2 * AppArmor security module
4 * This file contains AppArmor functions for unpacking policy loaded from
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
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/match.h"
28 #include "include/policy.h"
29 #include "include/policy_unpack.h"
30 #include "include/sid.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.
46 AA_NAME, /* same as string except it is items name */
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.
65 void *pos; /* pointer to current position in the buffer */
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);
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
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 COMMON_AUDIT_DATA_INIT(&sa, NONE);
101 aad.iface.pos = e->pos - e->start;
102 aad.iface.target = new;
107 return aa_audit(AUDIT_APPARMOR_STATUS, profile, GFP_KERNEL, &sa,
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)
128 if (!inbounds(e, sizeof(u16)))
130 size = le16_to_cpu(get_unaligned((u16 *) e->pos));
131 e->pos += sizeof(u16);
132 if (!inbounds(e, size))
139 /* unpack control byte */
140 static bool unpack_X(struct aa_ext *e, enum aa_code code)
144 if (*(u8 *) e->pos != code)
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)
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
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)) {
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)))
183 /* if a name is specified and there is no name tag fail */
187 /* now check if type code matches */
188 if (unpack_X(e, code))
196 static bool unpack_u16(struct aa_ext *e, u16 *data, const char *name)
198 if (unpack_nameX(e, AA_U16, name)) {
199 if (!inbounds(e, sizeof(u16)))
202 *data = le16_to_cpu(get_unaligned((u16 *) e->pos));
203 e->pos += sizeof(u16);
209 static bool unpack_u32(struct aa_ext *e, u32 *data, const char *name)
211 if (unpack_nameX(e, AA_U32, name)) {
212 if (!inbounds(e, sizeof(u32)))
215 *data = le32_to_cpu(get_unaligned((u32 *) e->pos));
216 e->pos += sizeof(u32);
222 static bool unpack_u64(struct aa_ext *e, u64 *data, const char *name)
224 if (unpack_nameX(e, AA_U64, name)) {
225 if (!inbounds(e, sizeof(u64)))
228 *data = le64_to_cpu(get_unaligned((u64 *) e->pos));
229 e->pos += sizeof(u64);
235 static size_t unpack_array(struct aa_ext *e, const char *name)
237 if (unpack_nameX(e, AA_ARRAY, name)) {
239 if (!inbounds(e, sizeof(u16)))
241 size = (int)le16_to_cpu(get_unaligned((u16 *) e->pos));
242 e->pos += sizeof(u16);
248 static size_t unpack_blob(struct aa_ext *e, char **blob, const char *name)
250 if (unpack_nameX(e, AA_BLOB, name)) {
252 if (!inbounds(e, sizeof(u32)))
254 size = le32_to_cpu(get_unaligned((u32 *) e->pos));
255 e->pos += sizeof(u32);
256 if (inbounds(e, (size_t) size)) {
265 static int unpack_str(struct aa_ext *e, const char **string, const char *name)
271 if (unpack_nameX(e, AA_STRING, name)) {
272 size = unpack_u16_chunk(e, &src_str);
274 /* strings are null terminated, length is size - 1 */
275 if (src_str[size - 1] != 0)
287 static int unpack_strdup(struct aa_ext *e, char **string, const char *name)
291 int res = unpack_str(e, &tmp, name);
297 *string = kmemdup(tmp, res, GFP_KERNEL);
307 * verify_accept - verify the accept tables of a dfa
308 * @dfa: dfa to verify accept tables of (NOT NULL)
309 * @flags: flags governing dfa
311 * Returns: 1 if valid accept tables else 0 if error
313 static bool verify_accept(struct aa_dfa *dfa, int flags)
317 /* verify accept permissions */
318 for (i = 0; i < dfa->tables[YYTD_ID_ACCEPT]->td_lolen; i++) {
319 int mode = ACCEPT_TABLE(dfa)[i];
321 if (mode & ~DFA_VALID_PERM_MASK)
324 if (ACCEPT_TABLE2(dfa)[i] & ~DFA_VALID_PERM2_MASK)
331 * unpack_dfa - unpack a file rule dfa
332 * @e: serialized data extent information (NOT NULL)
334 * returns dfa or ERR_PTR or NULL if no dfa
336 static struct aa_dfa *unpack_dfa(struct aa_ext *e)
340 struct aa_dfa *dfa = NULL;
342 size = unpack_blob(e, &blob, "aadfa");
345 * The dfa is aligned with in the blob to 8 bytes
346 * from the beginning of the stream.
348 size_t sz = blob - (char *)e->start;
349 size_t pad = ALIGN(sz, 8) - sz;
350 int flags = TO_ACCEPT1_FLAG(YYTD_DATA32) |
351 TO_ACCEPT2_FLAG(YYTD_DATA32);
354 if (aa_g_paranoid_load)
355 flags |= DFA_FLAG_VERIFY_STATES;
357 dfa = aa_dfa_unpack(blob + pad, size - pad, flags);
362 if (!verify_accept(dfa, flags))
370 return ERR_PTR(-EPROTO);
374 * unpack_trans_table - unpack a profile transition table
375 * @e: serialized data extent information (NOT NULL)
376 * @profile: profile to add the accept table to (NOT NULL)
378 * Returns: 1 if table successfully unpacked
380 static bool unpack_trans_table(struct aa_ext *e, struct aa_profile *profile)
384 /* exec table is optional */
385 if (unpack_nameX(e, AA_STRUCT, "xtable")) {
388 size = unpack_array(e, NULL);
389 /* currently 4 exec bits and entries 0-3 are reserved iupcx */
392 profile->file.trans.table = kzalloc(sizeof(char *) * size,
394 if (!profile->file.trans.table)
397 profile->file.trans.size = size;
398 for (i = 0; i < size; i++) {
400 int c, j, size2 = unpack_strdup(e, &str, NULL);
401 /* unpack_strdup verifies that the last character is
402 * null termination byte.
406 profile->file.trans.table[i] = str;
407 /* verify that name doesn't start with space */
411 /* count internal # of internal \0 */
412 for (c = j = 0; j < size2 - 2; j++) {
417 /* beginning with : requires an embedded \0,
418 * verify that exactly 1 internal \0 exists
419 * trailing \0 already verified by unpack_strdup
423 /* first character after : must be valid */
427 /* fail - all other cases with embedded \0 */
430 if (!unpack_nameX(e, AA_ARRAYEND, NULL))
432 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
438 aa_free_domain_entries(&profile->file.trans);
443 static bool unpack_rlimits(struct aa_ext *e, struct aa_profile *profile)
447 /* rlimits are optional */
448 if (unpack_nameX(e, AA_STRUCT, "rlimits")) {
451 if (!unpack_u32(e, &tmp, NULL))
453 profile->rlimits.mask = tmp;
455 size = unpack_array(e, NULL);
456 if (size > RLIM_NLIMITS)
458 for (i = 0; i < size; i++) {
460 int a = aa_map_resource(i);
461 if (!unpack_u64(e, &tmp2, NULL))
463 profile->rlimits.limits[a].rlim_max = tmp2;
465 if (!unpack_nameX(e, AA_ARRAYEND, NULL))
467 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
478 * unpack_profile - unpack a serialized profile
479 * @e: serialized data extent information (NOT NULL)
481 * NOTE: unpack profile sets audit struct if there is a failure
483 static struct aa_profile *unpack_profile(struct aa_ext *e)
485 struct aa_profile *profile = NULL;
486 const char *name = NULL;
488 int i, error = -EPROTO;
492 /* check that we have the right struct being passed */
493 if (!unpack_nameX(e, AA_STRUCT, "profile"))
495 if (!unpack_str(e, &name, NULL))
498 profile = aa_alloc_profile(name);
500 return ERR_PTR(-ENOMEM);
502 /* profile renaming is optional */
503 (void) unpack_str(e, &profile->rename, "rename");
505 /* xmatch is optional and may be NULL */
506 profile->xmatch = unpack_dfa(e);
507 if (IS_ERR(profile->xmatch)) {
508 error = PTR_ERR(profile->xmatch);
509 profile->xmatch = NULL;
512 /* xmatch_len is not optional if xmatch is set */
513 if (profile->xmatch) {
514 if (!unpack_u32(e, &tmp, NULL))
516 profile->xmatch_len = tmp;
519 /* per profile debug flags (complain, audit) */
520 if (!unpack_nameX(e, AA_STRUCT, "flags"))
522 if (!unpack_u32(e, &tmp, NULL))
525 profile->flags |= PFLAG_HAT;
526 if (!unpack_u32(e, &tmp, NULL))
529 profile->mode = APPARMOR_COMPLAIN;
530 if (!unpack_u32(e, &tmp, NULL))
533 profile->audit = AUDIT_ALL;
535 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
538 /* path_flags is optional */
539 if (unpack_u32(e, &profile->path_flags, "path_flags"))
540 profile->path_flags |= profile->flags & PFLAG_MEDIATE_DELETED;
542 /* set a default value if path_flags field is not present */
543 profile->path_flags = PFLAG_MEDIATE_DELETED;
545 if (!unpack_u32(e, &(profile->caps.allow.cap[0]), NULL))
547 if (!unpack_u32(e, &(profile->caps.audit.cap[0]), NULL))
549 if (!unpack_u32(e, &(profile->caps.quiet.cap[0]), NULL))
551 if (!unpack_u32(e, &tmpcap.cap[0], NULL))
554 if (unpack_nameX(e, AA_STRUCT, "caps64")) {
555 /* optional upper half of 64 bit caps */
556 if (!unpack_u32(e, &(profile->caps.allow.cap[1]), NULL))
558 if (!unpack_u32(e, &(profile->caps.audit.cap[1]), NULL))
560 if (!unpack_u32(e, &(profile->caps.quiet.cap[1]), NULL))
562 if (!unpack_u32(e, &(tmpcap.cap[1]), NULL))
564 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
568 if (unpack_nameX(e, AA_STRUCT, "capsx")) {
569 /* optional extended caps mediation mask */
570 if (!unpack_u32(e, &(profile->caps.extended.cap[0]), NULL))
572 if (!unpack_u32(e, &(profile->caps.extended.cap[1]), NULL))
574 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
578 if (!unpack_rlimits(e, profile))
581 size = unpack_array(e, "net_allowed_af");
584 for (i = 0; i < size; i++) {
585 /* discard extraneous rules that this kernel will
590 if (!unpack_u16(e, &tmp, NULL) ||
591 !unpack_u16(e, &tmp, NULL) ||
592 !unpack_u16(e, &tmp, NULL))
596 if (!unpack_u16(e, &profile->net.allow[i], NULL))
598 if (!unpack_u16(e, &profile->net.audit[i], NULL))
600 if (!unpack_u16(e, &profile->net.quiet[i], NULL))
603 if (!unpack_nameX(e, AA_ARRAYEND, NULL))
606 * allow unix domain and netlink sockets they are handled
610 profile->net.allow[AF_UNIX] = 0xffff;
611 profile->net.allow[AF_NETLINK] = 0xffff;
613 if (unpack_nameX(e, AA_STRUCT, "policydb")) {
614 /* generic policy dfa - optional and may be NULL */
615 profile->policy.dfa = unpack_dfa(e);
616 if (IS_ERR(profile->policy.dfa)) {
617 error = PTR_ERR(profile->policy.dfa);
618 profile->policy.dfa = NULL;
621 if (!unpack_u32(e, &profile->policy.start[0], "start"))
622 /* default start state */
623 profile->policy.start[0] = DFA_START;
624 /* setup class index */
625 for (i = AA_CLASS_FILE; i <= AA_CLASS_LAST; i++) {
626 profile->policy.start[i] =
627 aa_dfa_next(profile->policy.dfa,
628 profile->policy.start[0],
631 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
636 profile->file.dfa = unpack_dfa(e);
637 if (IS_ERR(profile->file.dfa)) {
638 error = PTR_ERR(profile->file.dfa);
639 profile->file.dfa = NULL;
643 if (!unpack_u32(e, &profile->file.start, "dfa_start"))
644 /* default start state */
645 profile->file.start = DFA_START;
647 if (!unpack_trans_table(e, profile))
650 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
660 audit_iface(profile, name, "failed to unpack profile", e, error);
661 aa_put_profile(profile);
663 return ERR_PTR(error);
667 * verify_head - unpack serialized stream header
668 * @e: serialized data read head (NOT NULL)
669 * @ns: Returns - namespace if one is specified else NULL (NOT NULL)
671 * Returns: error or 0 if header is good
673 static int verify_header(struct aa_ext *e, const char **ns)
675 int error = -EPROTONOSUPPORT;
676 /* get the interface version */
677 if (!unpack_u32(e, &e->version, "version")) {
678 audit_iface(NULL, NULL, "invalid profile format", e, error);
682 /* check that the interface version is currently supported */
683 if (e->version != 5) {
684 audit_iface(NULL, NULL, "unsupported interface version", e,
689 /* read the namespace if present */
690 if (!unpack_str(e, ns, "namespace"))
696 static bool verify_xindex(int xindex, int table_size)
699 xtype = xindex & AA_X_TYPE_MASK;
700 index = xindex & AA_X_INDEX_MASK;
701 if (xtype == AA_X_TABLE && index > table_size)
706 /* verify dfa xindexes are in range of transition tables */
707 static bool verify_dfa_xindex(struct aa_dfa *dfa, int table_size)
710 for (i = 0; i < dfa->tables[YYTD_ID_ACCEPT]->td_lolen; i++) {
711 if (!verify_xindex(dfa_user_xindex(dfa, i), table_size))
713 if (!verify_xindex(dfa_other_xindex(dfa, i), table_size))
720 * verify_profile - Do post unpack analysis to verify profile consistency
721 * @profile: profile to verify (NOT NULL)
723 * Returns: 0 if passes verification else error
725 static int verify_profile(struct aa_profile *profile)
727 if (aa_g_paranoid_load) {
728 if (profile->file.dfa &&
729 !verify_dfa_xindex(profile->file.dfa,
730 profile->file.trans.size)) {
731 audit_iface(profile, NULL, "Invalid named transition",
741 * aa_unpack - unpack packed binary profile data loaded from user space
742 * @udata: user data copied to kmem (NOT NULL)
743 * @size: the size of the user data
744 * @ns: Returns namespace profile is in if specified else NULL (NOT NULL)
746 * Unpack user data and return refcounted allocated profile or ERR_PTR
748 * Returns: profile else error pointer if fails to unpack
750 struct aa_profile *aa_unpack(void *udata, size_t size, const char **ns)
752 struct aa_profile *profile = NULL;
760 error = verify_header(&e, ns);
762 return ERR_PTR(error);
764 profile = unpack_profile(&e);
768 error = verify_profile(profile);
770 aa_put_profile(profile);
771 profile = ERR_PTR(error);
774 /* return refcount */