powerpc/vphn: move VPHN parsing logic to a separate file
[linux/fpc-iii.git] / security / apparmor / policy_unpack.c
bloba689f10930b5e825c4da751508e274d8715ef2b5
1 /*
2 * AppArmor security module
4 * This file contains AppArmor functions for unpacking policy loaded from
5 * userspace.
7 * Copyright (C) 1998-2008 Novell/SUSE
8 * Copyright 2009-2010 Canonical Ltd.
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation, version 2 of the
13 * License.
15 * AppArmor uses a serialized binary format for loading policy. To find
16 * policy format documentation look in Documentation/security/apparmor.txt
17 * All policy is validated before it is used.
20 #include <asm/unaligned.h>
21 #include <linux/ctype.h>
22 #include <linux/errno.h>
24 #include "include/apparmor.h"
25 #include "include/audit.h"
26 #include "include/context.h"
27 #include "include/crypto.h"
28 #include "include/match.h"
29 #include "include/policy.h"
30 #include "include/policy_unpack.h"
33 * The AppArmor interface treats data as a type byte followed by the
34 * actual data. The interface has the notion of a a named entry
35 * which has a name (AA_NAME typecode followed by name string) followed by
36 * the entries typecode and data. Named types allow for optional
37 * elements and extensions to be added and tested for without breaking
38 * backwards compatibility.
41 enum aa_code {
42 AA_U8,
43 AA_U16,
44 AA_U32,
45 AA_U64,
46 AA_NAME, /* same as string except it is items name */
47 AA_STRING,
48 AA_BLOB,
49 AA_STRUCT,
50 AA_STRUCTEND,
51 AA_LIST,
52 AA_LISTEND,
53 AA_ARRAY,
54 AA_ARRAYEND,
58 * aa_ext is the read of the buffer containing the serialized profile. The
59 * data is copied into a kernel buffer in apparmorfs and then handed off to
60 * the unpack routines.
62 struct aa_ext {
63 void *start;
64 void *end;
65 void *pos; /* pointer to current position in the buffer */
66 u32 version;
69 /* audit callback for unpack fields */
70 static void audit_cb(struct audit_buffer *ab, void *va)
72 struct common_audit_data *sa = va;
73 if (sa->aad->iface.target) {
74 struct aa_profile *name = sa->aad->iface.target;
75 audit_log_format(ab, " name=");
76 audit_log_untrustedstring(ab, name->base.hname);
78 if (sa->aad->iface.pos)
79 audit_log_format(ab, " offset=%ld", sa->aad->iface.pos);
82 /**
83 * audit_iface - do audit message for policy unpacking/load/replace/remove
84 * @new: profile if it has been allocated (MAYBE NULL)
85 * @name: name of the profile being manipulated (MAYBE NULL)
86 * @info: any extra info about the failure (MAYBE NULL)
87 * @e: buffer position info
88 * @error: error code
90 * Returns: %0 or error
92 static int audit_iface(struct aa_profile *new, const char *name,
93 const char *info, struct aa_ext *e, int error)
95 struct aa_profile *profile = __aa_current_profile();
96 struct common_audit_data sa;
97 struct apparmor_audit_data aad = {0,};
98 sa.type = LSM_AUDIT_DATA_NONE;
99 sa.aad = &aad;
100 if (e)
101 aad.iface.pos = e->pos - e->start;
102 aad.iface.target = new;
103 aad.name = name;
104 aad.info = info;
105 aad.error = error;
107 return aa_audit(AUDIT_APPARMOR_STATUS, profile, GFP_KERNEL, &sa,
108 audit_cb);
111 /* test if read will be in packed data bounds */
112 static bool inbounds(struct aa_ext *e, size_t size)
114 return (size <= e->end - e->pos);
118 * aa_u16_chunck - test and do bounds checking for a u16 size based chunk
119 * @e: serialized data read head (NOT NULL)
120 * @chunk: start address for chunk of data (NOT NULL)
122 * Returns: the size of chunk found with the read head at the end of the chunk.
124 static size_t unpack_u16_chunk(struct aa_ext *e, char **chunk)
126 size_t size = 0;
128 if (!inbounds(e, sizeof(u16)))
129 return 0;
130 size = le16_to_cpu(get_unaligned((u16 *) e->pos));
131 e->pos += sizeof(u16);
132 if (!inbounds(e, size))
133 return 0;
134 *chunk = e->pos;
135 e->pos += size;
136 return size;
139 /* unpack control byte */
140 static bool unpack_X(struct aa_ext *e, enum aa_code code)
142 if (!inbounds(e, 1))
143 return 0;
144 if (*(u8 *) e->pos != code)
145 return 0;
146 e->pos++;
147 return 1;
151 * unpack_nameX - check is the next element is of type X with a name of @name
152 * @e: serialized data extent information (NOT NULL)
153 * @code: type code
154 * @name: name to match to the serialized element. (MAYBE NULL)
156 * check that the next serialized data element is of type X and has a tag
157 * name @name. If @name is specified then there must be a matching
158 * name element in the stream. If @name is NULL any name element will be
159 * skipped and only the typecode will be tested.
161 * Returns 1 on success (both type code and name tests match) and the read
162 * head is advanced past the headers
164 * Returns: 0 if either match fails, the read head does not move
166 static bool unpack_nameX(struct aa_ext *e, enum aa_code code, const char *name)
169 * May need to reset pos if name or type doesn't match
171 void *pos = e->pos;
173 * Check for presence of a tagname, and if present name size
174 * AA_NAME tag value is a u16.
176 if (unpack_X(e, AA_NAME)) {
177 char *tag = NULL;
178 size_t size = unpack_u16_chunk(e, &tag);
179 /* if a name is specified it must match. otherwise skip tag */
180 if (name && (!size || strcmp(name, tag)))
181 goto fail;
182 } else if (name) {
183 /* if a name is specified and there is no name tag fail */
184 goto fail;
187 /* now check if type code matches */
188 if (unpack_X(e, code))
189 return 1;
191 fail:
192 e->pos = pos;
193 return 0;
196 static bool unpack_u32(struct aa_ext *e, u32 *data, const char *name)
198 if (unpack_nameX(e, AA_U32, name)) {
199 if (!inbounds(e, sizeof(u32)))
200 return 0;
201 if (data)
202 *data = le32_to_cpu(get_unaligned((u32 *) e->pos));
203 e->pos += sizeof(u32);
204 return 1;
206 return 0;
209 static bool unpack_u64(struct aa_ext *e, u64 *data, const char *name)
211 if (unpack_nameX(e, AA_U64, name)) {
212 if (!inbounds(e, sizeof(u64)))
213 return 0;
214 if (data)
215 *data = le64_to_cpu(get_unaligned((u64 *) e->pos));
216 e->pos += sizeof(u64);
217 return 1;
219 return 0;
222 static size_t unpack_array(struct aa_ext *e, const char *name)
224 if (unpack_nameX(e, AA_ARRAY, name)) {
225 int size;
226 if (!inbounds(e, sizeof(u16)))
227 return 0;
228 size = (int)le16_to_cpu(get_unaligned((u16 *) e->pos));
229 e->pos += sizeof(u16);
230 return size;
232 return 0;
235 static size_t unpack_blob(struct aa_ext *e, char **blob, const char *name)
237 if (unpack_nameX(e, AA_BLOB, name)) {
238 u32 size;
239 if (!inbounds(e, sizeof(u32)))
240 return 0;
241 size = le32_to_cpu(get_unaligned((u32 *) e->pos));
242 e->pos += sizeof(u32);
243 if (inbounds(e, (size_t) size)) {
244 *blob = e->pos;
245 e->pos += size;
246 return size;
249 return 0;
252 static int unpack_str(struct aa_ext *e, const char **string, const char *name)
254 char *src_str;
255 size_t size = 0;
256 void *pos = e->pos;
257 *string = NULL;
258 if (unpack_nameX(e, AA_STRING, name)) {
259 size = unpack_u16_chunk(e, &src_str);
260 if (size) {
261 /* strings are null terminated, length is size - 1 */
262 if (src_str[size - 1] != 0)
263 goto fail;
264 *string = src_str;
267 return size;
269 fail:
270 e->pos = pos;
271 return 0;
274 static int unpack_strdup(struct aa_ext *e, char **string, const char *name)
276 const char *tmp;
277 void *pos = e->pos;
278 int res = unpack_str(e, &tmp, name);
279 *string = NULL;
281 if (!res)
282 return 0;
284 *string = kmemdup(tmp, res, GFP_KERNEL);
285 if (!*string) {
286 e->pos = pos;
287 return 0;
290 return res;
293 #define DFA_VALID_PERM_MASK 0xffffffff
294 #define DFA_VALID_PERM2_MASK 0xffffffff
297 * verify_accept - verify the accept tables of a dfa
298 * @dfa: dfa to verify accept tables of (NOT NULL)
299 * @flags: flags governing dfa
301 * Returns: 1 if valid accept tables else 0 if error
303 static bool verify_accept(struct aa_dfa *dfa, int flags)
305 int i;
307 /* verify accept permissions */
308 for (i = 0; i < dfa->tables[YYTD_ID_ACCEPT]->td_lolen; i++) {
309 int mode = ACCEPT_TABLE(dfa)[i];
311 if (mode & ~DFA_VALID_PERM_MASK)
312 return 0;
314 if (ACCEPT_TABLE2(dfa)[i] & ~DFA_VALID_PERM2_MASK)
315 return 0;
317 return 1;
321 * unpack_dfa - unpack a file rule dfa
322 * @e: serialized data extent information (NOT NULL)
324 * returns dfa or ERR_PTR or NULL if no dfa
326 static struct aa_dfa *unpack_dfa(struct aa_ext *e)
328 char *blob = NULL;
329 size_t size;
330 struct aa_dfa *dfa = NULL;
332 size = unpack_blob(e, &blob, "aadfa");
333 if (size) {
335 * The dfa is aligned with in the blob to 8 bytes
336 * from the beginning of the stream.
337 * alignment adjust needed by dfa unpack
339 size_t sz = blob - (char *) e->start -
340 ((e->pos - e->start) & 7);
341 size_t pad = ALIGN(sz, 8) - sz;
342 int flags = TO_ACCEPT1_FLAG(YYTD_DATA32) |
343 TO_ACCEPT2_FLAG(YYTD_DATA32);
346 if (aa_g_paranoid_load)
347 flags |= DFA_FLAG_VERIFY_STATES;
349 dfa = aa_dfa_unpack(blob + pad, size - pad, flags);
351 if (IS_ERR(dfa))
352 return dfa;
354 if (!verify_accept(dfa, flags))
355 goto fail;
358 return dfa;
360 fail:
361 aa_put_dfa(dfa);
362 return ERR_PTR(-EPROTO);
366 * unpack_trans_table - unpack a profile transition table
367 * @e: serialized data extent information (NOT NULL)
368 * @profile: profile to add the accept table to (NOT NULL)
370 * Returns: 1 if table successfully unpacked
372 static bool unpack_trans_table(struct aa_ext *e, struct aa_profile *profile)
374 void *pos = e->pos;
376 /* exec table is optional */
377 if (unpack_nameX(e, AA_STRUCT, "xtable")) {
378 int i, size;
380 size = unpack_array(e, NULL);
381 /* currently 4 exec bits and entries 0-3 are reserved iupcx */
382 if (size > 16 - 4)
383 goto fail;
384 profile->file.trans.table = kzalloc(sizeof(char *) * size,
385 GFP_KERNEL);
386 if (!profile->file.trans.table)
387 goto fail;
389 profile->file.trans.size = size;
390 for (i = 0; i < size; i++) {
391 char *str;
392 int c, j, size2 = unpack_strdup(e, &str, NULL);
393 /* unpack_strdup verifies that the last character is
394 * null termination byte.
396 if (!size2)
397 goto fail;
398 profile->file.trans.table[i] = str;
399 /* verify that name doesn't start with space */
400 if (isspace(*str))
401 goto fail;
403 /* count internal # of internal \0 */
404 for (c = j = 0; j < size2 - 2; j++) {
405 if (!str[j])
406 c++;
408 if (*str == ':') {
409 /* beginning with : requires an embedded \0,
410 * verify that exactly 1 internal \0 exists
411 * trailing \0 already verified by unpack_strdup
413 if (c != 1)
414 goto fail;
415 /* first character after : must be valid */
416 if (!str[1])
417 goto fail;
418 } else if (c)
419 /* fail - all other cases with embedded \0 */
420 goto fail;
422 if (!unpack_nameX(e, AA_ARRAYEND, NULL))
423 goto fail;
424 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
425 goto fail;
427 return 1;
429 fail:
430 aa_free_domain_entries(&profile->file.trans);
431 e->pos = pos;
432 return 0;
435 static bool unpack_rlimits(struct aa_ext *e, struct aa_profile *profile)
437 void *pos = e->pos;
439 /* rlimits are optional */
440 if (unpack_nameX(e, AA_STRUCT, "rlimits")) {
441 int i, size;
442 u32 tmp = 0;
443 if (!unpack_u32(e, &tmp, NULL))
444 goto fail;
445 profile->rlimits.mask = tmp;
447 size = unpack_array(e, NULL);
448 if (size > RLIM_NLIMITS)
449 goto fail;
450 for (i = 0; i < size; i++) {
451 u64 tmp2 = 0;
452 int a = aa_map_resource(i);
453 if (!unpack_u64(e, &tmp2, NULL))
454 goto fail;
455 profile->rlimits.limits[a].rlim_max = tmp2;
457 if (!unpack_nameX(e, AA_ARRAYEND, NULL))
458 goto fail;
459 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
460 goto fail;
462 return 1;
464 fail:
465 e->pos = pos;
466 return 0;
470 * unpack_profile - unpack a serialized profile
471 * @e: serialized data extent information (NOT NULL)
473 * NOTE: unpack profile sets audit struct if there is a failure
475 static struct aa_profile *unpack_profile(struct aa_ext *e)
477 struct aa_profile *profile = NULL;
478 const char *name = NULL;
479 int i, error = -EPROTO;
480 kernel_cap_t tmpcap;
481 u32 tmp;
483 /* check that we have the right struct being passed */
484 if (!unpack_nameX(e, AA_STRUCT, "profile"))
485 goto fail;
486 if (!unpack_str(e, &name, NULL))
487 goto fail;
489 profile = aa_alloc_profile(name);
490 if (!profile)
491 return ERR_PTR(-ENOMEM);
493 /* profile renaming is optional */
494 (void) unpack_str(e, &profile->rename, "rename");
496 /* attachment string is optional */
497 (void) unpack_str(e, &profile->attach, "attach");
499 /* xmatch is optional and may be NULL */
500 profile->xmatch = unpack_dfa(e);
501 if (IS_ERR(profile->xmatch)) {
502 error = PTR_ERR(profile->xmatch);
503 profile->xmatch = NULL;
504 goto fail;
506 /* xmatch_len is not optional if xmatch is set */
507 if (profile->xmatch) {
508 if (!unpack_u32(e, &tmp, NULL))
509 goto fail;
510 profile->xmatch_len = tmp;
513 /* per profile debug flags (complain, audit) */
514 if (!unpack_nameX(e, AA_STRUCT, "flags"))
515 goto fail;
516 if (!unpack_u32(e, &tmp, NULL))
517 goto fail;
518 if (tmp & PACKED_FLAG_HAT)
519 profile->flags |= PFLAG_HAT;
520 if (!unpack_u32(e, &tmp, NULL))
521 goto fail;
522 if (tmp == PACKED_MODE_COMPLAIN)
523 profile->mode = APPARMOR_COMPLAIN;
524 else if (tmp == PACKED_MODE_KILL)
525 profile->mode = APPARMOR_KILL;
526 else if (tmp == PACKED_MODE_UNCONFINED)
527 profile->mode = APPARMOR_UNCONFINED;
528 if (!unpack_u32(e, &tmp, NULL))
529 goto fail;
530 if (tmp)
531 profile->audit = AUDIT_ALL;
533 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
534 goto fail;
536 /* path_flags is optional */
537 if (unpack_u32(e, &profile->path_flags, "path_flags"))
538 profile->path_flags |= profile->flags & PFLAG_MEDIATE_DELETED;
539 else
540 /* set a default value if path_flags field is not present */
541 profile->path_flags = PFLAG_MEDIATE_DELETED;
543 if (!unpack_u32(e, &(profile->caps.allow.cap[0]), NULL))
544 goto fail;
545 if (!unpack_u32(e, &(profile->caps.audit.cap[0]), NULL))
546 goto fail;
547 if (!unpack_u32(e, &(profile->caps.quiet.cap[0]), NULL))
548 goto fail;
549 if (!unpack_u32(e, &tmpcap.cap[0], NULL))
550 goto fail;
552 if (unpack_nameX(e, AA_STRUCT, "caps64")) {
553 /* optional upper half of 64 bit caps */
554 if (!unpack_u32(e, &(profile->caps.allow.cap[1]), NULL))
555 goto fail;
556 if (!unpack_u32(e, &(profile->caps.audit.cap[1]), NULL))
557 goto fail;
558 if (!unpack_u32(e, &(profile->caps.quiet.cap[1]), NULL))
559 goto fail;
560 if (!unpack_u32(e, &(tmpcap.cap[1]), NULL))
561 goto fail;
562 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
563 goto fail;
566 if (unpack_nameX(e, AA_STRUCT, "capsx")) {
567 /* optional extended caps mediation mask */
568 if (!unpack_u32(e, &(profile->caps.extended.cap[0]), NULL))
569 goto fail;
570 if (!unpack_u32(e, &(profile->caps.extended.cap[1]), NULL))
571 goto fail;
572 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
573 goto fail;
576 if (!unpack_rlimits(e, profile))
577 goto fail;
579 if (unpack_nameX(e, AA_STRUCT, "policydb")) {
580 /* generic policy dfa - optional and may be NULL */
581 profile->policy.dfa = unpack_dfa(e);
582 if (IS_ERR(profile->policy.dfa)) {
583 error = PTR_ERR(profile->policy.dfa);
584 profile->policy.dfa = NULL;
585 goto fail;
587 if (!unpack_u32(e, &profile->policy.start[0], "start"))
588 /* default start state */
589 profile->policy.start[0] = DFA_START;
590 /* setup class index */
591 for (i = AA_CLASS_FILE; i <= AA_CLASS_LAST; i++) {
592 profile->policy.start[i] =
593 aa_dfa_next(profile->policy.dfa,
594 profile->policy.start[0],
597 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
598 goto fail;
601 /* get file rules */
602 profile->file.dfa = unpack_dfa(e);
603 if (IS_ERR(profile->file.dfa)) {
604 error = PTR_ERR(profile->file.dfa);
605 profile->file.dfa = NULL;
606 goto fail;
609 if (!unpack_u32(e, &profile->file.start, "dfa_start"))
610 /* default start state */
611 profile->file.start = DFA_START;
613 if (!unpack_trans_table(e, profile))
614 goto fail;
616 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
617 goto fail;
619 return profile;
621 fail:
622 if (profile)
623 name = NULL;
624 else if (!name)
625 name = "unknown";
626 audit_iface(profile, name, "failed to unpack profile", e, error);
627 aa_free_profile(profile);
629 return ERR_PTR(error);
633 * verify_head - unpack serialized stream header
634 * @e: serialized data read head (NOT NULL)
635 * @required: whether the header is required or optional
636 * @ns: Returns - namespace if one is specified else NULL (NOT NULL)
638 * Returns: error or 0 if header is good
640 static int verify_header(struct aa_ext *e, int required, const char **ns)
642 int error = -EPROTONOSUPPORT;
643 const char *name = NULL;
644 *ns = NULL;
646 /* get the interface version */
647 if (!unpack_u32(e, &e->version, "version")) {
648 if (required) {
649 audit_iface(NULL, NULL, "invalid profile format", e,
650 error);
651 return error;
654 /* check that the interface version is currently supported */
655 if (e->version != 5) {
656 audit_iface(NULL, NULL, "unsupported interface version",
657 e, error);
658 return error;
663 /* read the namespace if present */
664 if (unpack_str(e, &name, "namespace")) {
665 if (*ns && strcmp(*ns, name))
666 audit_iface(NULL, NULL, "invalid ns change", e, error);
667 else if (!*ns)
668 *ns = name;
671 return 0;
674 static bool verify_xindex(int xindex, int table_size)
676 int index, xtype;
677 xtype = xindex & AA_X_TYPE_MASK;
678 index = xindex & AA_X_INDEX_MASK;
679 if (xtype == AA_X_TABLE && index > table_size)
680 return 0;
681 return 1;
684 /* verify dfa xindexes are in range of transition tables */
685 static bool verify_dfa_xindex(struct aa_dfa *dfa, int table_size)
687 int i;
688 for (i = 0; i < dfa->tables[YYTD_ID_ACCEPT]->td_lolen; i++) {
689 if (!verify_xindex(dfa_user_xindex(dfa, i), table_size))
690 return 0;
691 if (!verify_xindex(dfa_other_xindex(dfa, i), table_size))
692 return 0;
694 return 1;
698 * verify_profile - Do post unpack analysis to verify profile consistency
699 * @profile: profile to verify (NOT NULL)
701 * Returns: 0 if passes verification else error
703 static int verify_profile(struct aa_profile *profile)
705 if (aa_g_paranoid_load) {
706 if (profile->file.dfa &&
707 !verify_dfa_xindex(profile->file.dfa,
708 profile->file.trans.size)) {
709 audit_iface(profile, NULL, "Invalid named transition",
710 NULL, -EPROTO);
711 return -EPROTO;
715 return 0;
718 void aa_load_ent_free(struct aa_load_ent *ent)
720 if (ent) {
721 aa_put_profile(ent->rename);
722 aa_put_profile(ent->old);
723 aa_put_profile(ent->new);
724 kzfree(ent);
728 struct aa_load_ent *aa_load_ent_alloc(void)
730 struct aa_load_ent *ent = kzalloc(sizeof(*ent), GFP_KERNEL);
731 if (ent)
732 INIT_LIST_HEAD(&ent->list);
733 return ent;
737 * aa_unpack - unpack packed binary profile(s) data loaded from user space
738 * @udata: user data copied to kmem (NOT NULL)
739 * @size: the size of the user data
740 * @lh: list to place unpacked profiles in a aa_repl_ws
741 * @ns: Returns namespace profile is in if specified else NULL (NOT NULL)
743 * Unpack user data and return refcounted allocated profile(s) stored in
744 * @lh in order of discovery, with the list chain stored in base.list
745 * or error
747 * Returns: profile(s) on @lh else error pointer if fails to unpack
749 int aa_unpack(void *udata, size_t size, struct list_head *lh, const char **ns)
751 struct aa_load_ent *tmp, *ent;
752 struct aa_profile *profile = NULL;
753 int error;
754 struct aa_ext e = {
755 .start = udata,
756 .end = udata + size,
757 .pos = udata,
760 *ns = NULL;
761 while (e.pos < e.end) {
762 void *start;
763 error = verify_header(&e, e.pos == e.start, ns);
764 if (error)
765 goto fail;
767 start = e.pos;
768 profile = unpack_profile(&e);
769 if (IS_ERR(profile)) {
770 error = PTR_ERR(profile);
771 goto fail;
774 error = verify_profile(profile);
775 if (error)
776 goto fail_profile;
778 error = aa_calc_profile_hash(profile, e.version, start,
779 e.pos - start);
780 if (error)
781 goto fail_profile;
783 ent = aa_load_ent_alloc();
784 if (!ent) {
785 error = -ENOMEM;
786 goto fail_profile;
789 ent->new = profile;
790 list_add_tail(&ent->list, lh);
793 return 0;
795 fail_profile:
796 aa_put_profile(profile);
798 fail:
799 list_for_each_entry_safe(ent, tmp, lh, list) {
800 list_del_init(&ent->list);
801 aa_load_ent_free(ent);
804 return error;