1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
2 | /* |
3 | * AppArmor security module |
4 | * |
5 | * This file contains AppArmor policy dfa matching engine definitions. |
6 | * |
7 | * Copyright (C) 1998-2008 Novell/SUSE |
8 | * Copyright 2009-2012 Canonical Ltd. |
9 | */ |
10 | |
11 | #ifndef __AA_MATCH_H |
12 | #define __AA_MATCH_H |
13 | |
14 | #include <linux/kref.h> |
15 | |
16 | #define DFA_NOMATCH 0 |
17 | #define DFA_START 1 |
18 | |
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 |
24 | * used in the header is 0x1B5E783D instead of 0xF13C57B1 though, because |
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. |
36 | */ |
37 | |
38 | #define YYTH_MAGIC 0x1B5E783D |
39 | #define YYTH_FLAG_DIFF_ENCODE 1 |
40 | #define YYTH_FLAG_OOB_TRANS 2 |
41 | #define YYTH_FLAGS (YYTH_FLAG_DIFF_ENCODE | YYTH_FLAG_OOB_TRANS) |
42 | |
43 | #define MAX_OOB_SUPPORTED 1 |
44 | |
45 | struct { |
46 | u32 ; /* YYTH_MAGIC */ |
47 | u32 ; |
48 | u32 ; |
49 | u16 ; |
50 | char []; |
51 | }; |
52 | |
53 | /* The YYTD_ID are one less than flex table mappings. The flex id |
54 | * has 1 subtracted at table load time, this allows us to directly use the |
55 | * ID's as indexes. |
56 | */ |
57 | #define YYTD_ID_ACCEPT 0 |
58 | #define YYTD_ID_BASE 1 |
59 | #define YYTD_ID_CHK 2 |
60 | #define YYTD_ID_DEF 3 |
61 | #define YYTD_ID_EC 4 |
62 | #define YYTD_ID_META 5 |
63 | #define YYTD_ID_ACCEPT2 6 |
64 | #define YYTD_ID_NXT 7 |
65 | #define YYTD_ID_TSIZE 8 |
66 | #define YYTD_ID_MAX 8 |
67 | |
68 | #define YYTD_DATA8 1 |
69 | #define YYTD_DATA16 2 |
70 | #define YYTD_DATA32 4 |
71 | #define YYTD_DATA64 8 |
72 | |
73 | /* ACCEPT & ACCEPT2 tables gets 6 dedicated flags, YYTD_DATAX define the |
74 | * first flags |
75 | */ |
76 | #define ACCEPT1_FLAGS(X) ((X) & 0x3f) |
77 | #define ACCEPT2_FLAGS(X) ACCEPT1_FLAGS((X) >> YYTD_ID_ACCEPT2) |
78 | #define TO_ACCEPT1_FLAG(X) ACCEPT1_FLAGS(X) |
79 | #define TO_ACCEPT2_FLAG(X) (ACCEPT1_FLAGS(X) << YYTD_ID_ACCEPT2) |
80 | #define DFA_FLAG_VERIFY_STATES 0x1000 |
81 | |
82 | struct { |
83 | u16 ; |
84 | u16 ; |
85 | u32 ; |
86 | u32 ; |
87 | char []; |
88 | }; |
89 | |
90 | #define DEFAULT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_DEF]->td_data)) |
91 | #define BASE_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_BASE]->td_data)) |
92 | #define NEXT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_NXT]->td_data)) |
93 | #define CHECK_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_CHK]->td_data)) |
94 | #define EQUIV_TABLE(DFA) ((u8 *)((DFA)->tables[YYTD_ID_EC]->td_data)) |
95 | #define ACCEPT_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT]->td_data)) |
96 | #define ACCEPT_TABLE2(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT2]->td_data)) |
97 | |
98 | struct aa_dfa { |
99 | struct kref count; |
100 | u16 flags; |
101 | u32 max_oob; |
102 | struct table_header *tables[YYTD_ID_TSIZE]; |
103 | }; |
104 | |
105 | #define byte_to_byte(X) (X) |
106 | |
107 | #define UNPACK_ARRAY(TABLE, BLOB, LEN, TTYPE, BTYPE, NTOHX) \ |
108 | do { \ |
109 | typeof(LEN) __i; \ |
110 | TTYPE *__t = (TTYPE *) TABLE; \ |
111 | BTYPE *__b = (BTYPE *) BLOB; \ |
112 | for (__i = 0; __i < LEN; __i++) { \ |
113 | __t[__i] = NTOHX(__b[__i]); \ |
114 | } \ |
115 | } while (0) |
116 | |
117 | static inline size_t table_size(size_t len, size_t el_size) |
118 | { |
119 | return ALIGN(sizeof(struct table_header) + len * el_size, 8); |
120 | } |
121 | |
122 | #define aa_state_t unsigned int |
123 | |
124 | struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags); |
125 | aa_state_t aa_dfa_match_len(struct aa_dfa *dfa, aa_state_t start, |
126 | const char *str, int len); |
127 | aa_state_t aa_dfa_match(struct aa_dfa *dfa, aa_state_t start, |
128 | const char *str); |
129 | aa_state_t aa_dfa_next(struct aa_dfa *dfa, aa_state_t state, const char c); |
130 | aa_state_t aa_dfa_outofband_transition(struct aa_dfa *dfa, aa_state_t state); |
131 | aa_state_t aa_dfa_match_until(struct aa_dfa *dfa, aa_state_t start, |
132 | const char *str, const char **retpos); |
133 | aa_state_t aa_dfa_matchn_until(struct aa_dfa *dfa, aa_state_t start, |
134 | const char *str, int n, const char **retpos); |
135 | |
136 | void aa_dfa_free_kref(struct kref *kref); |
137 | |
138 | #define WB_HISTORY_SIZE 24 |
139 | struct match_workbuf { |
140 | unsigned int count; |
141 | unsigned int pos; |
142 | unsigned int len; |
143 | unsigned int size; /* power of 2, same as history size */ |
144 | unsigned int history[WB_HISTORY_SIZE]; |
145 | }; |
146 | #define DEFINE_MATCH_WB(N) \ |
147 | struct match_workbuf N = { \ |
148 | .count = 0, \ |
149 | .pos = 0, \ |
150 | .len = 0, \ |
151 | } |
152 | |
153 | aa_state_t aa_dfa_leftmatch(struct aa_dfa *dfa, aa_state_t start, |
154 | const char *str, unsigned int *count); |
155 | |
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(kref: &(dfa->count)); |
167 | |
168 | return dfa; |
169 | } |
170 | |
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(kref: &dfa->count, release: aa_dfa_free_kref); |
181 | } |
182 | |
183 | #define MATCH_FLAG_DIFF_ENCODE 0x80000000 |
184 | #define MARK_DIFF_ENCODE 0x40000000 |
185 | #define MATCH_FLAG_OOB_TRANSITION 0x20000000 |
186 | #define MATCH_FLAGS_MASK 0xff000000 |
187 | #define MATCH_FLAGS_VALID (MATCH_FLAG_DIFF_ENCODE | MATCH_FLAG_OOB_TRANSITION) |
188 | #define MATCH_FLAGS_INVALID (MATCH_FLAGS_MASK & ~MATCH_FLAGS_VALID) |
189 | |
190 | #endif /* __AA_MATCH_H */ |
191 | |