From a8a9745257a5071b03d06b82d4b05cabb38d9718 Mon Sep 17 00:00:00 2001 From: Andy Polyakov Date: Sun, 22 Jul 2018 16:28:20 +0200 Subject: [PATCH] ec/ecp_nistz256.c: fix ecp_nistz256_set_from_affine. ecp_nistz256_set_from_affine is called when application attempts to use custom generator, i.e. rarely. Even though it was wrong, it didn't affect point operations, they were just not as fast as expected. Reviewed-by: Paul Dale Reviewed-by: Rich Salz (Merged from https://github.com/openssl/openssl/pull/6761) --- crypto/ec/ecp_nistz256.c | 23 ++++++++++++++++------- 1 file changed, 16 insertions(+), 7 deletions(-) diff --git a/crypto/ec/ecp_nistz256.c b/crypto/ec/ecp_nistz256.c index 9a53a39a25..0579cac3a9 100644 --- a/crypto/ec/ecp_nistz256.c +++ b/crypto/ec/ecp_nistz256.c @@ -1118,23 +1118,32 @@ static int ecp_nistz256_set_from_affine(EC_POINT *out, const EC_GROUP *group, const P256_POINT_AFFINE *in, BN_CTX *ctx) { - BIGNUM x, y; - BN_ULONG d_x[P256_LIMBS], d_y[P256_LIMBS]; + BIGNUM x, y, z; int ret = 0; - memcpy(d_x, in->X, sizeof(d_x)); - x.d = d_x; + /* + * |const| qualifier omission is compensated by BN_FLG_STATIC_DATA + * flag, which effectively means "read-only data". + */ + x.d = (BN_ULONG *)in->X; x.dmax = x.top = P256_LIMBS; x.neg = 0; x.flags = BN_FLG_STATIC_DATA; - memcpy(d_y, in->Y, sizeof(d_y)); - y.d = d_y; + y.d = (BN_ULONG *)in->Y; y.dmax = y.top = P256_LIMBS; y.neg = 0; y.flags = BN_FLG_STATIC_DATA; - ret = EC_POINT_set_affine_coordinates_GFp(group, out, &x, &y, ctx); + z.d = (BN_ULONG *)ONE; + z.dmax = z.top = P256_LIMBS; + z.neg = 0; + z.flags = BN_FLG_STATIC_DATA; + + if ((ret = (BN_copy(&out->X, &x) != NULL)) + && (ret = (BN_copy(&out->Y, &y) != NULL)) + && (ret = (BN_copy(&out->Z, &z) != NULL))) + out->Z_is_one = 1; return ret; } -- 2.25.1