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1da177e4 LT |
1 | /* |
2 | * fs/cifs/link.c | |
3 | * | |
366781c1 | 4 | * Copyright (C) International Business Machines Corp., 2002,2008 |
1da177e4 LT |
5 | * Author(s): Steve French (sfrench@us.ibm.com) |
6 | * | |
7 | * This library is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU Lesser General Public License as published | |
9 | * by the Free Software Foundation; either version 2.1 of the License, or | |
10 | * (at your option) any later version. | |
11 | * | |
12 | * This library is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See | |
15 | * the GNU Lesser General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU Lesser General Public License | |
18 | * along with this library; if not, write to the Free Software | |
19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
20 | */ | |
21 | #include <linux/fs.h> | |
22 | #include <linux/stat.h> | |
5a0e3ad6 | 23 | #include <linux/slab.h> |
1da177e4 LT |
24 | #include <linux/namei.h> |
25 | #include "cifsfs.h" | |
26 | #include "cifspdu.h" | |
27 | #include "cifsglob.h" | |
28 | #include "cifsproto.h" | |
29 | #include "cifs_debug.h" | |
30 | #include "cifs_fs_sb.h" | |
c69c1b6e SM |
31 | #include "md5.h" |
32 | ||
33 | #define CIFS_MF_SYMLINK_LEN_OFFSET (4+1) | |
34 | #define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1)) | |
35 | #define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1)) | |
36 | #define CIFS_MF_SYMLINK_LINK_MAXLEN (1024) | |
37 | #define CIFS_MF_SYMLINK_FILE_SIZE \ | |
38 | (CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN) | |
39 | ||
40 | #define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n" | |
41 | #define CIFS_MF_SYMLINK_MD5_FORMAT \ | |
42 | "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n" | |
43 | #define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) \ | |
44 | md5_hash[0], md5_hash[1], md5_hash[2], md5_hash[3], \ | |
45 | md5_hash[4], md5_hash[5], md5_hash[6], md5_hash[7], \ | |
46 | md5_hash[8], md5_hash[9], md5_hash[10], md5_hash[11],\ | |
47 | md5_hash[12], md5_hash[13], md5_hash[14], md5_hash[15] | |
48 | ||
49 | static int | |
50 | CIFSParseMFSymlink(const u8 *buf, | |
51 | unsigned int buf_len, | |
52 | unsigned int *_link_len, | |
53 | char **_link_str) | |
54 | { | |
55 | int rc; | |
56 | unsigned int link_len; | |
57 | const char *md5_str1; | |
58 | const char *link_str; | |
59 | struct MD5Context md5_ctx; | |
60 | u8 md5_hash[16]; | |
61 | char md5_str2[34]; | |
62 | ||
63 | if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE) | |
64 | return -EINVAL; | |
65 | ||
66 | md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET]; | |
67 | link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET]; | |
68 | ||
69 | rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len); | |
70 | if (rc != 1) | |
71 | return -EINVAL; | |
72 | ||
73 | cifs_MD5_init(&md5_ctx); | |
74 | cifs_MD5_update(&md5_ctx, (const u8 *)link_str, link_len); | |
75 | cifs_MD5_final(md5_hash, &md5_ctx); | |
76 | ||
77 | snprintf(md5_str2, sizeof(md5_str2), | |
78 | CIFS_MF_SYMLINK_MD5_FORMAT, | |
79 | CIFS_MF_SYMLINK_MD5_ARGS(md5_hash)); | |
80 | ||
81 | if (strncmp(md5_str1, md5_str2, 17) != 0) | |
82 | return -EINVAL; | |
83 | ||
84 | if (_link_str) { | |
85 | *_link_str = kstrndup(link_str, link_len, GFP_KERNEL); | |
86 | if (!*_link_str) | |
87 | return -ENOMEM; | |
88 | } | |
89 | ||
90 | *_link_len = link_len; | |
91 | return 0; | |
92 | } | |
1da177e4 | 93 | |
8bfb50a8 SM |
94 | bool |
95 | CIFSCouldBeMFSymlink(const struct cifs_fattr *fattr) | |
96 | { | |
97 | if (!(fattr->cf_mode & S_IFREG)) | |
98 | /* it's not a symlink */ | |
99 | return false; | |
100 | ||
101 | if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE) | |
102 | /* it's not a symlink */ | |
103 | return false; | |
104 | ||
105 | return true; | |
106 | } | |
107 | ||
108 | int | |
109 | CIFSCheckMFSymlink(struct cifs_fattr *fattr, | |
110 | const unsigned char *path, | |
111 | struct cifs_sb_info *cifs_sb, int xid) | |
112 | { | |
113 | int rc; | |
114 | int oplock = 0; | |
115 | __u16 netfid = 0; | |
116 | struct cifsTconInfo *pTcon = cifs_sb->tcon; | |
117 | u8 *buf; | |
118 | char *pbuf; | |
119 | unsigned int bytes_read = 0; | |
120 | int buf_type = CIFS_NO_BUFFER; | |
121 | unsigned int link_len = 0; | |
122 | FILE_ALL_INFO file_info; | |
123 | ||
124 | if (!CIFSCouldBeMFSymlink(fattr)) | |
125 | /* it's not a symlink */ | |
126 | return 0; | |
127 | ||
128 | rc = CIFSSMBOpen(xid, pTcon, path, FILE_OPEN, GENERIC_READ, | |
129 | CREATE_NOT_DIR, &netfid, &oplock, &file_info, | |
130 | cifs_sb->local_nls, | |
131 | cifs_sb->mnt_cifs_flags & | |
132 | CIFS_MOUNT_MAP_SPECIAL_CHR); | |
133 | if (rc != 0) | |
134 | return rc; | |
135 | ||
136 | if (file_info.EndOfFile != CIFS_MF_SYMLINK_FILE_SIZE) { | |
137 | CIFSSMBClose(xid, pTcon, netfid); | |
138 | /* it's not a symlink */ | |
139 | return 0; | |
140 | } | |
141 | ||
142 | buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL); | |
143 | if (!buf) | |
144 | return -ENOMEM; | |
145 | pbuf = buf; | |
146 | ||
147 | rc = CIFSSMBRead(xid, pTcon, netfid, | |
148 | CIFS_MF_SYMLINK_FILE_SIZE /* length */, | |
149 | 0 /* offset */, | |
150 | &bytes_read, &pbuf, &buf_type); | |
151 | CIFSSMBClose(xid, pTcon, netfid); | |
152 | if (rc != 0) { | |
153 | kfree(buf); | |
154 | return rc; | |
155 | } | |
156 | ||
157 | rc = CIFSParseMFSymlink(buf, bytes_read, &link_len, NULL); | |
158 | kfree(buf); | |
159 | if (rc == -EINVAL) | |
160 | /* it's not a symlink */ | |
161 | return 0; | |
162 | if (rc != 0) | |
163 | return rc; | |
164 | ||
165 | /* it is a symlink */ | |
166 | fattr->cf_eof = link_len; | |
167 | fattr->cf_mode &= ~S_IFMT; | |
168 | fattr->cf_mode |= S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO; | |
169 | fattr->cf_dtype = DT_LNK; | |
170 | return 0; | |
171 | } | |
172 | ||
1da177e4 LT |
173 | int |
174 | cifs_hardlink(struct dentry *old_file, struct inode *inode, | |
175 | struct dentry *direntry) | |
176 | { | |
177 | int rc = -EACCES; | |
178 | int xid; | |
179 | char *fromName = NULL; | |
180 | char *toName = NULL; | |
181 | struct cifs_sb_info *cifs_sb_target; | |
182 | struct cifsTconInfo *pTcon; | |
183 | struct cifsInodeInfo *cifsInode; | |
184 | ||
185 | xid = GetXid(); | |
186 | ||
187 | cifs_sb_target = CIFS_SB(inode->i_sb); | |
188 | pTcon = cifs_sb_target->tcon; | |
189 | ||
190 | /* No need to check for cross device links since server will do that | |
191 | BB note DFS case in future though (when we may have to check) */ | |
192 | ||
7f57356b SF |
193 | fromName = build_path_from_dentry(old_file); |
194 | toName = build_path_from_dentry(direntry); | |
fb8c4b14 | 195 | if ((fromName == NULL) || (toName == NULL)) { |
1da177e4 LT |
196 | rc = -ENOMEM; |
197 | goto cifs_hl_exit; | |
198 | } | |
199 | ||
c18c842b SF |
200 | /* if (cifs_sb_target->tcon->ses->capabilities & CAP_UNIX)*/ |
201 | if (pTcon->unix_ext) | |
1da177e4 | 202 | rc = CIFSUnixCreateHardLink(xid, pTcon, fromName, toName, |
fb8c4b14 | 203 | cifs_sb_target->local_nls, |
737b758c SF |
204 | cifs_sb_target->mnt_cifs_flags & |
205 | CIFS_MOUNT_MAP_SPECIAL_CHR); | |
1da177e4 LT |
206 | else { |
207 | rc = CIFSCreateHardLink(xid, pTcon, fromName, toName, | |
fb8c4b14 | 208 | cifs_sb_target->local_nls, |
737b758c SF |
209 | cifs_sb_target->mnt_cifs_flags & |
210 | CIFS_MOUNT_MAP_SPECIAL_CHR); | |
fb8c4b14 SF |
211 | if ((rc == -EIO) || (rc == -EINVAL)) |
212 | rc = -EOPNOTSUPP; | |
1da177e4 LT |
213 | } |
214 | ||
31ec35d6 SF |
215 | d_drop(direntry); /* force new lookup from server of target */ |
216 | ||
217 | /* if source file is cached (oplocked) revalidate will not go to server | |
218 | until the file is closed or oplock broken so update nlinks locally */ | |
fb8c4b14 | 219 | if (old_file->d_inode) { |
31ec35d6 | 220 | cifsInode = CIFS_I(old_file->d_inode); |
fb8c4b14 | 221 | if (rc == 0) { |
31ec35d6 | 222 | old_file->d_inode->i_nlink++; |
1b2b2126 SF |
223 | /* BB should we make this contingent on superblock flag NOATIME? */ |
224 | /* old_file->d_inode->i_ctime = CURRENT_TIME;*/ | |
31ec35d6 SF |
225 | /* parent dir timestamps will update from srv |
226 | within a second, would it really be worth it | |
227 | to set the parent dir cifs inode time to zero | |
228 | to force revalidate (faster) for it too? */ | |
229 | } | |
fb8c4b14 | 230 | /* if not oplocked will force revalidate to get info |
31ec35d6 SF |
231 | on source file from srv */ |
232 | cifsInode->time = 0; | |
233 | ||
fb8c4b14 | 234 | /* Will update parent dir timestamps from srv within a second. |
31ec35d6 SF |
235 | Would it really be worth it to set the parent dir (cifs |
236 | inode) time field to zero to force revalidate on parent | |
fb8c4b14 | 237 | directory faster ie |
31ec35d6 | 238 | CIFS_I(inode)->time = 0; */ |
1da177e4 | 239 | } |
1da177e4 LT |
240 | |
241 | cifs_hl_exit: | |
f99d49ad JJ |
242 | kfree(fromName); |
243 | kfree(toName); | |
1da177e4 LT |
244 | FreeXid(xid); |
245 | return rc; | |
246 | } | |
247 | ||
cc314eef | 248 | void * |
1da177e4 LT |
249 | cifs_follow_link(struct dentry *direntry, struct nameidata *nd) |
250 | { | |
251 | struct inode *inode = direntry->d_inode; | |
8b6427a2 | 252 | int rc = -ENOMEM; |
1da177e4 LT |
253 | int xid; |
254 | char *full_path = NULL; | |
8b6427a2 JL |
255 | char *target_path = NULL; |
256 | struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb); | |
257 | struct cifsTconInfo *tcon = cifs_sb->tcon; | |
1da177e4 LT |
258 | |
259 | xid = GetXid(); | |
260 | ||
8b6427a2 JL |
261 | /* |
262 | * For now, we just handle symlinks with unix extensions enabled. | |
263 | * Eventually we should handle NTFS reparse points, and MacOS | |
264 | * symlink support. For instance... | |
265 | * | |
266 | * rc = CIFSSMBQueryReparseLinkInfo(...) | |
267 | * | |
268 | * For now, just return -EACCES when the server doesn't support posix | |
269 | * extensions. Note that we still allow querying symlinks when posix | |
270 | * extensions are manually disabled. We could disable these as well | |
271 | * but there doesn't seem to be any harm in allowing the client to | |
272 | * read them. | |
273 | */ | |
274 | if (!(tcon->ses->capabilities & CAP_UNIX)) { | |
275 | rc = -EACCES; | |
276 | goto out; | |
277 | } | |
1da177e4 | 278 | |
8b6427a2 | 279 | full_path = build_path_from_dentry(direntry); |
1da177e4 | 280 | if (!full_path) |
460b9696 | 281 | goto out; |
1da177e4 | 282 | |
b6b38f70 | 283 | cFYI(1, "Full path: %s inode = 0x%p", full_path, inode); |
1da177e4 | 284 | |
8b6427a2 JL |
285 | rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path, |
286 | cifs_sb->local_nls); | |
287 | kfree(full_path); | |
288 | out: | |
460b9696 | 289 | if (rc != 0) { |
1da177e4 LT |
290 | kfree(target_path); |
291 | target_path = ERR_PTR(rc); | |
292 | } | |
293 | ||
1da177e4 LT |
294 | FreeXid(xid); |
295 | nd_set_link(nd, target_path); | |
460b9696 | 296 | return NULL; |
1da177e4 LT |
297 | } |
298 | ||
299 | int | |
300 | cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname) | |
301 | { | |
302 | int rc = -EOPNOTSUPP; | |
303 | int xid; | |
304 | struct cifs_sb_info *cifs_sb; | |
305 | struct cifsTconInfo *pTcon; | |
306 | char *full_path = NULL; | |
307 | struct inode *newinode = NULL; | |
308 | ||
309 | xid = GetXid(); | |
310 | ||
311 | cifs_sb = CIFS_SB(inode->i_sb); | |
312 | pTcon = cifs_sb->tcon; | |
313 | ||
7f57356b | 314 | full_path = build_path_from_dentry(direntry); |
1da177e4 | 315 | |
fb8c4b14 | 316 | if (full_path == NULL) { |
0f3bc09e | 317 | rc = -ENOMEM; |
1da177e4 | 318 | FreeXid(xid); |
0f3bc09e | 319 | return rc; |
1da177e4 LT |
320 | } |
321 | ||
b6b38f70 JP |
322 | cFYI(1, "Full path: %s", full_path); |
323 | cFYI(1, "symname is %s", symname); | |
1da177e4 LT |
324 | |
325 | /* BB what if DFS and this volume is on different share? BB */ | |
c18c842b | 326 | if (pTcon->unix_ext) |
1da177e4 LT |
327 | rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname, |
328 | cifs_sb->local_nls); | |
329 | /* else | |
fb8c4b14 SF |
330 | rc = CIFSCreateReparseSymLink(xid, pTcon, fromName, toName, |
331 | cifs_sb_target->local_nls); */ | |
1da177e4 LT |
332 | |
333 | if (rc == 0) { | |
c18c842b | 334 | if (pTcon->unix_ext) |
1da177e4 | 335 | rc = cifs_get_inode_info_unix(&newinode, full_path, |
fb8c4b14 | 336 | inode->i_sb, xid); |
1da177e4 LT |
337 | else |
338 | rc = cifs_get_inode_info(&newinode, full_path, NULL, | |
8b1327f6 | 339 | inode->i_sb, xid, NULL); |
1da177e4 LT |
340 | |
341 | if (rc != 0) { | |
b6b38f70 JP |
342 | cFYI(1, "Create symlink ok, getinodeinfo fail rc = %d", |
343 | rc); | |
1da177e4 | 344 | } else { |
b92327fe SF |
345 | if (pTcon->nocase) |
346 | direntry->d_op = &cifs_ci_dentry_ops; | |
347 | else | |
348 | direntry->d_op = &cifs_dentry_ops; | |
1da177e4 LT |
349 | d_instantiate(direntry, newinode); |
350 | } | |
351 | } | |
352 | ||
f99d49ad | 353 | kfree(full_path); |
1da177e4 LT |
354 | FreeXid(xid); |
355 | return rc; | |
356 | } | |
357 | ||
cc314eef | 358 | void cifs_put_link(struct dentry *direntry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
359 | { |
360 | char *p = nd_get_link(nd); | |
361 | if (!IS_ERR(p)) | |
362 | kfree(p); | |
363 | } |