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Commit | Line | Data |
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6d5ae0de IM |
1 | /* |
2 | * Contains the CIFS DFS referral mounting routines used for handling | |
3 | * traversal via DFS junction point | |
4 | * | |
5 | * Copyright (c) 2007 Igor Mammedov | |
366781c1 | 6 | * Copyright (C) International Business Machines Corp., 2008 |
6d5ae0de | 7 | * Author(s): Igor Mammedov (niallain@gmail.com) |
366781c1 | 8 | * Steve French (sfrench@us.ibm.com) |
6d5ae0de IM |
9 | * This program is free software; you can redistribute it and/or |
10 | * modify it under the terms of the GNU General Public License | |
11 | * as published by the Free Software Foundation; either version | |
12 | * 2 of the License, or (at your option) any later version. | |
13 | */ | |
14 | ||
15 | #include <linux/dcache.h> | |
16 | #include <linux/mount.h> | |
17 | #include <linux/namei.h> | |
5a0e3ad6 | 18 | #include <linux/slab.h> |
6d5ae0de IM |
19 | #include <linux/vfs.h> |
20 | #include <linux/fs.h> | |
21 | #include "cifsglob.h" | |
22 | #include "cifsproto.h" | |
23 | #include "cifsfs.h" | |
24 | #include "dns_resolve.h" | |
25 | #include "cifs_debug.h" | |
26 | ||
8d142137 | 27 | static LIST_HEAD(cifs_dfs_automount_list); |
6d5ae0de | 28 | |
78d31a3a IM |
29 | static void cifs_dfs_expire_automounts(struct work_struct *work); |
30 | static DECLARE_DELAYED_WORK(cifs_dfs_automount_task, | |
31 | cifs_dfs_expire_automounts); | |
32 | static int cifs_dfs_mountpoint_expiry_timeout = 500 * HZ; | |
33 | ||
34 | static void cifs_dfs_expire_automounts(struct work_struct *work) | |
35 | { | |
36 | struct list_head *list = &cifs_dfs_automount_list; | |
37 | ||
38 | mark_mounts_for_expiry(list); | |
39 | if (!list_empty(list)) | |
40 | schedule_delayed_work(&cifs_dfs_automount_task, | |
41 | cifs_dfs_mountpoint_expiry_timeout); | |
42 | } | |
6d5ae0de | 43 | |
78d31a3a | 44 | void cifs_dfs_release_automount_timer(void) |
6d5ae0de | 45 | { |
78d31a3a IM |
46 | BUG_ON(!list_empty(&cifs_dfs_automount_list)); |
47 | cancel_delayed_work(&cifs_dfs_automount_task); | |
48 | flush_scheduled_work(); | |
6d5ae0de IM |
49 | } |
50 | ||
51 | /** | |
52 | * cifs_get_share_name - extracts share name from UNC | |
53 | * @node_name: pointer to UNC string | |
54 | * | |
55 | * Extracts sharename form full UNC. | |
56 | * i.e. strips from UNC trailing path that is not part of share | |
57 | * name and fixup missing '\' in the begining of DFS node refferal | |
3ad2f3fb | 58 | * if necessary. |
7b91e266 | 59 | * Returns pointer to share name on success or ERR_PTR on error. |
6d5ae0de IM |
60 | * Caller is responsible for freeing returned string. |
61 | */ | |
62 | static char *cifs_get_share_name(const char *node_name) | |
63 | { | |
64 | int len; | |
65 | char *UNC; | |
66 | char *pSep; | |
67 | ||
68 | len = strlen(node_name); | |
69 | UNC = kmalloc(len+2 /*for term null and additional \ if it's missed */, | |
70 | GFP_KERNEL); | |
71 | if (!UNC) | |
7b91e266 | 72 | return ERR_PTR(-ENOMEM); |
6d5ae0de IM |
73 | |
74 | /* get share name and server name */ | |
75 | if (node_name[1] != '\\') { | |
76 | UNC[0] = '\\'; | |
77 | strncpy(UNC+1, node_name, len); | |
78 | len++; | |
79 | UNC[len] = 0; | |
80 | } else { | |
81 | strncpy(UNC, node_name, len); | |
82 | UNC[len] = 0; | |
83 | } | |
84 | ||
85 | /* find server name end */ | |
86 | pSep = memchr(UNC+2, '\\', len-2); | |
87 | if (!pSep) { | |
b6b38f70 JP |
88 | cERROR(1, "%s: no server name end in node name: %s", |
89 | __func__, node_name); | |
6d5ae0de | 90 | kfree(UNC); |
7b91e266 | 91 | return ERR_PTR(-EINVAL); |
6d5ae0de IM |
92 | } |
93 | ||
94 | /* find sharename end */ | |
95 | pSep++; | |
96 | pSep = memchr(UNC+(pSep-UNC), '\\', len-(pSep-UNC)); | |
bf62fd88 IM |
97 | if (pSep) { |
98 | /* trim path up to sharename end | |
99 | * now we have share name in UNC */ | |
100 | *pSep = 0; | |
6d5ae0de | 101 | } |
6d5ae0de IM |
102 | |
103 | return UNC; | |
104 | } | |
105 | ||
106 | ||
107 | /** | |
c6c00919 | 108 | * cifs_compose_mount_options - creates mount options for refferral |
6d5ae0de | 109 | * @sb_mountdata: parent/root DFS mount options (template) |
c6c00919 | 110 | * @fullpath: full path in UNC format |
2c55608f | 111 | * @ref: server's referral |
6d5ae0de IM |
112 | * @devname: pointer for saving device name |
113 | * | |
114 | * creates mount options for submount based on template options sb_mountdata | |
115 | * and replacing unc,ip,prefixpath options with ones we've got form ref_unc. | |
116 | * | |
117 | * Returns: pointer to new mount options or ERR_PTR. | |
118 | * Caller is responcible for freeing retunrned value if it is not error. | |
119 | */ | |
c6c00919 SF |
120 | char *cifs_compose_mount_options(const char *sb_mountdata, |
121 | const char *fullpath, | |
2c55608f | 122 | const struct dfs_info3_param *ref, |
366781c1 | 123 | char **devname) |
6d5ae0de IM |
124 | { |
125 | int rc; | |
c6fbba05 | 126 | char *mountdata = NULL; |
6d5ae0de IM |
127 | int md_len; |
128 | char *tkn_e; | |
129 | char *srvIP = NULL; | |
130 | char sep = ','; | |
131 | int off, noff; | |
132 | ||
133 | if (sb_mountdata == NULL) | |
134 | return ERR_PTR(-EINVAL); | |
135 | ||
2c55608f | 136 | *devname = cifs_get_share_name(ref->node_name); |
7b91e266 JL |
137 | if (IS_ERR(*devname)) { |
138 | rc = PTR_ERR(*devname); | |
139 | *devname = NULL; | |
140 | goto compose_mount_options_err; | |
141 | } | |
142 | ||
6d5ae0de | 143 | rc = dns_resolve_server_name_to_ip(*devname, &srvIP); |
67b7626a | 144 | if (rc < 0) { |
b6b38f70 JP |
145 | cERROR(1, "%s: Failed to resolve server part of %s to IP: %d", |
146 | __func__, *devname, rc); | |
c6fbba05 | 147 | goto compose_mount_options_err; |
6d5ae0de | 148 | } |
2c55608f IM |
149 | /* md_len = strlen(...) + 12 for 'sep+prefixpath=' |
150 | * assuming that we have 'unc=' and 'ip=' in | |
151 | * the original sb_mountdata | |
152 | */ | |
67b7626a | 153 | md_len = strlen(sb_mountdata) + rc + strlen(ref->node_name) + 12; |
6d5ae0de IM |
154 | mountdata = kzalloc(md_len+1, GFP_KERNEL); |
155 | if (mountdata == NULL) { | |
c6fbba05 SF |
156 | rc = -ENOMEM; |
157 | goto compose_mount_options_err; | |
6d5ae0de IM |
158 | } |
159 | ||
160 | /* copy all options except of unc,ip,prefixpath */ | |
161 | off = 0; | |
162 | if (strncmp(sb_mountdata, "sep=", 4) == 0) { | |
163 | sep = sb_mountdata[4]; | |
164 | strncpy(mountdata, sb_mountdata, 5); | |
165 | off += 5; | |
166 | } | |
2c55608f IM |
167 | |
168 | do { | |
169 | tkn_e = strchr(sb_mountdata + off, sep); | |
170 | if (tkn_e == NULL) | |
171 | noff = strlen(sb_mountdata + off); | |
172 | else | |
173 | noff = tkn_e - (sb_mountdata + off) + 1; | |
174 | ||
175 | if (strnicmp(sb_mountdata + off, "unc=", 4) == 0) { | |
6d5ae0de IM |
176 | off += noff; |
177 | continue; | |
178 | } | |
2c55608f | 179 | if (strnicmp(sb_mountdata + off, "ip=", 3) == 0) { |
6d5ae0de IM |
180 | off += noff; |
181 | continue; | |
182 | } | |
2c55608f | 183 | if (strnicmp(sb_mountdata + off, "prefixpath=", 11) == 0) { |
6d5ae0de IM |
184 | off += noff; |
185 | continue; | |
186 | } | |
2c55608f | 187 | strncat(mountdata, sb_mountdata + off, noff); |
6d5ae0de | 188 | off += noff; |
2c55608f IM |
189 | } while (tkn_e); |
190 | strcat(mountdata, sb_mountdata + off); | |
6d5ae0de IM |
191 | mountdata[md_len] = '\0'; |
192 | ||
193 | /* copy new IP and ref share name */ | |
2c55608f IM |
194 | if (mountdata[strlen(mountdata) - 1] != sep) |
195 | strncat(mountdata, &sep, 1); | |
196 | strcat(mountdata, "ip="); | |
6d5ae0de | 197 | strcat(mountdata, srvIP); |
2c55608f IM |
198 | strncat(mountdata, &sep, 1); |
199 | strcat(mountdata, "unc="); | |
6d5ae0de IM |
200 | strcat(mountdata, *devname); |
201 | ||
202 | /* find & copy prefixpath */ | |
2c55608f | 203 | tkn_e = strchr(ref->node_name + 2, '\\'); |
c6fbba05 SF |
204 | if (tkn_e == NULL) { |
205 | /* invalid unc, missing share name*/ | |
206 | rc = -EINVAL; | |
207 | goto compose_mount_options_err; | |
208 | } | |
2c55608f | 209 | |
2c55608f | 210 | tkn_e = strchr(tkn_e + 1, '\\'); |
c6fbba05 | 211 | if (tkn_e || (strlen(fullpath) - ref->path_consumed)) { |
2c55608f IM |
212 | strncat(mountdata, &sep, 1); |
213 | strcat(mountdata, "prefixpath="); | |
214 | if (tkn_e) | |
215 | strcat(mountdata, tkn_e + 1); | |
c6fbba05 | 216 | strcat(mountdata, fullpath + ref->path_consumed); |
6d5ae0de IM |
217 | } |
218 | ||
b6b38f70 JP |
219 | /*cFYI(1, "%s: parent mountdata: %s", __func__,sb_mountdata);*/ |
220 | /*cFYI(1, "%s: submount mountdata: %s", __func__, mountdata );*/ | |
6d5ae0de IM |
221 | |
222 | compose_mount_options_out: | |
223 | kfree(srvIP); | |
224 | return mountdata; | |
c6fbba05 SF |
225 | |
226 | compose_mount_options_err: | |
227 | kfree(mountdata); | |
228 | mountdata = ERR_PTR(rc); | |
229 | goto compose_mount_options_out; | |
6d5ae0de IM |
230 | } |
231 | ||
f67909cf SF |
232 | /** |
233 | * cifs_dfs_do_refmount - mounts specified path using provided refferal | |
234 | * @cifs_sb: parent/root superblock | |
235 | * @fullpath: full path in UNC format | |
236 | * @ref: server's referral | |
237 | */ | |
238 | static struct vfsmount *cifs_dfs_do_refmount(struct cifs_sb_info *cifs_sb, | |
239 | const char *fullpath, const struct dfs_info3_param *ref) | |
6d5ae0de | 240 | { |
6d5ae0de IM |
241 | struct vfsmount *mnt; |
242 | char *mountdata; | |
366781c1 | 243 | char *devname = NULL; |
c6c00919 | 244 | |
f67909cf | 245 | /* strip first '\' from fullpath */ |
c6c00919 SF |
246 | mountdata = cifs_compose_mount_options(cifs_sb->mountdata, |
247 | fullpath + 1, ref, &devname); | |
6d5ae0de IM |
248 | |
249 | if (IS_ERR(mountdata)) | |
250 | return (struct vfsmount *)mountdata; | |
251 | ||
252 | mnt = vfs_kern_mount(&cifs_fs_type, 0, devname, mountdata); | |
253 | kfree(mountdata); | |
254 | kfree(devname); | |
255 | return mnt; | |
256 | ||
257 | } | |
258 | ||
6d5ae0de IM |
259 | static int add_mount_helper(struct vfsmount *newmnt, struct nameidata *nd, |
260 | struct list_head *mntlist) | |
261 | { | |
262 | /* stolen from afs code */ | |
263 | int err; | |
264 | ||
265 | mntget(newmnt); | |
7e1295d9 | 266 | err = do_add_mount(newmnt, &nd->path, nd->path.mnt->mnt_flags | MNT_SHRINKABLE, mntlist); |
6d5ae0de IM |
267 | switch (err) { |
268 | case 0: | |
78d31a3a | 269 | path_put(&nd->path); |
4ac91378 JB |
270 | nd->path.mnt = newmnt; |
271 | nd->path.dentry = dget(newmnt->mnt_root); | |
78d31a3a IM |
272 | schedule_delayed_work(&cifs_dfs_automount_task, |
273 | cifs_dfs_mountpoint_expiry_timeout); | |
6d5ae0de IM |
274 | break; |
275 | case -EBUSY: | |
276 | /* someone else made a mount here whilst we were busy */ | |
4ac91378 | 277 | while (d_mountpoint(nd->path.dentry) && |
9393bd07 | 278 | follow_down(&nd->path)) |
6d5ae0de IM |
279 | ; |
280 | err = 0; | |
281 | default: | |
282 | mntput(newmnt); | |
283 | break; | |
284 | } | |
285 | return err; | |
286 | } | |
287 | ||
366781c1 | 288 | static void dump_referral(const struct dfs_info3_param *ref) |
6d5ae0de | 289 | { |
b6b38f70 JP |
290 | cFYI(1, "DFS: ref path: %s", ref->path_name); |
291 | cFYI(1, "DFS: node path: %s", ref->node_name); | |
292 | cFYI(1, "DFS: fl: %hd, srv_type: %hd", ref->flags, ref->server_type); | |
293 | cFYI(1, "DFS: ref_flags: %hd, path_consumed: %hd", ref->ref_flag, | |
294 | ref->path_consumed); | |
6d5ae0de IM |
295 | } |
296 | ||
297 | ||
298 | static void* | |
299 | cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd) | |
300 | { | |
301 | struct dfs_info3_param *referrals = NULL; | |
302 | unsigned int num_referrals = 0; | |
303 | struct cifs_sb_info *cifs_sb; | |
304 | struct cifsSesInfo *ses; | |
305 | char *full_path = NULL; | |
306 | int xid, i; | |
307 | int rc = 0; | |
308 | struct vfsmount *mnt = ERR_PTR(-ENOENT); | |
309 | ||
b6b38f70 | 310 | cFYI(1, "in %s", __func__); |
6d5ae0de IM |
311 | BUG_ON(IS_ROOT(dentry)); |
312 | ||
313 | xid = GetXid(); | |
314 | ||
4ac91378 JB |
315 | dput(nd->path.dentry); |
316 | nd->path.dentry = dget(dentry); | |
6d5ae0de IM |
317 | |
318 | cifs_sb = CIFS_SB(dentry->d_inode->i_sb); | |
a6e8a845 | 319 | ses = cifs_sb_tcon(cifs_sb)->ses; |
6d5ae0de IM |
320 | |
321 | if (!ses) { | |
322 | rc = -EINVAL; | |
323 | goto out_err; | |
324 | } | |
325 | ||
c6fbba05 SF |
326 | /* |
327 | * The MSDFS spec states that paths in DFS referral requests and | |
328 | * responses must be prefixed by a single '\' character instead of | |
329 | * the double backslashes usually used in the UNC. This function | |
330 | * gives us the latter, so we must adjust the result. | |
331 | */ | |
de2db8d7 | 332 | full_path = build_path_from_dentry(dentry); |
6d5ae0de IM |
333 | if (full_path == NULL) { |
334 | rc = -ENOMEM; | |
335 | goto out_err; | |
336 | } | |
337 | ||
c6fbba05 | 338 | rc = get_dfs_path(xid, ses , full_path + 1, cifs_sb->local_nls, |
6d5ae0de IM |
339 | &num_referrals, &referrals, |
340 | cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR); | |
341 | ||
342 | for (i = 0; i < num_referrals; i++) { | |
cf398e3a | 343 | int len; |
6d5ae0de | 344 | dump_referral(referrals+i); |
1af28ceb | 345 | /* connect to a node */ |
1af28ceb IM |
346 | len = strlen(referrals[i].node_name); |
347 | if (len < 2) { | |
b6b38f70 JP |
348 | cERROR(1, "%s: Net Address path too short: %s", |
349 | __func__, referrals[i].node_name); | |
1af28ceb IM |
350 | rc = -EINVAL; |
351 | goto out_err; | |
352 | } | |
f67909cf SF |
353 | mnt = cifs_dfs_do_refmount(cifs_sb, |
354 | full_path, referrals + i); | |
b6b38f70 JP |
355 | cFYI(1, "%s: cifs_dfs_do_refmount:%s , mnt:%p", __func__, |
356 | referrals[i].node_name, mnt); | |
6d5ae0de | 357 | |
1af28ceb IM |
358 | /* complete mount procedure if we accured submount */ |
359 | if (!IS_ERR(mnt)) | |
360 | break; | |
6d5ae0de IM |
361 | } |
362 | ||
363 | /* we need it cause for() above could exit without valid submount */ | |
364 | rc = PTR_ERR(mnt); | |
365 | if (IS_ERR(mnt)) | |
366 | goto out_err; | |
367 | ||
6d5ae0de IM |
368 | rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list); |
369 | ||
370 | out: | |
371 | FreeXid(xid); | |
372 | free_dfs_info_array(referrals, num_referrals); | |
373 | kfree(full_path); | |
b6b38f70 | 374 | cFYI(1, "leaving %s" , __func__); |
6d5ae0de IM |
375 | return ERR_PTR(rc); |
376 | out_err: | |
1d957f9b | 377 | path_put(&nd->path); |
6d5ae0de IM |
378 | goto out; |
379 | } | |
380 | ||
6e1d5dcc | 381 | const struct inode_operations cifs_dfs_referral_inode_operations = { |
6d5ae0de IM |
382 | .follow_link = cifs_dfs_follow_mountpoint, |
383 | }; | |
384 |