File openssl-CVE-2018-0735.patch of Package openssl-1_1.16402
commit 56fb454d281a023b3f950d969693553d3f3ceea1
Author: Pauli <paul.dale@oracle.com>
Date: Fri Oct 26 10:54:58 2018 +1000
Timing vulnerability in ECDSA signature generation (CVE-2018-0735)
Preallocate an extra limb for some of the big numbers to avoid a reallocation
that can potentially provide a side channel.
Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
(Merged from https://github.com/openssl/openssl/pull/7486)
(cherry picked from commit 99540ec79491f59ed8b46b4edf130e17dc907f52)
Index: openssl-1.1.0i/crypto/ec/ec_mult.c
===================================================================
--- openssl-1.1.0i.orig/crypto/ec/ec_mult.c 2018-08-14 14:45:07.000000000 +0200
+++ openssl-1.1.0i/crypto/ec/ec_mult.c 2018-11-05 12:23:45.837619464 +0100
@@ -177,8 +177,8 @@ static int ec_mul_consttime(const EC_GRO
*/
cardinality_bits = BN_num_bits(cardinality);
group_top = bn_get_top(cardinality);
- if ((bn_wexpand(k, group_top + 1) == NULL)
- || (bn_wexpand(lambda, group_top + 1) == NULL))
+ if ((bn_wexpand(k, group_top + 2) == NULL)
+ || (bn_wexpand(lambda, group_top + 2) == NULL))
goto err;
if (!BN_copy(k, scalar))
@@ -205,7 +205,7 @@ static int ec_mul_consttime(const EC_GRO
* k := scalar + 2*cardinality
*/
kbit = BN_is_bit_set(lambda, cardinality_bits);
- BN_consttime_swap(kbit, k, lambda, group_top + 1);
+ BN_consttime_swap(kbit, k, lambda, group_top + 2);
group_top = bn_get_top(group->field);
if ((bn_wexpand(s->X, group_top) == NULL)