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| author | Tomas Mraz <tomas@openssl.org> | 2024-04-25 19:26:08 +0200 |
|---|---|---|
| committer | Tomas Mraz <tomas@openssl.org> | 2024-05-02 09:16:36 +0200 |
| commit | 13b3ca5c998e6db4f7251a56c43541cb1a422bd0 (patch) | |
| tree | 788f2653f7a71314fc32edb5e515be2c7d06e1bc /crypto/bn | |
| parent | Make ossl_gen_deterministic_nonce_rfc6979() constant time (diff) | |
| download | openssl-13b3ca5c998e6db4f7251a56c43541cb1a422bd0.tar.xz openssl-13b3ca5c998e6db4f7251a56c43541cb1a422bd0.zip | |
Add ossl_bn_priv_rand_range_fixed_top() and use it for EC/DSA
Reviewed-by: Paul Dale <ppzgs1@gmail.com>
Reviewed-by: Neil Horman <nhorman@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/24265)
Diffstat (limited to 'crypto/bn')
| -rw-r--r-- | crypto/bn/bn_rand.c | 45 |
1 files changed, 43 insertions, 2 deletions
diff --git a/crypto/bn/bn_rand.c b/crypto/bn/bn_rand.c index 6be0c5e941..1131987ac7 100644 --- a/crypto/bn/bn_rand.c +++ b/crypto/bn/bn_rand.c @@ -184,8 +184,8 @@ static int bnrand_range(BNRAND_FLAG flag, BIGNUM *r, const BIGNUM *range, } else { do { /* range = 11..._2 or range = 101..._2 */ - if (!bnrand(flag, r, n, BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY, 0, - ctx)) + if (!bnrand(flag, r, n, BN_RAND_TOP_ANY, BN_RAND_BOTTOM_ANY, + strength, ctx)) return 0; if (!--count) { @@ -238,6 +238,47 @@ int BN_pseudo_rand_range(BIGNUM *r, const BIGNUM *range) # endif #endif +int ossl_bn_priv_rand_range_fixed_top(BIGNUM *r, const BIGNUM *range, + unsigned int strength, BN_CTX *ctx) +{ + int n; + int count = 100; + + if (r == NULL) { + ERR_raise(ERR_LIB_BN, ERR_R_PASSED_NULL_PARAMETER); + return 0; + } + + if (range->neg || BN_is_zero(range)) { + ERR_raise(ERR_LIB_BN, 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 { + BN_set_flags(r, BN_FLG_CONSTTIME); + do { + if (!bnrand(PRIVATE, r, n + 1, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ANY, + strength, ctx)) + return 0; + + if (!--count) { + ERR_raise(ERR_LIB_BN, BN_R_TOO_MANY_ITERATIONS); + return 0; + } + ossl_bn_mask_bits_fixed_top(r, n); + } + while (BN_ucmp(r, range) >= 0); + } + + return 1; +} + /* * 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 |