Merge pull request #707 from JacobBarthelmeh/master

fix location in tfm.c that could result in potential cache attack

wolfcrypt/src/tfm.c

@@ -480,12 +480,11 @@ void fp_mul_comba(fp_int *A, fp_int *B, fp_int *C)
       pa = FP_SIZE-1;
    }
 
-   if (A == C || B == C) {
+   /* Always take branch to use tmp variable. This avoids a cache attack for
+    * determining if C equals A */
+   if (1) {
       fp_init(&tmp);
       dst = &tmp;
-   } else {
-      fp_zero(C);
-      dst = C;
    }
 
    for (ix = 0; ix < pa; ix++) {