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
);
346 if (aa_g_paranoid_load
)
347 flags
|= DFA_FLAG_VERIFY_STATES
;
349 dfa
= aa_dfa_unpack(blob
+ pad
, size
- pad
, flags
);
354 if (!verify_accept(dfa
, flags
))
362 return ERR_PTR(-EPROTO
);
366 * unpack_trans_table - unpack a profile transition table
367 * @e: serialized data extent information (NOT NULL)
368 * @profile: profile to add the accept table to (NOT NULL)
370 * Returns: 1 if table successfully unpacked
372 static bool unpack_trans_table(struct aa_ext
*e
, struct aa_profile
*profile
)
376 /* exec table is optional */
377 if (unpack_nameX(e
, AA_STRUCT
, "xtable")) {
380 size
= unpack_array(e
, NULL
);
381 /* currently 4 exec bits and entries 0-3 are reserved iupcx */
384 profile
->file
.trans
.table
= kzalloc(sizeof(char *) * size
,
386 if (!profile
->file
.trans
.table
)
389 profile
->file
.trans
.size
= size
;
390 for (i
= 0; i
< size
; i
++) {
392 int c
, j
, size2
= unpack_strdup(e
, &str
, NULL
);
393 /* unpack_strdup verifies that the last character is
394 * null termination byte.
398 profile
->file
.trans
.table
[i
] = str
;
399 /* verify that name doesn't start with space */
403 /* count internal # of internal \0 */
404 for (c
= j
= 0; j
< size2
- 2; j
++) {
409 /* beginning with : requires an embedded \0,
410 * verify that exactly 1 internal \0 exists
411 * trailing \0 already verified by unpack_strdup
415 /* first character after : must be valid */
419 /* fail - all other cases with embedded \0 */
422 if (!unpack_nameX(e
, AA_ARRAYEND
, NULL
))
424 if (!unpack_nameX(e
, AA_STRUCTEND
, NULL
))
430 aa_free_domain_entries(&profile
->file
.trans
);
435 static bool unpack_rlimits(struct aa_ext
*e
, struct aa_profile
*profile
)
439 /* rlimits are optional */
440 if (unpack_nameX(e
, AA_STRUCT
, "rlimits")) {
443 if (!unpack_u32(e
, &tmp
, NULL
))
445 profile
->rlimits
.mask
= tmp
;
447 size
= unpack_array(e
, NULL
);
448 if (size
> RLIM_NLIMITS
)
450 for (i
= 0; i
< size
; i
++) {
452 int a
= aa_map_resource(i
);
453 if (!unpack_u64(e
, &tmp2
, NULL
))
455 profile
->rlimits
.limits
[a
].rlim_max
= tmp2
;
457 if (!unpack_nameX(e
, AA_ARRAYEND
, NULL
))
459 if (!unpack_nameX(e
, AA_STRUCTEND
, NULL
))
470 * unpack_profile - unpack a serialized profile
471 * @e: serialized data extent information (NOT NULL)
473 * NOTE: unpack profile sets audit struct if there is a failure
475 static struct aa_profile
*unpack_profile(struct aa_ext
*e
)
477 struct aa_profile
*profile
= NULL
;
478 const char *name
= NULL
;
479 int i
, error
= -EPROTO
;
483 /* check that we have the right struct being passed */
484 if (!unpack_nameX(e
, AA_STRUCT
, "profile"))
486 if (!unpack_str(e
, &name
, NULL
))
489 profile
= aa_alloc_profile(name
);
491 return ERR_PTR(-ENOMEM
);
493 /* profile renaming is optional */
494 (void) unpack_str(e
, &profile
->rename
, "rename");
496 /* attachment string is optional */
497 (void) unpack_str(e
, &profile
->attach
, "attach");
499 /* xmatch is optional and may be NULL */
500 profile
->xmatch
= unpack_dfa(e
);
501 if (IS_ERR(profile
->xmatch
)) {
502 error
= PTR_ERR(profile
->xmatch
);
503 profile
->xmatch
= NULL
;
506 /* xmatch_len is not optional if xmatch is set */
507 if (profile
->xmatch
) {
508 if (!unpack_u32(e
, &tmp
, NULL
))
510 profile
->xmatch_len
= tmp
;
513 /* per profile debug flags (complain, audit) */
514 if (!unpack_nameX(e
, AA_STRUCT
, "flags"))
516 if (!unpack_u32(e
, &tmp
, NULL
))
518 if (tmp
& PACKED_FLAG_HAT
)
519 profile
->flags
|= PFLAG_HAT
;
520 if (!unpack_u32(e
, &tmp
, NULL
))
522 if (tmp
== PACKED_MODE_COMPLAIN
)
523 profile
->mode
= APPARMOR_COMPLAIN
;
524 else if (tmp
== PACKED_MODE_KILL
)
525 profile
->mode
= APPARMOR_KILL
;
526 else if (tmp
== PACKED_MODE_UNCONFINED
)
527 profile
->mode
= APPARMOR_UNCONFINED
;
528 if (!unpack_u32(e
, &tmp
, NULL
))
531 profile
->audit
= AUDIT_ALL
;
533 if (!unpack_nameX(e
, AA_STRUCTEND
, NULL
))
536 /* path_flags is optional */
537 if (unpack_u32(e
, &profile
->path_flags
, "path_flags"))
538 profile
->path_flags
|= profile
->flags
& PFLAG_MEDIATE_DELETED
;
540 /* set a default value if path_flags field is not present */
541 profile
->path_flags
= PFLAG_MEDIATE_DELETED
;
543 if (!unpack_u32(e
, &(profile
->caps
.allow
.cap
[0]), NULL
))
545 if (!unpack_u32(e
, &(profile
->caps
.audit
.cap
[0]), NULL
))
547 if (!unpack_u32(e
, &(profile
->caps
.quiet
.cap
[0]), NULL
))
549 if (!unpack_u32(e
, &tmpcap
.cap
[0], NULL
))
552 if (unpack_nameX(e
, AA_STRUCT
, "caps64")) {
553 /* optional upper half of 64 bit caps */
554 if (!unpack_u32(e
, &(profile
->caps
.allow
.cap
[1]), NULL
))
556 if (!unpack_u32(e
, &(profile
->caps
.audit
.cap
[1]), NULL
))
558 if (!unpack_u32(e
, &(profile
->caps
.quiet
.cap
[1]), NULL
))
560 if (!unpack_u32(e
, &(tmpcap
.cap
[1]), NULL
))
562 if (!unpack_nameX(e
, AA_STRUCTEND
, NULL
))
566 if (unpack_nameX(e
, AA_STRUCT
, "capsx")) {
567 /* optional extended caps mediation mask */
568 if (!unpack_u32(e
, &(profile
->caps
.extended
.cap
[0]), NULL
))
570 if (!unpack_u32(e
, &(profile
->caps
.extended
.cap
[1]), NULL
))
572 if (!unpack_nameX(e
, AA_STRUCTEND
, NULL
))
576 if (!unpack_rlimits(e
, profile
))
579 if (unpack_nameX(e
, AA_STRUCT
, "policydb")) {
580 /* generic policy dfa - optional and may be NULL */
581 profile
->policy
.dfa
= unpack_dfa(e
);
582 if (IS_ERR(profile
->policy
.dfa
)) {
583 error
= PTR_ERR(profile
->policy
.dfa
);
584 profile
->policy
.dfa
= NULL
;
587 if (!unpack_u32(e
, &profile
->policy
.start
[0], "start"))
588 /* default start state */
589 profile
->policy
.start
[0] = DFA_START
;
590 /* setup class index */
591 for (i
= AA_CLASS_FILE
; i
<= AA_CLASS_LAST
; i
++) {
592 profile
->policy
.start
[i
] =
593 aa_dfa_next(profile
->policy
.dfa
,
594 profile
->policy
.start
[0],
597 if (!unpack_nameX(e
, AA_STRUCTEND
, NULL
))
602 profile
->file
.dfa
= unpack_dfa(e
);
603 if (IS_ERR(profile
->file
.dfa
)) {
604 error
= PTR_ERR(profile
->file
.dfa
);
605 profile
->file
.dfa
= NULL
;
609 if (!unpack_u32(e
, &profile
->file
.start
, "dfa_start"))
610 /* default start state */
611 profile
->file
.start
= DFA_START
;
613 if (!unpack_trans_table(e
, profile
))
616 if (!unpack_nameX(e
, AA_STRUCTEND
, NULL
))
626 audit_iface(profile
, name
, "failed to unpack profile", e
, error
);
627 aa_free_profile(profile
);
629 return ERR_PTR(error
);
633 * verify_head - unpack serialized stream header
634 * @e: serialized data read head (NOT NULL)
635 * @required: whether the header is required or optional
636 * @ns: Returns - namespace if one is specified else NULL (NOT NULL)
638 * Returns: error or 0 if header is good
640 static int verify_header(struct aa_ext
*e
, int required
, const char **ns
)
642 int error
= -EPROTONOSUPPORT
;
643 const char *name
= NULL
;
646 /* get the interface version */
647 if (!unpack_u32(e
, &e
->version
, "version")) {
649 audit_iface(NULL
, NULL
, "invalid profile format", e
,
654 /* check that the interface version is currently supported */
655 if (e
->version
!= 5) {
656 audit_iface(NULL
, NULL
, "unsupported interface version",
663 /* read the namespace if present */
664 if (unpack_str(e
, &name
, "namespace")) {
665 if (*ns
&& strcmp(*ns
, name
))
666 audit_iface(NULL
, NULL
, "invalid ns change", e
, error
);
674 static bool verify_xindex(int xindex
, int table_size
)
677 xtype
= xindex
& AA_X_TYPE_MASK
;
678 index
= xindex
& AA_X_INDEX_MASK
;
679 if (xtype
== AA_X_TABLE
&& index
> table_size
)
684 /* verify dfa xindexes are in range of transition tables */
685 static bool verify_dfa_xindex(struct aa_dfa
*dfa
, int table_size
)
688 for (i
= 0; i
< dfa
->tables
[YYTD_ID_ACCEPT
]->td_lolen
; i
++) {
689 if (!verify_xindex(dfa_user_xindex(dfa
, i
), table_size
))
691 if (!verify_xindex(dfa_other_xindex(dfa
, i
), table_size
))
698 * verify_profile - Do post unpack analysis to verify profile consistency
699 * @profile: profile to verify (NOT NULL)
701 * Returns: 0 if passes verification else error
703 static int verify_profile(struct aa_profile
*profile
)
705 if (aa_g_paranoid_load
) {
706 if (profile
->file
.dfa
&&
707 !verify_dfa_xindex(profile
->file
.dfa
,
708 profile
->file
.trans
.size
)) {
709 audit_iface(profile
, NULL
, "Invalid named transition",
718 void aa_load_ent_free(struct aa_load_ent
*ent
)
721 aa_put_profile(ent
->rename
);
722 aa_put_profile(ent
->old
);
723 aa_put_profile(ent
->new);
728 struct aa_load_ent
*aa_load_ent_alloc(void)
730 struct aa_load_ent
*ent
= kzalloc(sizeof(*ent
), GFP_KERNEL
);
732 INIT_LIST_HEAD(&ent
->list
);
737 * aa_unpack - unpack packed binary profile(s) data loaded from user space
738 * @udata: user data copied to kmem (NOT NULL)
739 * @size: the size of the user data
740 * @lh: list to place unpacked profiles in a aa_repl_ws
741 * @ns: Returns namespace profile is in if specified else NULL (NOT NULL)
743 * Unpack user data and return refcounted allocated profile(s) stored in
744 * @lh in order of discovery, with the list chain stored in base.list
747 * Returns: profile(s) on @lh else error pointer if fails to unpack
749 int aa_unpack(void *udata
, size_t size
, struct list_head
*lh
, const char **ns
)
751 struct aa_load_ent
*tmp
, *ent
;
752 struct aa_profile
*profile
= NULL
;
761 while (e
.pos
< e
.end
) {
763 error
= verify_header(&e
, e
.pos
== e
.start
, ns
);
768 profile
= unpack_profile(&e
);
769 if (IS_ERR(profile
)) {
770 error
= PTR_ERR(profile
);
774 error
= verify_profile(profile
);
778 error
= aa_calc_profile_hash(profile
, e
.version
, start
,
783 ent
= aa_load_ent_alloc();
790 list_add_tail(&ent
->list
, lh
);
796 aa_put_profile(profile
);
799 list_for_each_entry_safe(ent
, tmp
, lh
, list
) {
800 list_del_init(&ent
->list
);
801 aa_load_ent_free(ent
);
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