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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
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
39struct 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
75struct 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
91struct 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
109static 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
114struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags);
115unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start,
116 const char *str, int len);
117unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start,
118 const char *str);
119void aa_dfa_free_kref(struct kref *kref);
120
121/**
122 * aa_put_dfa - put a dfa refcount
123 * @dfa: dfa to put refcount (MAYBE NULL)
124 *
125 * Requires: if @dfa != NULL that a valid refcount be held
126 */
127static inline void aa_put_dfa(struct aa_dfa *dfa)
128{
129 if (dfa)
130 kref_put(&dfa->count, aa_dfa_free_kref);
131}
132
133#endif /* __AA_MATCH_H */