/* * fs/cifs/link.c * * Copyright (C) International Business Machines Corp., 2002,2008 * Author(s): Steve French (sfrench@us.ibm.com) * * This library is free software; you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published * by the Free Software Foundation; either version 2.1 of the License, or * (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See * the GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include <linux/fs.h> #include <linux/stat.h> #include <linux/slab.h> #include <linux/namei.h> #include "cifsfs.h" #include "cifspdu.h" #include "cifsglob.h" #include "cifsproto.h" #include "cifs_debug.h" #include "cifs_fs_sb.h" #include "cifs_unicode.h" #ifdef CONFIG_CIFS_SMB2 #include "smb2proto.h" #endif /* * M-F Symlink Functions - Begin */ #define CIFS_MF_SYMLINK_LEN_OFFSET (4+1) #define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1)) #define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1)) #define CIFS_MF_SYMLINK_LINK_MAXLEN (1024) #define CIFS_MF_SYMLINK_FILE_SIZE \ (CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN) #define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n" #define CIFS_MF_SYMLINK_MD5_FORMAT "%16phN\n" #define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) md5_hash static int symlink_hash(unsigned int link_len, const char *link_str, u8 *md5_hash) { int rc; unsigned int size; struct crypto_shash *md5; struct sdesc *sdescmd5; md5 = crypto_alloc_shash("md5", 0, 0); if (IS_ERR(md5)) { rc = PTR_ERR(md5); cifs_dbg(VFS, "%s: Crypto md5 allocation error %d\n", __func__, rc); return rc; } size = sizeof(struct shash_desc) + crypto_shash_descsize(md5); sdescmd5 = kmalloc(size, GFP_KERNEL); if (!sdescmd5) { rc = -ENOMEM; goto symlink_hash_err; } sdescmd5->shash.tfm = md5; sdescmd5->shash.flags = 0x0; rc = crypto_shash_init(&sdescmd5->shash); if (rc) { cifs_dbg(VFS, "%s: Could not init md5 shash\n", __func__); goto symlink_hash_err; } rc = crypto_shash_update(&sdescmd5->shash, link_str, link_len); if (rc) { cifs_dbg(VFS, "%s: Could not update with link_str\n", __func__); goto symlink_hash_err; } rc = crypto_shash_final(&sdescmd5->shash, md5_hash); if (rc) cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__); symlink_hash_err: crypto_free_shash(md5); kfree(sdescmd5); return rc; } static int parse_mf_symlink(const u8 *buf, unsigned int buf_len, unsigned int *_link_len, char **_link_str) { int rc; unsigned int link_len; const char *md5_str1; const char *link_str; u8 md5_hash[16]; char md5_str2[34]; if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE) return -EINVAL; md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET]; link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET]; rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len); if (rc != 1) return -EINVAL; rc = symlink_hash(link_len, link_str, md5_hash); if (rc) { cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc); return rc; } snprintf(md5_str2, sizeof(md5_str2), CIFS_MF_SYMLINK_MD5_FORMAT, CIFS_MF_SYMLINK_MD5_ARGS(md5_hash)); if (strncmp(md5_str1, md5_str2, 17) != 0) return -EINVAL; if (_link_str) { *_link_str = kstrndup(link_str, link_len, GFP_KERNEL); if (!*_link_str) return -ENOMEM; } *_link_len = link_len; return 0; } static int format_mf_symlink(u8 *buf, unsigned int buf_len, const char *link_str) { int rc; unsigned int link_len; unsigned int ofs; u8 md5_hash[16]; if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE) return -EINVAL; link_len = strlen(link_str); if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN) return -ENAMETOOLONG; rc = symlink_hash(link_len, link_str, md5_hash); if (rc) { cifs_dbg(FYI, "%s: MD5 hash failure: %d\n", __func__, rc); return rc; } snprintf(buf, buf_len, CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT, link_len, CIFS_MF_SYMLINK_MD5_ARGS(md5_hash)); ofs = CIFS_MF_SYMLINK_LINK_OFFSET; memcpy(buf + ofs, link_str, link_len); ofs += link_len; if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) { buf[ofs] = '\n'; ofs++; } while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) { buf[ofs] = ' '; ofs++; } return 0; } bool couldbe_mf_symlink(const struct cifs_fattr *fattr) { if (!S_ISREG(fattr->cf_mode)) /* it's not a symlink */ return false; if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE) /* it's not a symlink */ return false; return true; } static int create_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon, struct cifs_sb_info *cifs_sb, const char *fromName, const char *toName) { int rc; u8 *buf; unsigned int bytes_written = 0; buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL); if (!buf) return -ENOMEM; rc = format_mf_symlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName); if (rc) goto out; if (tcon->ses->server->ops->create_mf_symlink) rc = tcon->ses->server->ops->create_mf_symlink(xid, tcon, cifs_sb, fromName, buf, &bytes_written); else rc = -EOPNOTSUPP; if (rc) goto out; if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE) rc = -EIO; out: kfree(buf); return rc; } static int query_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon, struct cifs_sb_info *cifs_sb, const unsigned char *path, char **symlinkinfo) { int rc; u8 *buf = NULL; unsigned int link_len = 0; unsigned int bytes_read = 0; buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL); if (!buf) return -ENOMEM; if (tcon->ses->server->ops->query_mf_symlink) rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon, cifs_sb, path, buf, &bytes_read); else rc = -ENOSYS; if (rc) goto out; if (bytes_read == 0) { /* not a symlink */ rc = -EINVAL; goto out; } rc = parse_mf_symlink(buf, bytes_read, &link_len, symlinkinfo); out: kfree(buf); return rc; } int check_mf_symlink(unsigned int xid, struct cifs_tcon *tcon, struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr, const unsigned char *path) { int rc; u8 *buf = NULL; unsigned int link_len = 0; unsigned int bytes_read = 0; if (!couldbe_mf_symlink(fattr)) /* it's not a symlink */ return 0; buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL); if (!buf) return -ENOMEM; if (tcon->ses->server->ops->query_mf_symlink) rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon, cifs_sb, path, buf, &bytes_read); else rc = -ENOSYS; if (rc) goto out; if (bytes_read == 0) /* not a symlink */ goto out; rc = parse_mf_symlink(buf, bytes_read, &link_len, NULL); if (rc == -EINVAL) { /* it's not a symlink */ rc = 0; goto out; } if (rc != 0) goto out; /* it is a symlink */ fattr->cf_eof = link_len; fattr->cf_mode &= ~S_IFMT; fattr->cf_mode |= S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO; fattr->cf_dtype = DT_LNK; out: kfree(buf); return rc; } /* * SMB 1.0 Protocol specific functions */ int cifs_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon, struct cifs_sb_info *cifs_sb, const unsigned char *path, char *pbuf, unsigned int *pbytes_read) { int rc; int oplock = 0; struct cifs_fid fid; struct cifs_open_parms oparms; struct cifs_io_parms io_parms; int buf_type = CIFS_NO_BUFFER; FILE_ALL_INFO file_info; oparms.tcon = tcon; oparms.cifs_sb = cifs_sb; oparms.desired_access = GENERIC_READ; oparms.create_options = CREATE_NOT_DIR; oparms.disposition = FILE_OPEN; oparms.path = path; oparms.fid = &fid; oparms.reconnect = false; rc = CIFS_open(xid, &oparms, &oplock, &file_info); if (rc) return rc; if (file_info.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) { rc = -ENOENT; /* it's not a symlink */ goto out; } io_parms.netfid = fid.netfid; io_parms.pid = current->tgid; io_parms.tcon = tcon; io_parms.offset = 0; io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE; rc = CIFSSMBRead(xid, &io_parms, pbytes_read, &pbuf, &buf_type); out: CIFSSMBClose(xid, tcon, fid.netfid); return rc; } int cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon, struct cifs_sb_info *cifs_sb, const unsigned char *path, char *pbuf, unsigned int *pbytes_written) { int rc; int oplock = 0; struct cifs_fid fid; struct cifs_open_parms oparms; struct cifs_io_parms io_parms; int create_options = CREATE_NOT_DIR; if (backup_cred(cifs_sb)) create_options |= CREATE_OPEN_BACKUP_INTENT; oparms.tcon = tcon; oparms.cifs_sb = cifs_sb; oparms.desired_access = GENERIC_WRITE; oparms.create_options = create_options; oparms.disposition = FILE_CREATE; oparms.path = path; oparms.fid = &fid; oparms.reconnect = false; rc = CIFS_open(xid, &oparms, &oplock, NULL); if (rc) return rc; io_parms.netfid = fid.netfid; io_parms.pid = current->tgid; io_parms.tcon = tcon; io_parms.offset = 0; io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE; rc = CIFSSMBWrite(xid, &io_parms, pbytes_written, pbuf); CIFSSMBClose(xid, tcon, fid.netfid); return rc; } /* * SMB 2.1/SMB3 Protocol specific functions */ #ifdef CONFIG_CIFS_SMB2 int smb3_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon, struct cifs_sb_info *cifs_sb, const unsigned char *path, char *pbuf, unsigned int *pbytes_read) { int rc; struct cifs_fid fid; struct cifs_open_parms oparms; struct cifs_io_parms io_parms; int buf_type = CIFS_NO_BUFFER; __le16 *utf16_path; __u8 oplock = SMB2_OPLOCK_LEVEL_II; struct smb2_file_all_info *pfile_info = NULL; oparms.tcon = tcon; oparms.cifs_sb = cifs_sb; oparms.desired_access = GENERIC_READ; oparms.create_options = CREATE_NOT_DIR; if (backup_cred(cifs_sb)) oparms.create_options |= CREATE_OPEN_BACKUP_INTENT; oparms.disposition = FILE_OPEN; oparms.fid = &fid; oparms.reconnect = false; utf16_path = cifs_convert_path_to_utf16(path, cifs_sb); if (utf16_path == NULL) return -ENOMEM; pfile_info = kzalloc(sizeof(struct smb2_file_all_info) + PATH_MAX * 2, GFP_KERNEL); if (pfile_info == NULL) { kfree(utf16_path); return -ENOMEM; } rc = SMB2_open(xid, &oparms, utf16_path, &oplock, pfile_info, NULL); if (rc) goto qmf_out_open_fail; if (pfile_info->EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) { /* it's not a symlink */ rc = -ENOENT; /* Is there a better rc to return? */ goto qmf_out; } io_parms.netfid = fid.netfid; io_parms.pid = current->tgid; io_parms.tcon = tcon; io_parms.offset = 0; io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE; io_parms.persistent_fid = fid.persistent_fid; io_parms.volatile_fid = fid.volatile_fid; rc = SMB2_read(xid, &io_parms, pbytes_read, &pbuf, &buf_type); qmf_out: SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid); qmf_out_open_fail: kfree(utf16_path); kfree(pfile_info); return rc; } int smb3_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon, struct cifs_sb_info *cifs_sb, const unsigned char *path, char *pbuf, unsigned int *pbytes_written) { int rc; struct cifs_fid fid; struct cifs_open_parms oparms; struct cifs_io_parms io_parms; int create_options = CREATE_NOT_DIR; __le16 *utf16_path; __u8 oplock = SMB2_OPLOCK_LEVEL_EXCLUSIVE; struct kvec iov[2]; if (backup_cred(cifs_sb)) create_options |= CREATE_OPEN_BACKUP_INTENT; cifs_dbg(FYI, "%s: path: %s\n", __func__, path); utf16_path = cifs_convert_path_to_utf16(path, cifs_sb); if (!utf16_path) return -ENOMEM; oparms.tcon = tcon; oparms.cifs_sb = cifs_sb; oparms.desired_access = GENERIC_WRITE; oparms.create_options = create_options; oparms.disposition = FILE_CREATE; oparms.fid = &fid; oparms.reconnect = false; rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL); if (rc) { kfree(utf16_path); return rc; } io_parms.netfid = fid.netfid; io_parms.pid = current->tgid; io_parms.tcon = tcon; io_parms.offset = 0; io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE; io_parms.persistent_fid = fid.persistent_fid; io_parms.volatile_fid = fid.volatile_fid; /* iov[0] is reserved for smb header */ iov[1].iov_base = pbuf; iov[1].iov_len = CIFS_MF_SYMLINK_FILE_SIZE; rc = SMB2_write(xid, &io_parms, pbytes_written, iov, 1); /* Make sure we wrote all of the symlink data */ if ((rc == 0) && (*pbytes_written != CIFS_MF_SYMLINK_FILE_SIZE)) rc = -EIO; SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid); kfree(utf16_path); return rc; } #endif /* CONFIG_CIFS_SMB2 */ /* * M-F Symlink Functions - End */ int cifs_hardlink(struct dentry *old_file, struct inode *inode, struct dentry *direntry) { int rc = -EACCES; unsigned int xid; char *from_name = NULL; char *to_name = NULL; struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb); struct tcon_link *tlink; struct cifs_tcon *tcon; struct TCP_Server_Info *server; struct cifsInodeInfo *cifsInode; tlink = cifs_sb_tlink(cifs_sb); if (IS_ERR(tlink)) return PTR_ERR(tlink); tcon = tlink_tcon(tlink); xid = get_xid(); from_name = build_path_from_dentry(old_file); to_name = build_path_from_dentry(direntry); if ((from_name == NULL) || (to_name == NULL)) { rc = -ENOMEM; goto cifs_hl_exit; } if (tcon->unix_ext) rc = CIFSUnixCreateHardLink(xid, tcon, from_name, to_name, cifs_sb->local_nls, cifs_remap(cifs_sb)); else { server = tcon->ses->server; if (!server->ops->create_hardlink) { rc = -ENOSYS; goto cifs_hl_exit; } rc = server->ops->create_hardlink(xid, tcon, from_name, to_name, cifs_sb); if ((rc == -EIO) || (rc == -EINVAL)) rc = -EOPNOTSUPP; } d_drop(direntry); /* force new lookup from server of target */ /* * if source file is cached (oplocked) revalidate will not go to server * until the file is closed or oplock broken so update nlinks locally */ if (d_really_is_positive(old_file)) { cifsInode = CIFS_I(d_inode(old_file)); if (rc == 0) { spin_lock(&d_inode(old_file)->i_lock); inc_nlink(d_inode(old_file)); spin_unlock(&d_inode(old_file)->i_lock); /* * parent dir timestamps will update from srv within a * second, would it really be worth it to set the parent * dir cifs inode time to zero to force revalidate * (faster) for it too? */ } /* * if not oplocked will force revalidate to get info on source * file from srv. Note Samba server prior to 4.2 has bug - * not updating src file ctime on hardlinks but Windows servers * handle it properly */ cifsInode->time = 0; /* * Will update parent dir timestamps from srv within a second. * Would it really be worth it to set the parent dir (cifs * inode) time field to zero to force revalidate on parent * directory faster ie * * CIFS_I(inode)->time = 0; */ } cifs_hl_exit: kfree(from_name); kfree(to_name); free_xid(xid); cifs_put_tlink(tlink); return rc; } const char * cifs_get_link(struct dentry *direntry, struct inode *inode, struct delayed_call *done) { int rc = -ENOMEM; unsigned int xid; char *full_path = NULL; char *target_path = NULL; struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb); struct tcon_link *tlink = NULL; struct cifs_tcon *tcon; struct TCP_Server_Info *server; if (!direntry) return ERR_PTR(-ECHILD); xid = get_xid(); tlink = cifs_sb_tlink(cifs_sb); if (IS_ERR(tlink)) { free_xid(xid); return ERR_CAST(tlink); } tcon = tlink_tcon(tlink); server = tcon->ses->server; full_path = build_path_from_dentry(direntry); if (!full_path) { free_xid(xid); cifs_put_tlink(tlink); return ERR_PTR(-ENOMEM); } cifs_dbg(FYI, "Full path: %s inode = 0x%p\n", full_path, inode); rc = -EACCES; /* * First try Minshall+French Symlinks, if configured * and fallback to UNIX Extensions Symlinks. */ if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) rc = query_mf_symlink(xid, tcon, cifs_sb, full_path, &target_path); if (rc != 0 && server->ops->query_symlink) rc = server->ops->query_symlink(xid, tcon, full_path, &target_path, cifs_sb); kfree(full_path); free_xid(xid); cifs_put_tlink(tlink); if (rc != 0) { kfree(target_path); return ERR_PTR(rc); } set_delayed_call(done, kfree_link, target_path); return target_path; } int cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname) { int rc = -EOPNOTSUPP; unsigned int xid; struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb); struct tcon_link *tlink; struct cifs_tcon *pTcon; char *full_path = NULL; struct inode *newinode = NULL; xid = get_xid(); tlink = cifs_sb_tlink(cifs_sb); if (IS_ERR(tlink)) { rc = PTR_ERR(tlink); goto symlink_exit; } pTcon = tlink_tcon(tlink); full_path = build_path_from_dentry(direntry); if (full_path == NULL) { rc = -ENOMEM; goto symlink_exit; } cifs_dbg(FYI, "Full path: %s\n", full_path); cifs_dbg(FYI, "symname is %s\n", symname); /* BB what if DFS and this volume is on different share? BB */ if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) rc = create_mf_symlink(xid, pTcon, cifs_sb, full_path, symname); else if (pTcon->unix_ext) rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname, cifs_sb->local_nls, cifs_remap(cifs_sb)); /* else rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName, cifs_sb_target->local_nls); */ if (rc == 0) { if (pTcon->unix_ext) rc = cifs_get_inode_info_unix(&newinode, full_path, inode->i_sb, xid); else rc = cifs_get_inode_info(&newinode, full_path, NULL, inode->i_sb, xid, NULL); if (rc != 0) { cifs_dbg(FYI, "Create symlink ok, getinodeinfo fail rc = %d\n", rc); } else { d_instantiate(direntry, newinode); } } symlink_exit: kfree(full_path); cifs_put_tlink(tlink); free_xid(xid); return rc; }