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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> | |
166faf21 | 21 | #include <linux/inet.h> |
6d5ae0de IM |
22 | #include "cifsglob.h" |
23 | #include "cifsproto.h" | |
24 | #include "cifsfs.h" | |
25 | #include "dns_resolve.h" | |
26 | #include "cifs_debug.h" | |
27 | ||
8d142137 | 28 | static LIST_HEAD(cifs_dfs_automount_list); |
6d5ae0de | 29 | |
78d31a3a IM |
30 | static void cifs_dfs_expire_automounts(struct work_struct *work); |
31 | static DECLARE_DELAYED_WORK(cifs_dfs_automount_task, | |
32 | cifs_dfs_expire_automounts); | |
33 | static int cifs_dfs_mountpoint_expiry_timeout = 500 * HZ; | |
34 | ||
35 | static void cifs_dfs_expire_automounts(struct work_struct *work) | |
36 | { | |
37 | struct list_head *list = &cifs_dfs_automount_list; | |
38 | ||
39 | mark_mounts_for_expiry(list); | |
40 | if (!list_empty(list)) | |
41 | schedule_delayed_work(&cifs_dfs_automount_task, | |
42 | cifs_dfs_mountpoint_expiry_timeout); | |
43 | } | |
6d5ae0de | 44 | |
78d31a3a | 45 | void cifs_dfs_release_automount_timer(void) |
6d5ae0de | 46 | { |
78d31a3a | 47 | BUG_ON(!list_empty(&cifs_dfs_automount_list)); |
3e24e132 | 48 | cancel_delayed_work_sync(&cifs_dfs_automount_task); |
6d5ae0de IM |
49 | } |
50 | ||
51 | /** | |
d9deef0a JL |
52 | * cifs_build_devname - build a devicename from a UNC and optional prepath |
53 | * @nodename: pointer to UNC string | |
54 | * @prepath: pointer to prefixpath (or NULL if there isn't one) | |
6d5ae0de | 55 | * |
d9deef0a JL |
56 | * Build a new cifs devicename after chasing a DFS referral. Allocate a buffer |
57 | * big enough to hold the final thing. Copy the UNC from the nodename, and | |
58 | * concatenate the prepath onto the end of it if there is one. | |
59 | * | |
60 | * Returns pointer to the built string, or a ERR_PTR. Caller is responsible | |
61 | * for freeing the returned string. | |
6d5ae0de | 62 | */ |
d9deef0a JL |
63 | static char * |
64 | cifs_build_devname(char *nodename, const char *prepath) | |
6d5ae0de | 65 | { |
d9deef0a JL |
66 | size_t pplen; |
67 | size_t unclen; | |
68 | char *dev; | |
69 | char *pos; | |
6d5ae0de | 70 | |
d9deef0a JL |
71 | /* skip over any preceding delimiters */ |
72 | nodename += strspn(nodename, "\\"); | |
73 | if (!*nodename) | |
7b91e266 | 74 | return ERR_PTR(-EINVAL); |
d9deef0a JL |
75 | |
76 | /* get length of UNC and set pos to last char */ | |
77 | unclen = strlen(nodename); | |
78 | pos = nodename + unclen - 1; | |
79 | ||
80 | /* trim off any trailing delimiters */ | |
81 | while (*pos == '\\') { | |
82 | --pos; | |
83 | --unclen; | |
6d5ae0de IM |
84 | } |
85 | ||
d9deef0a JL |
86 | /* allocate a buffer: |
87 | * +2 for preceding "//" | |
88 | * +1 for delimiter between UNC and prepath | |
89 | * +1 for trailing NULL | |
90 | */ | |
91 | pplen = prepath ? strlen(prepath) : 0; | |
92 | dev = kmalloc(2 + unclen + 1 + pplen + 1, GFP_KERNEL); | |
93 | if (!dev) | |
94 | return ERR_PTR(-ENOMEM); | |
95 | ||
96 | pos = dev; | |
97 | /* add the initial "//" */ | |
98 | *pos = '/'; | |
99 | ++pos; | |
100 | *pos = '/'; | |
101 | ++pos; | |
102 | ||
103 | /* copy in the UNC portion from referral */ | |
104 | memcpy(pos, nodename, unclen); | |
105 | pos += unclen; | |
106 | ||
107 | /* copy the prefixpath remainder (if there is one) */ | |
108 | if (pplen) { | |
109 | *pos = '/'; | |
110 | ++pos; | |
111 | memcpy(pos, prepath, pplen); | |
112 | pos += pplen; | |
6d5ae0de | 113 | } |
6d5ae0de | 114 | |
d9deef0a JL |
115 | /* NULL terminator */ |
116 | *pos = '\0'; | |
117 | ||
118 | convert_delimiter(dev, '/'); | |
119 | return dev; | |
6d5ae0de IM |
120 | } |
121 | ||
122 | ||
123 | /** | |
c6c00919 | 124 | * cifs_compose_mount_options - creates mount options for refferral |
6d5ae0de | 125 | * @sb_mountdata: parent/root DFS mount options (template) |
c6c00919 | 126 | * @fullpath: full path in UNC format |
2c55608f | 127 | * @ref: server's referral |
6d5ae0de IM |
128 | * @devname: pointer for saving device name |
129 | * | |
130 | * creates mount options for submount based on template options sb_mountdata | |
131 | * and replacing unc,ip,prefixpath options with ones we've got form ref_unc. | |
132 | * | |
133 | * Returns: pointer to new mount options or ERR_PTR. | |
134 | * Caller is responcible for freeing retunrned value if it is not error. | |
135 | */ | |
c6c00919 SF |
136 | char *cifs_compose_mount_options(const char *sb_mountdata, |
137 | const char *fullpath, | |
2c55608f | 138 | const struct dfs_info3_param *ref, |
366781c1 | 139 | char **devname) |
6d5ae0de IM |
140 | { |
141 | int rc; | |
c6fbba05 | 142 | char *mountdata = NULL; |
d9deef0a | 143 | const char *prepath = NULL; |
6d5ae0de IM |
144 | int md_len; |
145 | char *tkn_e; | |
146 | char *srvIP = NULL; | |
147 | char sep = ','; | |
148 | int off, noff; | |
149 | ||
150 | if (sb_mountdata == NULL) | |
151 | return ERR_PTR(-EINVAL); | |
152 | ||
d9deef0a JL |
153 | if (strlen(fullpath) - ref->path_consumed) |
154 | prepath = fullpath + ref->path_consumed; | |
155 | ||
156 | *devname = cifs_build_devname(ref->node_name, prepath); | |
7b91e266 JL |
157 | if (IS_ERR(*devname)) { |
158 | rc = PTR_ERR(*devname); | |
159 | *devname = NULL; | |
160 | goto compose_mount_options_err; | |
161 | } | |
162 | ||
6d5ae0de | 163 | rc = dns_resolve_server_name_to_ip(*devname, &srvIP); |
67b7626a | 164 | if (rc < 0) { |
f96637be JP |
165 | cifs_dbg(FYI, "%s: Failed to resolve server part of %s to IP: %d\n", |
166 | __func__, *devname, rc); | |
c6fbba05 | 167 | goto compose_mount_options_err; |
6d5ae0de | 168 | } |
b8028983 | 169 | |
d9deef0a JL |
170 | /* |
171 | * In most cases, we'll be building a shorter string than the original, | |
172 | * but we do have to assume that the address in the ip= option may be | |
173 | * much longer than the original. Add the max length of an address | |
174 | * string to the length of the original string to allow for worst case. | |
2c55608f | 175 | */ |
d9deef0a JL |
176 | md_len = strlen(sb_mountdata) + INET6_ADDRSTRLEN; |
177 | mountdata = kzalloc(md_len + 1, GFP_KERNEL); | |
6d5ae0de | 178 | if (mountdata == NULL) { |
c6fbba05 SF |
179 | rc = -ENOMEM; |
180 | goto compose_mount_options_err; | |
6d5ae0de IM |
181 | } |
182 | ||
183 | /* copy all options except of unc,ip,prefixpath */ | |
184 | off = 0; | |
185 | if (strncmp(sb_mountdata, "sep=", 4) == 0) { | |
186 | sep = sb_mountdata[4]; | |
187 | strncpy(mountdata, sb_mountdata, 5); | |
188 | off += 5; | |
189 | } | |
2c55608f IM |
190 | |
191 | do { | |
192 | tkn_e = strchr(sb_mountdata + off, sep); | |
193 | if (tkn_e == NULL) | |
194 | noff = strlen(sb_mountdata + off); | |
195 | else | |
196 | noff = tkn_e - (sb_mountdata + off) + 1; | |
197 | ||
198 | if (strnicmp(sb_mountdata + off, "unc=", 4) == 0) { | |
6d5ae0de IM |
199 | off += noff; |
200 | continue; | |
201 | } | |
2c55608f | 202 | if (strnicmp(sb_mountdata + off, "ip=", 3) == 0) { |
6d5ae0de IM |
203 | off += noff; |
204 | continue; | |
205 | } | |
2c55608f | 206 | if (strnicmp(sb_mountdata + off, "prefixpath=", 11) == 0) { |
6d5ae0de IM |
207 | off += noff; |
208 | continue; | |
209 | } | |
2c55608f | 210 | strncat(mountdata, sb_mountdata + off, noff); |
6d5ae0de | 211 | off += noff; |
2c55608f IM |
212 | } while (tkn_e); |
213 | strcat(mountdata, sb_mountdata + off); | |
6d5ae0de IM |
214 | mountdata[md_len] = '\0'; |
215 | ||
216 | /* copy new IP and ref share name */ | |
2c55608f IM |
217 | if (mountdata[strlen(mountdata) - 1] != sep) |
218 | strncat(mountdata, &sep, 1); | |
219 | strcat(mountdata, "ip="); | |
6d5ae0de | 220 | strcat(mountdata, srvIP); |
6d5ae0de | 221 | |
f96637be JP |
222 | /*cifs_dbg(FYI, "%s: parent mountdata: %s\n", __func__, sb_mountdata);*/ |
223 | /*cifs_dbg(FYI, "%s: submount mountdata: %s\n", __func__, mountdata );*/ | |
6d5ae0de IM |
224 | |
225 | compose_mount_options_out: | |
226 | kfree(srvIP); | |
227 | return mountdata; | |
c6fbba05 SF |
228 | |
229 | compose_mount_options_err: | |
230 | kfree(mountdata); | |
231 | mountdata = ERR_PTR(rc); | |
10b8c7df CD |
232 | kfree(*devname); |
233 | *devname = NULL; | |
c6fbba05 | 234 | goto compose_mount_options_out; |
6d5ae0de IM |
235 | } |
236 | ||
f67909cf SF |
237 | /** |
238 | * cifs_dfs_do_refmount - mounts specified path using provided refferal | |
239 | * @cifs_sb: parent/root superblock | |
240 | * @fullpath: full path in UNC format | |
241 | * @ref: server's referral | |
242 | */ | |
243 | static struct vfsmount *cifs_dfs_do_refmount(struct cifs_sb_info *cifs_sb, | |
244 | const char *fullpath, const struct dfs_info3_param *ref) | |
6d5ae0de | 245 | { |
6d5ae0de IM |
246 | struct vfsmount *mnt; |
247 | char *mountdata; | |
366781c1 | 248 | char *devname = NULL; |
c6c00919 | 249 | |
f67909cf | 250 | /* strip first '\' from fullpath */ |
c6c00919 SF |
251 | mountdata = cifs_compose_mount_options(cifs_sb->mountdata, |
252 | fullpath + 1, ref, &devname); | |
6d5ae0de IM |
253 | |
254 | if (IS_ERR(mountdata)) | |
255 | return (struct vfsmount *)mountdata; | |
256 | ||
257 | mnt = vfs_kern_mount(&cifs_fs_type, 0, devname, mountdata); | |
258 | kfree(mountdata); | |
259 | kfree(devname); | |
260 | return mnt; | |
261 | ||
262 | } | |
263 | ||
366781c1 | 264 | static void dump_referral(const struct dfs_info3_param *ref) |
6d5ae0de | 265 | { |
f96637be JP |
266 | cifs_dbg(FYI, "DFS: ref path: %s\n", ref->path_name); |
267 | cifs_dbg(FYI, "DFS: node path: %s\n", ref->node_name); | |
268 | cifs_dbg(FYI, "DFS: fl: %hd, srv_type: %hd\n", | |
269 | ref->flags, ref->server_type); | |
270 | cifs_dbg(FYI, "DFS: ref_flags: %hd, path_consumed: %hd\n", | |
271 | ref->ref_flag, ref->path_consumed); | |
6d5ae0de IM |
272 | } |
273 | ||
01c64fea DH |
274 | /* |
275 | * Create a vfsmount that we can automount | |
276 | */ | |
277 | static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt) | |
6d5ae0de IM |
278 | { |
279 | struct dfs_info3_param *referrals = NULL; | |
280 | unsigned int num_referrals = 0; | |
281 | struct cifs_sb_info *cifs_sb; | |
96daf2b0 | 282 | struct cifs_ses *ses; |
01c64fea | 283 | char *full_path; |
6d5786a3 PS |
284 | unsigned int xid; |
285 | int i; | |
01c64fea DH |
286 | int rc; |
287 | struct vfsmount *mnt; | |
7ffec372 | 288 | struct tcon_link *tlink; |
6d5ae0de | 289 | |
f96637be | 290 | cifs_dbg(FYI, "in %s\n", __func__); |
01c64fea | 291 | BUG_ON(IS_ROOT(mntpt)); |
6d5ae0de | 292 | |
c6fbba05 SF |
293 | /* |
294 | * The MSDFS spec states that paths in DFS referral requests and | |
295 | * responses must be prefixed by a single '\' character instead of | |
296 | * the double backslashes usually used in the UNC. This function | |
297 | * gives us the latter, so we must adjust the result. | |
298 | */ | |
01c64fea DH |
299 | mnt = ERR_PTR(-ENOMEM); |
300 | full_path = build_path_from_dentry(mntpt); | |
301 | if (full_path == NULL) | |
31c2659d | 302 | goto cdda_exit; |
6d5ae0de | 303 | |
01c64fea | 304 | cifs_sb = CIFS_SB(mntpt->d_inode->i_sb); |
7ffec372 JL |
305 | tlink = cifs_sb_tlink(cifs_sb); |
306 | if (IS_ERR(tlink)) { | |
01c64fea DH |
307 | mnt = ERR_CAST(tlink); |
308 | goto free_full_path; | |
7ffec372 JL |
309 | } |
310 | ses = tlink_tcon(tlink)->ses; | |
311 | ||
6d5786a3 | 312 | xid = get_xid(); |
7ffec372 | 313 | rc = get_dfs_path(xid, ses, full_path + 1, cifs_sb->local_nls, |
6d5ae0de IM |
314 | &num_referrals, &referrals, |
315 | cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR); | |
6d5786a3 | 316 | free_xid(xid); |
6d5ae0de | 317 | |
7ffec372 JL |
318 | cifs_put_tlink(tlink); |
319 | ||
01c64fea | 320 | mnt = ERR_PTR(-ENOENT); |
6d5ae0de | 321 | for (i = 0; i < num_referrals; i++) { |
cf398e3a | 322 | int len; |
01c64fea | 323 | dump_referral(referrals + i); |
1af28ceb | 324 | /* connect to a node */ |
1af28ceb IM |
325 | len = strlen(referrals[i].node_name); |
326 | if (len < 2) { | |
f96637be JP |
327 | cifs_dbg(VFS, "%s: Net Address path too short: %s\n", |
328 | __func__, referrals[i].node_name); | |
01c64fea DH |
329 | mnt = ERR_PTR(-EINVAL); |
330 | break; | |
1af28ceb | 331 | } |
f67909cf SF |
332 | mnt = cifs_dfs_do_refmount(cifs_sb, |
333 | full_path, referrals + i); | |
f96637be JP |
334 | cifs_dbg(FYI, "%s: cifs_dfs_do_refmount:%s , mnt:%p\n", |
335 | __func__, referrals[i].node_name, mnt); | |
1af28ceb | 336 | if (!IS_ERR(mnt)) |
01c64fea | 337 | goto success; |
6d5ae0de IM |
338 | } |
339 | ||
01c64fea DH |
340 | /* no valid submounts were found; return error from get_dfs_path() by |
341 | * preference */ | |
342 | if (rc != 0) | |
343 | mnt = ERR_PTR(rc); | |
6d5ae0de | 344 | |
01c64fea | 345 | success: |
6d5ae0de | 346 | free_dfs_info_array(referrals, num_referrals); |
01c64fea | 347 | free_full_path: |
6d5ae0de | 348 | kfree(full_path); |
31c2659d | 349 | cdda_exit: |
f96637be | 350 | cifs_dbg(FYI, "leaving %s\n" , __func__); |
01c64fea DH |
351 | return mnt; |
352 | } | |
353 | ||
354 | /* | |
355 | * Attempt to automount the referral | |
356 | */ | |
357 | struct vfsmount *cifs_dfs_d_automount(struct path *path) | |
358 | { | |
359 | struct vfsmount *newmnt; | |
01c64fea | 360 | |
f96637be | 361 | cifs_dbg(FYI, "in %s\n", __func__); |
01c64fea DH |
362 | |
363 | newmnt = cifs_dfs_do_automount(path->dentry); | |
364 | if (IS_ERR(newmnt)) { | |
f96637be | 365 | cifs_dbg(FYI, "leaving %s [automount failed]\n" , __func__); |
01c64fea DH |
366 | return newmnt; |
367 | } | |
368 | ||
ea5b778a DH |
369 | mntget(newmnt); /* prevent immediate expiration */ |
370 | mnt_set_expiry(newmnt, &cifs_dfs_automount_list); | |
371 | schedule_delayed_work(&cifs_dfs_automount_task, | |
372 | cifs_dfs_mountpoint_expiry_timeout); | |
f96637be | 373 | cifs_dbg(FYI, "leaving %s [ok]\n" , __func__); |
ea5b778a | 374 | return newmnt; |
6d5ae0de IM |
375 | } |
376 | ||
6e1d5dcc | 377 | const struct inode_operations cifs_dfs_referral_inode_operations = { |
6d5ae0de | 378 | }; |