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/workqueue.h>
  19
  20 #define DFA_NOMATCH                     0
  21 #define DFA_START                       1
  22
  23 #define DFA_VALID_PERM_MASK             0xffffffff
  24 #define DFA_VALID_PERM2_MASK            0xffffffff
  25
  26 /**
  27  * The format used for transition tables is based on the GNU flex table
  28  * file format (--tables-file option; see Table File Format in the flex
  29  * info pages and the flex sources for documentation). The magic number
  30  * used in the header is 0x1B5E783D insted of 0xF13C57B1 though, because
  31  * the YY_ID_CHK (check) and YY_ID_DEF (default) tables are used
  32  * slightly differently (see the apparmor-parser package).
  33  */
  34
  35 #define YYTH_MAGIC      0x1B5E783D
  36 #define YYTH_DEF_RECURSE 0x1                    /* DEF Table is recursive */
  37
  38 struct table_set_header {
  39         u32 th_magic;           /* YYTH_MAGIC */
  40         u32 th_hsize;
  41         u32 th_ssize;
  42         u16 th_flags;
  43         char th_version[];
  44 };
  45
  46 /* The YYTD_ID are one less than flex table mappings.  The flex id
  47  * has 1 subtracted at table load time, this allows us to directly use the
  48  * ID's as indexes.
  49  */
  50 #define YYTD_ID_ACCEPT  0
  51 #define YYTD_ID_BASE    1
  52 #define YYTD_ID_CHK     2
  53 #define YYTD_ID_DEF     3
  54 #define YYTD_ID_EC      4
  55 #define YYTD_ID_META    5
  56 #define YYTD_ID_ACCEPT2 6
  57 #define YYTD_ID_NXT     7
  58 #define YYTD_ID_TSIZE   8
  59
  60 #define YYTD_DATA8      1
  61 #define YYTD_DATA16     2
  62 #define YYTD_DATA32     4
  63 #define YYTD_DATA64     8
  64
  65 /* Each ACCEPT2 table gets 6 dedicated flags, YYTD_DATAX define the
  66  * first flags
  67  */
  68 #define ACCEPT1_FLAGS(X) ((X) & 0x3f)
  69 #define ACCEPT2_FLAGS(X) ACCEPT1_FLAGS((X) >> YYTD_ID_ACCEPT2)
  70 #define TO_ACCEPT1_FLAG(X) ACCEPT1_FLAGS(X)
  71 #define TO_ACCEPT2_FLAG(X) (ACCEPT1_FLAGS(X) << YYTD_ID_ACCEPT2)
  72 #define DFA_FLAG_VERIFY_STATES 0x1000
  73
  74 struct table_header {
  75         u16 td_id;
  76         u16 td_flags;
  77         u32 td_hilen;
  78         u32 td_lolen;
  79         char td_data[];
  80 };
  81
  82 #define DEFAULT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_DEF]->td_data))
  83 #define BASE_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_BASE]->td_data))
  84 #define NEXT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_NXT]->td_data))
  85 #define CHECK_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_CHK]->td_data))
  86 #define EQUIV_TABLE(DFA) ((u8 *)((DFA)->tables[YYTD_ID_EC]->td_data))
  87 #define ACCEPT_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT]->td_data))
  88 #define ACCEPT_TABLE2(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT2]->td_data))
  89
  90 struct aa_dfa {
  91         struct kref count;
  92         u16 flags;
  93         struct table_header *tables[YYTD_ID_TSIZE];
  94 };
  95
  96 #define byte_to_byte(X) (X)
  97
  98 #define UNPACK_ARRAY(TABLE, BLOB, LEN, TYPE, NTOHX) \
  99         do { \
 100                 typeof(LEN) __i; \
 101                 TYPE *__t = (TYPE *) TABLE; \
 102                 TYPE *__b = (TYPE *) BLOB; \
 103                 for (__i = 0; __i < LEN; __i++) { \
 104                         __t[__i] = NTOHX(__b[__i]); \
 105                 } \
 106         } while (0)
 107
 108 static inline size_t table_size(size_t len, size_t el_size)
 109 {
 110         return ALIGN(sizeof(struct table_header) + len * el_size, 8);
 111 }
 112
 113 struct aa_dfa *aa_dfa_unpack(void *blob, size_t size, int flags);
 114 unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start,
 115                               const char *str, int len);
 116 unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start,
 117                           const char *str);
 118 void aa_dfa_free_kref(struct kref *kref);
 119
 120 /**
 121  * aa_put_dfa - put a dfa refcount
 122  * @dfa: dfa to put refcount   (MAYBE NULL)
 123  *
 124  * Requires: if @dfa != NULL that a valid refcount be held
 125  */
 126 static inline void aa_put_dfa(struct aa_dfa *dfa)
 127 {
 128         if (dfa)
 129                 kref_put(&dfa->count, aa_dfa_free_kref);
 130 }
 131
 132 #endif /* __AA_MATCH_H */