1 // SPDX-License-Identifier: LGPL-2.1
2 /*
3 *
4 * Copyright (C) International Business Machines Corp., 2007,2008
5 * Author(s): Steve French (sfrench@us.ibm.com)
6 *
7 * Contains the routines for mapping CIFS/NTFS ACLs
8 *
9 */
10
11 #include <linux/fs.h>
12 #include <linux/slab.h>
13 #include <linux/string.h>
14 #include <linux/keyctl.h>
15 #include <linux/key-type.h>
16 #include <uapi/linux/posix_acl.h>
17 #include <linux/posix_acl.h>
18 #include <linux/posix_acl_xattr.h>
19 #include <keys/user-type.h>
20 #include "cifspdu.h"
21 #include "cifsglob.h"
22 #include "cifsacl.h"
23 #include "cifsproto.h"
24 #include "cifs_debug.h"
25 #include "fs_context.h"
26 #include "cifs_fs_sb.h"
27 #include "cifs_unicode.h"
28
29 /* security id for everyone/world system group */
30 static const struct cifs_sid sid_everyone = {
31 1, 1, {0, 0, 0, 0, 0, 1}, {0} };
32 /* security id for Authenticated Users system group */
33 static const struct cifs_sid sid_authusers = {
34 1, 1, {0, 0, 0, 0, 0, 5}, {cpu_to_le32(11)} };
35
36 /* S-1-22-1 Unmapped Unix users */
37 static const struct cifs_sid sid_unix_users = {1, 1, {0, 0, 0, 0, 0, 22},
38 {cpu_to_le32(1), 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} };
39
40 /* S-1-22-2 Unmapped Unix groups */
41 static const struct cifs_sid sid_unix_groups = { 1, 1, {0, 0, 0, 0, 0, 22},
42 {cpu_to_le32(2), 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} };
43
44 /*
45 * See https://technet.microsoft.com/en-us/library/hh509017(v=ws.10).aspx
46 */
47
48 /* S-1-5-88 MS NFS and Apple style UID/GID/mode */
49
50 /* S-1-5-88-1 Unix uid */
51 static const struct cifs_sid sid_unix_NFS_users = { 1, 2, {0, 0, 0, 0, 0, 5},
52 {cpu_to_le32(88),
53 cpu_to_le32(1), 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} };
54
55 /* S-1-5-88-2 Unix gid */
56 static const struct cifs_sid sid_unix_NFS_groups = { 1, 2, {0, 0, 0, 0, 0, 5},
57 {cpu_to_le32(88),
58 cpu_to_le32(2), 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} };
59
60 /* S-1-5-88-3 Unix mode */
61 static const struct cifs_sid sid_unix_NFS_mode = { 1, 2, {0, 0, 0, 0, 0, 5},
62 {cpu_to_le32(88),
63 cpu_to_le32(3), 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} };
64
65 static const struct cred *root_cred;
66
67 static int
68 cifs_idmap_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
69 {
70 char *payload;
71
72 /*
73 * If the payload is less than or equal to the size of a pointer, then
74 * an allocation here is wasteful. Just copy the data directly to the
75 * payload.value union member instead.
76 *
77 * With this however, you must check the datalen before trying to
78 * dereference payload.data!
79 */
80 if (prep->datalen <= sizeof(key->payload)) {
81 key->payload.data[0] = NULL;
82 memcpy(&key->payload, prep->data, prep->datalen);
83 } else {
84 payload = kmemdup(prep->data, prep->datalen, GFP_KERNEL);
85 if (!payload)
86 return -ENOMEM;
87 key->payload.data[0] = payload;
88 }
89
90 key->datalen = prep->datalen;
91 return 0;
92 }
93
94 static inline void
95 cifs_idmap_key_destroy(struct key *key)
96 {
97 if (key->datalen > sizeof(key->payload))
98 kfree(key->payload.data[0]);
99 }
100
101 static struct key_type cifs_idmap_key_type = {
102 .name = "cifs.idmap",
103 .instantiate = cifs_idmap_key_instantiate,
104 .destroy = cifs_idmap_key_destroy,
105 .describe = user_describe,
106 };
107
108 static char *
109 sid_to_key_str(struct cifs_sid *sidptr, unsigned int type)
110 {
111 int i, len;
112 unsigned int saval;
113 char *sidstr, *strptr;
114 unsigned long long id_auth_val;
115
116 /* 3 bytes for prefix */
117 sidstr = kmalloc(3 + SID_STRING_BASE_SIZE +
118 (SID_STRING_SUBAUTH_SIZE * sidptr->num_subauth),
119 GFP_KERNEL);
120 if (!sidstr)
121 return sidstr;
122
123 strptr = sidstr;
124 len = sprintf(strptr, "%cs:S-%hhu", type == SIDOWNER ? 'o' : 'g',
125 sidptr->revision);
126 strptr += len;
127
128 /* The authority field is a single 48-bit number */
129 id_auth_val = (unsigned long long)sidptr->authority[5];
130 id_auth_val |= (unsigned long long)sidptr->authority[4] << 8;
131 id_auth_val |= (unsigned long long)sidptr->authority[3] << 16;
132 id_auth_val |= (unsigned long long)sidptr->authority[2] << 24;
133 id_auth_val |= (unsigned long long)sidptr->authority[1] << 32;
134 id_auth_val |= (unsigned long long)sidptr->authority[0] << 48;
135
136 /*
137 * MS-DTYP states that if the authority is >= 2^32, then it should be
138 * expressed as a hex value.
139 */
140 if (id_auth_val <= UINT_MAX)
141 len = sprintf(strptr, "-%llu", id_auth_val);
142 else
143 len = sprintf(strptr, "-0x%llx", id_auth_val);
144
145 strptr += len;
146
147 for (i = 0; i < sidptr->num_subauth; ++i) {
148 saval = le32_to_cpu(sidptr->sub_auth[i]);
149 len = sprintf(strptr, "-%u", saval);
150 strptr += len;
151 }
152
153 return sidstr;
154 }
155
156 /*
157 * if the two SIDs (roughly equivalent to a UUID for a user or group) are
158 * the same returns zero, if they do not match returns non-zero.
159 */
160 static int
161 compare_sids(const struct cifs_sid *ctsid, const struct cifs_sid *cwsid)
162 {
163 int i;
164 int num_subauth, num_sat, num_saw;
165
166 if ((!ctsid) || (!cwsid))
167 return 1;
168
169 /* compare the revision */
170 if (ctsid->revision != cwsid->revision) {
171 if (ctsid->revision > cwsid->revision)
172 return 1;
173 else
174 return -1;
175 }
176
177 /* compare all of the six auth values */
178 for (i = 0; i < NUM_AUTHS; ++i) {
179 if (ctsid->authority[i] != cwsid->authority[i]) {
180 if (ctsid->authority[i] > cwsid->authority[i])
181 return 1;
182 else
183 return -1;
184 }
185 }
186
187 /* compare all of the subauth values if any */
188 num_sat = ctsid->num_subauth;
189 num_saw = cwsid->num_subauth;
190 num_subauth = num_sat < num_saw ? num_sat : num_saw;
191 if (num_subauth) {
192 for (i = 0; i < num_subauth; ++i) {
193 if (ctsid->sub_auth[i] != cwsid->sub_auth[i]) {
194 if (le32_to_cpu(ctsid->sub_auth[i]) >
195 le32_to_cpu(cwsid->sub_auth[i]))
196 return 1;
197 else
198 return -1;
199 }
200 }
201 }
202
203 return 0; /* sids compare/match */
204 }
205
206 static bool
207 is_well_known_sid(const struct cifs_sid *psid, uint32_t *puid, bool is_group)
208 {
209 int i;
210 int num_subauth;
211 const struct cifs_sid *pwell_known_sid;
212
213 if (!psid || (puid == NULL))
214 return false;
215
216 num_subauth = psid->num_subauth;
217
218 /* check if Mac (or Windows NFS) vs. Samba format for Unix owner SID */
219 if (num_subauth == 2) {
220 if (is_group)
221 pwell_known_sid = &sid_unix_groups;
222 else
223 pwell_known_sid = &sid_unix_users;
224 } else if (num_subauth == 3) {
225 if (is_group)
226 pwell_known_sid = &sid_unix_NFS_groups;
227 else
228 pwell_known_sid = &sid_unix_NFS_users;
229 } else
230 return false;
231
232 /* compare the revision */
233 if (psid->revision != pwell_known_sid->revision)
234 return false;
235
236 /* compare all of the six auth values */
237 for (i = 0; i < NUM_AUTHS; ++i) {
238 if (psid->authority[i] != pwell_known_sid->authority[i]) {
239 cifs_dbg(FYI, "auth %d did not match\n", i);
240 return false;
241 }
242 }
243
244 if (num_subauth == 2) {
245 if (psid->sub_auth[0] != pwell_known_sid->sub_auth[0])
246 return false;
247
248 *puid = le32_to_cpu(psid->sub_auth[1]);
249 } else /* 3 subauths, ie Windows/Mac style */ {
250 *puid = le32_to_cpu(psid->sub_auth[0]);
251 if ((psid->sub_auth[0] != pwell_known_sid->sub_auth[0]) ||
252 (psid->sub_auth[1] != pwell_known_sid->sub_auth[1]))
253 return false;
254
255 *puid = le32_to_cpu(psid->sub_auth[2]);
256 }
257
258 cifs_dbg(FYI, "Unix UID %d returned from SID\n", *puid);
259 return true; /* well known sid found, uid returned */
260 }
261
262 static __u16
263 cifs_copy_sid(struct cifs_sid *dst, const struct cifs_sid *src)
264 {
265 int i;
266 __u16 size = 1 + 1 + 6;
267
268 dst->revision = src->revision;
269 dst->num_subauth = min_t(u8, src->num_subauth, SID_MAX_SUB_AUTHORITIES);
270 for (i = 0; i < NUM_AUTHS; ++i)
271 dst->authority[i] = src->authority[i];
272 for (i = 0; i < dst->num_subauth; ++i)
273 dst->sub_auth[i] = src->sub_auth[i];
274 size += (dst->num_subauth * 4);
275
276 return size;
277 }
278
279 static int
280 id_to_sid(unsigned int cid, uint sidtype, struct cifs_sid *ssid)
281 {
282 int rc;
283 struct key *sidkey;
284 struct cifs_sid *ksid;
285 unsigned int ksid_size;
286 char desc[3 + 10 + 1]; /* 3 byte prefix + 10 bytes for value + NULL */
287 const struct cred *saved_cred;
288
289 rc = snprintf(desc, sizeof(desc), "%ci:%u",
290 sidtype == SIDOWNER ? 'o' : 'g', cid);
291 if (rc >= sizeof(desc))
292 return -EINVAL;
293
294 rc = 0;
295 saved_cred = override_creds(root_cred);
296 sidkey = request_key(&cifs_idmap_key_type, desc, "");
297 if (IS_ERR(sidkey)) {
298 rc = -EINVAL;
299 cifs_dbg(FYI, "%s: Can't map %cid %u to a SID\n",
300 __func__, sidtype == SIDOWNER ? 'u' : 'g', cid);
301 goto out_revert_creds;
302 } else if (sidkey->datalen < CIFS_SID_BASE_SIZE) {
303 rc = -EIO;
304 cifs_dbg(FYI, "%s: Downcall contained malformed key (datalen=%hu)\n",
305 __func__, sidkey->datalen);
306 goto invalidate_key;
307 }
308
309 /*
310 * A sid is usually too large to be embedded in payload.value, but if
311 * there are no subauthorities and the host has 8-byte pointers, then
312 * it could be.
313 */
314 ksid = sidkey->datalen <= sizeof(sidkey->payload) ?
315 (struct cifs_sid *)&sidkey->payload :
316 (struct cifs_sid *)sidkey->payload.data[0];
317
318 ksid_size = CIFS_SID_BASE_SIZE + (ksid->num_subauth * sizeof(__le32));
319 if (ksid_size > sidkey->datalen) {
320 rc = -EIO;
321 cifs_dbg(FYI, "%s: Downcall contained malformed key (datalen=%hu, ksid_size=%u)\n",
322 __func__, sidkey->datalen, ksid_size);
323 goto invalidate_key;
324 }
325
326 cifs_copy_sid(ssid, ksid);
327 out_key_put:
328 key_put(sidkey);
329 out_revert_creds:
330 revert_creds(saved_cred);
331 return rc;
332
333 invalidate_key:
334 key_invalidate(sidkey);
335 goto out_key_put;
336 }
337
338 int
339 sid_to_id(struct cifs_sb_info *cifs_sb, struct cifs_sid *psid,
340 struct cifs_fattr *fattr, uint sidtype)
341 {
342 int rc = 0;
343 struct key *sidkey;
344 char *sidstr;
345 const struct cred *saved_cred;
346 kuid_t fuid = cifs_sb->ctx->linux_uid;
347 kgid_t fgid = cifs_sb->ctx->linux_gid;
348
349 /*
350 * If we have too many subauthorities, then something is really wrong.
351 * Just return an error.
352 */
353 if (unlikely(psid->num_subauth > SID_MAX_SUB_AUTHORITIES)) {
354 cifs_dbg(FYI, "%s: %u subauthorities is too many!\n",
355 __func__, psid->num_subauth);
356 return -EIO;
357 }
358
359 if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UID_FROM_ACL) ||
360 (cifs_sb_master_tcon(cifs_sb)->posix_extensions)) {
361 uint32_t unix_id;
362 bool is_group;
363
364 if (sidtype != SIDOWNER)
365 is_group = true;
366 else
367 is_group = false;
368
369 if (is_well_known_sid(psid, &unix_id, is_group) == false)
370 goto try_upcall_to_get_id;
371
372 if (is_group) {
373 kgid_t gid;
374 gid_t id;
375
376 id = (gid_t)unix_id;
377 gid = make_kgid(&init_user_ns, id);
378 if (gid_valid(gid)) {
379 fgid = gid;
380 goto got_valid_id;
381 }
382 } else {
383 kuid_t uid;
384 uid_t id;
385
386 id = (uid_t)unix_id;
387 uid = make_kuid(&init_user_ns, id);
388 if (uid_valid(uid)) {
389 fuid = uid;
390 goto got_valid_id;
391 }
392 }
393 /* If unable to find uid/gid easily from SID try via upcall */
394 }
395
396 try_upcall_to_get_id:
397 sidstr = sid_to_key_str(psid, sidtype);
398 if (!sidstr)
399 return -ENOMEM;
400
401 saved_cred = override_creds(root_cred);
402 sidkey = request_key(&cifs_idmap_key_type, sidstr, "");
403 if (IS_ERR(sidkey)) {
404 cifs_dbg(FYI, "%s: Can't map SID %s to a %cid\n",
405 __func__, sidstr, sidtype == SIDOWNER ? 'u' : 'g');
406 goto out_revert_creds;
407 }
408
409 /*
410 * FIXME: Here we assume that uid_t and gid_t are same size. It's
411 * probably a safe assumption but might be better to check based on
412 * sidtype.
413 */
414 BUILD_BUG_ON(sizeof(uid_t) != sizeof(gid_t));
415 if (sidkey->datalen != sizeof(uid_t)) {
416 cifs_dbg(FYI, "%s: Downcall contained malformed key (datalen=%hu)\n",
417 __func__, sidkey->datalen);
418 key_invalidate(sidkey);
419 goto out_key_put;
420 }
421
422 if (sidtype == SIDOWNER) {
423 kuid_t uid;
424 uid_t id;
425 memcpy(&id, &sidkey->payload.data[0], sizeof(uid_t));
426 uid = make_kuid(&init_user_ns, id);
427 if (uid_valid(uid))
428 fuid = uid;
429 } else {
430 kgid_t gid;
431 gid_t id;
432 memcpy(&id, &sidkey->payload.data[0], sizeof(gid_t));
433 gid = make_kgid(&init_user_ns, id);
434 if (gid_valid(gid))
435 fgid = gid;
436 }
437
438 out_key_put:
439 key_put(sidkey);
440 out_revert_creds:
441 revert_creds(saved_cred);
442 kfree(sidstr);
443
444 /*
445 * Note that we return 0 here unconditionally. If the mapping
446 * fails then we just fall back to using the ctx->linux_uid/linux_gid.
447 */
448 got_valid_id:
449 rc = 0;
450 if (sidtype == SIDOWNER)
451 fattr->cf_uid = fuid;
452 else
453 fattr->cf_gid = fgid;
454 return rc;
455 }
456
457 int
458 init_cifs_idmap(void)
459 {
460 struct cred *cred;
461 struct key *keyring;
462 int ret;
463
464 cifs_dbg(FYI, "Registering the %s key type\n",
465 cifs_idmap_key_type.name);
466
467 /* create an override credential set with a special thread keyring in
468 * which requests are cached
469 *
470 * this is used to prevent malicious redirections from being installed
471 * with add_key().
472 */
473 cred = prepare_kernel_cred(&init_task);
474 if (!cred)
475 return -ENOMEM;
476
477 keyring = keyring_alloc(".cifs_idmap",
478 GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, cred,
479 (KEY_POS_ALL & ~KEY_POS_SETATTR) |
480 KEY_USR_VIEW | KEY_USR_READ,
481 KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
482 if (IS_ERR(keyring)) {
483 ret = PTR_ERR(keyring);
484 goto failed_put_cred;
485 }
486
487 ret = register_key_type(&cifs_idmap_key_type);
488 if (ret < 0)
489 goto failed_put_key;
490
491 /* instruct request_key() to use this special keyring as a cache for
492 * the results it looks up */
493 set_bit(KEY_FLAG_ROOT_CAN_CLEAR, &keyring->flags);
494 cred->thread_keyring = keyring;
495 cred->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
496 root_cred = cred;
497
498 cifs_dbg(FYI, "cifs idmap keyring: %d\n", key_serial(keyring));
499 return 0;
500
501 failed_put_key:
502 key_put(keyring);
503 failed_put_cred:
504 put_cred(cred);
505 return ret;
506 }
507
508 void
509 exit_cifs_idmap(void)
510 {
511 key_revoke(root_cred->thread_keyring);
512 unregister_key_type(&cifs_idmap_key_type);
513 put_cred(root_cred);
514 cifs_dbg(FYI, "Unregistered %s key type\n", cifs_idmap_key_type.name);
515 }
516
517 /* copy ntsd, owner sid, and group sid from a security descriptor to another */
518 static __u32 copy_sec_desc(const struct cifs_ntsd *pntsd,
519 struct cifs_ntsd *pnntsd,
520 __u32 sidsoffset,
521 struct cifs_sid *pownersid,
522 struct cifs_sid *pgrpsid)
523 {
524 struct cifs_sid *owner_sid_ptr, *group_sid_ptr;
525 struct cifs_sid *nowner_sid_ptr, *ngroup_sid_ptr;
526
527 /* copy security descriptor control portion */
528 pnntsd->revision = pntsd->revision;
529 pnntsd->type = pntsd->type;
530 pnntsd->dacloffset = cpu_to_le32(sizeof(struct cifs_ntsd));
531 pnntsd->sacloffset = 0;
532 pnntsd->osidoffset = cpu_to_le32(sidsoffset);
533 pnntsd->gsidoffset = cpu_to_le32(sidsoffset + sizeof(struct cifs_sid));
534
535 /* copy owner sid */
536 if (pownersid)
537 owner_sid_ptr = pownersid;
538 else
539 owner_sid_ptr = (struct cifs_sid *)((char *)pntsd +
540 le32_to_cpu(pntsd->osidoffset));
541 nowner_sid_ptr = (struct cifs_sid *)((char *)pnntsd + sidsoffset);
542 cifs_copy_sid(nowner_sid_ptr, owner_sid_ptr);
543
544 /* copy group sid */
545 if (pgrpsid)
546 group_sid_ptr = pgrpsid;
547 else
548 group_sid_ptr = (struct cifs_sid *)((char *)pntsd +
549 le32_to_cpu(pntsd->gsidoffset));
550 ngroup_sid_ptr = (struct cifs_sid *)((char *)pnntsd + sidsoffset +
551 sizeof(struct cifs_sid));
552 cifs_copy_sid(ngroup_sid_ptr, group_sid_ptr);
553
554 return sidsoffset + (2 * sizeof(struct cifs_sid));
555 }
556
557
558 /*
559 change posix mode to reflect permissions
560 pmode is the existing mode (we only want to overwrite part of this
561 bits to set can be: S_IRWXU, S_IRWXG or S_IRWXO ie 00700 or 00070 or 00007
562 */
563 static void access_flags_to_mode(__le32 ace_flags, int type, umode_t *pmode,
564 umode_t *pdenied, umode_t mask)
565 {
566 __u32 flags = le32_to_cpu(ace_flags);
567 /*
568 * Do not assume "preferred" or "canonical" order.
569 * The first DENY or ALLOW ACE which matches perfectly is
570 * the permission to be used. Once allowed or denied, same
571 * permission in later ACEs do not matter.
572 */
573
574 /* If not already allowed, deny these bits */
575 if (type == ACCESS_DENIED) {
576 if (flags & GENERIC_ALL &&
577 !(*pmode & mask & 0777))
578 *pdenied |= mask & 0777;
579
580 if (((flags & GENERIC_WRITE) ||
581 ((flags & FILE_WRITE_RIGHTS) == FILE_WRITE_RIGHTS)) &&
582 !(*pmode & mask & 0222))
583 *pdenied |= mask & 0222;
584
585 if (((flags & GENERIC_READ) ||
586 ((flags & FILE_READ_RIGHTS) == FILE_READ_RIGHTS)) &&
587 !(*pmode & mask & 0444))
588 *pdenied |= mask & 0444;
589
590 if (((flags & GENERIC_EXECUTE) ||
591 ((flags & FILE_EXEC_RIGHTS) == FILE_EXEC_RIGHTS)) &&
592 !(*pmode & mask & 0111))
593 *pdenied |= mask & 0111;
594
595 return;
596 } else if (type != ACCESS_ALLOWED) {
597 cifs_dbg(VFS, "unknown access control type %d\n", type);
598 return;
599 }
600 /* else ACCESS_ALLOWED type */
601
602 if ((flags & GENERIC_ALL) &&
603 !(*pdenied & mask & 0777)) {
604 *pmode |= mask & 0777;
605 cifs_dbg(NOISY, "all perms\n");
606 return;
607 }
608
609 if (((flags & GENERIC_WRITE) ||
610 ((flags & FILE_WRITE_RIGHTS) == FILE_WRITE_RIGHTS)) &&
611 !(*pdenied & mask & 0222))
612 *pmode |= mask & 0222;
613
614 if (((flags & GENERIC_READ) ||
615 ((flags & FILE_READ_RIGHTS) == FILE_READ_RIGHTS)) &&
616 !(*pdenied & mask & 0444))
617 *pmode |= mask & 0444;
618
619 if (((flags & GENERIC_EXECUTE) ||
620 ((flags & FILE_EXEC_RIGHTS) == FILE_EXEC_RIGHTS)) &&
621 !(*pdenied & mask & 0111))
622 *pmode |= mask & 0111;
623
624 /* If DELETE_CHILD is set only on an owner ACE, set sticky bit */
625 if (flags & FILE_DELETE_CHILD) {
626 if (mask == ACL_OWNER_MASK) {
627 if (!(*pdenied & 01000))
628 *pmode |= 01000;
629 } else if (!(*pdenied & 01000)) {
630 *pmode &= ~01000;
631 *pdenied |= 01000;
632 }
633 }
634
635 cifs_dbg(NOISY, "access flags 0x%x mode now %04o\n", flags, *pmode);
636 return;
637 }
638
639 /*
640 Generate access flags to reflect permissions mode is the existing mode.
641 This function is called for every ACE in the DACL whose SID matches
642 with either owner or group or everyone.
643 */
644
645 static void mode_to_access_flags(umode_t mode, umode_t bits_to_use,
646 __u32 *pace_flags)
647 {
648 /* reset access mask */
649 *pace_flags = 0x0;
650
651 /* bits to use are either S_IRWXU or S_IRWXG or S_IRWXO */
652 mode &= bits_to_use;
653
654 /* check for R/W/X UGO since we do not know whose flags
655 is this but we have cleared all the bits sans RWX for
656 either user or group or other as per bits_to_use */
657 if (mode & S_IRUGO)
658 *pace_flags |= SET_FILE_READ_RIGHTS;
659 if (mode & S_IWUGO)
660 *pace_flags |= SET_FILE_WRITE_RIGHTS;
661 if (mode & S_IXUGO)
662 *pace_flags |= SET_FILE_EXEC_RIGHTS;
663
664 cifs_dbg(NOISY, "mode: %04o, access flags now 0x%x\n",
665 mode, *pace_flags);
666 return;
667 }
668
669 static __u16 cifs_copy_ace(struct cifs_ace *dst, struct cifs_ace *src, struct cifs_sid *psid)
670 {
671 __u16 size = 1 + 1 + 2 + 4;
672
673 dst->type = src->type;
674 dst->flags = src->flags;
675 dst->access_req = src->access_req;
676
677 /* Check if there's a replacement sid specified */
678 if (psid)
679 size += cifs_copy_sid(&dst->sid, psid);
680 else
681 size += cifs_copy_sid(&dst->sid, &src->sid);
682
683 dst->size = cpu_to_le16(size);
684
685 return size;
686 }
687
688 static __u16 fill_ace_for_sid(struct cifs_ace *pntace,
689 const struct cifs_sid *psid, __u64 nmode,
690 umode_t bits, __u8 access_type,
691 bool allow_delete_child)
692 {
693 int i;
694 __u16 size = 0;
695 __u32 access_req = 0;
696
697 pntace->type = access_type;
698 pntace->flags = 0x0;
699 mode_to_access_flags(nmode, bits, &access_req);
700
701 if (access_type == ACCESS_ALLOWED && allow_delete_child)
702 access_req |= FILE_DELETE_CHILD;
703
704 if (access_type == ACCESS_ALLOWED && !access_req)
705 access_req = SET_MINIMUM_RIGHTS;
706 else if (access_type == ACCESS_DENIED)
707 access_req &= ~SET_MINIMUM_RIGHTS;
708
709 pntace->access_req = cpu_to_le32(access_req);
710
711 pntace->sid.revision = psid->revision;
712 pntace->sid.num_subauth = psid->num_subauth;
713 for (i = 0; i < NUM_AUTHS; i++)
714 pntace->sid.authority[i] = psid->authority[i];
715 for (i = 0; i < psid->num_subauth; i++)
716 pntace->sid.sub_auth[i] = psid->sub_auth[i];
717
718 size = 1 + 1 + 2 + 4 + 1 + 1 + 6 + (psid->num_subauth * 4);
719 pntace->size = cpu_to_le16(size);
720
721 return size;
722 }
723
724
725 #ifdef CONFIG_CIFS_DEBUG2
726 static void dump_ace(struct cifs_ace *pace, char *end_of_acl)
727 {
728 int num_subauth;
729
730 /* validate that we do not go past end of acl */
731
732 if (le16_to_cpu(pace->size) < 16) {
733 cifs_dbg(VFS, "ACE too small %d\n", le16_to_cpu(pace->size));
734 return;
735 }
736
737 if (end_of_acl < (char *)pace + le16_to_cpu(pace->size)) {
738 cifs_dbg(VFS, "ACL too small to parse ACE\n");
739 return;
740 }
741
742 num_subauth = pace->sid.num_subauth;
743 if (num_subauth) {
744 int i;
745 cifs_dbg(FYI, "ACE revision %d num_auth %d type %d flags %d size %d\n",
746 pace->sid.revision, pace->sid.num_subauth, pace->type,
747 pace->flags, le16_to_cpu(pace->size));
748 for (i = 0; i < num_subauth; ++i) {
749 cifs_dbg(FYI, "ACE sub_auth[%d]: 0x%x\n",
750 i, le32_to_cpu(pace->sid.sub_auth[i]));
751 }
752
753 /* BB add length check to make sure that we do not have huge
754 num auths and therefore go off the end */
755 }
756
757 return;
758 }
759 #endif
760
761 static void parse_dacl(struct cifs_acl *pdacl, char *end_of_acl,
762 struct cifs_sid *pownersid, struct cifs_sid *pgrpsid,
763 struct cifs_fattr *fattr, bool mode_from_special_sid)
764 {
765 int i;
766 int num_aces = 0;
767 int acl_size;
768 char *acl_base;
769 struct cifs_ace **ppace;
770
771 /* BB need to add parm so we can store the SID BB */
772
773 if (!pdacl) {
774 /* no DACL in the security descriptor, set
775 all the permissions for user/group/other */
776 fattr->cf_mode |= 0777;
777 return;
778 }
779
780 /* validate that we do not go past end of acl */
781 if (end_of_acl < (char *)pdacl + le16_to_cpu(pdacl->size)) {
782 cifs_dbg(VFS, "ACL too small to parse DACL\n");
783 return;
784 }
785
786 cifs_dbg(NOISY, "DACL revision %d size %d num aces %d\n",
787 le16_to_cpu(pdacl->revision), le16_to_cpu(pdacl->size),
788 le32_to_cpu(pdacl->num_aces));
789
790 /* reset rwx permissions for user/group/other.
791 Also, if num_aces is 0 i.e. DACL has no ACEs,
792 user/group/other have no permissions */
793 fattr->cf_mode &= ~(0777);
794
795 acl_base = (char *)pdacl;
796 acl_size = sizeof(struct cifs_acl);
797
798 num_aces = le32_to_cpu(pdacl->num_aces);
799 if (num_aces > 0) {
800 umode_t denied_mode = 0;
801
802 if (num_aces > ULONG_MAX / sizeof(struct cifs_ace *))
803 return;
804 ppace = kmalloc_array(num_aces, sizeof(struct cifs_ace *),
805 GFP_KERNEL);
806 if (!ppace)
807 return;
808
809 for (i = 0; i < num_aces; ++i) {
810 ppace[i] = (struct cifs_ace *) (acl_base + acl_size);
811 #ifdef CONFIG_CIFS_DEBUG2
812 dump_ace(ppace[i], end_of_acl);
813 #endif
814 if (mode_from_special_sid &&
815 (compare_sids(&(ppace[i]->sid),
816 &sid_unix_NFS_mode) == 0)) {
817 /*
818 * Full permissions are:
819 * 07777 = S_ISUID | S_ISGID | S_ISVTX |
820 * S_IRWXU | S_IRWXG | S_IRWXO
821 */
822 fattr->cf_mode &= ~07777;
823 fattr->cf_mode |=
824 le32_to_cpu(ppace[i]->sid.sub_auth[2]);
825 break;
826 } else {
827 if (compare_sids(&(ppace[i]->sid), pownersid) == 0) {
828 access_flags_to_mode(ppace[i]->access_req,
829 ppace[i]->type,
830 &fattr->cf_mode,
831 &denied_mode,
832 ACL_OWNER_MASK);
833 } else if (compare_sids(&(ppace[i]->sid), pgrpsid) == 0) {
834 access_flags_to_mode(ppace[i]->access_req,
835 ppace[i]->type,
836 &fattr->cf_mode,
837 &denied_mode,
838 ACL_GROUP_MASK);
839 } else if ((compare_sids(&(ppace[i]->sid), &sid_everyone) == 0) ||
840 (compare_sids(&(ppace[i]->sid), &sid_authusers) == 0)) {
841 access_flags_to_mode(ppace[i]->access_req,
842 ppace[i]->type,
843 &fattr->cf_mode,
844 &denied_mode,
845 ACL_EVERYONE_MASK);
846 }
847 }
848
849
850 /* memcpy((void *)(&(cifscred->aces[i])),
851 (void *)ppace[i],
852 sizeof(struct cifs_ace)); */
853
854 acl_base = (char *)ppace[i];
855 acl_size = le16_to_cpu(ppace[i]->size);
856 }
857
858 kfree(ppace);
859 }
860
861 return;
862 }
863
864 unsigned int setup_authusers_ACE(struct cifs_ace *pntace)
865 {
866 int i;
867 unsigned int ace_size = 20;
868
869 pntace->type = ACCESS_ALLOWED_ACE_TYPE;
870 pntace->flags = 0x0;
871 pntace->access_req = cpu_to_le32(GENERIC_ALL);
872 pntace->sid.num_subauth = 1;
873 pntace->sid.revision = 1;
874 for (i = 0; i < NUM_AUTHS; i++)
875 pntace->sid.authority[i] = sid_authusers.authority[i];
876
877 pntace->sid.sub_auth[0] = sid_authusers.sub_auth[0];
878
879 /* size = 1 + 1 + 2 + 4 + 1 + 1 + 6 + (psid->num_subauth*4) */
880 pntace->size = cpu_to_le16(ace_size);
881 return ace_size;
882 }
883
884 /*
885 * Fill in the special SID based on the mode. See
886 * https://technet.microsoft.com/en-us/library/hh509017(v=ws.10).aspx
887 */
888 unsigned int setup_special_mode_ACE(struct cifs_ace *pntace, __u64 nmode)
889 {
890 int i;
891 unsigned int ace_size = 28;
892
893 pntace->type = ACCESS_DENIED_ACE_TYPE;
894 pntace->flags = 0x0;
895 pntace->access_req = 0;
896 pntace->sid.num_subauth = 3;
897 pntace->sid.revision = 1;
898 for (i = 0; i < NUM_AUTHS; i++)
899 pntace->sid.authority[i] = sid_unix_NFS_mode.authority[i];
900
901 pntace->sid.sub_auth[0] = sid_unix_NFS_mode.sub_auth[0];
902 pntace->sid.sub_auth[1] = sid_unix_NFS_mode.sub_auth[1];
903 pntace->sid.sub_auth[2] = cpu_to_le32(nmode & 07777);
904
905 /* size = 1 + 1 + 2 + 4 + 1 + 1 + 6 + (psid->num_subauth*4) */
906 pntace->size = cpu_to_le16(ace_size);
907 return ace_size;
908 }
909
910 unsigned int setup_special_user_owner_ACE(struct cifs_ace *pntace)
911 {
912 int i;
913 unsigned int ace_size = 28;
914
915 pntace->type = ACCESS_ALLOWED_ACE_TYPE;
916 pntace->flags = 0x0;
917 pntace->access_req = cpu_to_le32(GENERIC_ALL);
918 pntace->sid.num_subauth = 3;
919 pntace->sid.revision = 1;
920 for (i = 0; i < NUM_AUTHS; i++)
921 pntace->sid.authority[i] = sid_unix_NFS_users.authority[i];
922
923 pntace->sid.sub_auth[0] = sid_unix_NFS_users.sub_auth[0];
924 pntace->sid.sub_auth[1] = sid_unix_NFS_users.sub_auth[1];
925 pntace->sid.sub_auth[2] = cpu_to_le32(current_fsgid().val);
926
927 /* size = 1 + 1 + 2 + 4 + 1 + 1 + 6 + (psid->num_subauth*4) */
928 pntace->size = cpu_to_le16(ace_size);
929 return ace_size;
930 }
931
932 static void populate_new_aces(char *nacl_base,
933 struct cifs_sid *pownersid,
934 struct cifs_sid *pgrpsid,
935 __u64 *pnmode, u32 *pnum_aces, u16 *pnsize,
936 bool modefromsid)
937 {
938 __u64 nmode;
939 u32 num_aces = 0;
940 u16 nsize = 0;
941 __u64 user_mode;
942 __u64 group_mode;
943 __u64 other_mode;
944 __u64 deny_user_mode = 0;
945 __u64 deny_group_mode = 0;
946 bool sticky_set = false;
947 struct cifs_ace *pnntace = NULL;
948
949 nmode = *pnmode;
950 num_aces = *pnum_aces;
951 nsize = *pnsize;
952
953 if (modefromsid) {
954 pnntace = (struct cifs_ace *) (nacl_base + nsize);
955 nsize += setup_special_mode_ACE(pnntace, nmode);
956 num_aces++;
957 pnntace = (struct cifs_ace *) (nacl_base + nsize);
958 nsize += setup_authusers_ACE(pnntace);
959 num_aces++;
960 goto set_size;
961 }
962
963 /*
964 * We'll try to keep the mode as requested by the user.
965 * But in cases where we cannot meaningfully convert that
966 * into ACL, return back the updated mode, so that it is
967 * updated in the inode.
968 */
969
970 if (!memcmp(pownersid, pgrpsid, sizeof(struct cifs_sid))) {
971 /*
972 * Case when owner and group SIDs are the same.
973 * Set the more restrictive of the two modes.
974 */
975 user_mode = nmode & (nmode << 3) & 0700;
976 group_mode = nmode & (nmode >> 3) & 0070;
977 } else {
978 user_mode = nmode & 0700;
979 group_mode = nmode & 0070;
980 }
981
982 other_mode = nmode & 0007;
983
984 /* We need DENY ACE when the perm is more restrictive than the next sets. */
985 deny_user_mode = ~(user_mode) & ((group_mode << 3) | (other_mode << 6)) & 0700;
986 deny_group_mode = ~(group_mode) & (other_mode << 3) & 0070;
987
988 *pnmode = user_mode | group_mode | other_mode | (nmode & ~0777);
989
990 /* This tells if we should allow delete child for group and everyone. */
991 if (nmode & 01000)
992 sticky_set = true;
993
994 if (deny_user_mode) {
995 pnntace = (struct cifs_ace *) (nacl_base + nsize);
996 nsize += fill_ace_for_sid(pnntace, pownersid, deny_user_mode,
997 0700, ACCESS_DENIED, false);
998 num_aces++;
999 }
1000
1001 /* Group DENY ACE does not conflict with owner ALLOW ACE. Keep in preferred order*/
1002 if (deny_group_mode && !(deny_group_mode & (user_mode >> 3))) {
1003 pnntace = (struct cifs_ace *) (nacl_base + nsize);
1004 nsize += fill_ace_for_sid(pnntace, pgrpsid, deny_group_mode,
1005 0070, ACCESS_DENIED, false);
1006 num_aces++;
1007 }
1008
1009 pnntace = (struct cifs_ace *) (nacl_base + nsize);
1010 nsize += fill_ace_for_sid(pnntace, pownersid, user_mode,
1011 0700, ACCESS_ALLOWED, true);
1012 num_aces++;
1013
1014 /* Group DENY ACE conflicts with owner ALLOW ACE. So keep it after. */
1015 if (deny_group_mode && (deny_group_mode & (user_mode >> 3))) {
1016 pnntace = (struct cifs_ace *) (nacl_base + nsize);
1017 nsize += fill_ace_for_sid(pnntace, pgrpsid, deny_group_mode,
1018 0070, ACCESS_DENIED, false);
1019 num_aces++;
1020 }
1021
1022 pnntace = (struct cifs_ace *) (nacl_base + nsize);
1023 nsize += fill_ace_for_sid(pnntace, pgrpsid, group_mode,
1024 0070, ACCESS_ALLOWED, !sticky_set);
1025 num_aces++;
1026
1027 pnntace = (struct cifs_ace *) (nacl_base + nsize);
1028 nsize += fill_ace_for_sid(pnntace, &sid_everyone, other_mode,
1029 0007, ACCESS_ALLOWED, !sticky_set);
1030 num_aces++;
1031
1032 set_size:
1033 *pnum_aces = num_aces;
1034 *pnsize = nsize;
1035 }
1036
1037 static __u16 replace_sids_and_copy_aces(struct cifs_acl *pdacl, struct cifs_acl *pndacl,
1038 struct cifs_sid *pownersid, struct cifs_sid *pgrpsid,
1039 struct cifs_sid *pnownersid, struct cifs_sid *pngrpsid)
1040 {
1041 int i;
1042 u16 size = 0;
1043 struct cifs_ace *pntace = NULL;
1044 char *acl_base = NULL;
1045 u32 src_num_aces = 0;
1046 u16 nsize = 0;
1047 struct cifs_ace *pnntace = NULL;
1048 char *nacl_base = NULL;
1049 u16 ace_size = 0;
1050
1051 acl_base = (char *)pdacl;
1052 size = sizeof(struct cifs_acl);
1053 src_num_aces = le32_to_cpu(pdacl->num_aces);
1054
1055 nacl_base = (char *)pndacl;
1056 nsize = sizeof(struct cifs_acl);
1057
1058 /* Go through all the ACEs */
1059 for (i = 0; i < src_num_aces; ++i) {
1060 pntace = (struct cifs_ace *) (acl_base + size);
1061 pnntace = (struct cifs_ace *) (nacl_base + nsize);
1062
1063 if (pnownersid && compare_sids(&pntace->sid, pownersid) == 0)
1064 ace_size = cifs_copy_ace(pnntace, pntace, pnownersid);
1065 else if (pngrpsid && compare_sids(&pntace->sid, pgrpsid) == 0)
1066 ace_size = cifs_copy_ace(pnntace, pntace, pngrpsid);
1067 else
1068 ace_size = cifs_copy_ace(pnntace, pntace, NULL);
1069
1070 size += le16_to_cpu(pntace->size);
1071 nsize += ace_size;
1072 }
1073
1074 return nsize;
1075 }
1076
1077 static int set_chmod_dacl(struct cifs_acl *pdacl, struct cifs_acl *pndacl,
1078 struct cifs_sid *pownersid, struct cifs_sid *pgrpsid,
1079 __u64 *pnmode, bool mode_from_sid)
1080 {
1081 int i;
1082 u16 size = 0;
1083 struct cifs_ace *pntace = NULL;
1084 char *acl_base = NULL;
1085 u32 src_num_aces = 0;
1086 u16 nsize = 0;
1087 struct cifs_ace *pnntace = NULL;
1088 char *nacl_base = NULL;
1089 u32 num_aces = 0;
1090 bool new_aces_set = false;
1091
1092 /* Assuming that pndacl and pnmode are never NULL */
1093 nacl_base = (char *)pndacl;
1094 nsize = sizeof(struct cifs_acl);
1095
1096 /* If pdacl is NULL, we don't have a src. Simply populate new ACL. */
1097 if (!pdacl) {
1098 populate_new_aces(nacl_base,
1099 pownersid, pgrpsid,
1100 pnmode, &num_aces, &nsize,
1101 mode_from_sid);
1102 goto finalize_dacl;
1103 }
1104
1105 acl_base = (char *)pdacl;
1106 size = sizeof(struct cifs_acl);
1107 src_num_aces = le32_to_cpu(pdacl->num_aces);
1108
1109 /* Retain old ACEs which we can retain */
1110 for (i = 0; i < src_num_aces; ++i) {
1111 pntace = (struct cifs_ace *) (acl_base + size);
1112
1113 if (!new_aces_set && (pntace->flags & INHERITED_ACE)) {
1114 /* Place the new ACEs in between existing explicit and inherited */
1115 populate_new_aces(nacl_base,
1116 pownersid, pgrpsid,
1117 pnmode, &num_aces, &nsize,
1118 mode_from_sid);
1119
1120 new_aces_set = true;
1121 }
1122
1123 /* If it's any one of the ACE we're replacing, skip! */
1124 if (((compare_sids(&pntace->sid, &sid_unix_NFS_mode) == 0) ||
1125 (compare_sids(&pntace->sid, pownersid) == 0) ||
1126 (compare_sids(&pntace->sid, pgrpsid) == 0) ||
1127 (compare_sids(&pntace->sid, &sid_everyone) == 0) ||
1128 (compare_sids(&pntace->sid, &sid_authusers) == 0))) {
1129 goto next_ace;
1130 }
1131
1132 /* update the pointer to the next ACE to populate*/
1133 pnntace = (struct cifs_ace *) (nacl_base + nsize);
1134
1135 nsize += cifs_copy_ace(pnntace, pntace, NULL);
1136 num_aces++;
1137
1138 next_ace:
1139 size += le16_to_cpu(pntace->size);
1140 }
1141
1142 /* If inherited ACEs are not present, place the new ones at the tail */
1143 if (!new_aces_set) {
1144 populate_new_aces(nacl_base,
1145 pownersid, pgrpsid,
1146 pnmode, &num_aces, &nsize,
1147 mode_from_sid);
1148
1149 new_aces_set = true;
1150 }
1151
1152 finalize_dacl:
1153 pndacl->num_aces = cpu_to_le32(num_aces);
1154 pndacl->size = cpu_to_le16(nsize);
1155
1156 return 0;
1157 }
1158
1159 static int parse_sid(struct cifs_sid *psid, char *end_of_acl)
1160 {
1161 /* BB need to add parm so we can store the SID BB */
1162
1163 /* validate that we do not go past end of ACL - sid must be at least 8
1164 bytes long (assuming no sub-auths - e.g. the null SID */
1165 if (end_of_acl < (char *)psid + 8) {
1166 cifs_dbg(VFS, "ACL too small to parse SID %p\n", psid);
1167 return -EINVAL;
1168 }
1169
1170 #ifdef CONFIG_CIFS_DEBUG2
1171 if (psid->num_subauth) {
1172 int i;
1173 cifs_dbg(FYI, "SID revision %d num_auth %d\n",
1174 psid->revision, psid->num_subauth);
1175
1176 for (i = 0; i < psid->num_subauth; i++) {
1177 cifs_dbg(FYI, "SID sub_auth[%d]: 0x%x\n",
1178 i, le32_to_cpu(psid->sub_auth[i]));
1179 }
1180
1181 /* BB add length check to make sure that we do not have huge
1182 num auths and therefore go off the end */
1183 cifs_dbg(FYI, "RID 0x%x\n",
1184 le32_to_cpu(psid->sub_auth[psid->num_subauth-1]));
1185 }
1186 #endif
1187
1188 return 0;
1189 }
1190
1191
1192 /* Convert CIFS ACL to POSIX form */
1193 static int parse_sec_desc(struct cifs_sb_info *cifs_sb,
1194 struct cifs_ntsd *pntsd, int acl_len, struct cifs_fattr *fattr,
1195 bool get_mode_from_special_sid)
1196 {
1197 int rc = 0;
1198 struct cifs_sid *owner_sid_ptr, *group_sid_ptr;
1199 struct cifs_acl *dacl_ptr; /* no need for SACL ptr */
1200 char *end_of_acl = ((char *)pntsd) + acl_len;
1201 __u32 dacloffset;
1202
1203 if (pntsd == NULL)
1204 return -EIO;
1205
1206 owner_sid_ptr = (struct cifs_sid *)((char *)pntsd +
1207 le32_to_cpu(pntsd->osidoffset));
1208 group_sid_ptr = (struct cifs_sid *)((char *)pntsd +
1209 le32_to_cpu(pntsd->gsidoffset));
1210 dacloffset = le32_to_cpu(pntsd->dacloffset);
1211 dacl_ptr = (struct cifs_acl *)((char *)pntsd + dacloffset);
1212 cifs_dbg(NOISY, "revision %d type 0x%x ooffset 0x%x goffset 0x%x sacloffset 0x%x dacloffset 0x%x\n",
1213 pntsd->revision, pntsd->type, le32_to_cpu(pntsd->osidoffset),
1214 le32_to_cpu(pntsd->gsidoffset),
1215 le32_to_cpu(pntsd->sacloffset), dacloffset);
1216 /* cifs_dump_mem("owner_sid: ", owner_sid_ptr, 64); */
1217 rc = parse_sid(owner_sid_ptr, end_of_acl);
1218 if (rc) {
1219 cifs_dbg(FYI, "%s: Error %d parsing Owner SID\n", __func__, rc);
1220 return rc;
1221 }
1222 rc = sid_to_id(cifs_sb, owner_sid_ptr, fattr, SIDOWNER);
1223 if (rc) {
1224 cifs_dbg(FYI, "%s: Error %d mapping Owner SID to uid\n",
1225 __func__, rc);
1226 return rc;
1227 }
1228
1229 rc = parse_sid(group_sid_ptr, end_of_acl);
1230 if (rc) {
1231 cifs_dbg(FYI, "%s: Error %d mapping Owner SID to gid\n",
1232 __func__, rc);
1233 return rc;
1234 }
1235 rc = sid_to_id(cifs_sb, group_sid_ptr, fattr, SIDGROUP);
1236 if (rc) {
1237 cifs_dbg(FYI, "%s: Error %d mapping Group SID to gid\n",
1238 __func__, rc);
1239 return rc;
1240 }
1241
1242 if (dacloffset)
1243 parse_dacl(dacl_ptr, end_of_acl, owner_sid_ptr,
1244 group_sid_ptr, fattr, get_mode_from_special_sid);
1245 else
1246 cifs_dbg(FYI, "no ACL\n"); /* BB grant all or default perms? */
1247
1248 return rc;
1249 }
1250
1251 /* Convert permission bits from mode to equivalent CIFS ACL */
1252 static int build_sec_desc(struct cifs_ntsd *pntsd, struct cifs_ntsd *pnntsd,
1253 __u32 secdesclen, __u32 *pnsecdesclen, __u64 *pnmode, kuid_t uid, kgid_t gid,
1254 bool mode_from_sid, bool id_from_sid, int *aclflag)
1255 {
1256 int rc = 0;
1257 __u32 dacloffset;
1258 __u32 ndacloffset;
1259 __u32 sidsoffset;
1260 struct cifs_sid *owner_sid_ptr, *group_sid_ptr;
1261 struct cifs_sid *nowner_sid_ptr = NULL, *ngroup_sid_ptr = NULL;
1262 struct cifs_acl *dacl_ptr = NULL; /* no need for SACL ptr */
1263 struct cifs_acl *ndacl_ptr = NULL; /* no need for SACL ptr */
1264 char *end_of_acl = ((char *)pntsd) + secdesclen;
1265 u16 size = 0;
1266
1267 dacloffset = le32_to_cpu(pntsd->dacloffset);
1268 if (dacloffset) {
1269 dacl_ptr = (struct cifs_acl *)((char *)pntsd + dacloffset);
1270 if (end_of_acl < (char *)dacl_ptr + le16_to_cpu(dacl_ptr->size)) {
1271 cifs_dbg(VFS, "Server returned illegal ACL size\n");
1272 return -EINVAL;
1273 }
1274 }
1275
1276 owner_sid_ptr = (struct cifs_sid *)((char *)pntsd +
1277 le32_to_cpu(pntsd->osidoffset));
1278 group_sid_ptr = (struct cifs_sid *)((char *)pntsd +
1279 le32_to_cpu(pntsd->gsidoffset));
1280
1281 if (pnmode && *pnmode != NO_CHANGE_64) { /* chmod */
1282 ndacloffset = sizeof(struct cifs_ntsd);
1283 ndacl_ptr = (struct cifs_acl *)((char *)pnntsd + ndacloffset);
1284 ndacl_ptr->revision =
1285 dacloffset ? dacl_ptr->revision : cpu_to_le16(ACL_REVISION);
1286
1287 ndacl_ptr->size = cpu_to_le16(0);
1288 ndacl_ptr->num_aces = cpu_to_le32(0);
1289
1290 rc = set_chmod_dacl(dacl_ptr, ndacl_ptr, owner_sid_ptr, group_sid_ptr,
1291 pnmode, mode_from_sid);
1292
1293 sidsoffset = ndacloffset + le16_to_cpu(ndacl_ptr->size);
1294 /* copy the non-dacl portion of secdesc */
1295 *pnsecdesclen = copy_sec_desc(pntsd, pnntsd, sidsoffset,
1296 NULL, NULL);
1297
1298 *aclflag |= CIFS_ACL_DACL;
1299 } else {
1300 ndacloffset = sizeof(struct cifs_ntsd);
1301 ndacl_ptr = (struct cifs_acl *)((char *)pnntsd + ndacloffset);
1302 ndacl_ptr->revision =
1303 dacloffset ? dacl_ptr->revision : cpu_to_le16(ACL_REVISION);
1304 ndacl_ptr->num_aces = dacl_ptr ? dacl_ptr->num_aces : 0;
1305
1306 if (uid_valid(uid)) { /* chown */
1307 uid_t id;
1308 nowner_sid_ptr = kzalloc(sizeof(struct cifs_sid),
1309 GFP_KERNEL);
1310 if (!nowner_sid_ptr) {
1311 rc = -ENOMEM;
1312 goto chown_chgrp_exit;
1313 }
1314 id = from_kuid(&init_user_ns, uid);
1315 if (id_from_sid) {
1316 struct owner_sid *osid = (struct owner_sid *)nowner_sid_ptr;
1317 /* Populate the user ownership fields S-1-5-88-1 */
1318 osid->Revision = 1;
1319 osid->NumAuth = 3;
1320 osid->Authority[5] = 5;
1321 osid->SubAuthorities[0] = cpu_to_le32(88);
1322 osid->SubAuthorities[1] = cpu_to_le32(1);
1323 osid->SubAuthorities[2] = cpu_to_le32(id);
1324
1325 } else { /* lookup sid with upcall */
1326 rc = id_to_sid(id, SIDOWNER, nowner_sid_ptr);
1327 if (rc) {
1328 cifs_dbg(FYI, "%s: Mapping error %d for owner id %d\n",
1329 __func__, rc, id);
1330 goto chown_chgrp_exit;
1331 }
1332 }
1333 *aclflag |= CIFS_ACL_OWNER;
1334 }
1335 if (gid_valid(gid)) { /* chgrp */
1336 gid_t id;
1337 ngroup_sid_ptr = kzalloc(sizeof(struct cifs_sid),
1338 GFP_KERNEL);
1339 if (!ngroup_sid_ptr) {
1340 rc = -ENOMEM;
1341 goto chown_chgrp_exit;
1342 }
1343 id = from_kgid(&init_user_ns, gid);
1344 if (id_from_sid) {
1345 struct owner_sid *gsid = (struct owner_sid *)ngroup_sid_ptr;
1346 /* Populate the group ownership fields S-1-5-88-2 */
1347 gsid->Revision = 1;
1348 gsid->NumAuth = 3;
1349 gsid->Authority[5] = 5;
1350 gsid->SubAuthorities[0] = cpu_to_le32(88);
1351 gsid->SubAuthorities[1] = cpu_to_le32(2);
1352 gsid->SubAuthorities[2] = cpu_to_le32(id);
1353
1354 } else { /* lookup sid with upcall */
1355 rc = id_to_sid(id, SIDGROUP, ngroup_sid_ptr);
1356 if (rc) {
1357 cifs_dbg(FYI, "%s: Mapping error %d for group id %d\n",
1358 __func__, rc, id);
1359 goto chown_chgrp_exit;
1360 }
1361 }
1362 *aclflag |= CIFS_ACL_GROUP;
1363 }
1364
1365 if (dacloffset) {
1366 /* Replace ACEs for old owner with new one */
1367 size = replace_sids_and_copy_aces(dacl_ptr, ndacl_ptr,
1368 owner_sid_ptr, group_sid_ptr,
1369 nowner_sid_ptr, ngroup_sid_ptr);
1370 ndacl_ptr->size = cpu_to_le16(size);
1371 }
1372
1373 sidsoffset = ndacloffset + le16_to_cpu(ndacl_ptr->size);
1374 /* copy the non-dacl portion of secdesc */
1375 *pnsecdesclen = copy_sec_desc(pntsd, pnntsd, sidsoffset,
1376 nowner_sid_ptr, ngroup_sid_ptr);
1377
1378 chown_chgrp_exit:
1379 /* errors could jump here. So make sure we return soon after this */
1380 kfree(nowner_sid_ptr);
1381 kfree(ngroup_sid_ptr);
1382 }
1383
1384 return rc;
1385 }
1386
1387 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
1388 struct cifs_ntsd *get_cifs_acl_by_fid(struct cifs_sb_info *cifs_sb,
1389 const struct cifs_fid *cifsfid, u32 *pacllen,
1390 u32 __maybe_unused unused)
1391 {
1392 struct cifs_ntsd *pntsd = NULL;
1393 unsigned int xid;
1394 int rc;
1395 struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
1396
1397 if (IS_ERR(tlink))
1398 return ERR_CAST(tlink);
1399
1400 xid = get_xid();
1401 rc = CIFSSMBGetCIFSACL(xid, tlink_tcon(tlink), cifsfid->netfid, &pntsd,
1402 pacllen);
1403 free_xid(xid);
1404
1405 cifs_put_tlink(tlink);
1406
1407 cifs_dbg(FYI, "%s: rc = %d ACL len %d\n", __func__, rc, *pacllen);
1408 if (rc)
1409 return ERR_PTR(rc);
1410 return pntsd;
1411 }
1412
1413 static struct cifs_ntsd *get_cifs_acl_by_path(struct cifs_sb_info *cifs_sb,
1414 const char *path, u32 *pacllen)
1415 {
1416 struct cifs_ntsd *pntsd = NULL;
1417 int oplock = 0;
1418 unsigned int xid;
1419 int rc;
1420 struct cifs_tcon *tcon;
1421 struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
1422 struct cifs_fid fid;
1423 struct cifs_open_parms oparms;
1424
1425 if (IS_ERR(tlink))
1426 return ERR_CAST(tlink);
1427
1428 tcon = tlink_tcon(tlink);
1429 xid = get_xid();
1430
1431 oparms = (struct cifs_open_parms) {
1432 .tcon = tcon,
1433 .cifs_sb = cifs_sb,
1434 .desired_access = READ_CONTROL,
1435 .create_options = cifs_create_options(cifs_sb, 0),
1436 .disposition = FILE_OPEN,
1437 .path = path,
1438 .fid = &fid,
1439 };
1440
1441 rc = CIFS_open(xid, &oparms, &oplock, NULL);
1442 if (!rc) {
1443 rc = CIFSSMBGetCIFSACL(xid, tcon, fid.netfid, &pntsd, pacllen);
1444 CIFSSMBClose(xid, tcon, fid.netfid);
1445 }
1446
1447 cifs_put_tlink(tlink);
1448 free_xid(xid);
1449
1450 cifs_dbg(FYI, "%s: rc = %d ACL len %d\n", __func__, rc, *pacllen);
1451 if (rc)
1452 return ERR_PTR(rc);
1453 return pntsd;
1454 }
1455
1456 /* Retrieve an ACL from the server */
1457 struct cifs_ntsd *get_cifs_acl(struct cifs_sb_info *cifs_sb,
1458 struct inode *inode, const char *path,
1459 u32 *pacllen, u32 info)
1460 {
1461 struct cifs_ntsd *pntsd = NULL;
1462 struct cifsFileInfo *open_file = NULL;
1463
1464 if (inode)
1465 open_file = find_readable_file(CIFS_I(inode), true);
1466 if (!open_file)
1467 return get_cifs_acl_by_path(cifs_sb, path, pacllen);
1468
1469 pntsd = get_cifs_acl_by_fid(cifs_sb, &open_file->fid, pacllen, info);
1470 cifsFileInfo_put(open_file);
1471 return pntsd;
1472 }
1473
1474 /* Set an ACL on the server */
1475 int set_cifs_acl(struct cifs_ntsd *pnntsd, __u32 acllen,
1476 struct inode *inode, const char *path, int aclflag)
1477 {
1478 int oplock = 0;
1479 unsigned int xid;
1480 int rc, access_flags;
1481 struct cifs_tcon *tcon;
1482 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
1483 struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
1484 struct cifs_fid fid;
1485 struct cifs_open_parms oparms;
1486
1487 if (IS_ERR(tlink))
1488 return PTR_ERR(tlink);
1489
1490 tcon = tlink_tcon(tlink);
1491 xid = get_xid();
1492
1493 if (aclflag == CIFS_ACL_OWNER || aclflag == CIFS_ACL_GROUP)
1494 access_flags = WRITE_OWNER;
1495 else
1496 access_flags = WRITE_DAC;
1497
1498 oparms = (struct cifs_open_parms) {
1499 .tcon = tcon,
1500 .cifs_sb = cifs_sb,
1501 .desired_access = access_flags,
1502 .create_options = cifs_create_options(cifs_sb, 0),
1503 .disposition = FILE_OPEN,
1504 .path = path,
1505 .fid = &fid,
1506 };
1507
1508 rc = CIFS_open(xid, &oparms, &oplock, NULL);
1509 if (rc) {
1510 cifs_dbg(VFS, "Unable to open file to set ACL\n");
1511 goto out;
1512 }
1513
1514 rc = CIFSSMBSetCIFSACL(xid, tcon, fid.netfid, pnntsd, acllen, aclflag);
1515 cifs_dbg(NOISY, "SetCIFSACL rc = %d\n", rc);
1516
1517 CIFSSMBClose(xid, tcon, fid.netfid);
1518 out:
1519 free_xid(xid);
1520 cifs_put_tlink(tlink);
1521 return rc;
1522 }
1523 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
1524
1525 /* Translate the CIFS ACL (similar to NTFS ACL) for a file into mode bits */
1526 int
1527 cifs_acl_to_fattr(struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr,
1528 struct inode *inode, bool mode_from_special_sid,
1529 const char *path, const struct cifs_fid *pfid)
1530 {
1531 struct cifs_ntsd *pntsd = NULL;
1532 u32 acllen = 0;
1533 int rc = 0;
1534 struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
1535 struct smb_version_operations *ops;
1536 const u32 info = 0;
1537
1538 cifs_dbg(NOISY, "converting ACL to mode for %s\n", path);
1539
1540 if (IS_ERR(tlink))
1541 return PTR_ERR(tlink);
1542
1543 ops = tlink_tcon(tlink)->ses->server->ops;
1544
1545 if (pfid && (ops->get_acl_by_fid))
1546 pntsd = ops->get_acl_by_fid(cifs_sb, pfid, &acllen, info);
1547 else if (ops->get_acl)
1548 pntsd = ops->get_acl(cifs_sb, inode, path, &acllen, info);
1549 else {
1550 cifs_put_tlink(tlink);
1551 return -EOPNOTSUPP;
1552 }
1553 /* if we can retrieve the ACL, now parse Access Control Entries, ACEs */
1554 if (IS_ERR(pntsd)) {
1555 rc = PTR_ERR(pntsd);
1556 cifs_dbg(VFS, "%s: error %d getting sec desc\n", __func__, rc);
1557 } else if (mode_from_special_sid) {
1558 rc = parse_sec_desc(cifs_sb, pntsd, acllen, fattr, true);
1559 kfree(pntsd);
1560 } else {
1561 /* get approximated mode from ACL */
1562 rc = parse_sec_desc(cifs_sb, pntsd, acllen, fattr, false);
1563 kfree(pntsd);
1564 if (rc)
1565 cifs_dbg(VFS, "parse sec desc failed rc = %d\n", rc);
1566 }
1567
1568 cifs_put_tlink(tlink);
1569
1570 return rc;
1571 }
1572
1573 /* Convert mode bits to an ACL so we can update the ACL on the server */
1574 int
1575 id_mode_to_cifs_acl(struct inode *inode, const char *path, __u64 *pnmode,
1576 kuid_t uid, kgid_t gid)
1577 {
1578 int rc = 0;
1579 int aclflag = CIFS_ACL_DACL; /* default flag to set */
1580 __u32 secdesclen = 0;
1581 __u32 nsecdesclen = 0;
1582 __u32 dacloffset = 0;
1583 struct cifs_acl *dacl_ptr = NULL;
1584 struct cifs_ntsd *pntsd = NULL; /* acl obtained from server */
1585 struct cifs_ntsd *pnntsd = NULL; /* modified acl to be sent to server */
1586 struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
1587 struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
1588 struct smb_version_operations *ops;
1589 bool mode_from_sid, id_from_sid;
1590 const u32 info = 0;
1591
1592 if (IS_ERR(tlink))
1593 return PTR_ERR(tlink);
1594
1595 ops = tlink_tcon(tlink)->ses->server->ops;
1596
1597 cifs_dbg(NOISY, "set ACL from mode for %s\n", path);
1598
1599 /* Get the security descriptor */
1600
1601 if (ops->get_acl == NULL) {
1602 cifs_put_tlink(tlink);
1603 return -EOPNOTSUPP;
1604 }
1605
1606 pntsd = ops->get_acl(cifs_sb, inode, path, &secdesclen, info);
1607 if (IS_ERR(pntsd)) {
1608 rc = PTR_ERR(pntsd);
1609 cifs_dbg(VFS, "%s: error %d getting sec desc\n", __func__, rc);
1610 cifs_put_tlink(tlink);
1611 return rc;
1612 }
1613
1614 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MODE_FROM_SID)
1615 mode_from_sid = true;
1616 else
1617 mode_from_sid = false;
1618
1619 if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UID_FROM_ACL)
1620 id_from_sid = true;
1621 else
1622 id_from_sid = false;
1623
1624 /* Potentially, five new ACEs can be added to the ACL for U,G,O mapping */
1625 nsecdesclen = secdesclen;
1626 if (pnmode && *pnmode != NO_CHANGE_64) { /* chmod */
1627 if (mode_from_sid)
1628 nsecdesclen += 2 * sizeof(struct cifs_ace);
1629 else /* cifsacl */
1630 nsecdesclen += 5 * sizeof(struct cifs_ace);
1631 } else { /* chown */
1632 /* When ownership changes, changes new owner sid length could be different */
1633 nsecdesclen = sizeof(struct cifs_ntsd) + (sizeof(struct cifs_sid) * 2);
1634 dacloffset = le32_to_cpu(pntsd->dacloffset);
1635 if (dacloffset) {
1636 dacl_ptr = (struct cifs_acl *)((char *)pntsd + dacloffset);
1637 if (mode_from_sid)
1638 nsecdesclen +=
1639 le32_to_cpu(dacl_ptr->num_aces) * sizeof(struct cifs_ace);
1640 else /* cifsacl */
1641 nsecdesclen += le16_to_cpu(dacl_ptr->size);
1642 }
1643 }
1644
1645 /*
1646 * Add three ACEs for owner, group, everyone getting rid of other ACEs
1647 * as chmod disables ACEs and set the security descriptor. Allocate
1648 * memory for the smb header, set security descriptor request security
1649 * descriptor parameters, and security descriptor itself
1650 */
1651 nsecdesclen = max_t(u32, nsecdesclen, DEFAULT_SEC_DESC_LEN);
1652 pnntsd = kmalloc(nsecdesclen, GFP_KERNEL);
1653 if (!pnntsd) {
1654 kfree(pntsd);
1655 cifs_put_tlink(tlink);
1656 return -ENOMEM;
1657 }
1658
1659 rc = build_sec_desc(pntsd, pnntsd, secdesclen, &nsecdesclen, pnmode, uid, gid,
1660 mode_from_sid, id_from_sid, &aclflag);
1661
1662 cifs_dbg(NOISY, "build_sec_desc rc: %d\n", rc);
1663
1664 if (ops->set_acl == NULL)
1665 rc = -EOPNOTSUPP;
1666
1667 if (!rc) {
1668 /* Set the security descriptor */
1669 rc = ops->set_acl(pnntsd, nsecdesclen, inode, path, aclflag);
1670 cifs_dbg(NOISY, "set_cifs_acl rc: %d\n", rc);
1671 }
1672 cifs_put_tlink(tlink);
1673
1674 kfree(pnntsd);
1675 kfree(pntsd);
1676 return rc;
1677 }
1678
1679 struct posix_acl *cifs_get_acl(struct mnt_idmap *idmap,
1680 struct dentry *dentry, int type)
1681 {
1682 #if defined(CONFIG_CIFS_ALLOW_INSECURE_LEGACY) && defined(CONFIG_CIFS_POSIX)
1683 struct posix_acl *acl = NULL;
1684 ssize_t rc = -EOPNOTSUPP;
1685 unsigned int xid;
1686 struct super_block *sb = dentry->d_sb;
1687 struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
1688 struct tcon_link *tlink;
1689 struct cifs_tcon *pTcon;
1690 const char *full_path;
1691 void *page;
1692
1693 tlink = cifs_sb_tlink(cifs_sb);
1694 if (IS_ERR(tlink))
1695 return ERR_CAST(tlink);
1696 pTcon = tlink_tcon(tlink);
1697
1698 xid = get_xid();
1699 page = alloc_dentry_path();
1700
1701 full_path = build_path_from_dentry(dentry, page);
1702 if (IS_ERR(full_path)) {
1703 acl = ERR_CAST(full_path);
1704 goto out;
1705 }
1706
1707 /* return alt name if available as pseudo attr */
1708 switch (type) {
1709 case ACL_TYPE_ACCESS:
1710 if (sb->s_flags & SB_POSIXACL)
1711 rc = cifs_do_get_acl(xid, pTcon, full_path, &acl,
1712 ACL_TYPE_ACCESS,
1713 cifs_sb->local_nls,
1714 cifs_remap(cifs_sb));
1715 break;
1716
1717 case ACL_TYPE_DEFAULT:
1718 if (sb->s_flags & SB_POSIXACL)
1719 rc = cifs_do_get_acl(xid, pTcon, full_path, &acl,
1720 ACL_TYPE_DEFAULT,
1721 cifs_sb->local_nls,
1722 cifs_remap(cifs_sb));
1723 break;
1724 }
1725
1726 if (rc < 0) {
1727 if (rc == -EINVAL)
1728 acl = ERR_PTR(-EOPNOTSUPP);
1729 else
1730 acl = ERR_PTR(rc);
1731 }
1732
1733 out:
1734 free_dentry_path(page);
1735 free_xid(xid);
1736 cifs_put_tlink(tlink);
1737 return acl;
1738 #else
1739 return ERR_PTR(-EOPNOTSUPP);
1740 #endif
1741 }
1742
1743 int cifs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
1744 struct posix_acl *acl, int type)
1745 {
1746 #if defined(CONFIG_CIFS_ALLOW_INSECURE_LEGACY) && defined(CONFIG_CIFS_POSIX)
1747 int rc = -EOPNOTSUPP;
1748 unsigned int xid;
1749 struct super_block *sb = dentry->d_sb;
1750 struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
1751 struct tcon_link *tlink;
1752 struct cifs_tcon *pTcon;
1753 const char *full_path;
1754 void *page;
1755
1756 tlink = cifs_sb_tlink(cifs_sb);
1757 if (IS_ERR(tlink))
1758 return PTR_ERR(tlink);
1759 pTcon = tlink_tcon(tlink);
1760
1761 xid = get_xid();
1762 page = alloc_dentry_path();
1763
1764 full_path = build_path_from_dentry(dentry, page);
1765 if (IS_ERR(full_path)) {
1766 rc = PTR_ERR(full_path);
1767 goto out;
1768 }
1769
1770 if (!acl)
1771 goto out;
1772
1773 /* return dos attributes as pseudo xattr */
1774 /* return alt name if available as pseudo attr */
1775
1776 /* if proc/fs/cifs/streamstoxattr is set then
1777 search server for EAs or streams to
1778 returns as xattrs */
1779 if (posix_acl_xattr_size(acl->a_count) > CIFSMaxBufSize) {
1780 cifs_dbg(FYI, "size of EA value too large\n");
1781 rc = -EOPNOTSUPP;
1782 goto out;
1783 }
1784
1785 switch (type) {
1786 case ACL_TYPE_ACCESS:
1787 if (sb->s_flags & SB_POSIXACL)
1788 rc = cifs_do_set_acl(xid, pTcon, full_path, acl,
1789 ACL_TYPE_ACCESS,
1790 cifs_sb->local_nls,
1791 cifs_remap(cifs_sb));
1792 break;
1793
1794 case ACL_TYPE_DEFAULT:
1795 if (sb->s_flags & SB_POSIXACL)
1796 rc = cifs_do_set_acl(xid, pTcon, full_path, acl,
1797 ACL_TYPE_DEFAULT,
1798 cifs_sb->local_nls,
1799 cifs_remap(cifs_sb));
1800 break;
1801 }
1802
1803 out:
1804 free_dentry_path(page);
1805 free_xid(xid);
1806 cifs_put_tlink(tlink);
1807 return rc;
1808 #else
1809 return -EOPNOTSUPP;
1810 #endif
1811 }
1812
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