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/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.
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 sa.type = LSM_AUDIT_DATA_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_u32(struct aa_ext *e, u32 *data, const char *name)
198 if (unpack_nameX(e, AA_U32, name)) {
199 if (!inbounds(e, sizeof(u32)))
202 *data = le32_to_cpu(get_unaligned((u32 *) e->pos));
203 e->pos += sizeof(u32);
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)))
215 *data = le64_to_cpu(get_unaligned((u64 *) e->pos));
216 e->pos += sizeof(u64);
222 static size_t unpack_array(struct aa_ext *e, const char *name)
224 if (unpack_nameX(e, AA_ARRAY, name)) {
226 if (!inbounds(e, sizeof(u16)))
228 size = (int)le16_to_cpu(get_unaligned((u16 *) e->pos));
229 e->pos += sizeof(u16);
235 static size_t unpack_blob(struct aa_ext *e, char **blob, const char *name)
237 if (unpack_nameX(e, AA_BLOB, name)) {
239 if (!inbounds(e, sizeof(u32)))
241 size = le32_to_cpu(get_unaligned((u32 *) e->pos));
242 e->pos += sizeof(u32);
243 if (inbounds(e, (size_t) size)) {
252 static int unpack_str(struct aa_ext *e, const char **string, const char *name)
258 if (unpack_nameX(e, AA_STRING, name)) {
259 size = unpack_u16_chunk(e, &src_str);
261 /* strings are null terminated, length is size - 1 */
262 if (src_str[size - 1] != 0)
274 static int unpack_strdup(struct aa_ext *e, char **string, const char *name)
278 int res = unpack_str(e, &tmp, name);
284 *string = kmemdup(tmp, res, GFP_KERNEL);
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)
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)
314 if (ACCEPT_TABLE2(dfa)[i] & ~DFA_VALID_PERM2_MASK)
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)
330 struct aa_dfa *dfa = NULL;
332 size = unpack_blob(e, &blob, "aadfa");
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) | DFA_FLAG_VERIFY_STATES;
344 dfa = aa_dfa_unpack(blob + pad, size - pad, flags);
349 if (!verify_accept(dfa, flags))
357 return ERR_PTR(-EPROTO);
361 * unpack_trans_table - unpack a profile transition table
362 * @e: serialized data extent information (NOT NULL)
363 * @profile: profile to add the accept table to (NOT NULL)
365 * Returns: 1 if table successfully unpacked
367 static bool unpack_trans_table(struct aa_ext *e, struct aa_profile *profile)
371 /* exec table is optional */
372 if (unpack_nameX(e, AA_STRUCT, "xtable")) {
375 size = unpack_array(e, NULL);
376 /* currently 4 exec bits and entries 0-3 are reserved iupcx */
379 profile->file.trans.table = kzalloc(sizeof(char *) * size,
381 if (!profile->file.trans.table)
384 profile->file.trans.size = size;
385 for (i = 0; i < size; i++) {
387 int c, j, size2 = unpack_strdup(e, &str, NULL);
388 /* unpack_strdup verifies that the last character is
389 * null termination byte.
393 profile->file.trans.table[i] = str;
394 /* verify that name doesn't start with space */
398 /* count internal # of internal \0 */
399 for (c = j = 0; j < size2 - 2; j++) {
404 /* beginning with : requires an embedded \0,
405 * verify that exactly 1 internal \0 exists
406 * trailing \0 already verified by unpack_strdup
410 /* first character after : must be valid */
414 /* fail - all other cases with embedded \0 */
417 if (!unpack_nameX(e, AA_ARRAYEND, NULL))
419 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
425 aa_free_domain_entries(&profile->file.trans);
430 static bool unpack_rlimits(struct aa_ext *e, struct aa_profile *profile)
434 /* rlimits are optional */
435 if (unpack_nameX(e, AA_STRUCT, "rlimits")) {
438 if (!unpack_u32(e, &tmp, NULL))
440 profile->rlimits.mask = tmp;
442 size = unpack_array(e, NULL);
443 if (size > RLIM_NLIMITS)
445 for (i = 0; i < size; i++) {
447 int a = aa_map_resource(i);
448 if (!unpack_u64(e, &tmp2, NULL))
450 profile->rlimits.limits[a].rlim_max = tmp2;
452 if (!unpack_nameX(e, AA_ARRAYEND, NULL))
454 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
465 * unpack_profile - unpack a serialized profile
466 * @e: serialized data extent information (NOT NULL)
468 * NOTE: unpack profile sets audit struct if there is a failure
470 static struct aa_profile *unpack_profile(struct aa_ext *e)
472 struct aa_profile *profile = NULL;
473 const char *name = NULL;
474 int i, error = -EPROTO;
478 /* check that we have the right struct being passed */
479 if (!unpack_nameX(e, AA_STRUCT, "profile"))
481 if (!unpack_str(e, &name, NULL))
484 profile = aa_alloc_profile(name, GFP_KERNEL);
486 return ERR_PTR(-ENOMEM);
488 /* profile renaming is optional */
489 (void) unpack_str(e, &profile->rename, "rename");
491 /* attachment string is optional */
492 (void) unpack_str(e, &profile->attach, "attach");
494 /* xmatch is optional and may be NULL */
495 profile->xmatch = unpack_dfa(e);
496 if (IS_ERR(profile->xmatch)) {
497 error = PTR_ERR(profile->xmatch);
498 profile->xmatch = NULL;
501 /* xmatch_len is not optional if xmatch is set */
502 if (profile->xmatch) {
503 if (!unpack_u32(e, &tmp, NULL))
505 profile->xmatch_len = tmp;
508 /* per profile debug flags (complain, audit) */
509 if (!unpack_nameX(e, AA_STRUCT, "flags"))
511 if (!unpack_u32(e, &tmp, NULL))
513 if (tmp & PACKED_FLAG_HAT)
514 profile->flags |= PFLAG_HAT;
515 if (!unpack_u32(e, &tmp, NULL))
517 if (tmp == PACKED_MODE_COMPLAIN)
518 profile->mode = APPARMOR_COMPLAIN;
519 else if (tmp == PACKED_MODE_KILL)
520 profile->mode = APPARMOR_KILL;
521 else if (tmp == PACKED_MODE_UNCONFINED)
522 profile->mode = APPARMOR_UNCONFINED;
523 if (!unpack_u32(e, &tmp, NULL))
526 profile->audit = AUDIT_ALL;
528 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
531 /* path_flags is optional */
532 if (unpack_u32(e, &profile->path_flags, "path_flags"))
533 profile->path_flags |= profile->flags & PFLAG_MEDIATE_DELETED;
535 /* set a default value if path_flags field is not present */
536 profile->path_flags = PFLAG_MEDIATE_DELETED;
538 if (!unpack_u32(e, &(profile->caps.allow.cap[0]), NULL))
540 if (!unpack_u32(e, &(profile->caps.audit.cap[0]), NULL))
542 if (!unpack_u32(e, &(profile->caps.quiet.cap[0]), NULL))
544 if (!unpack_u32(e, &tmpcap.cap[0], NULL))
547 if (unpack_nameX(e, AA_STRUCT, "caps64")) {
548 /* optional upper half of 64 bit caps */
549 if (!unpack_u32(e, &(profile->caps.allow.cap[1]), NULL))
551 if (!unpack_u32(e, &(profile->caps.audit.cap[1]), NULL))
553 if (!unpack_u32(e, &(profile->caps.quiet.cap[1]), NULL))
555 if (!unpack_u32(e, &(tmpcap.cap[1]), NULL))
557 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
561 if (unpack_nameX(e, AA_STRUCT, "capsx")) {
562 /* optional extended caps mediation mask */
563 if (!unpack_u32(e, &(profile->caps.extended.cap[0]), NULL))
565 if (!unpack_u32(e, &(profile->caps.extended.cap[1]), NULL))
567 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
571 if (!unpack_rlimits(e, profile))
574 if (unpack_nameX(e, AA_STRUCT, "policydb")) {
575 /* generic policy dfa - optional and may be NULL */
576 profile->policy.dfa = unpack_dfa(e);
577 if (IS_ERR(profile->policy.dfa)) {
578 error = PTR_ERR(profile->policy.dfa);
579 profile->policy.dfa = NULL;
581 } else if (!profile->policy.dfa) {
585 if (!unpack_u32(e, &profile->policy.start[0], "start"))
586 /* default start state */
587 profile->policy.start[0] = DFA_START;
588 /* setup class index */
589 for (i = AA_CLASS_FILE; i <= AA_CLASS_LAST; i++) {
590 profile->policy.start[i] =
591 aa_dfa_next(profile->policy.dfa,
592 profile->policy.start[0],
595 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
600 profile->file.dfa = unpack_dfa(e);
601 if (IS_ERR(profile->file.dfa)) {
602 error = PTR_ERR(profile->file.dfa);
603 profile->file.dfa = NULL;
607 if (!unpack_u32(e, &profile->file.start, "dfa_start"))
608 /* default start state */
609 profile->file.start = DFA_START;
611 if (!unpack_trans_table(e, profile))
614 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
624 audit_iface(profile, name, "failed to unpack profile", e, error);
625 aa_free_profile(profile);
627 return ERR_PTR(error);
631 * verify_head - unpack serialized stream header
632 * @e: serialized data read head (NOT NULL)
633 * @required: whether the header is required or optional
634 * @ns: Returns - namespace if one is specified else NULL (NOT NULL)
636 * Returns: error or 0 if header is good
638 static int verify_header(struct aa_ext *e, int required, const char **ns)
640 int error = -EPROTONOSUPPORT;
641 const char *name = NULL;
644 /* get the interface version */
645 if (!unpack_u32(e, &e->version, "version")) {
647 audit_iface(NULL, NULL, "invalid profile format", e,
652 /* check that the interface version is currently supported */
653 if (e->version != 5) {
654 audit_iface(NULL, NULL, "unsupported interface version",
661 /* read the namespace if present */
662 if (unpack_str(e, &name, "namespace")) {
663 if (*ns && strcmp(*ns, name))
664 audit_iface(NULL, NULL, "invalid ns change", e, error);
672 static bool verify_xindex(int xindex, int table_size)
675 xtype = xindex & AA_X_TYPE_MASK;
676 index = xindex & AA_X_INDEX_MASK;
677 if (xtype == AA_X_TABLE && index >= table_size)
682 /* verify dfa xindexes are in range of transition tables */
683 static bool verify_dfa_xindex(struct aa_dfa *dfa, int table_size)
686 for (i = 0; i < dfa->tables[YYTD_ID_ACCEPT]->td_lolen; i++) {
687 if (!verify_xindex(dfa_user_xindex(dfa, i), table_size))
689 if (!verify_xindex(dfa_other_xindex(dfa, i), table_size))
696 * verify_profile - Do post unpack analysis to verify profile consistency
697 * @profile: profile to verify (NOT NULL)
699 * Returns: 0 if passes verification else error
701 static int verify_profile(struct aa_profile *profile)
703 if (profile->file.dfa &&
704 !verify_dfa_xindex(profile->file.dfa,
705 profile->file.trans.size)) {
706 audit_iface(profile, NULL, "Invalid named transition",
714 void aa_load_ent_free(struct aa_load_ent *ent)
717 aa_put_profile(ent->rename);
718 aa_put_profile(ent->old);
719 aa_put_profile(ent->new);
724 struct aa_load_ent *aa_load_ent_alloc(void)
726 struct aa_load_ent *ent = kzalloc(sizeof(*ent), GFP_KERNEL);
728 INIT_LIST_HEAD(&ent->list);
733 * aa_unpack - unpack packed binary profile(s) data loaded from user space
734 * @udata: user data copied to kmem (NOT NULL)
735 * @size: the size of the user data
736 * @lh: list to place unpacked profiles in a aa_repl_ws
737 * @ns: Returns namespace profile is in if specified else NULL (NOT NULL)
739 * Unpack user data and return refcounted allocated profile(s) stored in
740 * @lh in order of discovery, with the list chain stored in base.list
743 * Returns: profile(s) on @lh else error pointer if fails to unpack
745 int aa_unpack(void *udata, size_t size, struct list_head *lh, const char **ns)
747 struct aa_load_ent *tmp, *ent;
748 struct aa_profile *profile = NULL;
757 while (e.pos < e.end) {
759 error = verify_header(&e, e.pos == e.start, ns);
764 profile = unpack_profile(&e);
765 if (IS_ERR(profile)) {
766 error = PTR_ERR(profile);
770 error = verify_profile(profile);
774 error = aa_calc_profile_hash(profile, e.version, start,
779 ent = aa_load_ent_alloc();
786 list_add_tail(&ent->list, lh);
792 aa_put_profile(profile);
795 list_for_each_entry_safe(ent, tmp, lh, list) {
796 list_del_init(&ent->list);
797 aa_load_ent_free(ent);