blob: 6873bb634a97652f36bc477b08044e164c749b30 [file] [log] [blame]
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +00001/*
2 * Contains the CIFS DFS referral mounting routines used for handling
3 * traversal via DFS junction point
4 *
5 * Copyright (c) 2007 Igor Mammedov
Steve French366781c2008-01-25 10:12:41 +00006 * Copyright (C) International Business Machines Corp., 2008
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +00007 * Author(s): Igor Mammedov (niallain@gmail.com)
Steve French366781c2008-01-25 10:12:41 +00008 * Steve French (sfrench@us.ibm.com)
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +00009 * 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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090018#include <linux/slab.h>
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000019#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
Steve French8d142132008-04-16 03:56:51 +000027static LIST_HEAD(cifs_dfs_automount_list);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000028
Igor Mammedov78d31a32008-04-24 12:56:07 +040029static void cifs_dfs_expire_automounts(struct work_struct *work);
30static DECLARE_DELAYED_WORK(cifs_dfs_automount_task,
31 cifs_dfs_expire_automounts);
32static int cifs_dfs_mountpoint_expiry_timeout = 500 * HZ;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000033
Igor Mammedov78d31a32008-04-24 12:56:07 +040034static void cifs_dfs_expire_automounts(struct work_struct *work)
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000035{
Igor Mammedov78d31a32008-04-24 12:56:07 +040036 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}
43
44void cifs_dfs_release_automount_timer(void)
45{
46 BUG_ON(!list_empty(&cifs_dfs_automount_list));
Tejun Heo3e24e132010-10-19 17:55:54 +020047 cancel_delayed_work_sync(&cifs_dfs_automount_task);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000048}
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
Lucas De Marchi25985ed2011-03-30 22:57:33 -030056 * name and fixup missing '\' in the beginning of DFS node refferal
Daniel Mack3ad2f3f2010-02-03 08:01:28 +080057 * if necessary.
Jeff Layton7b91e262009-07-23 15:22:30 -040058 * Returns pointer to share name on success or ERR_PTR on error.
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000059 * Caller is responsible for freeing returned string.
60 */
61static 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)
Jeff Layton7b91e262009-07-23 15:22:30 -040071 return ERR_PTR(-ENOMEM);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000072
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) {
Joe Perchesb6b38f72010-04-21 03:50:45 +000087 cERROR(1, "%s: no server name end in node name: %s",
88 __func__, node_name);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000089 kfree(UNC);
Jeff Layton7b91e262009-07-23 15:22:30 -040090 return ERR_PTR(-EINVAL);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000091 }
92
93 /* find sharename end */
94 pSep++;
95 pSep = memchr(UNC+(pSep-UNC), '\\', len-(pSep-UNC));
Igor Mammedovbf62fd82008-04-28 23:05:58 +000096 if (pSep) {
97 /* trim path up to sharename end
98 * now we have share name in UNC */
99 *pSep = 0;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000100 }
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000101
102 return UNC;
103}
104
105
106/**
Steve Frenchc6c00912009-03-18 05:50:07 +0000107 * cifs_compose_mount_options - creates mount options for refferral
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000108 * @sb_mountdata: parent/root DFS mount options (template)
Steve Frenchc6c00912009-03-18 05:50:07 +0000109 * @fullpath: full path in UNC format
Igor Mammedov2c556082008-10-23 13:58:42 +0400110 * @ref: server's referral
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000111 * @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 */
Steve Frenchc6c00912009-03-18 05:50:07 +0000119char *cifs_compose_mount_options(const char *sb_mountdata,
120 const char *fullpath,
Igor Mammedov2c556082008-10-23 13:58:42 +0400121 const struct dfs_info3_param *ref,
Steve French366781c2008-01-25 10:12:41 +0000122 char **devname)
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000123{
124 int rc;
Steve Frenchc6fbba02008-12-18 01:41:20 +0000125 char *mountdata = NULL;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000126 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
Igor Mammedov2c556082008-10-23 13:58:42 +0400135 *devname = cifs_get_share_name(ref->node_name);
Jeff Layton7b91e262009-07-23 15:22:30 -0400136 if (IS_ERR(*devname)) {
137 rc = PTR_ERR(*devname);
138 *devname = NULL;
139 goto compose_mount_options_err;
140 }
141
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000142 rc = dns_resolve_server_name_to_ip(*devname, &srvIP);
David Howells67b76262010-07-22 18:33:01 +0100143 if (rc < 0) {
Jeff Laytonb8028982011-07-26 12:20:18 -0400144 cFYI(1, "%s: Failed to resolve server part of %s to IP: %d",
145 __func__, *devname, rc);
Steve Frenchc6fbba02008-12-18 01:41:20 +0000146 goto compose_mount_options_err;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000147 }
Jeff Laytonb8028982011-07-26 12:20:18 -0400148
Igor Mammedov2c556082008-10-23 13:58:42 +0400149 /* md_len = strlen(...) + 12 for 'sep+prefixpath='
150 * assuming that we have 'unc=' and 'ip=' in
151 * the original sb_mountdata
152 */
David Howells67b76262010-07-22 18:33:01 +0100153 md_len = strlen(sb_mountdata) + rc + strlen(ref->node_name) + 12;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000154 mountdata = kzalloc(md_len+1, GFP_KERNEL);
155 if (mountdata == NULL) {
Steve Frenchc6fbba02008-12-18 01:41:20 +0000156 rc = -ENOMEM;
157 goto compose_mount_options_err;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000158 }
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 }
Igor Mammedov2c556082008-10-23 13:58:42 +0400167
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) {
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000176 off += noff;
177 continue;
178 }
Igor Mammedov2c556082008-10-23 13:58:42 +0400179 if (strnicmp(sb_mountdata + off, "ip=", 3) == 0) {
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000180 off += noff;
181 continue;
182 }
Igor Mammedov2c556082008-10-23 13:58:42 +0400183 if (strnicmp(sb_mountdata + off, "prefixpath=", 11) == 0) {
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000184 off += noff;
185 continue;
186 }
Igor Mammedov2c556082008-10-23 13:58:42 +0400187 strncat(mountdata, sb_mountdata + off, noff);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000188 off += noff;
Igor Mammedov2c556082008-10-23 13:58:42 +0400189 } while (tkn_e);
190 strcat(mountdata, sb_mountdata + off);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000191 mountdata[md_len] = '\0';
192
193 /* copy new IP and ref share name */
Igor Mammedov2c556082008-10-23 13:58:42 +0400194 if (mountdata[strlen(mountdata) - 1] != sep)
195 strncat(mountdata, &sep, 1);
196 strcat(mountdata, "ip=");
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000197 strcat(mountdata, srvIP);
Igor Mammedov2c556082008-10-23 13:58:42 +0400198 strncat(mountdata, &sep, 1);
199 strcat(mountdata, "unc=");
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000200 strcat(mountdata, *devname);
201
202 /* find & copy prefixpath */
Igor Mammedov2c556082008-10-23 13:58:42 +0400203 tkn_e = strchr(ref->node_name + 2, '\\');
Steve Frenchc6fbba02008-12-18 01:41:20 +0000204 if (tkn_e == NULL) {
205 /* invalid unc, missing share name*/
206 rc = -EINVAL;
207 goto compose_mount_options_err;
208 }
Igor Mammedov2c556082008-10-23 13:58:42 +0400209
Igor Mammedov2c556082008-10-23 13:58:42 +0400210 tkn_e = strchr(tkn_e + 1, '\\');
Steve Frenchc6fbba02008-12-18 01:41:20 +0000211 if (tkn_e || (strlen(fullpath) - ref->path_consumed)) {
Igor Mammedov2c556082008-10-23 13:58:42 +0400212 strncat(mountdata, &sep, 1);
213 strcat(mountdata, "prefixpath=");
214 if (tkn_e)
215 strcat(mountdata, tkn_e + 1);
Steve Frenchc6fbba02008-12-18 01:41:20 +0000216 strcat(mountdata, fullpath + ref->path_consumed);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000217 }
218
Joe Perchesb6b38f72010-04-21 03:50:45 +0000219 /*cFYI(1, "%s: parent mountdata: %s", __func__,sb_mountdata);*/
220 /*cFYI(1, "%s: submount mountdata: %s", __func__, mountdata );*/
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000221
222compose_mount_options_out:
223 kfree(srvIP);
224 return mountdata;
Steve Frenchc6fbba02008-12-18 01:41:20 +0000225
226compose_mount_options_err:
227 kfree(mountdata);
228 mountdata = ERR_PTR(rc);
229 goto compose_mount_options_out;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000230}
231
Steve Frenchf67909c2010-07-26 18:20:16 +0000232/**
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 */
238static struct vfsmount *cifs_dfs_do_refmount(struct cifs_sb_info *cifs_sb,
239 const char *fullpath, const struct dfs_info3_param *ref)
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000240{
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000241 struct vfsmount *mnt;
242 char *mountdata;
Steve French366781c2008-01-25 10:12:41 +0000243 char *devname = NULL;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000244
Steve Frenchf67909c2010-07-26 18:20:16 +0000245 /* strip first '\' from fullpath */
Steve Frenchc6c00912009-03-18 05:50:07 +0000246 mountdata = cifs_compose_mount_options(cifs_sb->mountdata,
247 fullpath + 1, ref, &devname);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000248
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
Steve French366781c2008-01-25 10:12:41 +0000259static void dump_referral(const struct dfs_info3_param *ref)
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000260{
Joe Perchesb6b38f72010-04-21 03:50:45 +0000261 cFYI(1, "DFS: ref path: %s", ref->path_name);
262 cFYI(1, "DFS: node path: %s", ref->node_name);
263 cFYI(1, "DFS: fl: %hd, srv_type: %hd", ref->flags, ref->server_type);
264 cFYI(1, "DFS: ref_flags: %hd, path_consumed: %hd", ref->ref_flag,
265 ref->path_consumed);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000266}
267
David Howells01c64fe2011-01-14 18:45:47 +0000268/*
269 * Create a vfsmount that we can automount
270 */
271static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt)
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000272{
273 struct dfs_info3_param *referrals = NULL;
274 unsigned int num_referrals = 0;
275 struct cifs_sb_info *cifs_sb;
Steve French96daf2b2011-05-27 04:34:02 +0000276 struct cifs_ses *ses;
David Howells01c64fe2011-01-14 18:45:47 +0000277 char *full_path;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000278 int xid, i;
David Howells01c64fe2011-01-14 18:45:47 +0000279 int rc;
280 struct vfsmount *mnt;
Jeff Layton7ffec372010-09-29 19:51:11 -0400281 struct tcon_link *tlink;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000282
Joe Perchesb6b38f72010-04-21 03:50:45 +0000283 cFYI(1, "in %s", __func__);
David Howells01c64fe2011-01-14 18:45:47 +0000284 BUG_ON(IS_ROOT(mntpt));
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000285
Steve Frenchc6fbba02008-12-18 01:41:20 +0000286 /*
287 * The MSDFS spec states that paths in DFS referral requests and
288 * responses must be prefixed by a single '\' character instead of
289 * the double backslashes usually used in the UNC. This function
290 * gives us the latter, so we must adjust the result.
291 */
David Howells01c64fe2011-01-14 18:45:47 +0000292 mnt = ERR_PTR(-ENOMEM);
293 full_path = build_path_from_dentry(mntpt);
294 if (full_path == NULL)
Jeff Layton31c26592011-01-31 07:24:46 -0500295 goto cdda_exit;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000296
David Howells01c64fe2011-01-14 18:45:47 +0000297 cifs_sb = CIFS_SB(mntpt->d_inode->i_sb);
Jeff Layton7ffec372010-09-29 19:51:11 -0400298 tlink = cifs_sb_tlink(cifs_sb);
299 if (IS_ERR(tlink)) {
David Howells01c64fe2011-01-14 18:45:47 +0000300 mnt = ERR_CAST(tlink);
301 goto free_full_path;
Jeff Layton7ffec372010-09-29 19:51:11 -0400302 }
303 ses = tlink_tcon(tlink)->ses;
304
Jeff Layton31c26592011-01-31 07:24:46 -0500305 xid = GetXid();
Jeff Layton7ffec372010-09-29 19:51:11 -0400306 rc = get_dfs_path(xid, ses, full_path + 1, cifs_sb->local_nls,
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000307 &num_referrals, &referrals,
308 cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
Jeff Layton31c26592011-01-31 07:24:46 -0500309 FreeXid(xid);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000310
Jeff Layton7ffec372010-09-29 19:51:11 -0400311 cifs_put_tlink(tlink);
312
David Howells01c64fe2011-01-14 18:45:47 +0000313 mnt = ERR_PTR(-ENOENT);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000314 for (i = 0; i < num_referrals; i++) {
Steve Frenchcf398e32009-05-01 03:50:42 +0000315 int len;
David Howells01c64fe2011-01-14 18:45:47 +0000316 dump_referral(referrals + i);
Igor Mammedov1af28ce2009-03-17 19:00:30 +0300317 /* connect to a node */
Igor Mammedov1af28ce2009-03-17 19:00:30 +0300318 len = strlen(referrals[i].node_name);
319 if (len < 2) {
Joe Perchesb6b38f72010-04-21 03:50:45 +0000320 cERROR(1, "%s: Net Address path too short: %s",
321 __func__, referrals[i].node_name);
David Howells01c64fe2011-01-14 18:45:47 +0000322 mnt = ERR_PTR(-EINVAL);
323 break;
Igor Mammedov1af28ce2009-03-17 19:00:30 +0300324 }
Steve Frenchf67909c2010-07-26 18:20:16 +0000325 mnt = cifs_dfs_do_refmount(cifs_sb,
326 full_path, referrals + i);
Joe Perchesb6b38f72010-04-21 03:50:45 +0000327 cFYI(1, "%s: cifs_dfs_do_refmount:%s , mnt:%p", __func__,
328 referrals[i].node_name, mnt);
Igor Mammedov1af28ce2009-03-17 19:00:30 +0300329 if (!IS_ERR(mnt))
David Howells01c64fe2011-01-14 18:45:47 +0000330 goto success;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000331 }
332
David Howells01c64fe2011-01-14 18:45:47 +0000333 /* no valid submounts were found; return error from get_dfs_path() by
334 * preference */
335 if (rc != 0)
336 mnt = ERR_PTR(rc);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000337
David Howells01c64fe2011-01-14 18:45:47 +0000338success:
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000339 free_dfs_info_array(referrals, num_referrals);
David Howells01c64fe2011-01-14 18:45:47 +0000340free_full_path:
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000341 kfree(full_path);
Jeff Layton31c26592011-01-31 07:24:46 -0500342cdda_exit:
Joe Perchesb6b38f72010-04-21 03:50:45 +0000343 cFYI(1, "leaving %s" , __func__);
David Howells01c64fe2011-01-14 18:45:47 +0000344 return mnt;
345}
346
347/*
348 * Attempt to automount the referral
349 */
350struct vfsmount *cifs_dfs_d_automount(struct path *path)
351{
352 struct vfsmount *newmnt;
David Howells01c64fe2011-01-14 18:45:47 +0000353
354 cFYI(1, "in %s", __func__);
355
356 newmnt = cifs_dfs_do_automount(path->dentry);
357 if (IS_ERR(newmnt)) {
358 cFYI(1, "leaving %s [automount failed]" , __func__);
359 return newmnt;
360 }
361
David Howellsea5b7782011-01-14 19:10:03 +0000362 mntget(newmnt); /* prevent immediate expiration */
363 mnt_set_expiry(newmnt, &cifs_dfs_automount_list);
364 schedule_delayed_work(&cifs_dfs_automount_task,
365 cifs_dfs_mountpoint_expiry_timeout);
366 cFYI(1, "leaving %s [ok]" , __func__);
367 return newmnt;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000368}
369
Alexey Dobriyan6e1d5dc2009-09-21 17:01:11 -0700370const struct inode_operations cifs_dfs_referral_inode_operations = {
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000371};