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/workqueue.h> 19 20#define DFA_NOMATCH 0 21#define DFA_START 1 22 23#define DFA_VALID_PERM_MASK 0xffffffff 24#define DFA_VALID_PERM2_MASK 0xffffffff 25 26/** 27 * The format used for transition tables is based on the GNU flex table 28 * file format (--tables-file option; see Table File Format in the flex 29 * info pages and the flex sources for documentation). The magic number 30 * used in the header is 0x1B5E783D insted of 0xF13C57B1 though, because 31 * the YY_ID_CHK (check) and YY_ID_DEF (default) tables are used 32 * slightly differently (see the apparmor-parser package). 33 */ 34 35#define YYTH_MAGIC 0x1B5E783D 36#define YYTH_DEF_RECURSE 0x1 /* DEF Table is recursive */ 37 38struct table_set_header { 39 u32 th_magic; /* YYTH_MAGIC */ 40 u32 th_hsize; 41 u32 th_ssize; 42 u16 th_flags; 43 char th_version[]; 44}; 45 46/* The YYTD_ID are one less than flex table mappings. The flex id 47 * has 1 subtracted at table load time, this allows us to directly use the 48 * ID's as indexes. 49 */ 50#define YYTD_ID_ACCEPT 0 51#define YYTD_ID_BASE 1 52#define YYTD_ID_CHK 2 53#define YYTD_ID_DEF 3 54#define YYTD_ID_EC 4 55#define YYTD_ID_META 5 56#define YYTD_ID_ACCEPT2 6 57#define YYTD_ID_NXT 7 58#define YYTD_ID_TSIZE 8 59 60#define YYTD_DATA8 1 61#define YYTD_DATA16 2 62#define YYTD_DATA32 4 63#define YYTD_DATA64 8 64 65/* Each ACCEPT2 table gets 6 dedicated flags, YYTD_DATAX define the 66 * first flags 67 */ 68#define ACCEPT1_FLAGS(X) ((X) & 0x3f) 69#define ACCEPT2_FLAGS(X) ACCEPT1_FLAGS((X) >> YYTD_ID_ACCEPT2) 70#define TO_ACCEPT1_FLAG(X) ACCEPT1_FLAGS(X) 71#define TO_ACCEPT2_FLAG(X) (ACCEPT1_FLAGS(X) << YYTD_ID_ACCEPT2) 72#define DFA_FLAG_VERIFY_STATES 0x1000 73 74struct table_header { 75 u16 td_id; 76 u16 td_flags; 77 u32 td_hilen; 78 u32 td_lolen; 79 char td_data[]; 80}; 81 82#define DEFAULT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_DEF]->td_data)) 83#define BASE_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_BASE]->td_data)) 84#define NEXT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_NXT]->td_data)) 85#define CHECK_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_CHK]->td_data)) 86#define EQUIV_TABLE(DFA) ((u8 *)((DFA)->tables[YYTD_ID_EC]->td_data)) 87#define ACCEPT_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT]->td_data)) 88#define ACCEPT_TABLE2(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT2]->td_data)) 89 90struct aa_dfa { 91 struct kref count; 92 u16 flags; 93 struct table_header *tables[YYTD_ID_TSIZE]; 94}; 95 96#define byte_to_byte(X) (X) 97 98#define UNPACK_ARRAY(TABLE, BLOB, LEN, TYPE, NTOHX) \ 99 do { \ 100 typeof(LEN) __i; \ 101 TYPE *__t = (TYPE *) TABLE; \ 102 TYPE *__b = (TYPE *) BLOB; \ 103 for (__i = 0; __i < LEN; __i++) { \ 104 __t[__i] = NTOHX(__b[__i]); \ 105 } \ 106 } while (0) 107 108static inline size_t table_size(size_t len, size_t el_size) 109{ 110 return ALIGN(sizeof(struct table_header) + len * el_size, 8); 111} 112 113struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags); 114unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start, 115 const char *str, int len); 116unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start, 117 const char *str); 118void aa_dfa_free_kref(struct kref *kref); 119 120/** 121 * aa_put_dfa - put a dfa refcount 122 * @dfa: dfa to put refcount (MAYBE NULL) 123 * 124 * Requires: if @dfa != NULL that a valid refcount be held 125 */ 126static inline void aa_put_dfa(struct aa_dfa *dfa) 127{ 128 if (dfa) 129 kref_put(&dfa->count, aa_dfa_free_kref); 130} 131 132#endif /* __AA_MATCH_H */ 133