diff options
Diffstat (limited to 'openssl-1.1.0h/crypto/bn/bn_rand.c')
| -rw-r--r-- | openssl-1.1.0h/crypto/bn/bn_rand.c | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/openssl-1.1.0h/crypto/bn/bn_rand.c b/openssl-1.1.0h/crypto/bn/bn_rand.c new file mode 100644 index 0000000..9ce4c5f --- /dev/null +++ b/openssl-1.1.0h/crypto/bn/bn_rand.c @@ -0,0 +1,258 @@ +/* + * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. + * + * Licensed under the OpenSSL license (the "License"). You may not use + * this file except in compliance with the License. You can obtain a copy + * in the file LICENSE in the source distribution or at + * https://www.openssl.org/source/license.html + */ + +#include <stdio.h> +#include <time.h> +#include "internal/cryptlib.h" +#include "bn_lcl.h" +#include <openssl/rand.h> +#include <openssl/sha.h> + +static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom) +{ + unsigned char *buf = NULL; + int ret = 0, bit, bytes, mask; + time_t tim; + + if (bits == 0) { + if (top != BN_RAND_TOP_ANY || bottom != BN_RAND_BOTTOM_ANY) + goto toosmall; + BN_zero(rnd); + return 1; + } + if (bits < 0 || (bits == 1 && top > 0)) + goto toosmall; + + bytes = (bits + 7) / 8; + bit = (bits - 1) % 8; + mask = 0xff << (bit + 1); + + buf = OPENSSL_malloc(bytes); + if (buf == NULL) { + BNerr(BN_F_BNRAND, ERR_R_MALLOC_FAILURE); + goto err; + } + + /* make a random number and set the top and bottom bits */ + time(&tim); + RAND_add(&tim, sizeof(tim), 0.0); + + if (RAND_bytes(buf, bytes) <= 0) + goto err; + + if (pseudorand == 2) { + /* + * generate patterns that are more likely to trigger BN library bugs + */ + int i; + unsigned char c; + + for (i = 0; i < bytes; i++) { + if (RAND_bytes(&c, 1) <= 0) + goto err; + if (c >= 128 && i > 0) + buf[i] = buf[i - 1]; + else if (c < 42) + buf[i] = 0; + else if (c < 84) + buf[i] = 255; + } + } + + if (top >= 0) { + if (top) { + if (bit == 0) { + buf[0] = 1; + buf[1] |= 0x80; + } else { + buf[0] |= (3 << (bit - 1)); + } + } else { + buf[0] |= (1 << bit); + } + } + buf[0] &= ~mask; + if (bottom) /* set bottom bit if requested */ + buf[bytes - 1] |= 1; + if (!BN_bin2bn(buf, bytes, rnd)) + goto err; + ret = 1; + err: + OPENSSL_clear_free(buf, bytes); + bn_check_top(rnd); + return (ret); + +toosmall: + BNerr(BN_F_BNRAND, BN_R_BITS_TOO_SMALL); + return 0; +} + +int BN_rand(BIGNUM *rnd, int bits, int top, int bottom) +{ + return bnrand(0, rnd, bits, top, bottom); +} + +int BN_pseudo_rand(BIGNUM *rnd, int bits, int top, int bottom) +{ + return bnrand(1, rnd, bits, top, bottom); +} + +int BN_bntest_rand(BIGNUM *rnd, int bits, int top, int bottom) +{ + return bnrand(2, rnd, bits, top, bottom); +} + +/* random number r: 0 <= r < range */ +static int bn_rand_range(int pseudo, BIGNUM *r, const BIGNUM *range) +{ + int (*bn_rand) (BIGNUM *, int, int, int) = + pseudo ? BN_pseudo_rand : BN_rand; + int n; + int count = 100; + + if (range->neg || BN_is_zero(range)) { + BNerr(BN_F_BN_RAND_RANGE, BN_R_INVALID_RANGE); + return 0; + } + + n = BN_num_bits(range); /* n > 0 */ + + /* BN_is_bit_set(range, n - 1) always holds */ + + if (n == 1) + BN_zero(r); + else if (!BN_is_bit_set(range, n - 2) && !BN_is_bit_set(range, n - 3)) { + /* + * range = 100..._2, so 3*range (= 11..._2) is exactly one bit longer + * than range + */ + do { + 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 once more. Since + * 3*range = 11..._2, each iteration succeeds with probability >= + * .75. + */ + if (BN_cmp(r, range) >= 0) { + if (!BN_sub(r, r, range)) + return 0; + if (BN_cmp(r, range) >= 0) + if (!BN_sub(r, r, range)) + return 0; + } + + if (!--count) { + BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS); + return 0; + } + + } + while (BN_cmp(r, range) >= 0); + } else { + do { + /* range = 11..._2 or range = 101..._2 */ + if (!bn_rand(r, n, BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY)) + return 0; + + if (!--count) { + BNerr(BN_F_BN_RAND_RANGE, BN_R_TOO_MANY_ITERATIONS); + return 0; + } + } + while (BN_cmp(r, range) >= 0); + } + + bn_check_top(r); + return 1; +} + +int BN_rand_range(BIGNUM *r, const BIGNUM *range) +{ + return bn_rand_range(0, r, range); +} + +int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range) +{ + return bn_rand_range(1, r, range); +} + +/* + * BN_generate_dsa_nonce generates a random number 0 <= out < range. Unlike + * BN_rand_range, it also includes the contents of |priv| and |message| in + * the generation so that an RNG failure isn't fatal as long as |priv| + * remains secret. This is intended for use in DSA and ECDSA where an RNG + * weakness leads directly to private key exposure unless this function is + * used. + */ +int BN_generate_dsa_nonce(BIGNUM *out, const BIGNUM *range, + const BIGNUM *priv, const unsigned char *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. + */ + unsigned char random_bytes[64]; + unsigned char digest[SHA512_DIGEST_LENGTH]; + unsigned done, todo; + /* We generate |range|+8 bytes of random output. */ + const unsigned num_k_bytes = BN_num_bytes(range) + 8; + unsigned char private_bytes[96]; + unsigned char *k_bytes; + int ret = 0; + + k_bytes = OPENSSL_malloc(num_k_bytes); + if (k_bytes == NULL) + goto err; + + /* We copy |priv| into a local buffer to avoid 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. + */ + BNerr(BN_F_BN_GENERATE_DSA_NONCE, BN_R_PRIVATE_KEY_TOO_LARGE); + goto err; + } + memcpy(private_bytes, priv->d, todo); + memset(private_bytes + todo, 0, sizeof(private_bytes) - todo); + + for (done = 0; done < num_k_bytes;) { + if (RAND_bytes(random_bytes, sizeof(random_bytes)) != 1) + goto err; + SHA512_Init(&sha); + 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; + memcpy(k_bytes + done, digest, todo); + done += todo; + } + + if (!BN_bin2bn(k_bytes, num_k_bytes, out)) + goto err; + if (BN_mod(out, out, range, ctx) != 1) + goto err; + ret = 1; + + err: + OPENSSL_free(k_bytes); + OPENSSL_cleanse(private_bytes, sizeof(private_bytes)); + return ret; +} |