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: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Stephan Mueller
Herbert Xu
Родитель
541af946fe
Коммит
3e16f959b9
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/*
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* DRBG based on NIST SP800-90A
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*
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* Copyright Stephan Mueller <smueller@chronox.de>, 2014
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, and the entire permission notice in its entirety,
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* including the disclaimer of warranties.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior
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* written permission.
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*
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* ALTERNATIVELY, this product may be distributed under the terms of
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* the GNU General Public License, in which case the provisions of the GPL are
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* required INSTEAD OF the above restrictions. (This clause is
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* necessary due to a potential bad interaction between the GPL and
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* the restrictions contained in a BSD-style copyright.)
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
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* WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
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* USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*/
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#ifndef _DRBG_H
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#define _DRBG_H
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#include <linux/random.h>
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#include <linux/scatterlist.h>
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#include <crypto/hash.h>
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#include <linux/module.h>
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#include <linux/crypto.h>
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#include <linux/slab.h>
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#include <crypto/internal/rng.h>
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#include <crypto/rng.h>
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#include <linux/fips.h>
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#include <linux/spinlock.h>
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/*
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* Concatenation Helper and string operation helper
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*
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* SP800-90A requires the concatenation of different data. To avoid copying
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* buffers around or allocate additional memory, the following data structure
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* is used to point to the original memory with its size. In addition, it
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* is used to build a linked list. The linked list defines the concatenation
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* of individual buffers. The order of memory block referenced in that
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* linked list determines the order of concatenation.
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*/
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struct drbg_string {
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const unsigned char *buf;
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size_t len;
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struct drbg_string *next;
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};
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static inline void drbg_string_fill(struct drbg_string *string,
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const unsigned char *buf, size_t len)
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{
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string->buf = buf;
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string->len = len;
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string->next = NULL;
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}
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struct drbg_state;
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typedef uint32_t drbg_flag_t;
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struct drbg_core {
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drbg_flag_t flags; /* flags for the cipher */
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__u8 statelen; /* maximum state length */
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/*
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* maximum length of personalization string or additional input
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* string -- exponent for base 2
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*/
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__u8 max_addtllen;
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/* maximum bits per RNG request -- exponent for base 2*/
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__u8 max_bits;
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/* maximum number of requests -- exponent for base 2 */
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__u8 max_req;
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__u8 blocklen_bytes; /* block size of output in bytes */
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char cra_name[CRYPTO_MAX_ALG_NAME]; /* mapping to kernel crypto API */
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/* kernel crypto API backend cipher name */
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char backend_cra_name[CRYPTO_MAX_ALG_NAME];
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};
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struct drbg_state_ops {
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int (*update)(struct drbg_state *drbg, struct drbg_string *seed,
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int reseed);
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int (*generate)(struct drbg_state *drbg,
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unsigned char *buf, unsigned int buflen,
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struct drbg_string *addtl);
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int (*crypto_init)(struct drbg_state *drbg);
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int (*crypto_fini)(struct drbg_state *drbg);
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};
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struct drbg_test_data {
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struct drbg_string *testentropy; /* TEST PARAMETER: test entropy */
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};
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struct drbg_state {
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spinlock_t drbg_lock; /* lock around DRBG */
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unsigned char *V; /* internal state 10.1.1.1 1a) */
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/* hash: static value 10.1.1.1 1b) hmac / ctr: key */
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unsigned char *C;
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/* Number of RNG requests since last reseed -- 10.1.1.1 1c) */
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size_t reseed_ctr;
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/* some memory the DRBG can use for its operation */
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unsigned char *scratchpad;
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void *priv_data; /* Cipher handle */
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bool seeded; /* DRBG fully seeded? */
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bool pr; /* Prediction resistance enabled? */
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#ifdef CONFIG_CRYPTO_FIPS
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bool fips_primed; /* Continuous test primed? */
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unsigned char *prev; /* FIPS 140-2 continuous test value */
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#endif
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const struct drbg_state_ops *d_ops;
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const struct drbg_core *core;
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struct drbg_test_data *test_data;
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};
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static inline __u8 drbg_statelen(struct drbg_state *drbg)
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{
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if (drbg && drbg->core)
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return drbg->core->statelen;
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return 0;
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}
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static inline __u8 drbg_blocklen(struct drbg_state *drbg)
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{
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if (drbg && drbg->core)
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return drbg->core->blocklen_bytes;
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return 0;
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}
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static inline __u8 drbg_keylen(struct drbg_state *drbg)
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{
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if (drbg && drbg->core)
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return (drbg->core->statelen - drbg->core->blocklen_bytes);
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return 0;
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}
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static inline size_t drbg_max_request_bytes(struct drbg_state *drbg)
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{
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/* max_bits is in bits, but buflen is in bytes */
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return (1 << (drbg->core->max_bits - 3));
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}
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static inline size_t drbg_max_addtl(struct drbg_state *drbg)
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{
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return (1UL<<(drbg->core->max_addtllen));
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}
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static inline size_t drbg_max_requests(struct drbg_state *drbg)
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{
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return (1UL<<(drbg->core->max_req));
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}
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/*
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* kernel crypto API input data structure for DRBG generate in case dlen
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* is set to 0
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*/
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struct drbg_gen {
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unsigned char *outbuf; /* output buffer for random numbers */
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unsigned int outlen; /* size of output buffer */
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struct drbg_string *addtl; /* additional information string */
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struct drbg_test_data *test_data; /* test data */
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};
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/*
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* This is a wrapper to the kernel crypto API function of
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* crypto_rng_get_bytes() to allow the caller to provide additional data.
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*
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* @drng DRBG handle -- see crypto_rng_get_bytes
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* @outbuf output buffer -- see crypto_rng_get_bytes
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* @outlen length of output buffer -- see crypto_rng_get_bytes
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* @addtl_input additional information string input buffer
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* @addtllen length of additional information string buffer
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*
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* return
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* see crypto_rng_get_bytes
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*/
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static inline int crypto_drbg_get_bytes_addtl(struct crypto_rng *drng,
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unsigned char *outbuf, unsigned int outlen,
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struct drbg_string *addtl)
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{
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int ret;
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struct drbg_gen genbuf;
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genbuf.outbuf = outbuf;
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genbuf.outlen = outlen;
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genbuf.addtl = addtl;
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genbuf.test_data = NULL;
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ret = crypto_rng_get_bytes(drng, (u8 *)&genbuf, 0);
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return ret;
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}
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/*
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* TEST code
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*
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* This is a wrapper to the kernel crypto API function of
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* crypto_rng_get_bytes() to allow the caller to provide additional data and
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* allow furnishing of test_data
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*
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* @drng DRBG handle -- see crypto_rng_get_bytes
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* @outbuf output buffer -- see crypto_rng_get_bytes
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* @outlen length of output buffer -- see crypto_rng_get_bytes
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* @addtl_input additional information string input buffer
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* @addtllen length of additional information string buffer
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* @test_data filled test data
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*
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* return
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* see crypto_rng_get_bytes
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*/
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static inline int crypto_drbg_get_bytes_addtl_test(struct crypto_rng *drng,
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unsigned char *outbuf, unsigned int outlen,
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struct drbg_string *addtl,
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struct drbg_test_data *test_data)
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{
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int ret;
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struct drbg_gen genbuf;
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genbuf.outbuf = outbuf;
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genbuf.outlen = outlen;
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genbuf.addtl = addtl;
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genbuf.test_data = test_data;
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ret = crypto_rng_get_bytes(drng, (u8 *)&genbuf, 0);
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return ret;
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}
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/*
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* TEST code
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*
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* This is a wrapper to the kernel crypto API function of
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* crypto_rng_reset() to allow the caller to provide test_data
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*
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* @drng DRBG handle -- see crypto_rng_reset
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* @pers personalization string input buffer
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* @perslen length of additional information string buffer
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* @test_data filled test data
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*
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* return
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* see crypto_rng_reset
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*/
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static inline int crypto_drbg_reset_test(struct crypto_rng *drng,
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struct drbg_string *pers,
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struct drbg_test_data *test_data)
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{
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int ret;
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struct drbg_gen genbuf;
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genbuf.outbuf = NULL;
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genbuf.outlen = 0;
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genbuf.addtl = pers;
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genbuf.test_data = test_data;
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ret = crypto_rng_reset(drng, (u8 *)&genbuf, 0);
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return ret;
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}
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/* DRBG type flags */
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#define DRBG_CTR ((drbg_flag_t)1<<0)
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#define DRBG_HMAC ((drbg_flag_t)1<<1)
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#define DRBG_HASH ((drbg_flag_t)1<<2)
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#define DRBG_TYPE_MASK (DRBG_CTR | DRBG_HMAC | DRBG_HASH)
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/* DRBG strength flags */
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#define DRBG_STRENGTH128 ((drbg_flag_t)1<<3)
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#define DRBG_STRENGTH192 ((drbg_flag_t)1<<4)
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#define DRBG_STRENGTH256 ((drbg_flag_t)1<<5)
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#define DRBG_STRENGTH_MASK (DRBG_STRENGTH128 | DRBG_STRENGTH192 | \
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DRBG_STRENGTH256)
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enum drbg_prefixes {
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DRBG_PREFIX0 = 0x00,
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DRBG_PREFIX1,
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DRBG_PREFIX2,
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DRBG_PREFIX3
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};
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#endif /* _DRBG_H */
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