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Diffstat (limited to 'include/crypto/drbg.h')
| -rw-r--r-- | include/crypto/drbg.h | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/include/crypto/drbg.h b/include/crypto/drbg.h new file mode 100644 index 000000000..af5ad51d3 --- /dev/null +++ b/include/crypto/drbg.h @@ -0,0 +1,286 @@ +/* + * 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 <crypto/skcipher.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/mutex.h> +#include <linux/list.h> +#include <linux/workqueue.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 list_head list; +}; + +static inline void drbg_string_fill(struct drbg_string *string, + const unsigned char *buf, size_t len) +{ + string->buf = buf; + string->len = len; + INIT_LIST_HEAD(&string->list); +} + +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 */ + __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 list_head *seed, + int reseed); + int (*generate)(struct drbg_state *drbg, + unsigned char *buf, unsigned int buflen, + struct list_head *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 */ +}; + +enum drbg_seed_state { + DRBG_SEED_STATE_UNSEEDED, + DRBG_SEED_STATE_PARTIAL, /* Seeded with !rng_is_initialized() */ + DRBG_SEED_STATE_FULL, +}; + +struct drbg_state { + struct mutex drbg_mutex; /* lock around DRBG */ + unsigned char *V; /* internal state 10.1.1.1 1a) */ + unsigned char *Vbuf; + /* hash: static value 10.1.1.1 1b) hmac / ctr: key */ + unsigned char *C; + unsigned char *Cbuf; + /* Number of RNG requests since last reseed -- 10.1.1.1 1c) */ + size_t reseed_ctr; + size_t reseed_threshold; + /* some memory the DRBG can use for its operation */ + unsigned char *scratchpad; + unsigned char *scratchpadbuf; + void *priv_data; /* Cipher handle */ + + struct crypto_skcipher *ctr_handle; /* CTR mode cipher handle */ + struct skcipher_request *ctr_req; /* CTR mode request handle */ + __u8 *outscratchpadbuf; /* CTR mode output scratchpad */ + __u8 *outscratchpad; /* CTR mode aligned outbuf */ + struct crypto_wait ctr_wait; /* CTR mode async wait obj */ + struct scatterlist sg_in, sg_out; /* CTR mode SGLs */ + + enum drbg_seed_state seeded; /* DRBG fully seeded? */ + unsigned long last_seed_time; + bool pr; /* Prediction resistance enabled? */ + bool fips_primed; /* Continuous test primed? */ + unsigned char *prev; /* FIPS 140-2 continuous test value */ + struct crypto_rng *jent; + const struct drbg_state_ops *d_ops; + const struct drbg_core *core; + struct drbg_string 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) +{ + /* SP800-90A requires the limit 2**19 bits, but we return bytes */ + return (1 << 16); +} + +static inline size_t drbg_max_addtl(struct drbg_state *drbg) +{ + /* SP800-90A requires 2**35 bytes additional info str / pers str */ +#if (__BITS_PER_LONG == 32) + /* + * SP800-90A allows smaller maximum numbers to be returned -- we + * return SIZE_MAX - 1 to allow the verification of the enforcement + * of this value in drbg_healthcheck_sanity. + */ + return (SIZE_MAX - 1); +#else + return (1UL<<35); +#endif +} + +static inline size_t drbg_max_requests(struct drbg_state *drbg) +{ + /* SP800-90A requires 2**48 maximum requests before reseeding */ + return (1<<20); +} + +/* + * This is a wrapper to the kernel crypto API function of + * crypto_rng_generate() 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) +{ + return crypto_rng_generate(drng, addtl->buf, addtl->len, + outbuf, outlen); +} + +/* + * TEST code + * + * This is a wrapper to the kernel crypto API function of + * crypto_rng_generate() 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) +{ + crypto_rng_set_entropy(drng, test_data->testentropy->buf, + test_data->testentropy->len); + return crypto_rng_generate(drng, addtl->buf, addtl->len, + outbuf, outlen); +} + +/* + * 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) +{ + crypto_rng_set_entropy(drng, test_data->testentropy->buf, + test_data->testentropy->len); + return crypto_rng_reset(drng, pers->buf, pers->len); +} + +/* 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 */ |