/* * 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/drbg.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> 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 */
