| /* |
| * 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 */ |
| }; |
| |
| 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 */ |
| |
| bool seeded; /* DRBG fully seeded? */ |
| bool pr; /* Prediction resistance enabled? */ |
| struct work_struct seed_work; /* asynchronous seeding support */ |
| struct crypto_rng *jent; |
| const struct drbg_state_ops *d_ops; |
| const struct drbg_core *core; |
| struct drbg_string test_data; |
| struct random_ready_callback random_ready; |
| }; |
| |
| 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 */ |
| #if (__BITS_PER_LONG == 32) |
| return SIZE_MAX; |
| #else |
| return (1UL<<48); |
| #endif |
| } |
| |
| /* |
| * 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 */ |