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"
32 * The AppArmor interface treats data as a type byte followed by the
33 * actual data. The interface has the notion of a a named entry
34 * which has a name (AA_NAME typecode followed by name string) followed by
35 * the entries typecode and data. Named types allow for optional
36 * elements and extensions to be added and tested for without breaking
37 * backwards compatibility.
45 AA_NAME
, /* same as string except it is items name */
57 * aa_ext is the read of the buffer containing the serialized profile. The
58 * data is copied into a kernel buffer in apparmorfs and then handed off to
59 * the unpack routines.
64 void *pos
; /* pointer to current position in the buffer */
68 /* audit callback for unpack fields */
69 static void audit_cb(struct audit_buffer
*ab
, void *va
)
71 struct common_audit_data
*sa
= va
;
72 if (sa
->aad
->iface
.target
) {
73 struct aa_profile
*name
= sa
->aad
->iface
.target
;
74 audit_log_format(ab
, " name=");
75 audit_log_untrustedstring(ab
, name
->base
.hname
);
77 if (sa
->aad
->iface
.pos
)
78 audit_log_format(ab
, " offset=%ld", sa
->aad
->iface
.pos
);
82 * audit_iface - do audit message for policy unpacking/load/replace/remove
83 * @new: profile if it has been allocated (MAYBE NULL)
84 * @name: name of the profile being manipulated (MAYBE NULL)
85 * @info: any extra info about the failure (MAYBE NULL)
86 * @e: buffer position info
89 * Returns: %0 or error
91 static int audit_iface(struct aa_profile
*new, const char *name
,
92 const char *info
, struct aa_ext
*e
, int error
)
94 struct aa_profile
*profile
= __aa_current_profile();
95 struct common_audit_data sa
;
96 struct apparmor_audit_data aad
= {0,};
97 sa
.type
= LSM_AUDIT_DATA_NONE
;
100 aad
.iface
.pos
= e
->pos
- e
->start
;
101 aad
.iface
.target
= new;
106 return aa_audit(AUDIT_APPARMOR_STATUS
, profile
, GFP_KERNEL
, &sa
,
110 /* test if read will be in packed data bounds */
111 static bool inbounds(struct aa_ext
*e
, size_t size
)
113 return (size
<= e
->end
- e
->pos
);
117 * aa_u16_chunck - test and do bounds checking for a u16 size based chunk
118 * @e: serialized data read head (NOT NULL)
119 * @chunk: start address for chunk of data (NOT NULL)
121 * Returns: the size of chunk found with the read head at the end of the chunk.
123 static size_t unpack_u16_chunk(struct aa_ext
*e
, char **chunk
)
127 if (!inbounds(e
, sizeof(u16
)))
129 size
= le16_to_cpu(get_unaligned((u16
*) e
->pos
));
130 e
->pos
+= sizeof(u16
);
131 if (!inbounds(e
, size
))
138 /* unpack control byte */
139 static bool unpack_X(struct aa_ext
*e
, enum aa_code code
)
143 if (*(u8
*) e
->pos
!= code
)
150 * unpack_nameX - check is the next element is of type X with a name of @name
151 * @e: serialized data extent information (NOT NULL)
153 * @name: name to match to the serialized element. (MAYBE NULL)
155 * check that the next serialized data element is of type X and has a tag
156 * name @name. If @name is specified then there must be a matching
157 * name element in the stream. If @name is NULL any name element will be
158 * skipped and only the typecode will be tested.
160 * Returns 1 on success (both type code and name tests match) and the read
161 * head is advanced past the headers
163 * Returns: 0 if either match fails, the read head does not move
165 static bool unpack_nameX(struct aa_ext
*e
, enum aa_code code
, const char *name
)
168 * May need to reset pos if name or type doesn't match
172 * Check for presence of a tagname, and if present name size
173 * AA_NAME tag value is a u16.
175 if (unpack_X(e
, AA_NAME
)) {
177 size_t size
= unpack_u16_chunk(e
, &tag
);
178 /* if a name is specified it must match. otherwise skip tag */
179 if (name
&& (!size
|| strcmp(name
, tag
)))
182 /* if a name is specified and there is no name tag fail */
186 /* now check if type code matches */
187 if (unpack_X(e
, code
))
195 static bool unpack_u32(struct aa_ext
*e
, u32
*data
, const char *name
)
197 if (unpack_nameX(e
, AA_U32
, name
)) {
198 if (!inbounds(e
, sizeof(u32
)))
201 *data
= le32_to_cpu(get_unaligned((u32
*) e
->pos
));
202 e
->pos
+= sizeof(u32
);
208 static bool unpack_u64(struct aa_ext
*e
, u64
*data
, const char *name
)
210 if (unpack_nameX(e
, AA_U64
, name
)) {
211 if (!inbounds(e
, sizeof(u64
)))
214 *data
= le64_to_cpu(get_unaligned((u64
*) e
->pos
));
215 e
->pos
+= sizeof(u64
);
221 static size_t unpack_array(struct aa_ext
*e
, const char *name
)
223 if (unpack_nameX(e
, AA_ARRAY
, name
)) {
225 if (!inbounds(e
, sizeof(u16
)))
227 size
= (int)le16_to_cpu(get_unaligned((u16
*) e
->pos
));
228 e
->pos
+= sizeof(u16
);
234 static size_t unpack_blob(struct aa_ext
*e
, char **blob
, const char *name
)
236 if (unpack_nameX(e
, AA_BLOB
, name
)) {
238 if (!inbounds(e
, sizeof(u32
)))
240 size
= le32_to_cpu(get_unaligned((u32
*) e
->pos
));
241 e
->pos
+= sizeof(u32
);
242 if (inbounds(e
, (size_t) size
)) {
251 static int unpack_str(struct aa_ext
*e
, const char **string
, const char *name
)
257 if (unpack_nameX(e
, AA_STRING
, name
)) {
258 size
= unpack_u16_chunk(e
, &src_str
);
260 /* strings are null terminated, length is size - 1 */
261 if (src_str
[size
- 1] != 0)
273 static int unpack_strdup(struct aa_ext
*e
, char **string
, const char *name
)
277 int res
= unpack_str(e
, &tmp
, name
);
283 *string
= kmemdup(tmp
, res
, GFP_KERNEL
);
292 #define DFA_VALID_PERM_MASK 0xffffffff
293 #define DFA_VALID_PERM2_MASK 0xffffffff
296 * verify_accept - verify the accept tables of a dfa
297 * @dfa: dfa to verify accept tables of (NOT NULL)
298 * @flags: flags governing dfa
300 * Returns: 1 if valid accept tables else 0 if error
302 static bool verify_accept(struct aa_dfa
*dfa
, int flags
)
306 /* verify accept permissions */
307 for (i
= 0; i
< dfa
->tables
[YYTD_ID_ACCEPT
]->td_lolen
; i
++) {
308 int mode
= ACCEPT_TABLE(dfa
)[i
];
310 if (mode
& ~DFA_VALID_PERM_MASK
)
313 if (ACCEPT_TABLE2(dfa
)[i
] & ~DFA_VALID_PERM2_MASK
)
320 * unpack_dfa - unpack a file rule dfa
321 * @e: serialized data extent information (NOT NULL)
323 * returns dfa or ERR_PTR or NULL if no dfa
325 static struct aa_dfa
*unpack_dfa(struct aa_ext
*e
)
329 struct aa_dfa
*dfa
= NULL
;
331 size
= unpack_blob(e
, &blob
, "aadfa");
334 * The dfa is aligned with in the blob to 8 bytes
335 * from the beginning of the stream.
337 size_t sz
= blob
- (char *)e
->start
;
338 size_t pad
= ALIGN(sz
, 8) - sz
;
339 int flags
= TO_ACCEPT1_FLAG(YYTD_DATA32
) |
340 TO_ACCEPT2_FLAG(YYTD_DATA32
);
343 if (aa_g_paranoid_load
)
344 flags
|= DFA_FLAG_VERIFY_STATES
;
346 dfa
= aa_dfa_unpack(blob
+ pad
, size
- pad
, flags
);
351 if (!verify_accept(dfa
, flags
))
359 return ERR_PTR(-EPROTO
);
363 * unpack_trans_table - unpack a profile transition table
364 * @e: serialized data extent information (NOT NULL)
365 * @profile: profile to add the accept table to (NOT NULL)
367 * Returns: 1 if table successfully unpacked
369 static bool unpack_trans_table(struct aa_ext
*e
, struct aa_profile
*profile
)
373 /* exec table is optional */
374 if (unpack_nameX(e
, AA_STRUCT
, "xtable")) {
377 size
= unpack_array(e
, NULL
);
378 /* currently 4 exec bits and entries 0-3 are reserved iupcx */
381 profile
->file
.trans
.table
= kzalloc(sizeof(char *) * size
,
383 if (!profile
->file
.trans
.table
)
386 profile
->file
.trans
.size
= size
;
387 for (i
= 0; i
< size
; i
++) {
389 int c
, j
, size2
= unpack_strdup(e
, &str
, NULL
);
390 /* unpack_strdup verifies that the last character is
391 * null termination byte.
395 profile
->file
.trans
.table
[i
] = str
;
396 /* verify that name doesn't start with space */
400 /* count internal # of internal \0 */
401 for (c
= j
= 0; j
< size2
- 2; j
++) {
406 /* beginning with : requires an embedded \0,
407 * verify that exactly 1 internal \0 exists
408 * trailing \0 already verified by unpack_strdup
412 /* first character after : must be valid */
416 /* fail - all other cases with embedded \0 */
419 if (!unpack_nameX(e
, AA_ARRAYEND
, NULL
))
421 if (!unpack_nameX(e
, AA_STRUCTEND
, NULL
))
427 aa_free_domain_entries(&profile
->file
.trans
);
432 static bool unpack_rlimits(struct aa_ext
*e
, struct aa_profile
*profile
)
436 /* rlimits are optional */
437 if (unpack_nameX(e
, AA_STRUCT
, "rlimits")) {
440 if (!unpack_u32(e
, &tmp
, NULL
))
442 profile
->rlimits
.mask
= tmp
;
444 size
= unpack_array(e
, NULL
);
445 if (size
> RLIM_NLIMITS
)
447 for (i
= 0; i
< size
; i
++) {
449 int a
= aa_map_resource(i
);
450 if (!unpack_u64(e
, &tmp2
, NULL
))
452 profile
->rlimits
.limits
[a
].rlim_max
= tmp2
;
454 if (!unpack_nameX(e
, AA_ARRAYEND
, NULL
))
456 if (!unpack_nameX(e
, AA_STRUCTEND
, NULL
))
467 * unpack_profile - unpack a serialized profile
468 * @e: serialized data extent information (NOT NULL)
470 * NOTE: unpack profile sets audit struct if there is a failure
472 static struct aa_profile
*unpack_profile(struct aa_ext
*e
)
474 struct aa_profile
*profile
= NULL
;
475 const char *name
= NULL
;
476 int i
, error
= -EPROTO
;
480 /* check that we have the right struct being passed */
481 if (!unpack_nameX(e
, AA_STRUCT
, "profile"))
483 if (!unpack_str(e
, &name
, NULL
))
486 profile
= aa_alloc_profile(name
);
488 return ERR_PTR(-ENOMEM
);
490 /* profile renaming is optional */
491 (void) unpack_str(e
, &profile
->rename
, "rename");
493 /* xmatch is optional and may be NULL */
494 profile
->xmatch
= unpack_dfa(e
);
495 if (IS_ERR(profile
->xmatch
)) {
496 error
= PTR_ERR(profile
->xmatch
);
497 profile
->xmatch
= NULL
;
500 /* xmatch_len is not optional if xmatch is set */
501 if (profile
->xmatch
) {
502 if (!unpack_u32(e
, &tmp
, NULL
))
504 profile
->xmatch_len
= tmp
;
507 /* per profile debug flags (complain, audit) */
508 if (!unpack_nameX(e
, AA_STRUCT
, "flags"))
510 if (!unpack_u32(e
, &tmp
, NULL
))
513 profile
->flags
|= PFLAG_HAT
;
514 if (!unpack_u32(e
, &tmp
, NULL
))
517 profile
->mode
= APPARMOR_COMPLAIN
;
518 if (!unpack_u32(e
, &tmp
, NULL
))
521 profile
->audit
= AUDIT_ALL
;
523 if (!unpack_nameX(e
, AA_STRUCTEND
, NULL
))
526 /* path_flags is optional */
527 if (unpack_u32(e
, &profile
->path_flags
, "path_flags"))
528 profile
->path_flags
|= profile
->flags
& PFLAG_MEDIATE_DELETED
;
530 /* set a default value if path_flags field is not present */
531 profile
->path_flags
= PFLAG_MEDIATE_DELETED
;
533 if (!unpack_u32(e
, &(profile
->caps
.allow
.cap
[0]), NULL
))
535 if (!unpack_u32(e
, &(profile
->caps
.audit
.cap
[0]), NULL
))
537 if (!unpack_u32(e
, &(profile
->caps
.quiet
.cap
[0]), NULL
))
539 if (!unpack_u32(e
, &tmpcap
.cap
[0], NULL
))
542 if (unpack_nameX(e
, AA_STRUCT
, "caps64")) {
543 /* optional upper half of 64 bit caps */
544 if (!unpack_u32(e
, &(profile
->caps
.allow
.cap
[1]), NULL
))
546 if (!unpack_u32(e
, &(profile
->caps
.audit
.cap
[1]), NULL
))
548 if (!unpack_u32(e
, &(profile
->caps
.quiet
.cap
[1]), NULL
))
550 if (!unpack_u32(e
, &(tmpcap
.cap
[1]), NULL
))
552 if (!unpack_nameX(e
, AA_STRUCTEND
, NULL
))
556 if (unpack_nameX(e
, AA_STRUCT
, "capsx")) {
557 /* optional extended caps mediation mask */
558 if (!unpack_u32(e
, &(profile
->caps
.extended
.cap
[0]), NULL
))
560 if (!unpack_u32(e
, &(profile
->caps
.extended
.cap
[1]), NULL
))
562 if (!unpack_nameX(e
, AA_STRUCTEND
, NULL
))
566 if (!unpack_rlimits(e
, profile
))
569 if (unpack_nameX(e
, AA_STRUCT
, "policydb")) {
570 /* generic policy dfa - optional and may be NULL */
571 profile
->policy
.dfa
= unpack_dfa(e
);
572 if (IS_ERR(profile
->policy
.dfa
)) {
573 error
= PTR_ERR(profile
->policy
.dfa
);
574 profile
->policy
.dfa
= NULL
;
577 if (!unpack_u32(e
, &profile
->policy
.start
[0], "start"))
578 /* default start state */
579 profile
->policy
.start
[0] = DFA_START
;
580 /* setup class index */
581 for (i
= AA_CLASS_FILE
; i
<= AA_CLASS_LAST
; i
++) {
582 profile
->policy
.start
[i
] =
583 aa_dfa_next(profile
->policy
.dfa
,
584 profile
->policy
.start
[0],
587 if (!unpack_nameX(e
, AA_STRUCTEND
, NULL
))
592 profile
->file
.dfa
= unpack_dfa(e
);
593 if (IS_ERR(profile
->file
.dfa
)) {
594 error
= PTR_ERR(profile
->file
.dfa
);
595 profile
->file
.dfa
= NULL
;
599 if (!unpack_u32(e
, &profile
->file
.start
, "dfa_start"))
600 /* default start state */
601 profile
->file
.start
= DFA_START
;
603 if (!unpack_trans_table(e
, profile
))
606 if (!unpack_nameX(e
, AA_STRUCTEND
, NULL
))
616 audit_iface(profile
, name
, "failed to unpack profile", e
, error
);
617 aa_put_profile(profile
);
619 return ERR_PTR(error
);
623 * verify_head - unpack serialized stream header
624 * @e: serialized data read head (NOT NULL)
625 * @ns: Returns - namespace if one is specified else NULL (NOT NULL)
627 * Returns: error or 0 if header is good
629 static int verify_header(struct aa_ext
*e
, const char **ns
)
631 int error
= -EPROTONOSUPPORT
;
632 /* get the interface version */
633 if (!unpack_u32(e
, &e
->version
, "version")) {
634 audit_iface(NULL
, NULL
, "invalid profile format", e
, error
);
638 /* check that the interface version is currently supported */
639 if (e
->version
!= 5) {
640 audit_iface(NULL
, NULL
, "unsupported interface version", e
,
645 /* read the namespace if present */
646 if (!unpack_str(e
, ns
, "namespace"))
652 static bool verify_xindex(int xindex
, int table_size
)
655 xtype
= xindex
& AA_X_TYPE_MASK
;
656 index
= xindex
& AA_X_INDEX_MASK
;
657 if (xtype
== AA_X_TABLE
&& index
> table_size
)
662 /* verify dfa xindexes are in range of transition tables */
663 static bool verify_dfa_xindex(struct aa_dfa
*dfa
, int table_size
)
666 for (i
= 0; i
< dfa
->tables
[YYTD_ID_ACCEPT
]->td_lolen
; i
++) {
667 if (!verify_xindex(dfa_user_xindex(dfa
, i
), table_size
))
669 if (!verify_xindex(dfa_other_xindex(dfa
, i
), table_size
))
676 * verify_profile - Do post unpack analysis to verify profile consistency
677 * @profile: profile to verify (NOT NULL)
679 * Returns: 0 if passes verification else error
681 static int verify_profile(struct aa_profile
*profile
)
683 if (aa_g_paranoid_load
) {
684 if (profile
->file
.dfa
&&
685 !verify_dfa_xindex(profile
->file
.dfa
,
686 profile
->file
.trans
.size
)) {
687 audit_iface(profile
, NULL
, "Invalid named transition",
697 * aa_unpack - unpack packed binary profile data loaded from user space
698 * @udata: user data copied to kmem (NOT NULL)
699 * @size: the size of the user data
700 * @ns: Returns namespace profile is in if specified else NULL (NOT NULL)
702 * Unpack user data and return refcounted allocated profile or ERR_PTR
704 * Returns: profile else error pointer if fails to unpack
706 struct aa_profile
*aa_unpack(void *udata
, size_t size
, const char **ns
)
708 struct aa_profile
*profile
= NULL
;
716 error
= verify_header(&e
, ns
);
718 return ERR_PTR(error
);
720 profile
= unpack_profile(&e
);
724 error
= verify_profile(profile
);
726 aa_put_profile(profile
);
727 profile
= ERR_PTR(error
);
730 /* return refcount */