blob: 58df174deb10e5b354a9003ea3ccbfc5240e5cd0 [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>
Jeff Layton166faf22013-05-24 07:40:04 -040021#include <linux/inet.h>
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000022#include "cifsglob.h"
23#include "cifsproto.h"
24#include "cifsfs.h"
25#include "dns_resolve.h"
26#include "cifs_debug.h"
27
Steve French8d142132008-04-16 03:56:51 +000028static LIST_HEAD(cifs_dfs_automount_list);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000029
Igor Mammedov78d31a32008-04-24 12:56:07 +040030static void cifs_dfs_expire_automounts(struct work_struct *work);
31static DECLARE_DELAYED_WORK(cifs_dfs_automount_task,
32 cifs_dfs_expire_automounts);
33static int cifs_dfs_mountpoint_expiry_timeout = 500 * HZ;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000034
Igor Mammedov78d31a32008-04-24 12:56:07 +040035static void cifs_dfs_expire_automounts(struct work_struct *work)
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000036{
Igor Mammedov78d31a32008-04-24 12:56:07 +040037 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}
44
45void cifs_dfs_release_automount_timer(void)
46{
47 BUG_ON(!list_empty(&cifs_dfs_automount_list));
Tejun Heo3e24e132010-10-19 17:55:54 +020048 cancel_delayed_work_sync(&cifs_dfs_automount_task);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000049}
50
51/**
Jeff Laytond9deef02013-05-24 07:40:06 -040052 * 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)
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000055 *
Jeff Laytond9deef02013-05-24 07:40:06 -040056 * 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.
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000062 */
Jeff Laytond9deef02013-05-24 07:40:06 -040063static char *
64cifs_build_devname(char *nodename, const char *prepath)
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000065{
Jeff Laytond9deef02013-05-24 07:40:06 -040066 size_t pplen;
67 size_t unclen;
68 char *dev;
69 char *pos;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000070
Jeff Laytond9deef02013-05-24 07:40:06 -040071 /* skip over any preceding delimiters */
72 nodename += strspn(nodename, "\\");
73 if (!*nodename)
74 return ERR_PTR(-EINVAL);
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;
84 }
85
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)
Jeff Layton7b91e262009-07-23 15:22:30 -040094 return ERR_PTR(-ENOMEM);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +000095
Jeff Laytond9deef02013-05-24 07:40:06 -040096 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;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000113 }
114
Jeff Laytond9deef02013-05-24 07:40:06 -0400115 /* NULL terminator */
116 *pos = '\0';
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000117
Jeff Laytond9deef02013-05-24 07:40:06 -0400118 convert_delimiter(dev, '/');
119 return dev;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000120}
121
122
123/**
Steve Frenchc6c00912009-03-18 05:50:07 +0000124 * cifs_compose_mount_options - creates mount options for refferral
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000125 * @sb_mountdata: parent/root DFS mount options (template)
Steve Frenchc6c00912009-03-18 05:50:07 +0000126 * @fullpath: full path in UNC format
Igor Mammedov2c556082008-10-23 13:58:42 +0400127 * @ref: server's referral
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000128 * @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 */
Steve Frenchc6c00912009-03-18 05:50:07 +0000136char *cifs_compose_mount_options(const char *sb_mountdata,
137 const char *fullpath,
Igor Mammedov2c556082008-10-23 13:58:42 +0400138 const struct dfs_info3_param *ref,
Steve French366781c2008-01-25 10:12:41 +0000139 char **devname)
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000140{
141 int rc;
Steve Frenchc6fbba02008-12-18 01:41:20 +0000142 char *mountdata = NULL;
Jeff Laytond9deef02013-05-24 07:40:06 -0400143 const char *prepath = NULL;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000144 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
Jeff Laytond9deef02013-05-24 07:40:06 -0400153 if (strlen(fullpath) - ref->path_consumed)
154 prepath = fullpath + ref->path_consumed;
155
156 *devname = cifs_build_devname(ref->node_name, prepath);
Jeff Layton7b91e262009-07-23 15:22:30 -0400157 if (IS_ERR(*devname)) {
158 rc = PTR_ERR(*devname);
159 *devname = NULL;
160 goto compose_mount_options_err;
161 }
162
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000163 rc = dns_resolve_server_name_to_ip(*devname, &srvIP);
David Howells67b76262010-07-22 18:33:01 +0100164 if (rc < 0) {
Joe Perchesf96637b2013-05-04 22:12:25 -0500165 cifs_dbg(FYI, "%s: Failed to resolve server part of %s to IP: %d\n",
166 __func__, *devname, rc);
Steve Frenchc6fbba02008-12-18 01:41:20 +0000167 goto compose_mount_options_err;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000168 }
Jeff Laytonb8028982011-07-26 12:20:18 -0400169
Jeff Laytond9deef02013-05-24 07:40:06 -0400170 /*
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.
Igor Mammedov2c556082008-10-23 13:58:42 +0400175 */
Jeff Laytond9deef02013-05-24 07:40:06 -0400176 md_len = strlen(sb_mountdata) + INET6_ADDRSTRLEN;
177 mountdata = kzalloc(md_len + 1, GFP_KERNEL);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000178 if (mountdata == NULL) {
Steve Frenchc6fbba02008-12-18 01:41:20 +0000179 rc = -ENOMEM;
180 goto compose_mount_options_err;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000181 }
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 }
Igor Mammedov2c556082008-10-23 13:58:42 +0400190
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) {
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000199 off += noff;
200 continue;
201 }
Igor Mammedov2c556082008-10-23 13:58:42 +0400202 if (strnicmp(sb_mountdata + off, "ip=", 3) == 0) {
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000203 off += noff;
204 continue;
205 }
Igor Mammedov2c556082008-10-23 13:58:42 +0400206 if (strnicmp(sb_mountdata + off, "prefixpath=", 11) == 0) {
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000207 off += noff;
208 continue;
209 }
Igor Mammedov2c556082008-10-23 13:58:42 +0400210 strncat(mountdata, sb_mountdata + off, noff);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000211 off += noff;
Igor Mammedov2c556082008-10-23 13:58:42 +0400212 } while (tkn_e);
213 strcat(mountdata, sb_mountdata + off);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000214 mountdata[md_len] = '\0';
215
216 /* copy new IP and ref share name */
Igor Mammedov2c556082008-10-23 13:58:42 +0400217 if (mountdata[strlen(mountdata) - 1] != sep)
218 strncat(mountdata, &sep, 1);
219 strcat(mountdata, "ip=");
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000220 strcat(mountdata, srvIP);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000221
Joe Perchesf96637b2013-05-04 22:12:25 -0500222 /*cifs_dbg(FYI, "%s: parent mountdata: %s\n", __func__, sb_mountdata);*/
223 /*cifs_dbg(FYI, "%s: submount mountdata: %s\n", __func__, mountdata );*/
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000224
225compose_mount_options_out:
226 kfree(srvIP);
227 return mountdata;
Steve Frenchc6fbba02008-12-18 01:41:20 +0000228
229compose_mount_options_err:
230 kfree(mountdata);
231 mountdata = ERR_PTR(rc);
Cong Ding10b8c7d2013-01-22 19:20:58 -0500232 kfree(*devname);
233 *devname = NULL;
Steve Frenchc6fbba02008-12-18 01:41:20 +0000234 goto compose_mount_options_out;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000235}
236
Steve Frenchf67909c2010-07-26 18:20:16 +0000237/**
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 */
243static struct vfsmount *cifs_dfs_do_refmount(struct cifs_sb_info *cifs_sb,
244 const char *fullpath, const struct dfs_info3_param *ref)
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000245{
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000246 struct vfsmount *mnt;
247 char *mountdata;
Steve French366781c2008-01-25 10:12:41 +0000248 char *devname = NULL;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000249
Steve Frenchf67909c2010-07-26 18:20:16 +0000250 /* strip first '\' from fullpath */
Steve Frenchc6c00912009-03-18 05:50:07 +0000251 mountdata = cifs_compose_mount_options(cifs_sb->mountdata,
252 fullpath + 1, ref, &devname);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000253
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
Steve French366781c2008-01-25 10:12:41 +0000264static void dump_referral(const struct dfs_info3_param *ref)
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000265{
Joe Perchesf96637b2013-05-04 22:12:25 -0500266 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);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000272}
273
David Howells01c64fe2011-01-14 18:45:47 +0000274/*
275 * Create a vfsmount that we can automount
276 */
277static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt)
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000278{
279 struct dfs_info3_param *referrals = NULL;
280 unsigned int num_referrals = 0;
281 struct cifs_sb_info *cifs_sb;
Steve French96daf2b2011-05-27 04:34:02 +0000282 struct cifs_ses *ses;
David Howells01c64fe2011-01-14 18:45:47 +0000283 char *full_path;
Pavel Shilovsky6d5786a2012-06-20 11:21:16 +0400284 unsigned int xid;
285 int i;
David Howells01c64fe2011-01-14 18:45:47 +0000286 int rc;
287 struct vfsmount *mnt;
Jeff Layton7ffec372010-09-29 19:51:11 -0400288 struct tcon_link *tlink;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000289
Joe Perchesf96637b2013-05-04 22:12:25 -0500290 cifs_dbg(FYI, "in %s\n", __func__);
David Howells01c64fe2011-01-14 18:45:47 +0000291 BUG_ON(IS_ROOT(mntpt));
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000292
Steve Frenchc6fbba02008-12-18 01:41:20 +0000293 /*
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 */
David Howells01c64fe2011-01-14 18:45:47 +0000299 mnt = ERR_PTR(-ENOMEM);
300 full_path = build_path_from_dentry(mntpt);
301 if (full_path == NULL)
Jeff Layton31c26592011-01-31 07:24:46 -0500302 goto cdda_exit;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000303
David Howells01c64fe2011-01-14 18:45:47 +0000304 cifs_sb = CIFS_SB(mntpt->d_inode->i_sb);
Jeff Layton7ffec372010-09-29 19:51:11 -0400305 tlink = cifs_sb_tlink(cifs_sb);
306 if (IS_ERR(tlink)) {
David Howells01c64fe2011-01-14 18:45:47 +0000307 mnt = ERR_CAST(tlink);
308 goto free_full_path;
Jeff Layton7ffec372010-09-29 19:51:11 -0400309 }
310 ses = tlink_tcon(tlink)->ses;
311
Pavel Shilovsky6d5786a2012-06-20 11:21:16 +0400312 xid = get_xid();
Jeff Layton7ffec372010-09-29 19:51:11 -0400313 rc = get_dfs_path(xid, ses, full_path + 1, cifs_sb->local_nls,
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000314 &num_referrals, &referrals,
315 cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
Pavel Shilovsky6d5786a2012-06-20 11:21:16 +0400316 free_xid(xid);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000317
Jeff Layton7ffec372010-09-29 19:51:11 -0400318 cifs_put_tlink(tlink);
319
David Howells01c64fe2011-01-14 18:45:47 +0000320 mnt = ERR_PTR(-ENOENT);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000321 for (i = 0; i < num_referrals; i++) {
Steve Frenchcf398e32009-05-01 03:50:42 +0000322 int len;
David Howells01c64fe2011-01-14 18:45:47 +0000323 dump_referral(referrals + i);
Igor Mammedov1af28ce2009-03-17 19:00:30 +0300324 /* connect to a node */
Igor Mammedov1af28ce2009-03-17 19:00:30 +0300325 len = strlen(referrals[i].node_name);
326 if (len < 2) {
Joe Perchesf96637b2013-05-04 22:12:25 -0500327 cifs_dbg(VFS, "%s: Net Address path too short: %s\n",
328 __func__, referrals[i].node_name);
David Howells01c64fe2011-01-14 18:45:47 +0000329 mnt = ERR_PTR(-EINVAL);
330 break;
Igor Mammedov1af28ce2009-03-17 19:00:30 +0300331 }
Steve Frenchf67909c2010-07-26 18:20:16 +0000332 mnt = cifs_dfs_do_refmount(cifs_sb,
333 full_path, referrals + i);
Joe Perchesf96637b2013-05-04 22:12:25 -0500334 cifs_dbg(FYI, "%s: cifs_dfs_do_refmount:%s , mnt:%p\n",
335 __func__, referrals[i].node_name, mnt);
Igor Mammedov1af28ce2009-03-17 19:00:30 +0300336 if (!IS_ERR(mnt))
David Howells01c64fe2011-01-14 18:45:47 +0000337 goto success;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000338 }
339
David Howells01c64fe2011-01-14 18:45:47 +0000340 /* no valid submounts were found; return error from get_dfs_path() by
341 * preference */
342 if (rc != 0)
343 mnt = ERR_PTR(rc);
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000344
David Howells01c64fe2011-01-14 18:45:47 +0000345success:
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000346 free_dfs_info_array(referrals, num_referrals);
David Howells01c64fe2011-01-14 18:45:47 +0000347free_full_path:
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000348 kfree(full_path);
Jeff Layton31c26592011-01-31 07:24:46 -0500349cdda_exit:
Joe Perchesf96637b2013-05-04 22:12:25 -0500350 cifs_dbg(FYI, "leaving %s\n" , __func__);
David Howells01c64fe2011-01-14 18:45:47 +0000351 return mnt;
352}
353
354/*
355 * Attempt to automount the referral
356 */
357struct vfsmount *cifs_dfs_d_automount(struct path *path)
358{
359 struct vfsmount *newmnt;
David Howells01c64fe2011-01-14 18:45:47 +0000360
Joe Perchesf96637b2013-05-04 22:12:25 -0500361 cifs_dbg(FYI, "in %s\n", __func__);
David Howells01c64fe2011-01-14 18:45:47 +0000362
363 newmnt = cifs_dfs_do_automount(path->dentry);
364 if (IS_ERR(newmnt)) {
Joe Perchesf96637b2013-05-04 22:12:25 -0500365 cifs_dbg(FYI, "leaving %s [automount failed]\n" , __func__);
David Howells01c64fe2011-01-14 18:45:47 +0000366 return newmnt;
367 }
368
David Howellsea5b7782011-01-14 19:10:03 +0000369 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);
Joe Perchesf96637b2013-05-04 22:12:25 -0500373 cifs_dbg(FYI, "leaving %s [ok]\n" , __func__);
David Howellsea5b7782011-01-14 19:10:03 +0000374 return newmnt;
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000375}
376
Alexey Dobriyan6e1d5dc2009-09-21 17:01:11 -0700377const struct inode_operations cifs_dfs_referral_inode_operations = {
Igor Mammedov6d5ae0d2008-01-25 03:28:31 +0000378};