;

        if (rcu)
                return ERR_PTR(-ECHILD);

        osb = OCFS2_SB(inode->i_sb);
        if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
                return NULL;

        had_lock = ocfs2_inode_lock_tracker(inode, &di_bh, 0, &oh);
        if (had_lock < 0)
                return ERR_PTR(had_lock);

        down_read(&OCFS2_I(inode)->ip_xattr_sem);
        acl = ocfs2_get_acl_nolock(inode, type, di_bh);
        up_read(&OCFS2_I(inode)->ip_xattr_sem);

        ocfs2_inode_unlock_tracker(inode, 0, &oh, had_lock);
        brelse(di_bh);
        return acl;
}

int ocfs2_acl_chmod(struct inode *inode, struct buffer_head *bh)
{
        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
        struct posix_acl *acl;
        int ret;

        if (S_ISLNK(inode->i_mode))
                return -EOPNOTSUPP;

        if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL))
                return 0;

        down_read(&OCFS2_I(inode)->ip_xattr_sem);
        acl = ocfs2_get_acl_nolock(inode, ACL_TYPE_ACCESS, bh);
        up_read(&OCFS2_I(inode)->ip_xattr_sem);
        if (IS_ERR_OR_NULL(acl))
                return PTR_ERR_OR_ZERO(acl);
        ret = __posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
        if (ret)
                return ret;
        ret = ocfs2_set_acl(NULL, inode, NULL, ACL_TYPE_ACCESS,
                            acl, NULL, NULL);
        posix_acl_release(acl);
        return ret;
}

/*
 * Initialize the ACLs of a new inode. If parent directory has default ACL,
 * then clone to new inode. Called from ocfs2_mknod.
 */
int ocfs2_init_acl(handle_t *handle,
                   struct inode *inode,
                   struct inode *dir,
                   struct buffer_head *di_bh,
                   struct buffer_head *dir_bh,
                   struct ocfs2_alloc_context *meta_ac,
                   struct ocfs2_alloc_context *data_ac)
{
        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
        struct posix_acl *acl = NULL;
        int ret = 0, ret2;
        umode_t mode;

        if (!S_ISLNK(inode->i_mode)) {
                if (osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL) {
                        down_read(&OCFS2_I(dir)->ip_xattr_sem);
                        acl = ocfs2_get_acl_nolock(dir, ACL_TYPE_DEFAULT,
                                                   dir_bh);
                        up_read(&OCFS2_I(dir)->ip_xattr_sem);
                        if (IS_ERR(acl))
                                return PTR_ERR(acl);
                }
                if (!acl) {
                        mode = inode->i_mode & ~current_umask();
                        ret = ocfs2_acl_set_mode(inode, di_bh, handle, mode);
                        if (ret) {
                                mlog_errno(ret);
                                goto cleanup;
                        }
                }
        }
        if ((osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL) && acl) {
                if (S_ISDIR(inode->i_mode)) {
                        ret = ocfs2_set_acl(handle, inode, di_bh,
                                            ACL_TYPE_DEFAULT, acl,
                                            meta_ac, data_ac);
                        if (ret)
                                goto cleanup;
                }
                mode = inode->i_mode;
                ret = __posix_acl_create(&acl, GFP_NOFS, &mode);
                if (ret < 0)
                        return ret;

                ret2 = ocfs2_acl_set_mode(inode, di_bh, handle, mode);
                if (ret2) {
                        mlog_errno(ret2);
                        ret = ret2;
                        goto cleanup;
                }
                if (ret > 0) {
                        ret = ocfs2_set_acl(handle, inode,
                                            di_bh, ACL_TYPE_ACCESS,
                                            acl, meta_ac, data_ac);
                }
        }
cleanup:
        posix_acl_release(acl);
        return ret;
}