1e06f75a6SJohn Johansen /* 2e06f75a6SJohn Johansen * AppArmor security module 3e06f75a6SJohn Johansen * 4e06f75a6SJohn Johansen * This file contains AppArmor policy dfa matching engine definitions. 5e06f75a6SJohn Johansen * 6e06f75a6SJohn Johansen * Copyright (C) 1998-2008 Novell/SUSE 78e4ff109SJohn Johansen * Copyright 2009-2012 Canonical Ltd. 8e06f75a6SJohn Johansen * 9e06f75a6SJohn Johansen * This program is free software; you can redistribute it and/or 10e06f75a6SJohn Johansen * modify it under the terms of the GNU General Public License as 11e06f75a6SJohn Johansen * published by the Free Software Foundation, version 2 of the 12e06f75a6SJohn Johansen * License. 13e06f75a6SJohn Johansen */ 14e06f75a6SJohn Johansen 15e06f75a6SJohn Johansen #ifndef __AA_MATCH_H 16e06f75a6SJohn Johansen #define __AA_MATCH_H 17e06f75a6SJohn Johansen 1857cc7215SAlexey Dobriyan #include <linux/kref.h> 19e06f75a6SJohn Johansen 20e06f75a6SJohn Johansen #define DFA_NOMATCH 0 21e06f75a6SJohn Johansen #define DFA_START 1 22e06f75a6SJohn Johansen 23e06f75a6SJohn Johansen 24e06f75a6SJohn Johansen /** 25e06f75a6SJohn Johansen * The format used for transition tables is based on the GNU flex table 26e06f75a6SJohn Johansen * file format (--tables-file option; see Table File Format in the flex 27e06f75a6SJohn Johansen * info pages and the flex sources for documentation). The magic number 28b595076aSUwe Kleine-König * used in the header is 0x1B5E783D instead of 0xF13C57B1 though, because 298e4ff109SJohn Johansen * new tables have been defined and others YY_ID_CHK (check) and YY_ID_DEF 308e4ff109SJohn Johansen * (default) tables are used slightly differently (see the apparmor-parser 318e4ff109SJohn Johansen * package). 328e4ff109SJohn Johansen * 338e4ff109SJohn Johansen * 348e4ff109SJohn Johansen * The data in the packed dfa is stored in network byte order, and the tables 358e4ff109SJohn Johansen * are arranged for flexibility. We convert the table data to host native 368e4ff109SJohn Johansen * byte order. 378e4ff109SJohn Johansen * 388e4ff109SJohn Johansen * The dfa begins with a table set header, and is followed by the actual 398e4ff109SJohn Johansen * tables. 40e06f75a6SJohn Johansen */ 41e06f75a6SJohn Johansen 42e06f75a6SJohn Johansen #define YYTH_MAGIC 0x1B5E783D 43e06f75a6SJohn Johansen 44e06f75a6SJohn Johansen struct table_set_header { 45e06f75a6SJohn Johansen u32 th_magic; /* YYTH_MAGIC */ 46e06f75a6SJohn Johansen u32 th_hsize; 47e06f75a6SJohn Johansen u32 th_ssize; 48e06f75a6SJohn Johansen u16 th_flags; 49e06f75a6SJohn Johansen char th_version[]; 50e06f75a6SJohn Johansen }; 51e06f75a6SJohn Johansen 52e06f75a6SJohn Johansen /* The YYTD_ID are one less than flex table mappings. The flex id 53e06f75a6SJohn Johansen * has 1 subtracted at table load time, this allows us to directly use the 54e06f75a6SJohn Johansen * ID's as indexes. 55e06f75a6SJohn Johansen */ 56e06f75a6SJohn Johansen #define YYTD_ID_ACCEPT 0 57e06f75a6SJohn Johansen #define YYTD_ID_BASE 1 58e06f75a6SJohn Johansen #define YYTD_ID_CHK 2 59e06f75a6SJohn Johansen #define YYTD_ID_DEF 3 60e06f75a6SJohn Johansen #define YYTD_ID_EC 4 61e06f75a6SJohn Johansen #define YYTD_ID_META 5 62e06f75a6SJohn Johansen #define YYTD_ID_ACCEPT2 6 63e06f75a6SJohn Johansen #define YYTD_ID_NXT 7 64e06f75a6SJohn Johansen #define YYTD_ID_TSIZE 8 6515756178SJohn Johansen #define YYTD_ID_MAX 8 66e06f75a6SJohn Johansen 67e06f75a6SJohn Johansen #define YYTD_DATA8 1 68e06f75a6SJohn Johansen #define YYTD_DATA16 2 69e06f75a6SJohn Johansen #define YYTD_DATA32 4 70e06f75a6SJohn Johansen #define YYTD_DATA64 8 71e06f75a6SJohn Johansen 728e4ff109SJohn Johansen /* ACCEPT & ACCEPT2 tables gets 6 dedicated flags, YYTD_DATAX define the 73e06f75a6SJohn Johansen * first flags 74e06f75a6SJohn Johansen */ 75e06f75a6SJohn Johansen #define ACCEPT1_FLAGS(X) ((X) & 0x3f) 76e06f75a6SJohn Johansen #define ACCEPT2_FLAGS(X) ACCEPT1_FLAGS((X) >> YYTD_ID_ACCEPT2) 77e06f75a6SJohn Johansen #define TO_ACCEPT1_FLAG(X) ACCEPT1_FLAGS(X) 78e06f75a6SJohn Johansen #define TO_ACCEPT2_FLAG(X) (ACCEPT1_FLAGS(X) << YYTD_ID_ACCEPT2) 79e06f75a6SJohn Johansen #define DFA_FLAG_VERIFY_STATES 0x1000 80e06f75a6SJohn Johansen 81e06f75a6SJohn Johansen struct table_header { 82e06f75a6SJohn Johansen u16 td_id; 83e06f75a6SJohn Johansen u16 td_flags; 84e06f75a6SJohn Johansen u32 td_hilen; 85e06f75a6SJohn Johansen u32 td_lolen; 86e06f75a6SJohn Johansen char td_data[]; 87e06f75a6SJohn Johansen }; 88e06f75a6SJohn Johansen 89e06f75a6SJohn Johansen #define DEFAULT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_DEF]->td_data)) 90e06f75a6SJohn Johansen #define BASE_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_BASE]->td_data)) 91e06f75a6SJohn Johansen #define NEXT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_NXT]->td_data)) 92e06f75a6SJohn Johansen #define CHECK_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_CHK]->td_data)) 93e06f75a6SJohn Johansen #define EQUIV_TABLE(DFA) ((u8 *)((DFA)->tables[YYTD_ID_EC]->td_data)) 94e06f75a6SJohn Johansen #define ACCEPT_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT]->td_data)) 95e06f75a6SJohn Johansen #define ACCEPT_TABLE2(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT2]->td_data)) 96e06f75a6SJohn Johansen 97e06f75a6SJohn Johansen struct aa_dfa { 98e06f75a6SJohn Johansen struct kref count; 99e06f75a6SJohn Johansen u16 flags; 100e06f75a6SJohn Johansen struct table_header *tables[YYTD_ID_TSIZE]; 101e06f75a6SJohn Johansen }; 102e06f75a6SJohn Johansen 10311c236b8SJohn Johansen extern struct aa_dfa *nulldfa; 10411c236b8SJohn Johansen 105e06f75a6SJohn Johansen #define byte_to_byte(X) (X) 106e06f75a6SJohn Johansen 107e06f75a6SJohn Johansen #define UNPACK_ARRAY(TABLE, BLOB, LEN, TYPE, NTOHX) \ 108e06f75a6SJohn Johansen do { \ 109e06f75a6SJohn Johansen typeof(LEN) __i; \ 110e06f75a6SJohn Johansen TYPE *__t = (TYPE *) TABLE; \ 111e06f75a6SJohn Johansen TYPE *__b = (TYPE *) BLOB; \ 112e06f75a6SJohn Johansen for (__i = 0; __i < LEN; __i++) { \ 113e06f75a6SJohn Johansen __t[__i] = NTOHX(__b[__i]); \ 114e06f75a6SJohn Johansen } \ 115e06f75a6SJohn Johansen } while (0) 116e06f75a6SJohn Johansen 117e06f75a6SJohn Johansen static inline size_t table_size(size_t len, size_t el_size) 118e06f75a6SJohn Johansen { 119e06f75a6SJohn Johansen return ALIGN(sizeof(struct table_header) + len * el_size, 8); 120e06f75a6SJohn Johansen } 121e06f75a6SJohn Johansen 12211c236b8SJohn Johansen int aa_setup_dfa_engine(void); 12311c236b8SJohn Johansen void aa_teardown_dfa_engine(void); 12411c236b8SJohn Johansen 125e06f75a6SJohn Johansen struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags); 126e06f75a6SJohn Johansen unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start, 127e06f75a6SJohn Johansen const char *str, int len); 128e06f75a6SJohn Johansen unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start, 129e06f75a6SJohn Johansen const char *str); 1300fe1212dSJohn Johansen unsigned int aa_dfa_next(struct aa_dfa *dfa, unsigned int state, 1310fe1212dSJohn Johansen const char c); 1320fe1212dSJohn Johansen 133e06f75a6SJohn Johansen void aa_dfa_free_kref(struct kref *kref); 134e06f75a6SJohn Johansen 135e06f75a6SJohn Johansen /** 136293a4886SJohn Johansen * aa_get_dfa - increment refcount on dfa @p 137293a4886SJohn Johansen * @dfa: dfa (MAYBE NULL) 138293a4886SJohn Johansen * 139293a4886SJohn Johansen * Returns: pointer to @dfa if @dfa is NULL will return NULL 140293a4886SJohn Johansen * Requires: @dfa must be held with valid refcount when called 141293a4886SJohn Johansen */ 142293a4886SJohn Johansen static inline struct aa_dfa *aa_get_dfa(struct aa_dfa *dfa) 143293a4886SJohn Johansen { 144293a4886SJohn Johansen if (dfa) 145293a4886SJohn Johansen kref_get(&(dfa->count)); 146293a4886SJohn Johansen 147293a4886SJohn Johansen return dfa; 148293a4886SJohn Johansen } 149293a4886SJohn Johansen 150293a4886SJohn Johansen /** 151e06f75a6SJohn Johansen * aa_put_dfa - put a dfa refcount 152e06f75a6SJohn Johansen * @dfa: dfa to put refcount (MAYBE NULL) 153e06f75a6SJohn Johansen * 154e06f75a6SJohn Johansen * Requires: if @dfa != NULL that a valid refcount be held 155e06f75a6SJohn Johansen */ 156e06f75a6SJohn Johansen static inline void aa_put_dfa(struct aa_dfa *dfa) 157e06f75a6SJohn Johansen { 158e06f75a6SJohn Johansen if (dfa) 159e06f75a6SJohn Johansen kref_put(&dfa->count, aa_dfa_free_kref); 160e06f75a6SJohn Johansen } 161e06f75a6SJohn Johansen 162e06f75a6SJohn Johansen #endif /* __AA_MATCH_H */ 163