diff options
Diffstat (limited to 'crypto/bn/bn_exp.c')
| -rw-r--r-- | crypto/bn/bn_exp.c | 64 |
1 files changed, 33 insertions, 31 deletions
diff --git a/crypto/bn/bn_exp.c b/crypto/bn/bn_exp.c index 83b0e5afee..9ea120be18 100644 --- a/crypto/bn/bn_exp.c +++ b/crypto/bn/bn_exp.c @@ -648,34 +648,41 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, goto err; } + if (a->neg || BN_ucmp(a, m) >= 0) { + BIGNUM *reduced = BN_CTX_get(ctx); + if (reduced == NULL + || !BN_nnmod(reduced, a, m, ctx)) { + goto err; + } + a = reduced; + } + #ifdef RSAZ_ENABLED - if (!a->neg) { - /* - * If the size of the operands allow it, perform the optimized - * RSAZ exponentiation. For further information see - * crypto/bn/rsaz_exp.c and accompanying assembly modules. - */ - if ((16 == a->top) && (16 == p->top) && (BN_num_bits(m) == 1024) - && rsaz_avx2_eligible()) { - if (NULL == bn_wexpand(rr, 16)) - goto err; - RSAZ_1024_mod_exp_avx2(rr->d, a->d, p->d, m->d, mont->RR.d, - mont->n0[0]); - rr->top = 16; - rr->neg = 0; - bn_correct_top(rr); - ret = 1; + /* + * If the size of the operands allow it, perform the optimized + * RSAZ exponentiation. For further information see + * crypto/bn/rsaz_exp.c and accompanying assembly modules. + */ + if ((16 == a->top) && (16 == p->top) && (BN_num_bits(m) == 1024) + && rsaz_avx2_eligible()) { + if (NULL == bn_wexpand(rr, 16)) goto err; - } else if ((8 == a->top) && (8 == p->top) && (BN_num_bits(m) == 512)) { - if (NULL == bn_wexpand(rr, 8)) - goto err; - RSAZ_512_mod_exp(rr->d, a->d, p->d, m->d, mont->n0[0], mont->RR.d); - rr->top = 8; - rr->neg = 0; - bn_correct_top(rr); - ret = 1; + RSAZ_1024_mod_exp_avx2(rr->d, a->d, p->d, m->d, mont->RR.d, + mont->n0[0]); + rr->top = 16; + rr->neg = 0; + bn_correct_top(rr); + ret = 1; + goto err; + } else if ((8 == a->top) && (8 == p->top) && (BN_num_bits(m) == 512)) { + if (NULL == bn_wexpand(rr, 8)) goto err; - } + RSAZ_512_mod_exp(rr->d, a->d, p->d, m->d, mont->n0[0], mont->RR.d); + rr->top = 8; + rr->neg = 0; + bn_correct_top(rr); + ret = 1; + goto err; } #endif @@ -747,12 +754,7 @@ int BN_mod_exp_mont_consttime(BIGNUM *rr, const BIGNUM *a, const BIGNUM *p, goto err; /* prepare a^1 in Montgomery domain */ - if (a->neg || BN_ucmp(a, m) >= 0) { - if (!BN_nnmod(&am, a, m, ctx)) - goto err; - if (!bn_to_mont_fixed_top(&am, &am, mont, ctx)) - goto err; - } else if (!bn_to_mont_fixed_top(&am, a, mont, ctx)) + if (!bn_to_mont_fixed_top(&am, a, mont, ctx)) goto err; #if defined(SPARC_T4_MONT) |