auth/rsa: side-step potential side-channel

Remove branching that depends on secret data.

Signed-off-by: Alexander Sosedkin <asosedkin@redhat.com>
Signed-off-by: Hubert Kario <hkario@redhat.com>
Tested-by: Hubert Kario <hkario@redhat.com>

diff --git a/lib/auth/rsa.c b/lib/auth/rsa.c
index 8108ee841d05bcef9f9e77828306ce6ca3d45533..6b158bacb246722f29a6910f081c38fad2e18bde 100644 (file)
--- a/lib/auth/rsa.c
+++ b/lib/auth/rsa.c
@@ -155,7 +155,6 @@ static int
 proc_rsa_client_kx(gnutls_session_t session, uint8_t * data,
                   size_t _data_size)
 {
-       const char attack_error[] = "auth_rsa: Possible PKCS #1 attack\n";
        gnutls_datum_t ciphertext;
        int ret, dsize;
        ssize_t data_size = _data_size;
@@ -235,15 +234,6 @@ proc_rsa_client_kx(gnutls_session_t session, uint8_t * data,
        ok &= CONSTCHECK_NOT_EQUAL(check_ver_min, 0) &
                CONSTCHECK_EQUAL(session->key.key.data[1], ver_min);
 
-       if (ok) {
-               /* call logging function unconditionally so all branches are
-                * indistinguishable for timing and cache access when debug
-                * logging is disabled */
-               _gnutls_no_log("%s", attack_error);
-       } else {
-               _gnutls_debug_log("%s", attack_error);
-       }
-
        /* This is here to avoid the version check attack
         * discussed above.
         */