From 113f799ec7d1728f0a5d7ab5b0e3b42e3de56407 Mon Sep 17 00:00:00 2001
From: djm <>
Date: Thu, 3 Nov 2011 02:32:23 +0000
Subject: import OpenSSL 1.0.0e

---
 src/lib/libcrypto/ecdsa/ecs_ossl.c | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'src/lib/libcrypto/ecdsa/ecs_ossl.c')

diff --git a/src/lib/libcrypto/ecdsa/ecs_ossl.c b/src/lib/libcrypto/ecdsa/ecs_ossl.c
index 551cf5068f..1bbf328de5 100644
--- a/src/lib/libcrypto/ecdsa/ecs_ossl.c
+++ b/src/lib/libcrypto/ecdsa/ecs_ossl.c
@@ -144,6 +144,14 @@ static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
 			}
 		while (BN_is_zero(k));
 
+		/* We do not want timing information to leak the length of k,
+		 * so we compute G*k using an equivalent scalar of fixed
+		 * bit-length. */
+
+		if (!BN_add(k, k, order)) goto err;
+		if (BN_num_bits(k) <= BN_num_bits(order))
+			if (!BN_add(k, k, order)) goto err;
+
 		/* compute r the x-coordinate of generator * k */
 		if (!EC_POINT_mul(group, tmp_point, k, NULL, NULL, ctx))
 		{
-- 
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