John Johansen | e06f75a | 2010-07-29 14:48:01 -0700 | [diff] [blame] | 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 | |
Alexey Dobriyan | 57cc721 | 2011-01-10 08:18:25 +0200 | [diff] [blame] | 18 | #include <linux/kref.h> |
John Johansen | e06f75a | 2010-07-29 14:48:01 -0700 | [diff] [blame] | 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 |
Uwe Kleine-König | b595076 | 2010-11-01 15:38:34 -0400 | [diff] [blame] | 31 | * used in the header is 0x1B5E783D instead of 0xF13C57B1 though, because |
John Johansen | e06f75a | 2010-07-29 14:48:01 -0700 | [diff] [blame] | 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 | |
| 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); |
John Johansen | 0fe1212 | 2012-02-16 06:20:26 -0800 | [diff] [blame] | 119 | unsigned int aa_dfa_next(struct aa_dfa *dfa, unsigned int state, |
| 120 | const char c); |
| 121 | |
John Johansen | e06f75a | 2010-07-29 14:48:01 -0700 | [diff] [blame] | 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 | */ |
| 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 */ |