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Diffstat (limited to 'security/apparmor/include/match.h')
| -rw-r--r-- | security/apparmor/include/match.h | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/security/apparmor/include/match.h b/security/apparmor/include/match.h new file mode 100644 index 000000000..958d2b52a --- /dev/null +++ b/security/apparmor/include/match.h @@ -0,0 +1,190 @@ +/* + * 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); + +#define WB_HISTORY_SIZE 8 +struct match_workbuf { + unsigned int count; + unsigned int pos; + unsigned int len; + unsigned int size; /* power of 2, same as history size */ + unsigned int history[WB_HISTORY_SIZE]; +}; +#define DEFINE_MATCH_WB(N) \ +struct match_workbuf N = { \ + .count = 0, \ + .pos = 0, \ + .len = 0, \ + .size = WB_HISTORY_SIZE, \ +} + +unsigned int aa_dfa_leftmatch(struct aa_dfa *dfa, unsigned int start, + const char *str, unsigned int *count); + +/** + * 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 */ |