Release 4.11 security/apparmor/include/match.h

/*
 * 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


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;


#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);
}

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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);

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;
}

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/**
 * 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);
}

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#endif /* __AA_MATCH_H */
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Directory: security/apparmor/include

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