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1/*2 * DRBG based on NIST SP800-90A3 *4 * Copyright Stephan Mueller <smueller@chronox.de>, 20145 *6 * Redistribution and use in source and binary forms, with or without7 * modification, are permitted provided that the following conditions8 * are met:9 * 1. Redistributions of source code must retain the above copyright10 * notice, and the entire permission notice in its entirety,11 * including the disclaimer of warranties.12 * 2. Redistributions in binary form must reproduce the above copyright13 * notice, this list of conditions and the following disclaimer in the14 * documentation and/or other materials provided with the distribution.15 * 3. The name of the author may not be used to endorse or promote16 * products derived from this software without specific prior17 * written permission.18 *19 * ALTERNATIVELY, this product may be distributed under the terms of20 * the GNU General Public License, in which case the provisions of the GPL are21 * required INSTEAD OF the above restrictions. (This clause is22 * necessary due to a potential bad interaction between the GPL and23 * the restrictions contained in a BSD-style copyright.)24 *25 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED26 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF28 * WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE29 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT31 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR32 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF33 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE35 * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH36 * DAMAGE.37 */38 39#ifndef _DRBG_H40#define _DRBG_H41 42 43#include <linux/random.h>44#include <linux/scatterlist.h>45#include <crypto/hash.h>46#include <crypto/skcipher.h>47#include <linux/module.h>48#include <linux/crypto.h>49#include <linux/slab.h>50#include <crypto/internal/rng.h>51#include <crypto/rng.h>52#include <linux/fips.h>53#include <linux/mutex.h>54#include <linux/list.h>55#include <linux/workqueue.h>56 57/*58 * Concatenation Helper and string operation helper59 *60 * SP800-90A requires the concatenation of different data. To avoid copying61 * buffers around or allocate additional memory, the following data structure62 * is used to point to the original memory with its size. In addition, it63 * is used to build a linked list. The linked list defines the concatenation64 * of individual buffers. The order of memory block referenced in that65 * linked list determines the order of concatenation.66 */67struct drbg_string {68 const unsigned char *buf;69 size_t len;70 struct list_head list;71};72 73static inline void drbg_string_fill(struct drbg_string *string,74 const unsigned char *buf, size_t len)75{76 string->buf = buf;77 string->len = len;78 INIT_LIST_HEAD(&string->list);79}80 81struct drbg_state;82typedef uint32_t drbg_flag_t;83 84struct drbg_core {85 drbg_flag_t flags; /* flags for the cipher */86 __u8 statelen; /* maximum state length */87 __u8 blocklen_bytes; /* block size of output in bytes */88 char cra_name[CRYPTO_MAX_ALG_NAME]; /* mapping to kernel crypto API */89 /* kernel crypto API backend cipher name */90 char backend_cra_name[CRYPTO_MAX_ALG_NAME];91};92 93struct drbg_state_ops {94 int (*update)(struct drbg_state *drbg, struct list_head *seed,95 int reseed);96 int (*generate)(struct drbg_state *drbg,97 unsigned char *buf, unsigned int buflen,98 struct list_head *addtl);99 int (*crypto_init)(struct drbg_state *drbg);100 int (*crypto_fini)(struct drbg_state *drbg);101 102};103 104struct drbg_test_data {105 struct drbg_string *testentropy; /* TEST PARAMETER: test entropy */106};107 108enum drbg_seed_state {109 DRBG_SEED_STATE_UNSEEDED,110 DRBG_SEED_STATE_PARTIAL, /* Seeded with !rng_is_initialized() */111 DRBG_SEED_STATE_FULL,112};113 114struct drbg_state {115 struct mutex drbg_mutex; /* lock around DRBG */116 unsigned char *V; /* internal state 10.1.1.1 1a) */117 unsigned char *Vbuf;118 /* hash: static value 10.1.1.1 1b) hmac / ctr: key */119 unsigned char *C;120 unsigned char *Cbuf;121 /* Number of RNG requests since last reseed -- 10.1.1.1 1c) */122 size_t reseed_ctr;123 size_t reseed_threshold;124 /* some memory the DRBG can use for its operation */125 unsigned char *scratchpad;126 unsigned char *scratchpadbuf;127 void *priv_data; /* Cipher handle */128 129 struct crypto_skcipher *ctr_handle; /* CTR mode cipher handle */130 struct skcipher_request *ctr_req; /* CTR mode request handle */131 __u8 *outscratchpadbuf; /* CTR mode output scratchpad */132 __u8 *outscratchpad; /* CTR mode aligned outbuf */133 struct crypto_wait ctr_wait; /* CTR mode async wait obj */134 struct scatterlist sg_in, sg_out; /* CTR mode SGLs */135 136 enum drbg_seed_state seeded; /* DRBG fully seeded? */137 unsigned long last_seed_time;138 bool pr; /* Prediction resistance enabled? */139 bool fips_primed; /* Continuous test primed? */140 unsigned char *prev; /* FIPS 140-2 continuous test value */141 struct crypto_rng *jent;142 const struct drbg_state_ops *d_ops;143 const struct drbg_core *core;144 struct drbg_string test_data;145};146 147static inline __u8 drbg_statelen(struct drbg_state *drbg)148{149 if (drbg && drbg->core)150 return drbg->core->statelen;151 return 0;152}153 154static inline __u8 drbg_blocklen(struct drbg_state *drbg)155{156 if (drbg && drbg->core)157 return drbg->core->blocklen_bytes;158 return 0;159}160 161static inline __u8 drbg_keylen(struct drbg_state *drbg)162{163 if (drbg && drbg->core)164 return (drbg->core->statelen - drbg->core->blocklen_bytes);165 return 0;166}167 168static inline size_t drbg_max_request_bytes(struct drbg_state *drbg)169{170 /* SP800-90A requires the limit 2**19 bits, but we return bytes */171 return (1 << 16);172}173 174static inline size_t drbg_max_addtl(struct drbg_state *drbg)175{176 /* SP800-90A requires 2**35 bytes additional info str / pers str */177#if (__BITS_PER_LONG == 32)178 /*179 * SP800-90A allows smaller maximum numbers to be returned -- we180 * return SIZE_MAX - 1 to allow the verification of the enforcement181 * of this value in drbg_healthcheck_sanity.182 */183 return (SIZE_MAX - 1);184#else185 return (1UL<<35);186#endif187}188 189static inline size_t drbg_max_requests(struct drbg_state *drbg)190{191 /* SP800-90A requires 2**48 maximum requests before reseeding */192 return (1<<20);193}194 195/*196 * This is a wrapper to the kernel crypto API function of197 * crypto_rng_generate() to allow the caller to provide additional data.198 *199 * @drng DRBG handle -- see crypto_rng_get_bytes200 * @outbuf output buffer -- see crypto_rng_get_bytes201 * @outlen length of output buffer -- see crypto_rng_get_bytes202 * @addtl_input additional information string input buffer203 * @addtllen length of additional information string buffer204 *205 * return206 * see crypto_rng_get_bytes207 */208static inline int crypto_drbg_get_bytes_addtl(struct crypto_rng *drng,209 unsigned char *outbuf, unsigned int outlen,210 struct drbg_string *addtl)211{212 return crypto_rng_generate(drng, addtl->buf, addtl->len,213 outbuf, outlen);214}215 216/*217 * TEST code218 *219 * This is a wrapper to the kernel crypto API function of220 * crypto_rng_generate() to allow the caller to provide additional data and221 * allow furnishing of test_data222 *223 * @drng DRBG handle -- see crypto_rng_get_bytes224 * @outbuf output buffer -- see crypto_rng_get_bytes225 * @outlen length of output buffer -- see crypto_rng_get_bytes226 * @addtl_input additional information string input buffer227 * @addtllen length of additional information string buffer228 * @test_data filled test data229 *230 * return231 * see crypto_rng_get_bytes232 */233static inline int crypto_drbg_get_bytes_addtl_test(struct crypto_rng *drng,234 unsigned char *outbuf, unsigned int outlen,235 struct drbg_string *addtl,236 struct drbg_test_data *test_data)237{238 crypto_rng_set_entropy(drng, test_data->testentropy->buf,239 test_data->testentropy->len);240 return crypto_rng_generate(drng, addtl->buf, addtl->len,241 outbuf, outlen);242}243 244/*245 * TEST code246 *247 * This is a wrapper to the kernel crypto API function of248 * crypto_rng_reset() to allow the caller to provide test_data249 *250 * @drng DRBG handle -- see crypto_rng_reset251 * @pers personalization string input buffer252 * @perslen length of additional information string buffer253 * @test_data filled test data254 *255 * return256 * see crypto_rng_reset257 */258static inline int crypto_drbg_reset_test(struct crypto_rng *drng,259 struct drbg_string *pers,260 struct drbg_test_data *test_data)261{262 crypto_rng_set_entropy(drng, test_data->testentropy->buf,263 test_data->testentropy->len);264 return crypto_rng_reset(drng, pers->buf, pers->len);265}266 267/* DRBG type flags */268#define DRBG_CTR ((drbg_flag_t)1<<0)269#define DRBG_HMAC ((drbg_flag_t)1<<1)270#define DRBG_HASH ((drbg_flag_t)1<<2)271#define DRBG_TYPE_MASK (DRBG_CTR | DRBG_HMAC | DRBG_HASH)272/* DRBG strength flags */273#define DRBG_STRENGTH128 ((drbg_flag_t)1<<3)274#define DRBG_STRENGTH192 ((drbg_flag_t)1<<4)275#define DRBG_STRENGTH256 ((drbg_flag_t)1<<5)276#define DRBG_STRENGTH_MASK (DRBG_STRENGTH128 | DRBG_STRENGTH192 | \277 DRBG_STRENGTH256)278 279enum drbg_prefixes {280 DRBG_PREFIX0 = 0x00,281 DRBG_PREFIX1,282 DRBG_PREFIX2,283 DRBG_PREFIX3284};285 286#endif /* _DRBG_H */287