diff options
| author | Andy Polyakov <appro@openssl.org> | 2018-08-10 19:31:22 +0200 |
|---|---|---|
| committer | Andy Polyakov <appro@openssl.org> | 2018-08-23 22:20:35 +0200 |
| commit | fcc4ee09473cac511eca90faa003661c7786e4f9 (patch) | |
| tree | b632f6792647ed32472a8d898437553df80a5ba3 /crypto/bn/bn_mont.c | |
| parent | 0b89db6b2acb6cca36f812ba51119927563b3cac (diff) | |
crypto/bn: add more fixed-top routines.
Add bn_{mul|sqr}_fixed_top, bn_from_mont_fixed_top, bn_mod_sub_fixed_top.
Switch to bn_{mul|sqr}_fixed_top in bn_mul_mont_fixed_top and remove
memset in bn_from_montgomery_word.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/6915)
Diffstat (limited to 'crypto/bn/bn_mont.c')
| -rw-r--r-- | crypto/bn/bn_mont.c | 26 |
1 files changed, 19 insertions, 7 deletions
diff --git a/crypto/bn/bn_mont.c b/crypto/bn/bn_mont.c index 683e8e946b..393d27c392 100644 --- a/crypto/bn/bn_mont.c +++ b/crypto/bn/bn_mont.c @@ -64,10 +64,10 @@ int bn_mul_mont_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, bn_check_top(tmp); if (a == b) { - if (!BN_sqr(tmp, a, ctx)) + if (!bn_sqr_fixed_top(tmp, a, ctx)) goto err; } else { - if (!BN_mul(tmp, a, b, ctx)) + if (!bn_mul_fixed_top(tmp, a, b, ctx)) goto err; } /* reduce from aRR to aR */ @@ -90,6 +90,7 @@ static int bn_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont) BIGNUM *n; BN_ULONG *ap, *np, *rp, n0, v, carry; int nl, max, i; + unsigned int rtop; n = &(mont->N); nl = n->top; @@ -107,9 +108,10 @@ static int bn_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont) rp = r->d; /* clear the top words of T */ - i = max - r->top; - if (i) - memset(&rp[r->top], 0, sizeof(*rp) * i); + for (rtop = r->top, i = 0; i < max; i++) { + v = (BN_ULONG)0 - ((i - rtop) >> (8 * sizeof(rtop) - 1)); + rp[i] &= v; + } r->top = max; r->flags |= BN_FLG_FIXED_TOP; @@ -160,6 +162,18 @@ static int bn_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont) int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont, BN_CTX *ctx) { + int retn; + + retn = bn_from_mont_fixed_top(ret, a, mont, ctx); + bn_correct_top(ret); + bn_check_top(ret); + + return retn; +} + +int bn_from_mont_fixed_top(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont, + BN_CTX *ctx) +{ int retn = 0; #ifdef MONT_WORD BIGNUM *t; @@ -167,8 +181,6 @@ int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont, BN_CTX_start(ctx); if ((t = BN_CTX_get(ctx)) && BN_copy(t, a)) { retn = bn_from_montgomery_word(ret, t, mont); - bn_correct_top(ret); - bn_check_top(ret); } BN_CTX_end(ctx); #else /* !MONT_WORD */ |