Commit 3e16f959 authored by Stephan Mueller's avatar Stephan Mueller Committed by Herbert Xu
Browse files

crypto: drbg - header file for DRBG 



The header file includes the definition of:

* DRBG data structures with
        - struct drbg_state as main structure
        - struct drbg_core referencing the backend ciphers
        - struct drbg_state_ops callbach handlers for specific code
          supporting the Hash, HMAC, CTR DRBG implementations
        - struct drbg_conc defining a linked list for input data
        - struct drbg_test_data holding the test "entropy" data for CAVS
          testing and testmgr.c
        - struct drbg_gen allowing test data, additional information
          string and personalization string data to be funneled through
          the kernel crypto API -- the DRBG requires additional
          parameters when invoking the reset and random number
          generation requests than intended by the kernel crypto API

* wrapper function to the kernel crypto API functions using struct
  drbg_gen to pass through all data needed for DRBG

* wrapper functions to kernel crypto API functions usable for testing
  code to inject test_data into the DRBG as needed by CAVS testing and
  testmgr.c.

* DRBG flags required for the operation of the DRBG and for selecting
  the particular DRBG type and backend cipher

* getter functions for data from struct drbg_core

Signed-off-by: default avatarStephan Mueller <smueller@chronox.de>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 541af946

include/crypto/drbg.h

0 → 100644
+289 −0
Original line number Diff line number Diff line 
/*

 * DRBG based on NIST SP800-90A

 *

 * Copyright Stephan Mueller <smueller@chronox.de>, 2014

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, and the entire permission notice in its entirety,

 *    including the disclaimer of warranties.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. The name of the author may not be used to endorse or promote

 *    products derived from this software without specific prior

 *    written permission.

 *

 * ALTERNATIVELY, this product may be distributed under the terms of

 * the GNU General Public License, in which case the provisions of the GPL are

 * required INSTEAD OF the above restrictions.  (This clause is

 * necessary due to a potential bad interaction between the GPL and

 * the restrictions contained in a BSD-style copyright.)

 *

 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED

 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF

 * WHICH ARE HEREBY DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE

 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT

 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR

 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE

 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH

 * DAMAGE.

 */



#ifndef _DRBG_H

#define _DRBG_H





#include <linux/random.h>

#include <linux/scatterlist.h>

#include <crypto/hash.h>

#include <linux/module.h>

#include <linux/crypto.h>

#include <linux/slab.h>

#include <crypto/internal/rng.h>

#include <crypto/rng.h>

#include <linux/fips.h>

#include <linux/spinlock.h>



/*

 * Concatenation Helper and string operation helper

 *

 * SP800-90A requires the concatenation of different data. To avoid copying

 * buffers around or allocate additional memory, the following data structure

 * is used to point to the original memory with its size. In addition, it

 * is used to build a linked list. The linked list defines the concatenation

 * of individual buffers. The order of memory block referenced in that

 * linked list determines the order of concatenation.

 */

struct drbg_string {

	const unsigned char *buf;

	size_t len;

	struct drbg_string *next;

};



static inline void drbg_string_fill(struct drbg_string *string,

				    const unsigned char *buf, size_t len)

{

	string->buf = buf;

	string->len = len;

	string->next = NULL;

}



struct drbg_state;

typedef uint32_t drbg_flag_t;



struct drbg_core {

	drbg_flag_t flags;	/* flags for the cipher */

	__u8 statelen;		/* maximum state length */

	/*

	 * maximum length of personalization string or additional input

	 * string -- exponent for base 2

	 */

	__u8 max_addtllen;

	/* maximum bits per RNG request -- exponent for base 2*/

	__u8 max_bits;

	/* maximum number of requests -- exponent for base 2 */

	__u8 max_req;

	__u8 blocklen_bytes;	/* block size of output in bytes */

	char cra_name[CRYPTO_MAX_ALG_NAME]; /* mapping to kernel crypto API */

	 /* kernel crypto API backend cipher name */

	char backend_cra_name[CRYPTO_MAX_ALG_NAME];

};



struct drbg_state_ops {

	int (*update)(struct drbg_state *drbg, struct drbg_string *seed,

		      int reseed);

	int (*generate)(struct drbg_state *drbg,

			unsigned char *buf, unsigned int buflen,

			struct drbg_string *addtl);

	int (*crypto_init)(struct drbg_state *drbg);

	int (*crypto_fini)(struct drbg_state *drbg);



};



struct drbg_test_data {

	struct drbg_string *testentropy; /* TEST PARAMETER: test entropy */

};



struct drbg_state {

	spinlock_t drbg_lock;	/* lock around DRBG */

	unsigned char *V;	/* internal state 10.1.1.1 1a) */

	/* hash: static value 10.1.1.1 1b) hmac / ctr: key */

	unsigned char *C;

	/* Number of RNG requests since last reseed -- 10.1.1.1 1c) */

	size_t reseed_ctr;

	 /* some memory the DRBG can use for its operation */

	unsigned char *scratchpad;

	void *priv_data;	/* Cipher handle */

	bool seeded;		/* DRBG fully seeded? */

	bool pr;		/* Prediction resistance enabled? */

#ifdef CONFIG_CRYPTO_FIPS

	bool fips_primed;	/* Continuous test primed? */

	unsigned char *prev;	/* FIPS 140-2 continuous test value */

#endif

	const struct drbg_state_ops *d_ops;

	const struct drbg_core *core;

	struct drbg_test_data *test_data;

};



static inline __u8 drbg_statelen(struct drbg_state *drbg)

{

	if (drbg && drbg->core)

		return drbg->core->statelen;

	return 0;

}



static inline __u8 drbg_blocklen(struct drbg_state *drbg)

{

	if (drbg && drbg->core)

		return drbg->core->blocklen_bytes;

	return 0;

}



static inline __u8 drbg_keylen(struct drbg_state *drbg)

{

	if (drbg && drbg->core)

		return (drbg->core->statelen - drbg->core->blocklen_bytes);

	return 0;

}



static inline size_t drbg_max_request_bytes(struct drbg_state *drbg)

{

	/* max_bits is in bits, but buflen is in bytes */

	return (1 << (drbg->core->max_bits - 3));

}



static inline size_t drbg_max_addtl(struct drbg_state *drbg)

{

	return (1UL<<(drbg->core->max_addtllen));

}



static inline size_t drbg_max_requests(struct drbg_state *drbg)

{

	return (1UL<<(drbg->core->max_req));

}



/*

 * kernel crypto API input data structure for DRBG generate in case dlen

 * is set to 0

 */

struct drbg_gen {

	unsigned char *outbuf;	/* output buffer for random numbers */

	unsigned int outlen;	/* size of output buffer */

	struct drbg_string *addtl;	/* additional information string */

	struct drbg_test_data *test_data;	/* test data */

};



/*

 * This is a wrapper to the kernel crypto API function of

 * crypto_rng_get_bytes() to allow the caller to provide additional data.

 *

 * @drng DRBG handle -- see crypto_rng_get_bytes

 * @outbuf output buffer -- see crypto_rng_get_bytes

 * @outlen length of output buffer -- see crypto_rng_get_bytes

 * @addtl_input additional information string input buffer

 * @addtllen length of additional information string buffer

 *

 * return

 *	see crypto_rng_get_bytes

 */

static inline int crypto_drbg_get_bytes_addtl(struct crypto_rng *drng,

			unsigned char *outbuf, unsigned int outlen,

			struct drbg_string *addtl)

{

	int ret;

	struct drbg_gen genbuf;

	genbuf.outbuf = outbuf;

	genbuf.outlen = outlen;

	genbuf.addtl = addtl;

	genbuf.test_data = NULL;

	ret = crypto_rng_get_bytes(drng, (u8 *)&genbuf, 0);

	return ret;

}



/*

 * TEST code

 *

 * This is a wrapper to the kernel crypto API function of

 * crypto_rng_get_bytes() to allow the caller to provide additional data and

 * allow furnishing of test_data

 *

 * @drng DRBG handle -- see crypto_rng_get_bytes

 * @outbuf output buffer -- see crypto_rng_get_bytes

 * @outlen length of output buffer -- see crypto_rng_get_bytes

 * @addtl_input additional information string input buffer

 * @addtllen length of additional information string buffer

 * @test_data filled test data

 *

 * return

 *	see crypto_rng_get_bytes

 */

static inline int crypto_drbg_get_bytes_addtl_test(struct crypto_rng *drng,

			unsigned char *outbuf, unsigned int outlen,

			struct drbg_string *addtl,

			struct drbg_test_data *test_data)

{

	int ret;

	struct drbg_gen genbuf;

	genbuf.outbuf = outbuf;

	genbuf.outlen = outlen;

	genbuf.addtl = addtl;

	genbuf.test_data = test_data;

	ret = crypto_rng_get_bytes(drng, (u8 *)&genbuf, 0);

	return ret;

}



/*

 * TEST code

 *

 * This is a wrapper to the kernel crypto API function of

 * crypto_rng_reset() to allow the caller to provide test_data

 *

 * @drng DRBG handle -- see crypto_rng_reset

 * @pers personalization string input buffer

 * @perslen length of additional information string buffer

 * @test_data filled test data

 *

 * return

 *	see crypto_rng_reset

 */

static inline int crypto_drbg_reset_test(struct crypto_rng *drng,

					 struct drbg_string *pers,

					 struct drbg_test_data *test_data)

{

	int ret;

	struct drbg_gen genbuf;

	genbuf.outbuf = NULL;

	genbuf.outlen = 0;

	genbuf.addtl = pers;

	genbuf.test_data = test_data;

	ret = crypto_rng_reset(drng, (u8 *)&genbuf, 0);

	return ret;

}



/* DRBG type flags */

#define DRBG_CTR	((drbg_flag_t)1<<0)

#define DRBG_HMAC	((drbg_flag_t)1<<1)

#define DRBG_HASH	((drbg_flag_t)1<<2)

#define DRBG_TYPE_MASK	(DRBG_CTR | DRBG_HMAC | DRBG_HASH)

/* DRBG strength flags */

#define DRBG_STRENGTH128	((drbg_flag_t)1<<3)

#define DRBG_STRENGTH192	((drbg_flag_t)1<<4)

#define DRBG_STRENGTH256	((drbg_flag_t)1<<5)

#define DRBG_STRENGTH_MASK	(DRBG_STRENGTH128 | DRBG_STRENGTH192 | \

				 DRBG_STRENGTH256)



enum drbg_prefixes {

	DRBG_PREFIX0 = 0x00,

	DRBG_PREFIX1,

	DRBG_PREFIX2,

	DRBG_PREFIX3

};



#endif /* _DRBG_H */

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