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 COMMON_AUDIT_DATA_INIT(&sa, NONE);
99 sa.aad.iface.pos = e->pos - e->start;
100 sa.aad.iface.target = new;
103 sa.aad.error = error;
105 return aa_audit(AUDIT_APPARMOR_STATUS, profile, GFP_KERNEL, &sa,
109 /* test if read will be in packed data bounds */
110 static bool inbounds(struct aa_ext *e, size_t size)
112 return (size <= e->end - e->pos);
116 * aa_u16_chunck - test and do bounds checking for a u16 size based chunk
117 * @e: serialized data read head (NOT NULL)
118 * @chunk: start address for chunk of data (NOT NULL)
120 * Returns: the size of chunk found with the read head at the end of the chunk.
122 static size_t unpack_u16_chunk(struct aa_ext *e, char **chunk)
126 if (!inbounds(e, sizeof(u16)))
128 size = le16_to_cpu(get_unaligned((u16 *) e->pos));
129 e->pos += sizeof(u16);
130 if (!inbounds(e, size))
137 /* unpack control byte */
138 static bool unpack_X(struct aa_ext *e, enum aa_code code)
142 if (*(u8 *) e->pos != code)
149 * unpack_nameX - check is the next element is of type X with a name of @name
150 * @e: serialized data extent information (NOT NULL)
152 * @name: name to match to the serialized element. (MAYBE NULL)
154 * check that the next serialized data element is of type X and has a tag
155 * name @name. If @name is specified then there must be a matching
156 * name element in the stream. If @name is NULL any name element will be
157 * skipped and only the typecode will be tested.
159 * Returns 1 on success (both type code and name tests match) and the read
160 * head is advanced past the headers
162 * Returns: 0 if either match fails, the read head does not move
164 static bool unpack_nameX(struct aa_ext *e, enum aa_code code, const char *name)
167 * May need to reset pos if name or type doesn't match
171 * Check for presence of a tagname, and if present name size
172 * AA_NAME tag value is a u16.
174 if (unpack_X(e, AA_NAME)) {
176 size_t size = unpack_u16_chunk(e, &tag);
177 /* if a name is specified it must match. otherwise skip tag */
178 if (name && (!size || strcmp(name, tag)))
181 /* if a name is specified and there is no name tag fail */
185 /* now check if type code matches */
186 if (unpack_X(e, code))
194 static bool unpack_u32(struct aa_ext *e, u32 *data, const char *name)
196 if (unpack_nameX(e, AA_U32, name)) {
197 if (!inbounds(e, sizeof(u32)))
200 *data = le32_to_cpu(get_unaligned((u32 *) e->pos));
201 e->pos += sizeof(u32);
207 static bool unpack_u64(struct aa_ext *e, u64 *data, const char *name)
209 if (unpack_nameX(e, AA_U64, name)) {
210 if (!inbounds(e, sizeof(u64)))
213 *data = le64_to_cpu(get_unaligned((u64 *) e->pos));
214 e->pos += sizeof(u64);
220 static size_t unpack_array(struct aa_ext *e, const char *name)
222 if (unpack_nameX(e, AA_ARRAY, name)) {
224 if (!inbounds(e, sizeof(u16)))
226 size = (int)le16_to_cpu(get_unaligned((u16 *) e->pos));
227 e->pos += sizeof(u16);
233 static size_t unpack_blob(struct aa_ext *e, char **blob, const char *name)
235 if (unpack_nameX(e, AA_BLOB, name)) {
237 if (!inbounds(e, sizeof(u32)))
239 size = le32_to_cpu(get_unaligned((u32 *) e->pos));
240 e->pos += sizeof(u32);
241 if (inbounds(e, (size_t) size)) {
250 static int unpack_str(struct aa_ext *e, const char **string, const char *name)
256 if (unpack_nameX(e, AA_STRING, name)) {
257 size = unpack_u16_chunk(e, &src_str);
259 /* strings are null terminated, length is size - 1 */
260 if (src_str[size - 1] != 0)
272 static int unpack_strdup(struct aa_ext *e, char **string, const char *name)
276 int res = unpack_str(e, &tmp, name);
282 *string = kmemdup(tmp, res, GFP_KERNEL);
292 * verify_accept - verify the accept tables of a dfa
293 * @dfa: dfa to verify accept tables of (NOT NULL)
294 * @flags: flags governing dfa
296 * Returns: 1 if valid accept tables else 0 if error
298 static bool verify_accept(struct aa_dfa *dfa, int flags)
302 /* verify accept permissions */
303 for (i = 0; i < dfa->tables[YYTD_ID_ACCEPT]->td_lolen; i++) {
304 int mode = ACCEPT_TABLE(dfa)[i];
306 if (mode & ~DFA_VALID_PERM_MASK)
309 if (ACCEPT_TABLE2(dfa)[i] & ~DFA_VALID_PERM2_MASK)
316 * unpack_dfa - unpack a file rule dfa
317 * @e: serialized data extent information (NOT NULL)
319 * returns dfa or ERR_PTR or NULL if no dfa
321 static struct aa_dfa *unpack_dfa(struct aa_ext *e)
325 struct aa_dfa *dfa = NULL;
327 size = unpack_blob(e, &blob, "aadfa");
330 * The dfa is aligned with in the blob to 8 bytes
331 * from the beginning of the stream.
333 size_t sz = blob - (char *)e->start;
334 size_t pad = ALIGN(sz, 8) - sz;
335 int flags = TO_ACCEPT1_FLAG(YYTD_DATA32) |
336 TO_ACCEPT2_FLAG(YYTD_DATA32);
339 if (aa_g_paranoid_load)
340 flags |= DFA_FLAG_VERIFY_STATES;
342 dfa = aa_dfa_unpack(blob + pad, size - pad, flags);
347 if (!verify_accept(dfa, flags))
355 return ERR_PTR(-EPROTO);
359 * unpack_trans_table - unpack a profile transition table
360 * @e: serialized data extent information (NOT NULL)
361 * @profile: profile to add the accept table to (NOT NULL)
363 * Returns: 1 if table successfully unpacked
365 static bool unpack_trans_table(struct aa_ext *e, struct aa_profile *profile)
369 /* exec table is optional */
370 if (unpack_nameX(e, AA_STRUCT, "xtable")) {
373 size = unpack_array(e, NULL);
374 /* currently 4 exec bits and entries 0-3 are reserved iupcx */
377 profile->file.trans.table = kzalloc(sizeof(char *) * size,
379 if (!profile->file.trans.table)
382 profile->file.trans.size = size;
383 for (i = 0; i < size; i++) {
385 int c, j, size2 = unpack_strdup(e, &str, NULL);
386 /* unpack_strdup verifies that the last character is
387 * null termination byte.
391 profile->file.trans.table[i] = str;
392 /* verify that name doesn't start with space */
396 /* count internal # of internal \0 */
397 for (c = j = 0; j < size2 - 2; j++) {
402 /* beginning with : requires an embedded \0,
403 * verify that exactly 1 internal \0 exists
404 * trailing \0 already verified by unpack_strdup
408 /* first character after : must be valid */
412 /* fail - all other cases with embedded \0 */
415 if (!unpack_nameX(e, AA_ARRAYEND, NULL))
417 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
423 aa_free_domain_entries(&profile->file.trans);
428 static bool unpack_rlimits(struct aa_ext *e, struct aa_profile *profile)
432 /* rlimits are optional */
433 if (unpack_nameX(e, AA_STRUCT, "rlimits")) {
436 if (!unpack_u32(e, &tmp, NULL))
438 profile->rlimits.mask = tmp;
440 size = unpack_array(e, NULL);
441 if (size > RLIM_NLIMITS)
443 for (i = 0; i < size; i++) {
445 int a = aa_map_resource(i);
446 if (!unpack_u64(e, &tmp2, NULL))
448 profile->rlimits.limits[a].rlim_max = tmp2;
450 if (!unpack_nameX(e, AA_ARRAYEND, NULL))
452 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
463 * unpack_profile - unpack a serialized profile
464 * @e: serialized data extent information (NOT NULL)
466 * NOTE: unpack profile sets audit struct if there is a failure
468 static struct aa_profile *unpack_profile(struct aa_ext *e)
470 struct aa_profile *profile = NULL;
471 const char *name = NULL;
472 int i, error = -EPROTO;
476 /* check that we have the right struct being passed */
477 if (!unpack_nameX(e, AA_STRUCT, "profile"))
479 if (!unpack_str(e, &name, NULL))
482 profile = aa_alloc_profile(name);
484 return ERR_PTR(-ENOMEM);
486 /* profile renaming is optional */
487 (void) unpack_str(e, &profile->rename, "rename");
489 /* xmatch is optional and may be NULL */
490 profile->xmatch = unpack_dfa(e);
491 if (IS_ERR(profile->xmatch)) {
492 error = PTR_ERR(profile->xmatch);
493 profile->xmatch = NULL;
496 /* xmatch_len is not optional if xmatch is set */
497 if (profile->xmatch) {
498 if (!unpack_u32(e, &tmp, NULL))
500 profile->xmatch_len = tmp;
503 /* per profile debug flags (complain, audit) */
504 if (!unpack_nameX(e, AA_STRUCT, "flags"))
506 if (!unpack_u32(e, &tmp, NULL))
509 profile->flags |= PFLAG_HAT;
510 if (!unpack_u32(e, &tmp, NULL))
513 profile->mode = APPARMOR_COMPLAIN;
514 if (!unpack_u32(e, &tmp, NULL))
517 profile->audit = AUDIT_ALL;
519 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
522 /* path_flags is optional */
523 if (unpack_u32(e, &profile->path_flags, "path_flags"))
524 profile->path_flags |= profile->flags & PFLAG_MEDIATE_DELETED;
526 /* set a default value if path_flags field is not present */
527 profile->path_flags = PFLAG_MEDIATE_DELETED;
529 if (!unpack_u32(e, &(profile->caps.allow.cap[0]), NULL))
531 if (!unpack_u32(e, &(profile->caps.audit.cap[0]), NULL))
533 if (!unpack_u32(e, &(profile->caps.quiet.cap[0]), NULL))
535 if (!unpack_u32(e, &tmpcap.cap[0], NULL))
538 if (unpack_nameX(e, AA_STRUCT, "caps64")) {
539 /* optional upper half of 64 bit caps */
540 if (!unpack_u32(e, &(profile->caps.allow.cap[1]), NULL))
542 if (!unpack_u32(e, &(profile->caps.audit.cap[1]), NULL))
544 if (!unpack_u32(e, &(profile->caps.quiet.cap[1]), NULL))
546 if (!unpack_u32(e, &(tmpcap.cap[1]), NULL))
548 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
552 if (unpack_nameX(e, AA_STRUCT, "capsx")) {
553 /* optional extended caps mediation mask */
554 if (!unpack_u32(e, &(profile->caps.extended.cap[0]), NULL))
556 if (!unpack_u32(e, &(profile->caps.extended.cap[1]), NULL))
558 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
562 if (!unpack_rlimits(e, profile))
565 if (unpack_nameX(e, AA_STRUCT, "policydb")) {
566 /* generic policy dfa - optional and may be NULL */
567 profile->policy.dfa = unpack_dfa(e);
568 if (IS_ERR(profile->policy.dfa)) {
569 error = PTR_ERR(profile->policy.dfa);
570 profile->policy.dfa = NULL;
573 if (!unpack_u32(e, &profile->policy.start[0], "start"))
574 /* default start state */
575 profile->policy.start[0] = DFA_START;
576 /* setup class index */
577 for (i = AA_CLASS_FILE; i <= AA_CLASS_LAST; i++) {
578 profile->policy.start[i] =
579 aa_dfa_next(profile->policy.dfa,
580 profile->policy.start[0],
583 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
588 profile->file.dfa = unpack_dfa(e);
589 if (IS_ERR(profile->file.dfa)) {
590 error = PTR_ERR(profile->file.dfa);
591 profile->file.dfa = NULL;
595 if (!unpack_u32(e, &profile->file.start, "dfa_start"))
596 /* default start state */
597 profile->file.start = DFA_START;
599 if (!unpack_trans_table(e, profile))
602 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
612 audit_iface(profile, name, "failed to unpack profile", e, error);
613 aa_put_profile(profile);
615 return ERR_PTR(error);
619 * verify_head - unpack serialized stream header
620 * @e: serialized data read head (NOT NULL)
621 * @ns: Returns - namespace if one is specified else NULL (NOT NULL)
623 * Returns: error or 0 if header is good
625 static int verify_header(struct aa_ext *e, const char **ns)
627 int error = -EPROTONOSUPPORT;
628 /* get the interface version */
629 if (!unpack_u32(e, &e->version, "version")) {
630 audit_iface(NULL, NULL, "invalid profile format", e, error);
634 /* check that the interface version is currently supported */
635 if (e->version != 5) {
636 audit_iface(NULL, NULL, "unsupported interface version", e,
641 /* read the namespace if present */
642 if (!unpack_str(e, ns, "namespace"))
648 static bool verify_xindex(int xindex, int table_size)
651 xtype = xindex & AA_X_TYPE_MASK;
652 index = xindex & AA_X_INDEX_MASK;
653 if (xtype == AA_X_TABLE && index > table_size)
658 /* verify dfa xindexes are in range of transition tables */
659 static bool verify_dfa_xindex(struct aa_dfa *dfa, int table_size)
662 for (i = 0; i < dfa->tables[YYTD_ID_ACCEPT]->td_lolen; i++) {
663 if (!verify_xindex(dfa_user_xindex(dfa, i), table_size))
665 if (!verify_xindex(dfa_other_xindex(dfa, i), table_size))
672 * verify_profile - Do post unpack analysis to verify profile consistency
673 * @profile: profile to verify (NOT NULL)
675 * Returns: 0 if passes verification else error
677 static int verify_profile(struct aa_profile *profile)
679 if (aa_g_paranoid_load) {
680 if (profile->file.dfa &&
681 !verify_dfa_xindex(profile->file.dfa,
682 profile->file.trans.size)) {
683 audit_iface(profile, NULL, "Invalid named transition",
693 * aa_unpack - unpack packed binary profile data loaded from user space
694 * @udata: user data copied to kmem (NOT NULL)
695 * @size: the size of the user data
696 * @ns: Returns namespace profile is in if specified else NULL (NOT NULL)
698 * Unpack user data and return refcounted allocated profile or ERR_PTR
700 * Returns: profile else error pointer if fails to unpack
702 struct aa_profile *aa_unpack(void *udata, size_t size, const char **ns)
704 struct aa_profile *profile = NULL;
712 error = verify_header(&e, ns);
714 return ERR_PTR(error);
716 profile = unpack_profile(&e);
720 error = verify_profile(profile);
722 aa_put_profile(profile);
723 profile = ERR_PTR(error);
726 /* return refcount */