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 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); 119 void 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 */ 127 static 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 */ 134