1 /*
2 * AppArmor security module
3 *
4 * This file contains AppArmor policy dfa matching engine definitions.
5 *
6 * Copyright (C) 1998-2008 Novell/SUSE
7 * Copyright 2009-2010 Canonical Ltd.
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License as
11 * published by the Free Software Foundation, version 2 of the
12 * License.
13 */
14
15 #ifndef __AA_MATCH_H
16 #define __AA_MATCH_H
17
18 #include <linux/kref.h>
19 #include <linux/workqueue.h>
20
21 #define DFA_NOMATCH 0
22 #define DFA_START 1
23
24 #define DFA_VALID_PERM_MASK 0xffffffff
25 #define DFA_VALID_PERM2_MASK 0xffffffff
26
27 /**
28 * The format used for transition tables is based on the GNU flex table
29 * file format (--tables-file option; see Table File Format in the flex
30 * info pages and the flex sources for documentation). The magic number
31 * used in the header is 0x1B5E783D instead of 0xF13C57B1 though, because
32 * the YY_ID_CHK (check) and YY_ID_DEF (default) tables are used
33 * slightly differently (see the apparmor-parser package).
34 */
35
36 #define YYTH_MAGIC 0x1B5E783D
37 #define YYTH_DEF_RECURSE 0x1 /* DEF Table is recursive */
38
39 struct table_set_header {
40 u32 th_magic; /* YYTH_MAGIC */
41 u32 th_hsize;
42 u32 th_ssize;
43 u16 th_flags;
44 char th_version[];
45 };
46
47 /* The YYTD_ID are one less than flex table mappings. The flex id
48 * has 1 subtracted at table load time, this allows us to directly use the
49 * ID's as indexes.
50 */
51 #define YYTD_ID_ACCEPT 0
52 #define YYTD_ID_BASE 1
53 #define YYTD_ID_CHK 2
54 #define YYTD_ID_DEF 3
55 #define YYTD_ID_EC 4
56 #define YYTD_ID_META 5
57 #define YYTD_ID_ACCEPT2 6
58 #define YYTD_ID_NXT 7
59 #define YYTD_ID_TSIZE 8
60
61 #define YYTD_DATA8 1
62 #define YYTD_DATA16 2
63 #define YYTD_DATA32 4
64 #define YYTD_DATA64 8
65
66 /* Each ACCEPT2 table gets 6 dedicated flags, YYTD_DATAX define the
67 * first flags
68 */
69 #define ACCEPT1_FLAGS(X) ((X) & 0x3f)
70 #define ACCEPT2_FLAGS(X) ACCEPT1_FLAGS((X) >> YYTD_ID_ACCEPT2)
71 #define TO_ACCEPT1_FLAG(X) ACCEPT1_FLAGS(X)
72 #define TO_ACCEPT2_FLAG(X) (ACCEPT1_FLAGS(X) << YYTD_ID_ACCEPT2)
73 #define DFA_FLAG_VERIFY_STATES 0x1000
74
75 struct table_header {
76 u16 td_id;
77 u16 td_flags;
78 u32 td_hilen;
79 u32 td_lolen;
80 char td_data[];
81 };
82
83 #define DEFAULT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_DEF]->td_data))
84 #define BASE_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_BASE]->td_data))
85 #define NEXT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_NXT]->td_data))
86 #define CHECK_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_CHK]->td_data))
87 #define EQUIV_TABLE(DFA) ((u8 *)((DFA)->tables[YYTD_ID_EC]->td_data))
88 #define ACCEPT_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT]->td_data))
89 #define ACCEPT_TABLE2(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT2]->td_data))
90
91 struct aa_dfa {
92 struct kref count;
93 u16 flags;
94 struct table_header *tables[YYTD_ID_TSIZE];
95 };
96
97 #define byte_to_byte(X) (X)
98
99 #define UNPACK_ARRAY(TABLE, BLOB, LEN, TYPE, NTOHX) \
100 do { \
101 typeof(LEN) __i; \
102 TYPE *__t = (TYPE *) TABLE; \
103 TYPE *__b = (TYPE *) BLOB; \
104 for (__i = 0; __i < LEN; __i++) { \
105 __t[__i] = NTOHX(__b[__i]); \
106 } \
107 } while (0)
108
table_size(size_t len,size_t el_size)109 static inline size_t table_size(size_t len, size_t el_size)
110 {
111 return ALIGN(sizeof(struct table_header) + len * el_size, 8);
112 }
113
114 struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags);
115 unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start,
116 const char *str, int len);
117 unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start,
118 const char *str);
119 unsigned int aa_dfa_next(struct aa_dfa *dfa, unsigned int state,
120 const char c);
121
122 void aa_dfa_free_kref(struct kref *kref);
123
124 /**
125 * aa_put_dfa - put a dfa refcount
126 * @dfa: dfa to put refcount (MAYBE NULL)
127 *
128 * Requires: if @dfa != NULL that a valid refcount be held
129 */
aa_put_dfa(struct aa_dfa * dfa)130 static inline void aa_put_dfa(struct aa_dfa *dfa)
131 {
132 if (dfa)
133 kref_put(&dfa->count, aa_dfa_free_kref);
134 }
135
136 #endif /* __AA_MATCH_H */
137