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b886d83c | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
e06f75a6 JJ |
2 | /* |
3 | * AppArmor security module | |
4 | * | |
5 | * This file contains AppArmor policy dfa matching engine definitions. | |
6 | * | |
7 | * Copyright (C) 1998-2008 Novell/SUSE | |
8e4ff109 | 8 | * Copyright 2009-2012 Canonical Ltd. |
e06f75a6 JJ |
9 | */ |
10 | ||
11 | #ifndef __AA_MATCH_H | |
12 | #define __AA_MATCH_H | |
13 | ||
57cc7215 | 14 | #include <linux/kref.h> |
e06f75a6 JJ |
15 | |
16 | #define DFA_NOMATCH 0 | |
17 | #define DFA_START 1 | |
18 | ||
e06f75a6 JJ |
19 | |
20 | /** | |
21 | * The format used for transition tables is based on the GNU flex table | |
22 | * file format (--tables-file option; see Table File Format in the flex | |
23 | * info pages and the flex sources for documentation). The magic number | |
b595076a | 24 | * used in the header is 0x1B5E783D instead of 0xF13C57B1 though, because |
8e4ff109 JJ |
25 | * new tables have been defined and others YY_ID_CHK (check) and YY_ID_DEF |
26 | * (default) tables are used slightly differently (see the apparmor-parser | |
27 | * package). | |
28 | * | |
29 | * | |
30 | * The data in the packed dfa is stored in network byte order, and the tables | |
31 | * are arranged for flexibility. We convert the table data to host native | |
32 | * byte order. | |
33 | * | |
34 | * The dfa begins with a table set header, and is followed by the actual | |
35 | * tables. | |
e06f75a6 JJ |
36 | */ |
37 | ||
38 | #define YYTH_MAGIC 0x1B5E783D | |
031dcc8f | 39 | #define YYTH_FLAG_DIFF_ENCODE 1 |
e06f75a6 JJ |
40 | |
41 | struct table_set_header { | |
42 | u32 th_magic; /* YYTH_MAGIC */ | |
43 | u32 th_hsize; | |
44 | u32 th_ssize; | |
45 | u16 th_flags; | |
46 | char th_version[]; | |
47 | }; | |
48 | ||
49 | /* The YYTD_ID are one less than flex table mappings. The flex id | |
50 | * has 1 subtracted at table load time, this allows us to directly use the | |
51 | * ID's as indexes. | |
52 | */ | |
53 | #define YYTD_ID_ACCEPT 0 | |
54 | #define YYTD_ID_BASE 1 | |
55 | #define YYTD_ID_CHK 2 | |
56 | #define YYTD_ID_DEF 3 | |
57 | #define YYTD_ID_EC 4 | |
58 | #define YYTD_ID_META 5 | |
59 | #define YYTD_ID_ACCEPT2 6 | |
60 | #define YYTD_ID_NXT 7 | |
61 | #define YYTD_ID_TSIZE 8 | |
15756178 | 62 | #define YYTD_ID_MAX 8 |
e06f75a6 JJ |
63 | |
64 | #define YYTD_DATA8 1 | |
65 | #define YYTD_DATA16 2 | |
66 | #define YYTD_DATA32 4 | |
67 | #define YYTD_DATA64 8 | |
68 | ||
8e4ff109 | 69 | /* ACCEPT & ACCEPT2 tables gets 6 dedicated flags, YYTD_DATAX define the |
e06f75a6 JJ |
70 | * first flags |
71 | */ | |
72 | #define ACCEPT1_FLAGS(X) ((X) & 0x3f) | |
73 | #define ACCEPT2_FLAGS(X) ACCEPT1_FLAGS((X) >> YYTD_ID_ACCEPT2) | |
74 | #define TO_ACCEPT1_FLAG(X) ACCEPT1_FLAGS(X) | |
75 | #define TO_ACCEPT2_FLAG(X) (ACCEPT1_FLAGS(X) << YYTD_ID_ACCEPT2) | |
76 | #define DFA_FLAG_VERIFY_STATES 0x1000 | |
77 | ||
78 | struct table_header { | |
79 | u16 td_id; | |
80 | u16 td_flags; | |
81 | u32 td_hilen; | |
82 | u32 td_lolen; | |
83 | char td_data[]; | |
84 | }; | |
85 | ||
86 | #define DEFAULT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_DEF]->td_data)) | |
87 | #define BASE_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_BASE]->td_data)) | |
88 | #define NEXT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_NXT]->td_data)) | |
89 | #define CHECK_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_CHK]->td_data)) | |
90 | #define EQUIV_TABLE(DFA) ((u8 *)((DFA)->tables[YYTD_ID_EC]->td_data)) | |
91 | #define ACCEPT_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT]->td_data)) | |
92 | #define ACCEPT_TABLE2(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT2]->td_data)) | |
93 | ||
94 | struct aa_dfa { | |
95 | struct kref count; | |
96 | u16 flags; | |
97 | struct table_header *tables[YYTD_ID_TSIZE]; | |
98 | }; | |
99 | ||
11c236b8 | 100 | extern struct aa_dfa *nulldfa; |
6e0654d2 | 101 | extern struct aa_dfa *stacksplitdfa; |
11c236b8 | 102 | |
e06f75a6 JJ |
103 | #define byte_to_byte(X) (X) |
104 | ||
e6e8bf41 | 105 | #define UNPACK_ARRAY(TABLE, BLOB, LEN, TTYPE, BTYPE, NTOHX) \ |
e06f75a6 JJ |
106 | do { \ |
107 | typeof(LEN) __i; \ | |
e6e8bf41 JJ |
108 | TTYPE *__t = (TTYPE *) TABLE; \ |
109 | BTYPE *__b = (BTYPE *) BLOB; \ | |
e06f75a6 JJ |
110 | for (__i = 0; __i < LEN; __i++) { \ |
111 | __t[__i] = NTOHX(__b[__i]); \ | |
112 | } \ | |
113 | } while (0) | |
114 | ||
115 | static inline size_t table_size(size_t len, size_t el_size) | |
116 | { | |
117 | return ALIGN(sizeof(struct table_header) + len * el_size, 8); | |
118 | } | |
119 | ||
11c236b8 JJ |
120 | int aa_setup_dfa_engine(void); |
121 | void aa_teardown_dfa_engine(void); | |
122 | ||
e06f75a6 JJ |
123 | struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags); |
124 | unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start, | |
125 | const char *str, int len); | |
126 | unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start, | |
127 | const char *str); | |
0fe1212d JJ |
128 | unsigned int aa_dfa_next(struct aa_dfa *dfa, unsigned int state, |
129 | const char c); | |
cf65fabc JJ |
130 | unsigned int aa_dfa_match_until(struct aa_dfa *dfa, unsigned int start, |
131 | const char *str, const char **retpos); | |
132 | unsigned int aa_dfa_matchn_until(struct aa_dfa *dfa, unsigned int start, | |
133 | const char *str, int n, const char **retpos); | |
0fe1212d | 134 | |
e06f75a6 JJ |
135 | void aa_dfa_free_kref(struct kref *kref); |
136 | ||
21f60661 JJ |
137 | #define WB_HISTORY_SIZE 8 |
138 | struct match_workbuf { | |
139 | unsigned int count; | |
140 | unsigned int pos; | |
141 | unsigned int len; | |
142 | unsigned int size; /* power of 2, same as history size */ | |
143 | unsigned int history[WB_HISTORY_SIZE]; | |
144 | }; | |
145 | #define DEFINE_MATCH_WB(N) \ | |
146 | struct match_workbuf N = { \ | |
147 | .count = 0, \ | |
148 | .pos = 0, \ | |
149 | .len = 0, \ | |
150 | .size = WB_HISTORY_SIZE, \ | |
151 | } | |
152 | ||
153 | unsigned int aa_dfa_leftmatch(struct aa_dfa *dfa, unsigned int start, | |
154 | const char *str, unsigned int *count); | |
155 | ||
293a4886 JJ |
156 | /** |
157 | * aa_get_dfa - increment refcount on dfa @p | |
158 | * @dfa: dfa (MAYBE NULL) | |
159 | * | |
160 | * Returns: pointer to @dfa if @dfa is NULL will return NULL | |
161 | * Requires: @dfa must be held with valid refcount when called | |
162 | */ | |
163 | static inline struct aa_dfa *aa_get_dfa(struct aa_dfa *dfa) | |
164 | { | |
165 | if (dfa) | |
166 | kref_get(&(dfa->count)); | |
167 | ||
168 | return dfa; | |
169 | } | |
170 | ||
e06f75a6 JJ |
171 | /** |
172 | * aa_put_dfa - put a dfa refcount | |
173 | * @dfa: dfa to put refcount (MAYBE NULL) | |
174 | * | |
175 | * Requires: if @dfa != NULL that a valid refcount be held | |
176 | */ | |
177 | static inline void aa_put_dfa(struct aa_dfa *dfa) | |
178 | { | |
179 | if (dfa) | |
180 | kref_put(&dfa->count, aa_dfa_free_kref); | |
181 | } | |
182 | ||
031dcc8f JJ |
183 | #define MATCH_FLAG_DIFF_ENCODE 0x80000000 |
184 | #define MARK_DIFF_ENCODE 0x40000000 | |
185 | ||
e06f75a6 | 186 | #endif /* __AA_MATCH_H */ |