// SPDX-License-Identifier: LGPL-2.1
/*
 *
 *   Copyright (C) International Business Machines  Corp., 2002, 2011
 *   Author(s): Steve French (sfrench@us.ibm.com),
 *              Pavel Shilovsky ((pshilovsky@samba.org) 2012
 *
 */
#include <linux/fs.h>
#include <linux/filelock.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <asm/div64.h>
#include "cifsfs.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifs_fs_sb.h"
#include "cifs_unicode.h"
#include "fscache.h"
#include "smb2proto.h"
#include "../common/smb2status.h"
#include "../common/smbfsctl.h"

static struct smb2_symlink_err_rsp *symlink_data(const struct kvec *iov)
{
        struct smb2_err_rsp *err = iov->iov_base;
        struct smb2_symlink_err_rsp *sym = ERR_PTR(-EINVAL);
        u32 len;

        if (err->ErrorContextCount) {
                struct smb2_error_context_rsp *p, *end;

                len = (u32)err->ErrorContextCount * (offsetof(struct smb2_error_context_rsp,
                                                              ErrorContextData) +
                                                     sizeof(struct smb2_symlink_err_rsp));
                if (le32_to_cpu(err->ByteCount) < len || iov->iov_len < len + sizeof(*err) + 1)
                        return ERR_PTR(-EINVAL);

                p = (struct smb2_error_context_rsp *)err->ErrorData;
                end = (struct smb2_error_context_rsp *)((u8 *)err + iov->iov_len);
                do {
                        if (le32_to_cpu(p->ErrorId) == SMB2_ERROR_ID_DEFAULT) {
                                sym = (struct smb2_symlink_err_rsp *)p->ErrorContextData;
                                break;
                        }
                        cifs_dbg(FYI, "%s: skipping unhandled error context: 0x%x\n",
                                 __func__, le32_to_cpu(p->ErrorId));

                        len = ALIGN(le32_to_cpu(p->ErrorDataLength), 8);
                        p = (struct smb2_error_context_rsp *)(p->ErrorContextData + len);
                } while (p < end);
        } else if (le32_to_cpu(err->ByteCount) >= sizeof(*sym) &&
                   iov->iov_len >= SMB2_SYMLINK_STRUCT_SIZE) {
                sym = (struct smb2_symlink_err_rsp *)err->ErrorData;
        }

        if (!IS_ERR(sym) && (le32_to_cpu(sym->SymLinkErrorTag) != SYMLINK_ERROR_TAG ||
                             le32_to_cpu(sym->ReparseTag) != IO_REPARSE_TAG_SYMLINK))
                sym = ERR_PTR(-EINVAL);

        return sym;
}

int smb2_fix_symlink_target_type(char **target, bool directory, struct cifs_sb_info *cifs_sb)
{
        char *buf;
        int len;

        /*
         * POSIX server does not distinguish between symlinks to file and
         * symlink directory. So nothing is needed to fix on the client side.
         */
        if (cifs_sb_flags(cifs_sb) & CIFS_MOUNT_POSIX_PATHS)
                return 0;

        if (!*target)
                return smb_EIO(smb_eio_trace_null_pointers);

        len = strlen(*target);
        if (!len)
                return smb_EIO1(smb_eio_trace_sym_target_len, len);

        /*
         * If this is directory symlink and it does not have trailing slash then
         * append it. Trailing slash simulates Windows/SMB behavior which do not
         * allow resolving directory symlink to file.
         */
        if (directory && (*target)[len-1] != '/') {
                buf = krealloc(*target, len+2, GFP_KERNEL);
                if (!buf)
                        return -ENOMEM;
                buf[len] = '/';
                buf[len+1] = '\0';
                *target = buf;
                len++;
        }

        /*
         * If this is a file (non-directory) symlink and it points to path name
         * with trailing slash then this is an invalid symlink because file name
         * cannot contain slash character. File name with slash is invalid on
         * both Windows and Linux systems. So return an error for such symlink.
         */
        if (!directory && (*target)[len-1] == '/')
                return smb_EIO(smb_eio_trace_sym_slash);

        return 0;
}

int smb2_parse_symlink_response(struct cifs_sb_info *cifs_sb, const struct kvec *iov,
                                const char *full_path, char **path)
{
        struct smb2_symlink_err_rsp *sym;
        unsigned int sub_offs, sub_len;
        unsigned int print_offs, print_len;

        if (!cifs_sb || !iov || !iov->iov_base || !iov->iov_len || !path)
                return -EINVAL;

        sym = symlink_data(iov);
        if (IS_ERR(sym))
                return PTR_ERR(sym);

        sub_len = le16_to_cpu(sym->SubstituteNameLength);
        sub_offs = le16_to_cpu(sym->SubstituteNameOffset);
        print_len = le16_to_cpu(sym->PrintNameLength);
        print_offs = le16_to_cpu(sym->PrintNameOffset);

        if (iov->iov_len < SMB2_SYMLINK_STRUCT_SIZE + sub_offs + sub_len ||
            iov->iov_len < SMB2_SYMLINK_STRUCT_SIZE + print_offs + print_len)
                return -EINVAL;

        return smb2_parse_native_symlink(path,
                                         (char *)sym->PathBuffer + sub_offs,
                                         sub_len,
                                         le32_to_cpu(sym->Flags) & SYMLINK_FLAG_RELATIVE,
                                         full_path,
                                         cifs_sb);
}

int smb2_open_file(const unsigned int xid, struct cifs_open_parms *oparms,
                   __u32 *oplock, void *buf)
{
        int rc;
        __le16 *smb2_path;
        __u8 smb2_oplock;
        struct cifs_open_info_data *data = buf;
        struct smb2_file_all_info file_info = {};
        struct smb2_file_all_info *smb2_data = data ? &file_info : NULL;
        struct kvec err_iov = {};
        int err_buftype = CIFS_NO_BUFFER;
        struct cifs_fid *fid = oparms->fid;
        struct network_resiliency_req nr_ioctl_req;
        bool retry_without_read_attributes = false;

        smb2_path = cifs_convert_path_to_utf16(oparms->path, oparms->cifs_sb);
        if (smb2_path == NULL)
                return -ENOMEM;

        /*
         * GENERIC_READ, GENERIC_EXECUTE, GENERIC_ALL and MAXIMUM_ALLOWED
         * contains also FILE_READ_ATTRIBUTES access right. So do not append
         * FILE_READ_ATTRIBUTES when not needed and prevent calling code path
         * for retry_without_read_attributes.
         */
        if (!(oparms->desired_access & FILE_READ_ATTRIBUTES) &&
            !(oparms->desired_access & GENERIC_READ) &&
            !(oparms->desired_access & GENERIC_EXECUTE) &&
            !(oparms->desired_access & GENERIC_ALL) &&
            !(oparms->desired_access & MAXIMUM_ALLOWED)) {
                oparms->desired_access |= FILE_READ_ATTRIBUTES;
                retry_without_read_attributes = true;
        }
        smb2_oplock = SMB2_OPLOCK_LEVEL_BATCH;

        rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data, NULL, &err_iov,
                       &err_buftype);
        if (rc == -EACCES && retry_without_read_attributes) {
                free_rsp_buf(err_buftype, err_iov.iov_base);
                memset(&err_iov, 0, sizeof(err_iov));
                err_buftype = CIFS_NO_BUFFER;
                oparms->desired_access &= ~FILE_READ_ATTRIBUTES;
                rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data, NULL, &err_iov,
                               &err_buftype);
        }
        if (rc && data) {
                struct smb2_hdr *hdr = err_iov.iov_base;

                if (unlikely(!err_iov.iov_base || err_buftype == CIFS_NO_BUFFER))
                        goto out;
                if (hdr->Status == STATUS_STOPPED_ON_SYMLINK) {
                        rc = smb2_parse_symlink_response(oparms->cifs_sb, &err_iov,
                                                         oparms->path,
                                                         &data->symlink_target);
                        if (!rc) {
                                memset(smb2_data, 0, sizeof(*smb2_data));
                                oparms->create_options |= OPEN_REPARSE_POINT;
                                rc = SMB2_open(xid, oparms, smb2_path, &smb2_oplock, smb2_data,
                                               NULL, NULL, NULL);
                                oparms->create_options &= ~OPEN_REPARSE_POINT;
                        }
                        if (!rc) {
                                bool directory = le32_to_cpu(data->fi.Attributes) & ATTR_DIRECTORY;
                                rc = smb2_fix_symlink_target_type(&data->symlink_target,
                                                                  directory, oparms->cifs_sb);
                        }
                }
        }

        if (rc)
                goto out;

        if (oparms->tcon->use_resilient) {
                /* default timeout is 0, servers pick default (120 seconds) */
                nr_ioctl_req.Timeout =
                        cpu_to_le32(oparms->tcon->handle_timeout);
                nr_ioctl_req.Reserved = 0;
                rc = SMB2_ioctl(xid, oparms->tcon, fid->persistent_fid,
                        fid->volatile_fid, FSCTL_LMR_REQUEST_RESILIENCY,
                        (char *)&nr_ioctl_req, sizeof(nr_ioctl_req),
                        CIFSMaxBufSize, NULL, NULL /* no return info */);
                if (rc == -EOPNOTSUPP) {
                        cifs_dbg(VFS,
                             "resiliency not supported by server, disabling\n");
                        oparms->tcon->use_resilient = false;
                } else if (rc)
                        cifs_dbg(FYI, "error %d setting resiliency\n", rc);

                rc = 0;
        }

        if (smb2_data) {
                /* if open response does not have IndexNumber field - get it */
                if (smb2_data->IndexNumber == 0) {
                        rc = SMB2_get_srv_num(xid, oparms->tcon,
                                      fid->persistent_fid,
                                      fid->volatile_fid,
                                      &smb2_data->IndexNumber);
                        if (rc) {
                                /*
                                 * let get_inode_info disable server inode
                                 * numbers
                                 */
                                smb2_data->IndexNumber = 0;
                                rc = 0;
                        }
                }
                memcpy(&data->fi, smb2_data, sizeof(data->fi));
        }

        *oplock = smb2_oplock;
out:
        free_rsp_buf(err_buftype, err_iov.iov_base);
        kfree(smb2_path);
        return rc;
}

int
smb2_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
                  const unsigned int xid)
{
        int rc = 0, stored_rc;
        unsigned int max_num, num = 0, max_buf;
        struct smb2_lock_element *buf, *cur;
        struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
        struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
        struct cifsLockInfo *li, *tmp;
        __u64 length = 1 + flock->fl_end - flock->fl_start;
        LIST_HEAD(tmp_llist);

        /*
         * Accessing maxBuf is racy with cifs_reconnect - need to store value
         * and check it before using.
         */
        max_buf = tcon->ses->server->maxBuf;
        if (max_buf < sizeof(struct smb2_lock_element))
                return -EINVAL;

        BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
        max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
        max_num = max_buf / sizeof(struct smb2_lock_element);
        buf = kzalloc_objs(struct smb2_lock_element, max_num);
        if (!buf)
                return -ENOMEM;

        cur = buf;

        cifs_down_write(&cinode->lock_sem);
        list_for_each_entry_safe(li, tmp, &cfile->llist->locks, llist) {
                if (flock->fl_start > li->offset ||
                    (flock->fl_start + length) <
                    (li->offset + li->length))
                        continue;
                if (current->tgid != li->pid)
                        /*
                         * flock and OFD lock are associated with an open
                         * file description, not the process.
                         */
                        if (!(flock->c.flc_flags & (FL_FLOCK | FL_OFDLCK)))
                                continue;
                if (cinode->can_cache_brlcks) {
                        /*
                         * We can cache brlock requests - simply remove a lock
                         * from the file's list.
                         */
                        list_del(&li->llist);
                        cifs_del_lock_waiters(li);
                        kfree(li);
                        continue;
                }
                cur->Length = cpu_to_le64(li->length);
                cur->Offset = cpu_to_le64(li->offset);
                cur->Flags = cpu_to_le32(SMB2_LOCKFLAG_UNLOCK);
                /*
                 * We need to save a lock here to let us add it again to the
                 * file's list if the unlock range request fails on the server.
                 */
                list_move(&li->llist, &tmp_llist);
                if (++num == max_num) {
                        stored_rc = smb2_lockv(xid, tcon,
                                               cfile->fid.persistent_fid,
                                               cfile->fid.volatile_fid,
                                               current->tgid, num, buf);
                        if (stored_rc) {
                                /*
                                 * We failed on the unlock range request - add
                                 * all locks from the tmp list to the head of
                                 * the file's list.
                                 */
                                cifs_move_llist(&tmp_llist,
                                                &cfile->llist->locks);
                                rc = stored_rc;
                        } else
                                /*
                                 * The unlock range request succeed - free the
                                 * tmp list.
                                 */
                                cifs_free_llist(&tmp_llist);
                        cur = buf;
                        num = 0;
                } else
                        cur++;
        }
        if (num) {
                stored_rc = smb2_lockv(xid, tcon, cfile->fid.persistent_fid,
                                       cfile->fid.volatile_fid, current->tgid,
                                       num, buf);
                if (stored_rc) {
                        cifs_move_llist(&tmp_llist, &cfile->llist->locks);
                        rc = stored_rc;
                } else
                        cifs_free_llist(&tmp_llist);
        }
        up_write(&cinode->lock_sem);

        kfree(buf);
        return rc;
}

static int
smb2_push_mand_fdlocks(struct cifs_fid_locks *fdlocks, const unsigned int xid,
                       struct smb2_lock_element *buf, unsigned int max_num)
{
        int rc = 0, stored_rc;
        struct cifsFileInfo *cfile = fdlocks->cfile;
        struct cifsLockInfo *li;
        unsigned int num = 0;
        struct smb2_lock_element *cur = buf;
        struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);

        list_for_each_entry(li, &fdlocks->locks, llist) {
                cur->Length = cpu_to_le64(li->length);
                cur->Offset = cpu_to_le64(li->offset);
                cur->Flags = cpu_to_le32(li->type |
                                                SMB2_LOCKFLAG_FAIL_IMMEDIATELY);
                if (++num == max_num) {
                        stored_rc = smb2_lockv(xid, tcon,
                                               cfile->fid.persistent_fid,
                                               cfile->fid.volatile_fid,
                                               current->tgid, num, buf);
                        if (stored_rc)
                                rc = stored_rc;
                        cur = buf;
                        num = 0;
                } else
                        cur++;
        }
        if (num) {
                stored_rc = smb2_lockv(xid, tcon,
                                       cfile->fid.persistent_fid,
                                       cfile->fid.volatile_fid,
                                       current->tgid, num, buf);
                if (stored_rc)
                        rc = stored_rc;
        }

        return rc;
}

int
smb2_push_mandatory_locks(struct cifsFileInfo *cfile)
{
        int rc = 0, stored_rc;
        unsigned int xid;
        unsigned int max_num, max_buf;
        struct smb2_lock_element *buf;
        struct cifsInodeInfo *cinode = CIFS_I(d_inode(cfile->dentry));
        struct cifs_fid_locks *fdlocks;

        xid = get_xid();

        /*
         * Accessing maxBuf is racy with cifs_reconnect - need to store value
         * and check it for zero before using.
         */
        max_buf = tlink_tcon(cfile->tlink)->ses->server->maxBuf;
        if (max_buf < sizeof(struct smb2_lock_element)) {
                free_xid(xid);
                return -EINVAL;
        }

        BUILD_BUG_ON(sizeof(struct smb2_lock_element) > PAGE_SIZE);
        max_buf = min_t(unsigned int, max_buf, PAGE_SIZE);
        max_num = max_buf / sizeof(struct smb2_lock_element);
        buf = kzalloc_objs(struct smb2_lock_element, max_num);
        if (!buf) {
                free_xid(xid);
                return -ENOMEM;
        }

        list_for_each_entry(fdlocks, &cinode->llist, llist) {
                stored_rc = smb2_push_mand_fdlocks(fdlocks, xid, buf, max_num);
                if (stored_rc)
                        rc = stored_rc;
        }

        kfree(buf);
        free_xid(xid);
        return rc;
}