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281 lines
8.9 KiB
281 lines
8.9 KiB
/* |
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* DRBG based on NIST SP800-90A |
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* |
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* Copyright Stephan Mueller <[email protected]>, 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 <crypto/skcipher.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/mutex.h> |
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#include <linux/list.h> |
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#include <linux/workqueue.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 list_head list; |
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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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INIT_LIST_HEAD(&string->list); |
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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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__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 list_head *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 list_head *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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struct mutex drbg_mutex; /* lock around DRBG */ |
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unsigned char *V; /* internal state 10.1.1.1 1a) */ |
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unsigned char *Vbuf; |
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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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unsigned char *Cbuf; |
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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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size_t reseed_threshold; |
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/* some memory the DRBG can use for its operation */ |
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unsigned char *scratchpad; |
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unsigned char *scratchpadbuf; |
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void *priv_data; /* Cipher handle */ |
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struct crypto_skcipher *ctr_handle; /* CTR mode cipher handle */ |
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struct skcipher_request *ctr_req; /* CTR mode request handle */ |
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__u8 *outscratchpadbuf; /* CTR mode output scratchpad */ |
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__u8 *outscratchpad; /* CTR mode aligned outbuf */ |
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struct crypto_wait ctr_wait; /* CTR mode async wait obj */ |
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struct scatterlist sg_in, sg_out; /* CTR mode SGLs */ |
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bool seeded; /* DRBG fully seeded? */ |
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bool pr; /* Prediction resistance enabled? */ |
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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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struct work_struct seed_work; /* asynchronous seeding support */ |
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struct crypto_rng *jent; |
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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_string test_data; |
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struct random_ready_callback random_ready; |
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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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/* SP800-90A requires the limit 2**19 bits, but we return bytes */ |
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return (1 << 16); |
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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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/* SP800-90A requires 2**35 bytes additional info str / pers str */ |
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#if (__BITS_PER_LONG == 32) |
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/* |
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* SP800-90A allows smaller maximum numbers to be returned -- we |
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* return SIZE_MAX - 1 to allow the verification of the enforcement |
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* of this value in drbg_healthcheck_sanity. |
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*/ |
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return (SIZE_MAX - 1); |
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#else |
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return (1UL<<35); |
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#endif |
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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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/* SP800-90A requires 2**48 maximum requests before reseeding */ |
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return (1<<20); |
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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_generate() 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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return crypto_rng_generate(drng, addtl->buf, addtl->len, |
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outbuf, outlen); |
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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_generate() 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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crypto_rng_set_entropy(drng, test_data->testentropy->buf, |
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test_data->testentropy->len); |
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return crypto_rng_generate(drng, addtl->buf, addtl->len, |
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outbuf, outlen); |
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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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crypto_rng_set_entropy(drng, test_data->testentropy->buf, |
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test_data->testentropy->len); |
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return crypto_rng_reset(drng, pers->buf, pers->len); |
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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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