LXR linux/security/apparmor/include/match.h

   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
  39struct 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
  75struct 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
  91struct 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
 109static 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
 114struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags);
 115unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start,
 116                              const char *str, int len);
 117unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start,
 118                          const char *str);
 119unsigned int aa_dfa_next(struct aa_dfa *dfa, unsigned int state,
 120                         const char c);
 121
 122void aa_dfa_free_kref(struct kref *kref);
 123
 124/**
 125 * aa_put_dfa - put a dfa refcount
 126 * @dfa: dfa to put refcount   (MAYBE NULL)
 127 *
 128 * Requires: if @dfa != NULL that a valid refcount be held
 129 */
 130static inline void aa_put_dfa(struct aa_dfa *dfa)
 131{
 132        if (dfa)
 133                kref_put(&dfa->count, aa_dfa_free_kref);
 134}
 135
 136#endif /* __AA_MATCH_H */
 137