From 584d8498f867d310a9a5b8374901c18c6ef7498c Mon Sep 17 00:00:00 2001
From: Sean Parkinson <sean@wolfssl.com>
Date: Thu, 16 Jan 2020 09:35:34 +1000
Subject: [PATCH] Fix for ecc and no cache resistance - set M[2]

Need to have a value in order to maintain timing resistance.
Small maths fails also.
---
 wolfcrypt/src/ecc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/wolfcrypt/src/ecc.c b/wolfcrypt/src/ecc.c
index 5f2672322..942d67b33 100644
--- a/wolfcrypt/src/ecc.c
+++ b/wolfcrypt/src/ecc.c
@@ -2769,6 +2769,10 @@ int wc_ecc_mulmod_ex(mp_int* k, ecc_point *G, ecc_point *R,
    /* M[1] == 2G */
    if (err == MP_OKAY)
        err = ecc_projective_dbl_point(tG, M[1], a, modulus, mp);
+#ifdef WC_NO_CACHE_RESISTANT
+   if (err == MP_OKAY)
+       err = wc_ecc_copy_point(M[0], M[2]);
+#endif
 
    /* setup sliding window */
    mode   = 0;