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 */