[mirror_ubuntu-zesty-kernel.git] / 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, TYPE, NTOHX) \
	do { \
		typeof(LEN) __i; \
		TYPE *__t = (TYPE *) TABLE; \
		TYPE *__b = (TYPE *) 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);

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);
}

#endif /* __AA_MATCH_H */
Commit	Line	Data
e06f75a6 JJ	1	/*
	2	* AppArmor security module
	3	*
	4	* This file contains AppArmor policy dfa matching engine definitions.
	5	*
	6	* Copyright (C) 1998-2008 Novell/SUSE
8e4ff109	7	* Copyright 2009-2012 Canonical Ltd.
e06f75a6 JJ	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
57cc7215	18	#include <linux/kref.h>
e06f75a6 JJ	19
	20	#define DFA_NOMATCH 0
	21	#define DFA_START 1
	22
e06f75a6 JJ	23
	24	/**
	25	* The format used for transition tables is based on the GNU flex table
	26	* file format (--tables-file option; see Table File Format in the flex
	27	* info pages and the flex sources for documentation). The magic number
b595076a	28	* used in the header is 0x1B5E783D instead of 0xF13C57B1 though, because
8e4ff109 JJ	29	* new tables have been defined and others YY_ID_CHK (check) and YY_ID_DEF
	30	* (default) tables are used slightly differently (see the apparmor-parser
	31	* package).
	32	*
	33	*
	34	* The data in the packed dfa is stored in network byte order, and the tables
	35	* are arranged for flexibility. We convert the table data to host native
	36	* byte order.
	37	*
	38	* The dfa begins with a table set header, and is followed by the actual
	39	* tables.
e06f75a6 JJ	40	*/
	41
	42	#define YYTH_MAGIC 0x1B5E783D
e06f75a6 JJ	43
	44	struct table_set_header {
	45	u32 th_magic; /* YYTH_MAGIC */
	46	u32 th_hsize;
	47	u32 th_ssize;
	48	u16 th_flags;
	49	char th_version[];
	50	};
	51
	52	/* The YYTD_ID are one less than flex table mappings. The flex id
	53	* has 1 subtracted at table load time, this allows us to directly use the
	54	* ID's as indexes.
	55	*/
	56	#define YYTD_ID_ACCEPT 0
	57	#define YYTD_ID_BASE 1
	58	#define YYTD_ID_CHK 2
	59	#define YYTD_ID_DEF 3
	60	#define YYTD_ID_EC 4
	61	#define YYTD_ID_META 5
	62	#define YYTD_ID_ACCEPT2 6
	63	#define YYTD_ID_NXT 7
	64	#define YYTD_ID_TSIZE 8
15756178	65	#define YYTD_ID_MAX 8
e06f75a6 JJ	66
	67	#define YYTD_DATA8 1
	68	#define YYTD_DATA16 2
	69	#define YYTD_DATA32 4
	70	#define YYTD_DATA64 8
	71
8e4ff109	72	/* ACCEPT & ACCEPT2 tables gets 6 dedicated flags, YYTD_DATAX define the
e06f75a6 JJ	73	* first flags
	74	*/
	75	#define ACCEPT1_FLAGS(X) ((X) & 0x3f)
	76	#define ACCEPT2_FLAGS(X) ACCEPT1_FLAGS((X) >> YYTD_ID_ACCEPT2)
	77	#define TO_ACCEPT1_FLAG(X) ACCEPT1_FLAGS(X)
	78	#define TO_ACCEPT2_FLAG(X) (ACCEPT1_FLAGS(X) << YYTD_ID_ACCEPT2)
	79	#define DFA_FLAG_VERIFY_STATES 0x1000
	80
	81	struct table_header {
	82	u16 td_id;
	83	u16 td_flags;
	84	u32 td_hilen;
	85	u32 td_lolen;
	86	char td_data[];
	87	};
	88
	89	#define DEFAULT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_DEF]->td_data))
	90	#define BASE_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_BASE]->td_data))
	91	#define NEXT_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_NXT]->td_data))
	92	#define CHECK_TABLE(DFA) ((u16 *)((DFA)->tables[YYTD_ID_CHK]->td_data))
	93	#define EQUIV_TABLE(DFA) ((u8 *)((DFA)->tables[YYTD_ID_EC]->td_data))
	94	#define ACCEPT_TABLE(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT]->td_data))
	95	#define ACCEPT_TABLE2(DFA) ((u32 *)((DFA)->tables[YYTD_ID_ACCEPT2]->td_data))
	96
	97	struct aa_dfa {
	98	struct kref count;
	99	u16 flags;
	100	struct table_header *tables[YYTD_ID_TSIZE];
	101	};
	102
80594fc2 JJ	103	extern struct aa_dfa *nulldfa;
80594fc2 JJ	104
e06f75a6 JJ	105	#define byte_to_byte(X) (X)
	106
	107	#define UNPACK_ARRAY(TABLE, BLOB, LEN, TYPE, NTOHX) \
	108	do { \
	109	typeof(LEN) __i; \
	110	TYPE __t = (TYPE ) TABLE; \
	111	TYPE __b = (TYPE ) BLOB; \
	112	for (__i = 0; __i < LEN; __i++) { \
	113	__t[__i] = NTOHX(__b[__i]); \
	114	} \
	115	} while (0)
	116
	117	static inline size_t table_size(size_t len, size_t el_size)
	118	{
	119	return ALIGN(sizeof(struct table_header) + len * el_size, 8);
	120	}
	121
80594fc2 JJ	122	int aa_setup_dfa_engine(void);
	123	void aa_teardown_dfa_engine(void);
	124
e06f75a6 JJ	125	struct aa_dfa aa_dfa_unpack(void blob, size_t size, int flags);
	126	unsigned int aa_dfa_match_len(struct aa_dfa *dfa, unsigned int start,
	127	const char *str, int len);
	128	unsigned int aa_dfa_match(struct aa_dfa *dfa, unsigned int start,
	129	const char *str);
0fe1212d JJ	130	unsigned int aa_dfa_next(struct aa_dfa *dfa, unsigned int state,
	131	const char c);
	132
e06f75a6 JJ	133	void aa_dfa_free_kref(struct kref *kref);
e06f75a6 JJ	134
80594fc2 JJ	135	/**
	136	* aa_get_dfa - increment refcount on dfa @p
	137	* @dfa: dfa (MAYBE NULL)
	138	*
	139	* Returns: pointer to @dfa if @dfa is NULL will return NULL
	140	* Requires: @dfa must be held with valid refcount when called
	141	*/
	142	static inline struct aa_dfa aa_get_dfa(struct aa_dfa dfa)
	143	{
	144	if (dfa)
	145	kref_get(&(dfa->count));
	146
	147	return dfa;
	148	}
	149
e06f75a6 JJ	150	/**
	151	* aa_put_dfa - put a dfa refcount
	152	* @dfa: dfa to put refcount (MAYBE NULL)
	153	*
	154	* Requires: if @dfa != NULL that a valid refcount be held
	155	*/
	156	static inline void aa_put_dfa(struct aa_dfa *dfa)
	157	{
	158	if (dfa)
	159	kref_put(&dfa->count, aa_dfa_free_kref);
	160	}
	161
	162	#endif /* __AA_MATCH_H */