/* * AppArmor security module * * This file contains AppArmor policy dfa matching engine definitions. * * Copyright (C) 1998-2008 Novell/SUSE * Copyright 2009-2012 Canonical Ltd. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation, version 2 of the * License. */ #ifndef __AA_MATCH_H #define __AA_MATCH_H #include <linux/kref.h> #define DFA_NOMATCH 0 #define DFA_START 1 /** * The format used for transition tables is based on the GNU flex table * file format (--tables-file option; see Table File Format in the flex * info pages and the flex sources for documentation). The magic number * used in the header is 0x1B5E783D instead of 0xF13C57B1 though, because * new tables have been defined and others YY_ID_CHK (check) and YY_ID_DEF * (default) tables are used slightly differently (see the apparmor-parser * package). * * * The data in the packed dfa is stored in network byte order, and the tables * are arranged for flexibility. We convert the table data to host native * byte order. * * The dfa begins with a table set header, and is followed by the actual * tables. */ #define YYTH_MAGIC 0x1B5E783D #define YYTH_FLAG_DIFF_ENCODE 1 struct table_set_header { u32 th_magic; /* YYTH_MAGIC */ u32 th_hsize; u32 th_ssize; u16 th_flags; char th_version[]; }; /* The YYTD_ID are one less than flex table mappings. The flex id * has 1 subtracted at table load time, this allows us to directly use the * ID's as indexes. */ #define YYTD_ID_ACCEPT 0 #define YYTD_ID_BASE 1 #define YYTD_ID_CHK 2 #define YYTD_ID_DEF 3 #define YYTD_ID_EC 4 #define YYTD_ID_META 5 #define YYTD_ID_ACCEPT2 6 #define YYTD_ID_NXT 7 #define YYTD_ID_TSIZE 8 #define YYTD_ID_MAX 8 #define YYTD_DATA8 1 #define YYTD_DATA16 2 #define YYTD_DATA32 4 #define YYTD_DATA64 8 /* ACCEPT & ACCEPT2 tables gets 6 dedicated flags, YYTD_DATAX define the * first flags */ #define ACCEPT1_FLAGS(X) ((X) & 0x3f) #define ACCEPT2_FLAGS(X) ACCEPT1_FLAGS((X) >> YYTD_ID_ACCEPT2) #define TO_ACCEPT1_FLAG(X) ACCEPT1_FLAGS(X) #define TO_ACCEPT2_FLAG(X) (ACCEPT1_FLAGS(X) << YYTD_ID_ACCEPT2) #define DFA_FLAG_VERIFY_STATES 0x1000 struct table_header { u16 td_id; u16 td_flags; u32 td_hilen; u32 td_lolen; char td_data[]; }; #define DEFAULT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_DEF]->td_data)) #define BASE_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_BASE]->td_data)) #define NEXT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_NXT]->td_data)) #define CHECK_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_CHK]->td_data)) #define EQUIV_TABLE(DFA) ((u8 *)((DFA)->tables[YYTD_ID_EC]->td_data)) #define ACCEPT_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT]->td_data)) #define ACCEPT_TABLE2(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT2]->td_data)) struct aa_dfa { struct kref count; u16 flags; struct table_header *tables[YYTD_ID_TSIZE]; }; extern struct aa_dfa *nulldfa; extern struct aa_dfa *stacksplitdfa; #define byte_to_byte(X) (X) #define UNPACK_ARRAY(TABLE, BLOB, LEN, TTYPE, BTYPE, NTOHX) \ do { \ typeof(LEN) __i; \ TTYPE *__t = (TTYPE *) TABLE; \ BTYPE *__b = (BTYPE *) BLOB; \ for (__i = 0; __i < LEN; __i++) { \ __t[__i] = NTOHX(__b[__i]); \ } \ } while (0) static inline size_t table_size(size_t len, size_t el_size) { return ALIGN(sizeof(struct table_header) + len * el_size, 8); } int aa_setup_dfa_engine(void); void aa_teardown_dfa_engine(void); struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags); unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start, const char *str, int len); unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start, const char *str); unsigned int aa_dfa_next(struct aa_dfa *dfa, unsigned int state, const char c); unsigned int aa_dfa_match_until(struct aa_dfa *dfa, unsigned int start, const char *str, const char **retpos); unsigned int aa_dfa_matchn_until(struct aa_dfa *dfa, unsigned int start, const char *str, int n, const char **retpos); void aa_dfa_free_kref(struct kref *kref); /** * aa_get_dfa - increment refcount on dfa @p * @dfa: dfa (MAYBE NULL) * * Returns: pointer to @dfa if @dfa is NULL will return NULL * Requires: @dfa must be held with valid refcount when called */ static inline struct aa_dfa *aa_get_dfa(struct aa_dfa *dfa) { if (dfa) kref_get(&(dfa->count)); return dfa; } /** * aa_put_dfa - put a dfa refcount * @dfa: dfa to put refcount (MAYBE NULL) * * Requires: if @dfa != NULL that a valid refcount be held */ static inline void aa_put_dfa(struct aa_dfa *dfa) { if (dfa) kref_put(&dfa->count, aa_dfa_free_kref); } #define MATCH_FLAG_DIFF_ENCODE 0x80000000 #define MARK_DIFF_ENCODE 0x40000000 #endif /* __AA_MATCH_H */