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[CIFS] Fix walking out end of cifs dacl
[mirror_ubuntu-artful-kernel.git] / fs / cifs / cifsacl.c
CommitLineData
bcb02034
SF
1/*
2 * fs/cifs/cifsacl.c
3 *
4 * Copyright (C) International Business Machines Corp., 2007
5 * Author(s): Steve French (sfrench@us.ibm.com)
6 *
7 * Contains the routines for mapping CIFS/NTFS ACLs
8 *
9 * This library is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU Lesser General Public License as published
11 * by the Free Software Foundation; either version 2.1 of the License, or
12 * (at your option) any later version.
13 *
14 * This library is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
17 * the GNU Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public License
20 * along with this library; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 */
23
65874007
SF
24#include <linux/fs.h>
25#include "cifspdu.h"
26#include "cifsglob.h"
d0d66c44 27#include "cifsacl.h"
65874007
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28#include "cifsproto.h"
29#include "cifs_debug.h"
65874007 30
297647c2
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31
32#ifdef CONFIG_CIFS_EXPERIMENTAL
33
af6f4612 34static struct cifs_wksid wksidarr[NUM_WK_SIDS] = {
297647c2
SF
35 {{1, 0, {0, 0, 0, 0, 0, 0}, {0, 0, 0, 0, 0} }, "null user"},
36 {{1, 1, {0, 0, 0, 0, 0, 1}, {0, 0, 0, 0, 0} }, "nobody"},
ce51ae14
DK
37 {{1, 1, {0, 0, 0, 0, 0, 5}, {cpu_to_le32(11), 0, 0, 0, 0} }, "net-users"},
38 {{1, 1, {0, 0, 0, 0, 0, 5}, {cpu_to_le32(18), 0, 0, 0, 0} }, "sys"},
39 {{1, 2, {0, 0, 0, 0, 0, 5}, {cpu_to_le32(32), cpu_to_le32(544), 0, 0, 0} }, "root"},
40 {{1, 2, {0, 0, 0, 0, 0, 5}, {cpu_to_le32(32), cpu_to_le32(545), 0, 0, 0} }, "users"},
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SF
41 {{1, 2, {0, 0, 0, 0, 0, 5}, {cpu_to_le32(32), cpu_to_le32(546), 0, 0, 0} }, "guest"} }
42;
297647c2
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43
44
bcb02034 45/* security id for everyone */
e01b6400
SP
46static const struct cifs_sid sid_everyone = {
47 1, 1, {0, 0, 0, 0, 0, 1}, {0} };
bcb02034
SF
48/* group users */
49static const struct cifs_sid sid_user =
d12fd121 50 {1, 2 , {0, 0, 0, 0, 0, 5}, {} };
d0d66c44 51
297647c2
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52
53int match_sid(struct cifs_sid *ctsid)
54{
55 int i, j;
56 int num_subauth, num_sat, num_saw;
57 struct cifs_sid *cwsid;
58
59 if (!ctsid)
60 return (-1);
61
62 for (i = 0; i < NUM_WK_SIDS; ++i) {
63 cwsid = &(wksidarr[i].cifssid);
64
65 /* compare the revision */
66 if (ctsid->revision != cwsid->revision)
67 continue;
68
69 /* compare all of the six auth values */
70 for (j = 0; j < 6; ++j) {
71 if (ctsid->authority[j] != cwsid->authority[j])
72 break;
73 }
74 if (j < 6)
75 continue; /* all of the auth values did not match */
76
77 /* compare all of the subauth values if any */
ce51ae14
DK
78 num_sat = ctsid->num_subauth;
79 num_saw = cwsid->num_subauth;
297647c2
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80 num_subauth = num_sat < num_saw ? num_sat : num_saw;
81 if (num_subauth) {
82 for (j = 0; j < num_subauth; ++j) {
83 if (ctsid->sub_auth[j] != cwsid->sub_auth[j])
84 break;
85 }
86 if (j < num_subauth)
87 continue; /* all sub_auth values do not match */
88 }
89
90 cFYI(1, ("matching sid: %s\n", wksidarr[i].sidname));
91 return (0); /* sids compare/match */
92 }
93
94 cFYI(1, ("No matching sid"));
95 return (-1);
96}
97
a750e77c
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98/* if the two SIDs (roughly equivalent to a UUID for a user or group) are
99 the same returns 1, if they do not match returns 0 */
630f3f0c 100int compare_sids(const struct cifs_sid *ctsid, const struct cifs_sid *cwsid)
297647c2
SF
101{
102 int i;
103 int num_subauth, num_sat, num_saw;
104
105 if ((!ctsid) || (!cwsid))
a750e77c 106 return (0);
297647c2
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107
108 /* compare the revision */
109 if (ctsid->revision != cwsid->revision)
a750e77c 110 return (0);
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111
112 /* compare all of the six auth values */
113 for (i = 0; i < 6; ++i) {
114 if (ctsid->authority[i] != cwsid->authority[i])
a750e77c 115 return (0);
297647c2
SF
116 }
117
118 /* compare all of the subauth values if any */
adbc0358 119 num_sat = ctsid->num_subauth;
adddd49d 120 num_saw = cwsid->num_subauth;
297647c2
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121 num_subauth = num_sat < num_saw ? num_sat : num_saw;
122 if (num_subauth) {
123 for (i = 0; i < num_subauth; ++i) {
124 if (ctsid->sub_auth[i] != cwsid->sub_auth[i])
a750e77c 125 return (0);
297647c2
SF
126 }
127 }
128
a750e77c 129 return (1); /* sids compare/match */
297647c2
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130}
131
630f3f0c
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132/*
133 change posix mode to reflect permissions
134 pmode is the existing mode (we only want to overwrite part of this
135 bits to set can be: S_IRWXU, S_IRWXG or S_IRWXO ie 00700 or 00070 or 00007
136*/
d61e5808 137static void access_flags_to_mode(__u32 ace_flags, umode_t *pmode,
630f3f0c
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138 umode_t bits_to_set)
139{
140
d61e5808
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141 if (ace_flags & GENERIC_ALL) {
142 *pmode |= (S_IRWXUGO & bits_to_set);
630f3f0c 143#ifdef CONFIG_CIFS_DEBUG2
d61e5808 144 cFYI(1, ("all perms"));
630f3f0c 145#endif
d61e5808
SF
146 return;
147 }
e01b6400
SP
148 if ((ace_flags & GENERIC_WRITE) ||
149 ((ace_flags & FILE_WRITE_RIGHTS) == FILE_WRITE_RIGHTS))
d61e5808 150 *pmode |= (S_IWUGO & bits_to_set);
e01b6400
SP
151 if ((ace_flags & GENERIC_READ) ||
152 ((ace_flags & FILE_READ_RIGHTS) == FILE_READ_RIGHTS))
d61e5808 153 *pmode |= (S_IRUGO & bits_to_set);
e01b6400
SP
154 if ((ace_flags & GENERIC_EXECUTE) ||
155 ((ace_flags & FILE_EXEC_RIGHTS) == FILE_EXEC_RIGHTS))
d61e5808 156 *pmode |= (S_IXUGO & bits_to_set);
630f3f0c 157
d61e5808 158#ifdef CONFIG_CIFS_DEBUG2
b9c7a2bb 159 cFYI(1, ("access flags 0x%x mode now 0x%x", ace_flags, *pmode));
d61e5808 160#endif
630f3f0c
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161 return;
162}
163
297647c2 164
953f8681
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165#ifdef CONFIG_CIFS_DEBUG2
166static void dump_ace(struct cifs_ace *pace, char *end_of_acl)
d0d66c44 167{
d0d66c44 168 int num_subauth;
d0d66c44
SP
169
170 /* validate that we do not go past end of acl */
297647c2 171
44093ca2
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172 if (le16_to_cpu(pace->size) < 16) {
173 cERROR(1, ("ACE too small, %d", le16_to_cpu(pace->size)));
174 return;
175 }
176
177 if (end_of_acl < (char *)pace + le16_to_cpu(pace->size)) {
d0d66c44
SP
178 cERROR(1, ("ACL too small to parse ACE"));
179 return;
44093ca2 180 }
d0d66c44 181
44093ca2 182 num_subauth = pace->sid.num_subauth;
d0d66c44 183 if (num_subauth) {
8f18c131 184 int i;
44093ca2
SF
185 cFYI(1, ("ACE revision %d num_auth %d type %d flags %d size %d",
186 pace->sid.revision, pace->sid.num_subauth, pace->type,
187 pace->flags, pace->size));
d12fd121
SF
188 for (i = 0; i < num_subauth; ++i) {
189 cFYI(1, ("ACE sub_auth[%d]: 0x%x", i,
44093ca2 190 le32_to_cpu(pace->sid.sub_auth[i])));
d12fd121
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191 }
192
193 /* BB add length check to make sure that we do not have huge
194 num auths and therefore go off the end */
d12fd121
SF
195 }
196
197 return;
198}
953f8681 199#endif
d12fd121 200
d0d66c44 201
a750e77c 202static void parse_dacl(struct cifs_acl *pdacl, char *end_of_acl,
d61e5808 203 struct cifs_sid *pownersid, struct cifs_sid *pgrpsid,
630f3f0c 204 struct inode *inode)
d0d66c44
SP
205{
206 int i;
207 int num_aces = 0;
208 int acl_size;
209 char *acl_base;
d0d66c44
SP
210 struct cifs_ace **ppace;
211
212 /* BB need to add parm so we can store the SID BB */
213
214 /* validate that we do not go past end of acl */
af6f4612 215 if (end_of_acl < (char *)pdacl + le16_to_cpu(pdacl->size)) {
d0d66c44
SP
216 cERROR(1, ("ACL too small to parse DACL"));
217 return;
218 }
219
220#ifdef CONFIG_CIFS_DEBUG2
221 cFYI(1, ("DACL revision %d size %d num aces %d",
af6f4612
SF
222 le16_to_cpu(pdacl->revision), le16_to_cpu(pdacl->size),
223 le32_to_cpu(pdacl->num_aces)));
d0d66c44
SP
224#endif
225
7505e052
SF
226 /* reset rwx permissions for user/group/other.
227 Also, if num_aces is 0 i.e. DACL has no ACEs,
228 user/group/other have no permissions */
229 inode->i_mode &= ~(S_IRWXUGO);
230
231 if (!pdacl) {
232 /* no DACL in the security descriptor, set
233 all the permissions for user/group/other */
234 inode->i_mode |= S_IRWXUGO;
235 return;
236 }
d0d66c44
SP
237 acl_base = (char *)pdacl;
238 acl_size = sizeof(struct cifs_acl);
239
adbc0358 240 num_aces = le32_to_cpu(pdacl->num_aces);
d0d66c44 241 if (num_aces > 0) {
d0d66c44
SP
242 ppace = kmalloc(num_aces * sizeof(struct cifs_ace *),
243 GFP_KERNEL);
244
d12fd121 245/* cifscred->cecount = pdacl->num_aces;
d12fd121
SF
246 cifscred->aces = kmalloc(num_aces *
247 sizeof(struct cifs_ace *), GFP_KERNEL);*/
d0d66c44 248
d0d66c44 249 for (i = 0; i < num_aces; ++i) {
44093ca2 250 ppace[i] = (struct cifs_ace *) (acl_base + acl_size);
953f8681
SF
251#ifdef CONFIG_CIFS_DEBUG2
252 dump_ace(ppace[i], end_of_acl);
253#endif
e01b6400
SP
254 if (compare_sids(&(ppace[i]->sid), pownersid))
255 access_flags_to_mode(ppace[i]->access_req,
256 &(inode->i_mode), S_IRWXU);
257 if (compare_sids(&(ppace[i]->sid), pgrpsid))
258 access_flags_to_mode(ppace[i]->access_req,
259 &(inode->i_mode), S_IRWXG);
260 if (compare_sids(&(ppace[i]->sid), &sid_everyone))
261 access_flags_to_mode(ppace[i]->access_req,
262 &(inode->i_mode), S_IRWXO);
263
44093ca2 264/* memcpy((void *)(&(cifscred->aces[i])),
d12fd121
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265 (void *)ppace[i],
266 sizeof(struct cifs_ace)); */
d0d66c44 267
44093ca2
SF
268 acl_base = (char *)ppace[i];
269 acl_size = le16_to_cpu(ppace[i]->size);
d0d66c44
SP
270 }
271
272 kfree(ppace);
d0d66c44
SP
273 }
274
275 return;
276}
277
bcb02034
SF
278
279static int parse_sid(struct cifs_sid *psid, char *end_of_acl)
280{
281 /* BB need to add parm so we can store the SID BB */
282
b9c7a2bb
SF
283 /* validate that we do not go past end of ACL - sid must be at least 8
284 bytes long (assuming no sub-auths - e.g. the null SID */
285 if (end_of_acl < (char *)psid + 8) {
286 cERROR(1, ("ACL too small to parse SID %p", psid));
bcb02034
SF
287 return -EINVAL;
288 }
d0d66c44 289
af6f4612 290 if (psid->num_subauth) {
bcb02034 291#ifdef CONFIG_CIFS_DEBUG2
8f18c131 292 int i;
44093ca2
SF
293 cFYI(1, ("SID revision %d num_auth %d",
294 psid->revision, psid->num_subauth));
bcb02034 295
af6f4612 296 for (i = 0; i < psid->num_subauth; i++) {
d0d66c44 297 cFYI(1, ("SID sub_auth[%d]: 0x%x ", i,
297647c2 298 le32_to_cpu(psid->sub_auth[i])));
d0d66c44
SP
299 }
300
d12fd121 301 /* BB add length check to make sure that we do not have huge
d0d66c44 302 num auths and therefore go off the end */
d12fd121 303 cFYI(1, ("RID 0x%x",
af6f4612 304 le32_to_cpu(psid->sub_auth[psid->num_subauth-1])));
bcb02034 305#endif
d0d66c44
SP
306 }
307
bcb02034
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308 return 0;
309}
310
d0d66c44 311
bcb02034 312/* Convert CIFS ACL to POSIX form */
630f3f0c
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313static int parse_sec_desc(struct cifs_ntsd *pntsd, int acl_len,
314 struct inode *inode)
bcb02034 315{
d0d66c44 316 int rc;
bcb02034
SF
317 struct cifs_sid *owner_sid_ptr, *group_sid_ptr;
318 struct cifs_acl *dacl_ptr; /* no need for SACL ptr */
bcb02034 319 char *end_of_acl = ((char *)pntsd) + acl_len;
7505e052 320 __u32 dacloffset;
bcb02034 321
b9c7a2bb
SF
322 if ((inode == NULL) || (pntsd == NULL))
323 return -EIO;
324
bcb02034 325 owner_sid_ptr = (struct cifs_sid *)((char *)pntsd +
af6f4612 326 le32_to_cpu(pntsd->osidoffset));
bcb02034 327 group_sid_ptr = (struct cifs_sid *)((char *)pntsd +
af6f4612 328 le32_to_cpu(pntsd->gsidoffset));
7505e052 329 dacloffset = le32_to_cpu(pntsd->dacloffset);
63d2583f 330 dacl_ptr = (struct cifs_acl *)((char *)pntsd + dacloffset);
bcb02034
SF
331#ifdef CONFIG_CIFS_DEBUG2
332 cFYI(1, ("revision %d type 0x%x ooffset 0x%x goffset 0x%x "
333 "sacloffset 0x%x dacloffset 0x%x",
af6f4612
SF
334 pntsd->revision, pntsd->type, le32_to_cpu(pntsd->osidoffset),
335 le32_to_cpu(pntsd->gsidoffset),
7505e052 336 le32_to_cpu(pntsd->sacloffset), dacloffset));
bcb02034 337#endif
b9c7a2bb 338/* cifs_dump_mem("owner_sid: ", owner_sid_ptr, 64); */
bcb02034
SF
339 rc = parse_sid(owner_sid_ptr, end_of_acl);
340 if (rc)
341 return rc;
342
343 rc = parse_sid(group_sid_ptr, end_of_acl);
344 if (rc)
345 return rc;
346
7505e052
SF
347 if (dacloffset)
348 parse_dacl(dacl_ptr, end_of_acl, owner_sid_ptr,
63d2583f 349 group_sid_ptr, inode);
7505e052
SF
350 else
351 cFYI(1, ("no ACL")); /* BB grant all or default perms? */
d0d66c44 352
bcb02034
SF
353/* cifscred->uid = owner_sid_ptr->rid;
354 cifscred->gid = group_sid_ptr->rid;
355 memcpy((void *)(&(cifscred->osid)), (void *)owner_sid_ptr,
630f3f0c 356 sizeof(struct cifs_sid));
bcb02034 357 memcpy((void *)(&(cifscred->gsid)), (void *)group_sid_ptr,
630f3f0c 358 sizeof(struct cifs_sid)); */
bcb02034 359
297647c2 360
bcb02034
SF
361 return (0);
362}
b9c7a2bb
SF
363
364
7505e052
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365/* Retrieve an ACL from the server */
366static struct cifs_ntsd *get_cifs_acl(u32 *pacllen, struct inode *inode,
367 const char *path)
b9c7a2bb
SF
368{
369 struct cifsFileInfo *open_file;
370 int unlock_file = FALSE;
371 int xid;
372 int rc = -EIO;
373 __u16 fid;
374 struct super_block *sb;
375 struct cifs_sb_info *cifs_sb;
376 struct cifs_ntsd *pntsd = NULL;
b9c7a2bb
SF
377
378 cFYI(1, ("get mode from ACL for %s", path));
379
380 if (inode == NULL)
7505e052 381 return NULL;
b9c7a2bb
SF
382
383 xid = GetXid();
384 open_file = find_readable_file(CIFS_I(inode));
385 sb = inode->i_sb;
386 if (sb == NULL) {
387 FreeXid(xid);
7505e052 388 return NULL;
b9c7a2bb
SF
389 }
390 cifs_sb = CIFS_SB(sb);
391
392 if (open_file) {
393 unlock_file = TRUE;
394 fid = open_file->netfid;
395 } else {
396 int oplock = FALSE;
397 /* open file */
398 rc = CIFSSMBOpen(xid, cifs_sb->tcon, path, FILE_OPEN,
953f8681 399 READ_CONTROL, 0, &fid, &oplock, NULL,
b9c7a2bb
SF
400 cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
401 CIFS_MOUNT_MAP_SPECIAL_CHR);
402 if (rc != 0) {
403 cERROR(1, ("Unable to open file to get ACL"));
404 FreeXid(xid);
7505e052 405 return NULL;
b9c7a2bb
SF
406 }
407 }
408
7505e052
SF
409 rc = CIFSSMBGetCIFSACL(xid, cifs_sb->tcon, fid, &pntsd, pacllen);
410 cFYI(1, ("GetCIFSACL rc = %d ACL len %d", rc, *pacllen));
b9c7a2bb
SF
411 if (unlock_file == TRUE)
412 atomic_dec(&open_file->wrtPending);
413 else
414 CIFSSMBClose(xid, cifs_sb->tcon, fid);
415
7505e052
SF
416 FreeXid(xid);
417 return pntsd;
418}
419
420/* Translate the CIFS ACL (simlar to NTFS ACL) for a file into mode bits */
421void acl_to_uid_mode(struct inode *inode, const char *path)
422{
423 struct cifs_ntsd *pntsd = NULL;
424 u32 acllen = 0;
425 int rc = 0;
426
427#ifdef CONFIG_CIFS_DEBUG2
428 cFYI(1, ("converting ACL to mode for %s", path));
429#endif
430 pntsd = get_cifs_acl(&acllen, inode, path);
431
432 /* if we can retrieve the ACL, now parse Access Control Entries, ACEs */
433 if (pntsd)
b9c7a2bb 434 rc = parse_sec_desc(pntsd, acllen, inode);
7505e052
SF
435 if (rc)
436 cFYI(1, ("parse sec desc failed rc = %d", rc));
437
b9c7a2bb 438 kfree(pntsd);
b9c7a2bb
SF
439 return;
440}
953f8681 441
7505e052 442/* Convert mode bits to an ACL so we can update the ACL on the server */
953f8681
SF
443int mode_to_acl(struct inode *inode, const char *path)
444{
445 int rc = 0;
446 __u32 acllen = 0;
447 struct cifs_ntsd *pntsd = NULL;
448
449 cFYI(1, ("set ACL from mode for %s", path));
450
451 /* Get the security descriptor */
7505e052 452 pntsd = get_cifs_acl(&acllen, inode, path);
953f8681 453
7505e052
SF
454 /* Add/Modify the three ACEs for owner, group, everyone
455 while retaining the other ACEs */
953f8681
SF
456
457 /* Set the security descriptor */
953f8681 458
7505e052
SF
459
460 kfree(pntsd);
953f8681
SF
461 return rc;
462}
297647c2 463#endif /* CONFIG_CIFS_EXPERIMENTAL */