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 (NOT NULL)
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);
98 sa.aad.iface.pos = e->pos - e->start;
99 sa.aad.iface.target = new;
102 sa.aad.error = error;
104 return aa_audit(AUDIT_APPARMOR_STATUS, profile, GFP_KERNEL, &sa,
108 /* test if read will be in packed data bounds */
109 static bool inbounds(struct aa_ext *e, size_t size)
111 return (size <= e->end - e->pos);
115 * aa_u16_chunck - test and do bounds checking for a u16 size based chunk
116 * @e: serialized data read head (NOT NULL)
117 * @chunk: start address for chunk of data (NOT NULL)
119 * Returns: the size of chunk found with the read head at the end of the chunk.
121 static size_t unpack_u16_chunk(struct aa_ext *e, char **chunk)
125 if (!inbounds(e, sizeof(u16)))
127 size = le16_to_cpu(get_unaligned((u16 *) e->pos));
128 e->pos += sizeof(u16);
129 if (!inbounds(e, size))
136 /* unpack control byte */
137 static bool unpack_X(struct aa_ext *e, enum aa_code code)
141 if (*(u8 *) e->pos != code)
148 * unpack_nameX - check is the next element is of type X with a name of @name
149 * @e: serialized data extent information (NOT NULL)
151 * @name: name to match to the serialized element. (MAYBE NULL)
153 * check that the next serialized data element is of type X and has a tag
154 * name @name. If @name is specified then there must be a matching
155 * name element in the stream. If @name is NULL any name element will be
156 * skipped and only the typecode will be tested.
158 * Returns 1 on success (both type code and name tests match) and the read
159 * head is advanced past the headers
161 * Returns: 0 if either match fails, the read head does not move
163 static bool unpack_nameX(struct aa_ext *e, enum aa_code code, const char *name)
166 * May need to reset pos if name or type doesn't match
170 * Check for presence of a tagname, and if present name size
171 * AA_NAME tag value is a u16.
173 if (unpack_X(e, AA_NAME)) {
175 size_t size = unpack_u16_chunk(e, &tag);
176 /* if a name is specified it must match. otherwise skip tag */
177 if (name && (!size || strcmp(name, tag)))
180 /* if a name is specified and there is no name tag fail */
184 /* now check if type code matches */
185 if (unpack_X(e, code))
193 static bool unpack_u32(struct aa_ext *e, u32 *data, const char *name)
195 if (unpack_nameX(e, AA_U32, name)) {
196 if (!inbounds(e, sizeof(u32)))
199 *data = le32_to_cpu(get_unaligned((u32 *) e->pos));
200 e->pos += sizeof(u32);
206 static bool unpack_u64(struct aa_ext *e, u64 *data, const char *name)
208 if (unpack_nameX(e, AA_U64, name)) {
209 if (!inbounds(e, sizeof(u64)))
212 *data = le64_to_cpu(get_unaligned((u64 *) e->pos));
213 e->pos += sizeof(u64);
219 static size_t unpack_array(struct aa_ext *e, const char *name)
221 if (unpack_nameX(e, AA_ARRAY, name)) {
223 if (!inbounds(e, sizeof(u16)))
225 size = (int)le16_to_cpu(get_unaligned((u16 *) e->pos));
226 e->pos += sizeof(u16);
232 static size_t unpack_blob(struct aa_ext *e, char **blob, const char *name)
234 if (unpack_nameX(e, AA_BLOB, name)) {
236 if (!inbounds(e, sizeof(u32)))
238 size = le32_to_cpu(get_unaligned((u32 *) e->pos));
239 e->pos += sizeof(u32);
240 if (inbounds(e, (size_t) size)) {
249 static int unpack_str(struct aa_ext *e, const char **string, const char *name)
255 if (unpack_nameX(e, AA_STRING, name)) {
256 size = unpack_u16_chunk(e, &src_str);
258 /* strings are null terminated, length is size - 1 */
259 if (src_str[size - 1] != 0)
271 static int unpack_strdup(struct aa_ext *e, char **string, const char *name)
275 int res = unpack_str(e, &tmp, name);
281 *string = kmemdup(tmp, res, GFP_KERNEL);
291 * verify_accept - verify the accept tables of a dfa
292 * @dfa: dfa to verify accept tables of (NOT NULL)
293 * @flags: flags governing dfa
295 * Returns: 1 if valid accept tables else 0 if error
297 static bool verify_accept(struct aa_dfa *dfa, int flags)
301 /* verify accept permissions */
302 for (i = 0; i < dfa->tables[YYTD_ID_ACCEPT]->td_lolen; i++) {
303 int mode = ACCEPT_TABLE(dfa)[i];
305 if (mode & ~DFA_VALID_PERM_MASK)
308 if (ACCEPT_TABLE2(dfa)[i] & ~DFA_VALID_PERM2_MASK)
315 * unpack_dfa - unpack a file rule dfa
316 * @e: serialized data extent information (NOT NULL)
318 * returns dfa or ERR_PTR or NULL if no dfa
320 static struct aa_dfa *unpack_dfa(struct aa_ext *e)
324 struct aa_dfa *dfa = NULL;
326 size = unpack_blob(e, &blob, "aadfa");
329 * The dfa is aligned with in the blob to 8 bytes
330 * from the beginning of the stream.
332 size_t sz = blob - (char *)e->start;
333 size_t pad = ALIGN(sz, 8) - sz;
334 int flags = TO_ACCEPT1_FLAG(YYTD_DATA32) |
335 TO_ACCEPT2_FLAG(YYTD_DATA32);
338 if (aa_g_paranoid_load)
339 flags |= DFA_FLAG_VERIFY_STATES;
341 dfa = aa_dfa_unpack(blob + pad, size - pad, flags);
346 if (!verify_accept(dfa, flags))
354 return ERR_PTR(-EPROTO);
358 * unpack_trans_table - unpack a profile transition table
359 * @e: serialized data extent information (NOT NULL)
360 * @profile: profile to add the accept table to (NOT NULL)
362 * Returns: 1 if table successfully unpacked
364 static bool unpack_trans_table(struct aa_ext *e, struct aa_profile *profile)
368 /* exec table is optional */
369 if (unpack_nameX(e, AA_STRUCT, "xtable")) {
372 size = unpack_array(e, NULL);
373 /* currently 4 exec bits and entries 0-3 are reserved iupcx */
376 profile->file.trans.table = kzalloc(sizeof(char *) * size,
378 if (!profile->file.trans.table)
381 profile->file.trans.size = size;
382 for (i = 0; i < size; i++) {
384 int c, j, size = unpack_strdup(e, &str, NULL);
385 /* unpack_strdup verifies that the last character is
386 * null termination byte.
390 profile->file.trans.table[i] = str;
391 /* verify that name doesn't start with space */
395 /* count internal # of internal \0 */
396 for (c = j = 0; j < size - 2; j++) {
401 /* beginning with : requires an embedded \0,
402 * verify that exactly 1 internal \0 exists
403 * trailing \0 already verified by unpack_strdup
407 /* first character after : must be valid */
411 /* fail - all other cases with embedded \0 */
414 if (!unpack_nameX(e, AA_ARRAYEND, NULL))
416 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
422 aa_free_domain_entries(&profile->file.trans);
427 static bool unpack_rlimits(struct aa_ext *e, struct aa_profile *profile)
431 /* rlimits are optional */
432 if (unpack_nameX(e, AA_STRUCT, "rlimits")) {
435 if (!unpack_u32(e, &tmp, NULL))
437 profile->rlimits.mask = tmp;
439 size = unpack_array(e, NULL);
440 if (size > RLIM_NLIMITS)
442 for (i = 0; i < size; i++) {
444 int a = aa_map_resource(i);
445 if (!unpack_u64(e, &tmp, NULL))
447 profile->rlimits.limits[a].rlim_max = tmp;
449 if (!unpack_nameX(e, AA_ARRAYEND, NULL))
451 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
462 * unpack_profile - unpack a serialized profile
463 * @e: serialized data extent information (NOT NULL)
465 * NOTE: unpack profile sets audit struct if there is a failure
467 static struct aa_profile *unpack_profile(struct aa_ext *e)
469 struct aa_profile *profile = NULL;
470 const char *name = NULL;
475 /* check that we have the right struct being passed */
476 if (!unpack_nameX(e, AA_STRUCT, "profile"))
478 if (!unpack_str(e, &name, NULL))
481 profile = aa_alloc_profile(name);
483 return ERR_PTR(-ENOMEM);
485 /* profile renaming is optional */
486 (void) unpack_str(e, &profile->rename, "rename");
488 /* xmatch is optional and may be NULL */
489 profile->xmatch = unpack_dfa(e);
490 if (IS_ERR(profile->xmatch)) {
491 error = PTR_ERR(profile->xmatch);
492 profile->xmatch = NULL;
495 /* xmatch_len is not optional if xmatch is set */
496 if (profile->xmatch) {
497 if (!unpack_u32(e, &tmp, NULL))
499 profile->xmatch_len = tmp;
502 /* per profile debug flags (complain, audit) */
503 if (!unpack_nameX(e, AA_STRUCT, "flags"))
505 if (!unpack_u32(e, &tmp, NULL))
508 profile->flags |= PFLAG_HAT;
509 if (!unpack_u32(e, &tmp, NULL))
512 profile->mode = APPARMOR_COMPLAIN;
513 if (!unpack_u32(e, &tmp, NULL))
516 profile->audit = AUDIT_ALL;
518 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
521 /* path_flags is optional */
522 if (unpack_u32(e, &profile->path_flags, "path_flags"))
523 profile->path_flags |= profile->flags & PFLAG_MEDIATE_DELETED;
525 /* set a default value if path_flags field is not present */
526 profile->path_flags = PFLAG_MEDIATE_DELETED;
528 if (!unpack_u32(e, &(profile->caps.allow.cap[0]), NULL))
530 if (!unpack_u32(e, &(profile->caps.audit.cap[0]), NULL))
532 if (!unpack_u32(e, &(profile->caps.quiet.cap[0]), NULL))
534 if (!unpack_u32(e, &tmpcap.cap[0], NULL))
537 if (unpack_nameX(e, AA_STRUCT, "caps64")) {
538 /* optional upper half of 64 bit caps */
539 if (!unpack_u32(e, &(profile->caps.allow.cap[1]), NULL))
541 if (!unpack_u32(e, &(profile->caps.audit.cap[1]), NULL))
543 if (!unpack_u32(e, &(profile->caps.quiet.cap[1]), NULL))
545 if (!unpack_u32(e, &(tmpcap.cap[1]), NULL))
547 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
551 if (unpack_nameX(e, AA_STRUCT, "capsx")) {
552 /* optional extended caps mediation mask */
553 if (!unpack_u32(e, &(profile->caps.extended.cap[0]), NULL))
555 if (!unpack_u32(e, &(profile->caps.extended.cap[1]), NULL))
559 if (!unpack_rlimits(e, profile))
563 profile->file.dfa = unpack_dfa(e);
564 if (IS_ERR(profile->file.dfa)) {
565 error = PTR_ERR(profile->file.dfa);
566 profile->file.dfa = NULL;
570 if (!unpack_u32(e, &profile->file.start, "dfa_start"))
571 /* default start state */
572 profile->file.start = DFA_START;
574 if (!unpack_trans_table(e, profile))
577 if (!unpack_nameX(e, AA_STRUCTEND, NULL))
587 audit_iface(profile, name, "failed to unpack profile", e, error);
588 aa_put_profile(profile);
590 return ERR_PTR(error);
594 * verify_head - unpack serialized stream header
595 * @e: serialized data read head (NOT NULL)
596 * @ns: Returns - namespace if one is specified else NULL (NOT NULL)
598 * Returns: error or 0 if header is good
600 static int verify_header(struct aa_ext *e, const char **ns)
602 int error = -EPROTONOSUPPORT;
603 /* get the interface version */
604 if (!unpack_u32(e, &e->version, "version")) {
605 audit_iface(NULL, NULL, "invalid profile format", e, error);
609 /* check that the interface version is currently supported */
610 if (e->version != 5) {
611 audit_iface(NULL, NULL, "unsupported interface version", e,
616 /* read the namespace if present */
617 if (!unpack_str(e, ns, "namespace"))
623 static bool verify_xindex(int xindex, int table_size)
626 xtype = xindex & AA_X_TYPE_MASK;
627 index = xindex & AA_X_INDEX_MASK;
628 if (xtype == AA_X_TABLE && index > table_size)
633 /* verify dfa xindexes are in range of transition tables */
634 static bool verify_dfa_xindex(struct aa_dfa *dfa, int table_size)
637 for (i = 0; i < dfa->tables[YYTD_ID_ACCEPT]->td_lolen; i++) {
638 if (!verify_xindex(dfa_user_xindex(dfa, i), table_size))
640 if (!verify_xindex(dfa_other_xindex(dfa, i), table_size))
647 * verify_profile - Do post unpack analysis to verify profile consistency
648 * @profile: profile to verify (NOT NULL)
650 * Returns: 0 if passes verification else error
652 static int verify_profile(struct aa_profile *profile)
654 if (aa_g_paranoid_load) {
655 if (profile->file.dfa &&
656 !verify_dfa_xindex(profile->file.dfa,
657 profile->file.trans.size)) {
658 audit_iface(profile, NULL, "Invalid named transition",
668 * aa_unpack - unpack packed binary profile data loaded from user space
669 * @udata: user data copied to kmem (NOT NULL)
670 * @size: the size of the user data
671 * @ns: Returns namespace profile is in if specified else NULL (NOT NULL)
673 * Unpack user data and return refcounted allocated profile or ERR_PTR
675 * Returns: profile else error pointer if fails to unpack
677 struct aa_profile *aa_unpack(void *udata, size_t size, const char **ns)
679 struct aa_profile *profile = NULL;
687 error = verify_header(&e, ns);
689 return ERR_PTR(error);
691 profile = unpack_profile(&e);
695 error = verify_profile(profile);
697 aa_put_profile(profile);
698 profile = ERR_PTR(error);
701 /* return refcount */