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1 | /* |
2 | * AppArmor security module | |
3 | * | |
4 | * This file contains AppArmor policy dfa matching engine definitions. | |
5 | * | |
6 | * Copyright (C) 1998-2008 Novell/SUSE | |
8e4ff109 | 7 | * Copyright 2009-2012 Canonical Ltd. |
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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 | ||
57cc7215 | 18 | #include <linux/kref.h> |
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19 | |
20 | #define DFA_NOMATCH 0 | |
21 | #define DFA_START 1 | |
22 | ||
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23 | |
24 | /** | |
25 | * The format used for transition tables is based on the GNU flex table | |
26 | * file format (--tables-file option; see Table File Format in the flex | |
27 | * info pages and the flex sources for documentation). The magic number | |
b595076a | 28 | * used in the header is 0x1B5E783D instead of 0xF13C57B1 though, because |
8e4ff109 JJ |
29 | * new tables have been defined and others YY_ID_CHK (check) and YY_ID_DEF |
30 | * (default) tables are used slightly differently (see the apparmor-parser | |
31 | * package). | |
32 | * | |
33 | * | |
34 | * The data in the packed dfa is stored in network byte order, and the tables | |
35 | * are arranged for flexibility. We convert the table data to host native | |
36 | * byte order. | |
37 | * | |
38 | * The dfa begins with a table set header, and is followed by the actual | |
39 | * tables. | |
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40 | */ |
41 | ||
42 | #define YYTH_MAGIC 0x1B5E783D | |
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43 | |
44 | struct table_set_header { | |
45 | u32 th_magic; /* YYTH_MAGIC */ | |
46 | u32 th_hsize; | |
47 | u32 th_ssize; | |
48 | u16 th_flags; | |
49 | char th_version[]; | |
50 | }; | |
51 | ||
52 | /* The YYTD_ID are one less than flex table mappings. The flex id | |
53 | * has 1 subtracted at table load time, this allows us to directly use the | |
54 | * ID's as indexes. | |
55 | */ | |
56 | #define YYTD_ID_ACCEPT 0 | |
57 | #define YYTD_ID_BASE 1 | |
58 | #define YYTD_ID_CHK 2 | |
59 | #define YYTD_ID_DEF 3 | |
60 | #define YYTD_ID_EC 4 | |
61 | #define YYTD_ID_META 5 | |
62 | #define YYTD_ID_ACCEPT2 6 | |
63 | #define YYTD_ID_NXT 7 | |
64 | #define YYTD_ID_TSIZE 8 | |
65 | ||
66 | #define YYTD_DATA8 1 | |
67 | #define YYTD_DATA16 2 | |
68 | #define YYTD_DATA32 4 | |
69 | #define YYTD_DATA64 8 | |
70 | ||
8e4ff109 | 71 | /* ACCEPT & ACCEPT2 tables gets 6 dedicated flags, YYTD_DATAX define the |
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72 | * first flags |
73 | */ | |
74 | #define ACCEPT1_FLAGS(X) ((X) & 0x3f) | |
75 | #define ACCEPT2_FLAGS(X) ACCEPT1_FLAGS((X) >> YYTD_ID_ACCEPT2) | |
76 | #define TO_ACCEPT1_FLAG(X) ACCEPT1_FLAGS(X) | |
77 | #define TO_ACCEPT2_FLAG(X) (ACCEPT1_FLAGS(X) << YYTD_ID_ACCEPT2) | |
78 | #define DFA_FLAG_VERIFY_STATES 0x1000 | |
79 | ||
80 | struct table_header { | |
81 | u16 td_id; | |
82 | u16 td_flags; | |
83 | u32 td_hilen; | |
84 | u32 td_lolen; | |
85 | char td_data[]; | |
86 | }; | |
87 | ||
88 | #define DEFAULT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_DEF]->td_data)) | |
89 | #define BASE_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_BASE]->td_data)) | |
90 | #define NEXT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_NXT]->td_data)) | |
91 | #define CHECK_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_CHK]->td_data)) | |
92 | #define EQUIV_TABLE(DFA) ((u8 *)((DFA)->tables[YYTD_ID_EC]->td_data)) | |
93 | #define ACCEPT_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT]->td_data)) | |
94 | #define ACCEPT_TABLE2(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT2]->td_data)) | |
95 | ||
96 | struct aa_dfa { | |
97 | struct kref count; | |
98 | u16 flags; | |
99 | struct table_header *tables[YYTD_ID_TSIZE]; | |
100 | }; | |
101 | ||
102 | #define byte_to_byte(X) (X) | |
103 | ||
104 | #define UNPACK_ARRAY(TABLE, BLOB, LEN, TYPE, NTOHX) \ | |
105 | do { \ | |
106 | typeof(LEN) __i; \ | |
107 | TYPE *__t = (TYPE *) TABLE; \ | |
108 | TYPE *__b = (TYPE *) BLOB; \ | |
109 | for (__i = 0; __i < LEN; __i++) { \ | |
110 | __t[__i] = NTOHX(__b[__i]); \ | |
111 | } \ | |
112 | } while (0) | |
113 | ||
114 | static inline size_t table_size(size_t len, size_t el_size) | |
115 | { | |
116 | return ALIGN(sizeof(struct table_header) + len * el_size, 8); | |
117 | } | |
118 | ||
119 | struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags); | |
120 | unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start, | |
121 | const char *str, int len); | |
122 | unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start, | |
123 | const char *str); | |
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124 | unsigned int aa_dfa_next(struct aa_dfa *dfa, unsigned int state, |
125 | const char c); | |
126 | ||
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127 | void aa_dfa_free_kref(struct kref *kref); |
128 | ||
129 | /** | |
130 | * aa_put_dfa - put a dfa refcount | |
131 | * @dfa: dfa to put refcount (MAYBE NULL) | |
132 | * | |
133 | * Requires: if @dfa != NULL that a valid refcount be held | |
134 | */ | |
135 | static inline void aa_put_dfa(struct aa_dfa *dfa) | |
136 | { | |
137 | if (dfa) | |
138 | kref_put(&dfa->count, aa_dfa_free_kref); | |
139 | } | |
140 | ||
141 | #endif /* __AA_MATCH_H */ |