[openssl] OpenSSL_1_1_1-stable update

[Matt Caswell]

The branch OpenSSL_1_1_1-stable has been updated
       via  51e236df41871871dabd2f5f7156e27a0eef3b3b (commit)
      from  4bdab2571782393e4ba3acb8578c415ce1575a75 (commit)


- Log -----------------------------------------------------------------
commit 51e236df41871871dabd2f5f7156e27a0eef3b3b
Author: Cesar Pereida Garcia <cesar.pereidagarcia at tut.fi>
Date:   Wed Aug 14 10:17:06 2019 +0300

    Fix SCA vulnerability when using PVK and MSBLOB key formats
    
    This commit addresses a side-channel vulnerability present when
    PVK and MSBLOB key formats are loaded into OpenSSL.
    The public key was not computed using a constant-time exponentiation
    function.
    
    This issue was discovered and reported by the NISEC group at TAU Finland.
    
    Reviewed-by: Nicola Tuveri <nic.tuv at gmail.com>
    Reviewed-by: Bernd Edlinger <bernd.edlinger at hotmail.de>
    Reviewed-by: Paul Dale <paul.dale at oracle.com>
    Reviewed-by: Matt Caswell <matt at openssl.org>
    (Merged from https://github.com/openssl/openssl/pull/9587)
    
    (cherry picked from commit 724339ff44235149c4e8ddae614e1dda6863e23e)

-----------------------------------------------------------------------

Summary of changes:
 crypto/pem/pvkfmt.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/crypto/pem/pvkfmt.c b/crypto/pem/pvkfmt.c
index e39c243814..609e3ad9ca 100644
--- a/crypto/pem/pvkfmt.c
+++ b/crypto/pem/pvkfmt.c
@@ -274,6 +274,9 @@ static EVP_PKEY *b2i_dss(const unsigned char **in,
         if (!read_lebn(&p, 20, &priv_key))
             goto memerr;
 
+        /* Set constant time flag before public key calculation */
+        BN_set_flags(priv_key, BN_FLG_CONSTTIME);
+
         /* Calculate public key */
         pub_key = BN_new();
         if (pub_key == NULL)