| CVE: CVE-2018-0735 |
| |
| Upstream-Status: Backport |
| |
| Signed-off-by: Kai Kang <kai.kang@windriver.com> |
| |
| From b1d6d55ece1c26fa2829e2b819b038d7b6d692b4 Mon Sep 17 00:00:00 2001 |
| From: Pauli <paul.dale@oracle.com> |
| Date: Fri, 26 Oct 2018 10:54:58 +1000 |
| Subject: [PATCH] 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) |
| --- |
| crypto/ec/ec_mult.c | 6 +++--- |
| 1 file changed, 3 insertions(+), 3 deletions(-) |
| |
| diff --git a/crypto/ec/ec_mult.c b/crypto/ec/ec_mult.c |
| index 7e1b3650e7..0e0a5e1394 100644 |
| --- a/crypto/ec/ec_mult.c |
| +++ b/crypto/ec/ec_mult.c |
| @@ -206,8 +206,8 @@ int ec_scalar_mul_ladder(const EC_GROUP *group, EC_POINT *r, |
| */ |
| 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)) { |
| ECerr(EC_F_EC_SCALAR_MUL_LADDER, ERR_R_BN_LIB); |
| goto err; |
| } |
| @@ -244,7 +244,7 @@ int ec_scalar_mul_ladder(const EC_GROUP *group, EC_POINT *r, |
| * 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) |
| -- |
| 2.17.0 |
| |