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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> | |
18 | #include <linux/vfs.h> | |
19 | #include <linux/fs.h> | |
20 | #include "cifsglob.h" | |
21 | #include "cifsproto.h" | |
22 | #include "cifsfs.h" | |
23 | #include "dns_resolve.h" | |
24 | #include "cifs_debug.h" | |
25 | ||
8d142137 | 26 | static LIST_HEAD(cifs_dfs_automount_list); |
6d5ae0de | 27 | |
78d31a3a IM |
28 | static void cifs_dfs_expire_automounts(struct work_struct *work); |
29 | static DECLARE_DELAYED_WORK(cifs_dfs_automount_task, | |
30 | cifs_dfs_expire_automounts); | |
31 | static int cifs_dfs_mountpoint_expiry_timeout = 500 * HZ; | |
32 | ||
33 | static void cifs_dfs_expire_automounts(struct work_struct *work) | |
34 | { | |
35 | struct list_head *list = &cifs_dfs_automount_list; | |
36 | ||
37 | mark_mounts_for_expiry(list); | |
38 | if (!list_empty(list)) | |
39 | schedule_delayed_work(&cifs_dfs_automount_task, | |
40 | cifs_dfs_mountpoint_expiry_timeout); | |
41 | } | |
6d5ae0de | 42 | |
78d31a3a | 43 | void cifs_dfs_release_automount_timer(void) |
6d5ae0de | 44 | { |
78d31a3a IM |
45 | BUG_ON(!list_empty(&cifs_dfs_automount_list)); |
46 | cancel_delayed_work(&cifs_dfs_automount_task); | |
47 | flush_scheduled_work(); | |
6d5ae0de IM |
48 | } |
49 | ||
50 | /** | |
51 | * cifs_get_share_name - extracts share name from UNC | |
52 | * @node_name: pointer to UNC string | |
53 | * | |
54 | * Extracts sharename form full UNC. | |
55 | * i.e. strips from UNC trailing path that is not part of share | |
56 | * name and fixup missing '\' in the begining of DFS node refferal | |
57 | * if neccessary. | |
58 | * Returns pointer to share name on success or NULL on error. | |
59 | * Caller is responsible for freeing returned string. | |
60 | */ | |
61 | static char *cifs_get_share_name(const char *node_name) | |
62 | { | |
63 | int len; | |
64 | char *UNC; | |
65 | char *pSep; | |
66 | ||
67 | len = strlen(node_name); | |
68 | UNC = kmalloc(len+2 /*for term null and additional \ if it's missed */, | |
69 | GFP_KERNEL); | |
70 | if (!UNC) | |
71 | return NULL; | |
72 | ||
73 | /* get share name and server name */ | |
74 | if (node_name[1] != '\\') { | |
75 | UNC[0] = '\\'; | |
76 | strncpy(UNC+1, node_name, len); | |
77 | len++; | |
78 | UNC[len] = 0; | |
79 | } else { | |
80 | strncpy(UNC, node_name, len); | |
81 | UNC[len] = 0; | |
82 | } | |
83 | ||
84 | /* find server name end */ | |
85 | pSep = memchr(UNC+2, '\\', len-2); | |
86 | if (!pSep) { | |
87 | cERROR(1, ("%s: no server name end in node name: %s", | |
55f78e17 | 88 | __func__, node_name)); |
6d5ae0de IM |
89 | kfree(UNC); |
90 | return NULL; | |
91 | } | |
92 | ||
93 | /* find sharename end */ | |
94 | pSep++; | |
95 | pSep = memchr(UNC+(pSep-UNC), '\\', len-(pSep-UNC)); | |
bf62fd88 IM |
96 | if (pSep) { |
97 | /* trim path up to sharename end | |
98 | * now we have share name in UNC */ | |
99 | *pSep = 0; | |
6d5ae0de | 100 | } |
6d5ae0de IM |
101 | |
102 | return UNC; | |
103 | } | |
104 | ||
105 | ||
106 | /** | |
c6c00919 | 107 | * cifs_compose_mount_options - creates mount options for refferral |
6d5ae0de | 108 | * @sb_mountdata: parent/root DFS mount options (template) |
c6c00919 | 109 | * @fullpath: full path in UNC format |
2c55608f | 110 | * @ref: server's referral |
6d5ae0de IM |
111 | * @devname: pointer for saving device name |
112 | * | |
113 | * creates mount options for submount based on template options sb_mountdata | |
114 | * and replacing unc,ip,prefixpath options with ones we've got form ref_unc. | |
115 | * | |
116 | * Returns: pointer to new mount options or ERR_PTR. | |
117 | * Caller is responcible for freeing retunrned value if it is not error. | |
118 | */ | |
c6c00919 SF |
119 | char *cifs_compose_mount_options(const char *sb_mountdata, |
120 | const char *fullpath, | |
2c55608f | 121 | const struct dfs_info3_param *ref, |
366781c1 | 122 | char **devname) |
6d5ae0de IM |
123 | { |
124 | int rc; | |
c6fbba05 | 125 | char *mountdata = NULL; |
6d5ae0de IM |
126 | int md_len; |
127 | char *tkn_e; | |
128 | char *srvIP = NULL; | |
129 | char sep = ','; | |
130 | int off, noff; | |
131 | ||
132 | if (sb_mountdata == NULL) | |
133 | return ERR_PTR(-EINVAL); | |
134 | ||
2c55608f | 135 | *devname = cifs_get_share_name(ref->node_name); |
6d5ae0de IM |
136 | rc = dns_resolve_server_name_to_ip(*devname, &srvIP); |
137 | if (rc != 0) { | |
c6fbba05 SF |
138 | cERROR(1, ("%s: Failed to resolve server part of %s to IP: %d", |
139 | __func__, *devname, rc));; | |
140 | goto compose_mount_options_err; | |
6d5ae0de | 141 | } |
2c55608f IM |
142 | /* md_len = strlen(...) + 12 for 'sep+prefixpath=' |
143 | * assuming that we have 'unc=' and 'ip=' in | |
144 | * the original sb_mountdata | |
145 | */ | |
146 | md_len = strlen(sb_mountdata) + strlen(srvIP) + | |
147 | strlen(ref->node_name) + 12; | |
6d5ae0de IM |
148 | mountdata = kzalloc(md_len+1, GFP_KERNEL); |
149 | if (mountdata == NULL) { | |
c6fbba05 SF |
150 | rc = -ENOMEM; |
151 | goto compose_mount_options_err; | |
6d5ae0de IM |
152 | } |
153 | ||
154 | /* copy all options except of unc,ip,prefixpath */ | |
155 | off = 0; | |
156 | if (strncmp(sb_mountdata, "sep=", 4) == 0) { | |
157 | sep = sb_mountdata[4]; | |
158 | strncpy(mountdata, sb_mountdata, 5); | |
159 | off += 5; | |
160 | } | |
2c55608f IM |
161 | |
162 | do { | |
163 | tkn_e = strchr(sb_mountdata + off, sep); | |
164 | if (tkn_e == NULL) | |
165 | noff = strlen(sb_mountdata + off); | |
166 | else | |
167 | noff = tkn_e - (sb_mountdata + off) + 1; | |
168 | ||
169 | if (strnicmp(sb_mountdata + off, "unc=", 4) == 0) { | |
6d5ae0de IM |
170 | off += noff; |
171 | continue; | |
172 | } | |
2c55608f | 173 | if (strnicmp(sb_mountdata + off, "ip=", 3) == 0) { |
6d5ae0de IM |
174 | off += noff; |
175 | continue; | |
176 | } | |
2c55608f | 177 | if (strnicmp(sb_mountdata + off, "prefixpath=", 11) == 0) { |
6d5ae0de IM |
178 | off += noff; |
179 | continue; | |
180 | } | |
2c55608f | 181 | strncat(mountdata, sb_mountdata + off, noff); |
6d5ae0de | 182 | off += noff; |
2c55608f IM |
183 | } while (tkn_e); |
184 | strcat(mountdata, sb_mountdata + off); | |
6d5ae0de IM |
185 | mountdata[md_len] = '\0'; |
186 | ||
187 | /* copy new IP and ref share name */ | |
2c55608f IM |
188 | if (mountdata[strlen(mountdata) - 1] != sep) |
189 | strncat(mountdata, &sep, 1); | |
190 | strcat(mountdata, "ip="); | |
6d5ae0de | 191 | strcat(mountdata, srvIP); |
2c55608f IM |
192 | strncat(mountdata, &sep, 1); |
193 | strcat(mountdata, "unc="); | |
6d5ae0de IM |
194 | strcat(mountdata, *devname); |
195 | ||
196 | /* find & copy prefixpath */ | |
2c55608f | 197 | tkn_e = strchr(ref->node_name + 2, '\\'); |
c6fbba05 SF |
198 | if (tkn_e == NULL) { |
199 | /* invalid unc, missing share name*/ | |
200 | rc = -EINVAL; | |
201 | goto compose_mount_options_err; | |
202 | } | |
2c55608f | 203 | |
2c55608f | 204 | tkn_e = strchr(tkn_e + 1, '\\'); |
c6fbba05 | 205 | if (tkn_e || (strlen(fullpath) - ref->path_consumed)) { |
2c55608f IM |
206 | strncat(mountdata, &sep, 1); |
207 | strcat(mountdata, "prefixpath="); | |
208 | if (tkn_e) | |
209 | strcat(mountdata, tkn_e + 1); | |
c6fbba05 | 210 | strcat(mountdata, fullpath + ref->path_consumed); |
6d5ae0de IM |
211 | } |
212 | ||
55f78e17 HH |
213 | /*cFYI(1,("%s: parent mountdata: %s", __func__,sb_mountdata));*/ |
214 | /*cFYI(1, ("%s: submount mountdata: %s", __func__, mountdata ));*/ | |
6d5ae0de IM |
215 | |
216 | compose_mount_options_out: | |
217 | kfree(srvIP); | |
218 | return mountdata; | |
c6fbba05 SF |
219 | |
220 | compose_mount_options_err: | |
221 | kfree(mountdata); | |
222 | mountdata = ERR_PTR(rc); | |
223 | goto compose_mount_options_out; | |
6d5ae0de IM |
224 | } |
225 | ||
226 | ||
366781c1 | 227 | static struct vfsmount *cifs_dfs_do_refmount(const struct vfsmount *mnt_parent, |
2c55608f | 228 | struct dentry *dentry, const struct dfs_info3_param *ref) |
6d5ae0de IM |
229 | { |
230 | struct cifs_sb_info *cifs_sb; | |
231 | struct vfsmount *mnt; | |
232 | char *mountdata; | |
366781c1 | 233 | char *devname = NULL; |
c6c00919 | 234 | char *fullpath; |
6d5ae0de IM |
235 | |
236 | cifs_sb = CIFS_SB(dentry->d_inode->i_sb); | |
c6c00919 SF |
237 | /* |
238 | * this function gives us a path with a double backslash prefix. We | |
239 | * require a single backslash for DFS. | |
240 | */ | |
241 | fullpath = build_path_from_dentry(dentry); | |
242 | if (!fullpath) | |
243 | return ERR_PTR(-ENOMEM); | |
244 | ||
245 | mountdata = cifs_compose_mount_options(cifs_sb->mountdata, | |
246 | fullpath + 1, ref, &devname); | |
247 | kfree(fullpath); | |
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); | |
8d66bf54 | 266 | err = do_add_mount(newmnt, &nd->path, nd->path.mnt->mnt_flags, 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 JB |
277 | while (d_mountpoint(nd->path.dentry) && |
278 | follow_down(&nd->path.mnt, &nd->path.dentry)) | |
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 IM |
289 | { |
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, | |
8aad018b | 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 | ||
55f78e17 | 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); | |
319 | ses = cifs_sb->tcon->ses; | |
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++) { | |
343 | dump_referral(referrals+i); | |
1af28ceb IM |
344 | /* connect to a node */ |
345 | int len; | |
346 | len = strlen(referrals[i].node_name); | |
347 | if (len < 2) { | |
348 | cERROR(1, ("%s: Net Address path too short: %s", | |
55f78e17 | 349 | __func__, referrals[i].node_name)); |
1af28ceb IM |
350 | rc = -EINVAL; |
351 | goto out_err; | |
352 | } | |
353 | mnt = cifs_dfs_do_refmount(nd->path.mnt, | |
354 | nd->path.dentry, referrals + i); | |
355 | cFYI(1, ("%s: cifs_dfs_do_refmount:%s , mnt:%p", __func__, | |
6d5ae0de IM |
356 | referrals[i].node_name, mnt)); |
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 | ||
4ac91378 | 368 | nd->path.mnt->mnt_flags |= MNT_SHRINKABLE; |
6d5ae0de IM |
369 | rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list); |
370 | ||
371 | out: | |
372 | FreeXid(xid); | |
373 | free_dfs_info_array(referrals, num_referrals); | |
374 | kfree(full_path); | |
55f78e17 | 375 | cFYI(1, ("leaving %s" , __func__)); |
6d5ae0de IM |
376 | return ERR_PTR(rc); |
377 | out_err: | |
1d957f9b | 378 | path_put(&nd->path); |
6d5ae0de IM |
379 | goto out; |
380 | } | |
381 | ||
382 | struct inode_operations cifs_dfs_referral_inode_operations = { | |
383 | .follow_link = cifs_dfs_follow_mountpoint, | |
384 | }; | |
385 |