pigweed / third_party / boringssl / boringssl / 17cf2cb1d226b0ba2401304242df7ddd3b6f1ff2 / . / crypto / bn / random.c

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) | |

* All rights reserved. | |

* | |

* This package is an SSL implementation written | |

* by Eric Young (eay@cryptsoft.com). | |

* The implementation was written so as to conform with Netscapes SSL. | |

* | |

* This library is free for commercial and non-commercial use as long as | |

* the following conditions are aheared to. The following conditions | |

* apply to all code found in this distribution, be it the RC4, RSA, | |

* lhash, DES, etc., code; not just the SSL code. The SSL documentation | |

* included with this distribution is covered by the same copyright terms | |

* except that the holder is Tim Hudson (tjh@cryptsoft.com). | |

* | |

* Copyright remains Eric Young's, and as such any Copyright notices in | |

* the code are not to be removed. | |

* If this package is used in a product, Eric Young should be given attribution | |

* as the author of the parts of the library used. | |

* This can be in the form of a textual message at program startup or | |

* in documentation (online or textual) provided with the package. | |

* | |

* 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 copyright | |

* notice, this list of conditions and the following disclaimer. | |

* 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. All advertising materials mentioning features or use of this software | |

* must display the following acknowledgement: | |

* "This product includes cryptographic software written by | |

* Eric Young (eay@cryptsoft.com)" | |

* The word 'cryptographic' can be left out if the rouines from the library | |

* being used are not cryptographic related :-). | |

* 4. If you include any Windows specific code (or a derivative thereof) from | |

* the apps directory (application code) you must include an acknowledgement: | |

* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" | |

* | |

* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND | |

* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |

* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |

* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS 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 ADVISED OF THE POSSIBILITY OF | |

* SUCH DAMAGE. | |

* | |

* The licence and distribution terms for any publically available version or | |

* derivative of this code cannot be changed. i.e. this code cannot simply be | |

* copied and put under another distribution licence | |

* [including the GNU Public Licence.] | |

*/ | |

/* ==================================================================== | |

* Copyright (c) 1998-2001 The OpenSSL Project. All rights reserved. | |

* | |

* 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, this list of conditions and the following disclaimer. | |

* | |

* 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. All advertising materials mentioning features or use of this | |

* software must display the following acknowledgment: | |

* "This product includes software developed by the OpenSSL Project | |

* for use in the OpenSSL Toolkit. (http://www.openssl.org/)" | |

* | |

* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to | |

* endorse or promote products derived from this software without | |

* prior written permission. For written permission, please contact | |

* openssl-core@openssl.org. | |

* | |

* 5. Products derived from this software may not be called "OpenSSL" | |

* nor may "OpenSSL" appear in their names without prior written | |

* permission of the OpenSSL Project. | |

* | |

* 6. Redistributions of any form whatsoever must retain the following | |

* acknowledgment: | |

* "This product includes software developed by the OpenSSL Project | |

* for use in the OpenSSL Toolkit (http://www.openssl.org/)" | |

* | |

* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY | |

* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |

* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |

* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR | |

* ITS CONTRIBUTORS 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 ADVISED | |

* OF THE POSSIBILITY OF SUCH DAMAGE. | |

* ==================================================================== | |

* | |

* This product includes cryptographic software written by Eric Young | |

* (eay@cryptsoft.com). This product includes software written by Tim | |

* Hudson (tjh@cryptsoft.com). */ | |

#include <openssl/bn.h> | |

#include <string.h> | |

#include <openssl/err.h> | |

#include <openssl/mem.h> | |

#include <openssl/rand.h> | |

#include <openssl/sha.h> | |

#include "../internal.h" | |

int BN_rand(BIGNUM *rnd, int bits, int top, int bottom) { | |

uint8_t *buf = NULL; | |

int ret = 0, bit, bytes, mask; | |

if (rnd == NULL) { | |

return 0; | |

} | |

if (top != BN_RAND_TOP_ANY && top != BN_RAND_TOP_ONE && | |

top != BN_RAND_TOP_TWO) { | |

OPENSSL_PUT_ERROR(BN, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); | |

return 0; | |

} | |

if (bottom != BN_RAND_BOTTOM_ANY && bottom != BN_RAND_BOTTOM_ODD) { | |

OPENSSL_PUT_ERROR(BN, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED); | |

return 0; | |

} | |

if (bits == 0) { | |

BN_zero(rnd); | |

return 1; | |

} | |

bytes = (bits + 7) / 8; | |

bit = (bits - 1) % 8; | |

mask = 0xff << (bit + 1); | |

buf = OPENSSL_malloc(bytes); | |

if (buf == NULL) { | |

OPENSSL_PUT_ERROR(BN, ERR_R_MALLOC_FAILURE); | |

goto err; | |

} | |

/* Make a random number and set the top and bottom bits. */ | |

if (!RAND_bytes(buf, bytes)) { | |

goto err; | |

} | |

if (top != BN_RAND_TOP_ANY) { | |

if (top == BN_RAND_TOP_TWO && bits > 1) { | |

if (bit == 0) { | |

buf[0] = 1; | |

buf[1] |= 0x80; | |

} else { | |

buf[0] |= (3 << (bit - 1)); | |

} | |

} else { | |

buf[0] |= (1 << bit); | |

} | |

} | |

buf[0] &= ~mask; | |

/* Set the bottom bit if requested, */ | |

if (bottom == BN_RAND_BOTTOM_ODD) { | |

buf[bytes - 1] |= 1; | |

} | |

if (!BN_bin2bn(buf, bytes, rnd)) { | |

goto err; | |

} | |

ret = 1; | |

err: | |

if (buf != NULL) { | |

OPENSSL_cleanse(buf, bytes); | |

OPENSSL_free(buf); | |

} | |

return (ret); | |

} | |

int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom) { | |

return BN_rand(rnd, bits, top, bottom); | |

} | |

int BN_rand_range_ex(BIGNUM *r, BN_ULONG min_inclusive, | |

const BIGNUM *max_exclusive) { | |

unsigned n; | |

unsigned count = 100; | |

if (BN_cmp_word(max_exclusive, min_inclusive) <= 0) { | |

OPENSSL_PUT_ERROR(BN, BN_R_INVALID_RANGE); | |

return 0; | |

} | |

n = BN_num_bits(max_exclusive); /* n > 0 */ | |

/* BN_is_bit_set(range, n - 1) always holds */ | |

if (n == 1) { | |

BN_zero(r); | |

return 1; | |

} | |

do { | |

if (!--count) { | |

OPENSSL_PUT_ERROR(BN, BN_R_TOO_MANY_ITERATIONS); | |

return 0; | |

} | |

if (!BN_is_bit_set(max_exclusive, n - 2) && | |

!BN_is_bit_set(max_exclusive, n - 3)) { | |

/* range = 100..._2, so 3*range (= 11..._2) is exactly one bit longer | |

* than range. This is a common scenario when generating a random value | |

* modulo an RSA public modulus, e.g. for RSA base blinding. */ | |

if (!BN_rand(r, n + 1, BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY)) { | |

return 0; | |

} | |

/* If r < 3*range, use r := r MOD range (which is either r, r - range, or | |

* r - 2*range). Otherwise, iterate again. Since 3*range = 11..._2, each | |

* iteration succeeds with probability >= .75. */ | |

if (BN_cmp(r, max_exclusive) >= 0) { | |

if (!BN_sub(r, r, max_exclusive)) { | |

return 0; | |

} | |

if (BN_cmp(r, max_exclusive) >= 0) { | |

if (!BN_sub(r, r, max_exclusive)) { | |

return 0; | |

} | |

} | |

} | |

} else { | |

/* range = 11..._2 or range = 101..._2 */ | |

if (!BN_rand(r, n, BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY)) { | |

return 0; | |

} | |

} | |

} while (BN_cmp_word(r, min_inclusive) < 0 || | |

BN_cmp(r, max_exclusive) >= 0); | |

return 1; | |

} | |

int BN_rand_range(BIGNUM *r, const BIGNUM *range) { | |

return BN_rand_range_ex(r, 0, range); | |

} | |

int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range) { | |

return BN_rand_range(r, range); | |

} | |

int BN_generate_dsa_nonce(BIGNUM *out, const BIGNUM *range, const BIGNUM *priv, | |

const uint8_t *message, size_t message_len, | |

BN_CTX *ctx) { | |

SHA512_CTX sha; | |

/* We use 512 bits of random data per iteration to | |

* ensure that we have at least |range| bits of randomness. */ | |

uint8_t random_bytes[64]; | |

uint8_t digest[SHA512_DIGEST_LENGTH]; | |

size_t done, todo, attempt; | |

const unsigned num_k_bytes = BN_num_bytes(range); | |

const unsigned bits_to_mask = (8 - (BN_num_bits(range) % 8)) % 8; | |

uint8_t private_bytes[96]; | |

uint8_t *k_bytes = NULL; | |

int ret = 0; | |

if (out == NULL) { | |

return 0; | |

} | |

if (BN_is_zero(range)) { | |

OPENSSL_PUT_ERROR(BN, BN_R_DIV_BY_ZERO); | |

goto err; | |

} | |

k_bytes = OPENSSL_malloc(num_k_bytes); | |

if (!k_bytes) { | |

OPENSSL_PUT_ERROR(BN, ERR_R_MALLOC_FAILURE); | |

goto err; | |

} | |

/* We copy |priv| into a local buffer to avoid furthur exposing its | |

* length. */ | |

todo = sizeof(priv->d[0]) * priv->top; | |

if (todo > sizeof(private_bytes)) { | |

/* No reasonable DSA or ECDSA key should have a private key | |

* this large and we don't handle this case in order to avoid | |

* leaking the length of the private key. */ | |

OPENSSL_PUT_ERROR(BN, BN_R_PRIVATE_KEY_TOO_LARGE); | |

goto err; | |

} | |

OPENSSL_memcpy(private_bytes, priv->d, todo); | |

OPENSSL_memset(private_bytes + todo, 0, sizeof(private_bytes) - todo); | |

for (attempt = 0;; attempt++) { | |

for (done = 0; done < num_k_bytes;) { | |

if (!RAND_bytes(random_bytes, sizeof(random_bytes))) { | |

goto err; | |

} | |

SHA512_Init(&sha); | |

SHA512_Update(&sha, &attempt, sizeof(attempt)); | |

SHA512_Update(&sha, &done, sizeof(done)); | |

SHA512_Update(&sha, private_bytes, sizeof(private_bytes)); | |

SHA512_Update(&sha, message, message_len); | |

SHA512_Update(&sha, random_bytes, sizeof(random_bytes)); | |

SHA512_Final(digest, &sha); | |

todo = num_k_bytes - done; | |

if (todo > SHA512_DIGEST_LENGTH) { | |

todo = SHA512_DIGEST_LENGTH; | |

} | |

OPENSSL_memcpy(k_bytes + done, digest, todo); | |

done += todo; | |

} | |

k_bytes[0] &= 0xff >> bits_to_mask; | |

if (!BN_bin2bn(k_bytes, num_k_bytes, out)) { | |

goto err; | |

} | |

if (BN_cmp(out, range) < 0) { | |

break; | |

} | |

} | |

ret = 1; | |

err: | |

OPENSSL_free(k_bytes); | |

return ret; | |

} |