1 files changed, 4 insertions, 21 deletions
diff --git a/src/crypto/bn/add.c b/src/crypto/bn/add.c
index a043d83..23f9f80 100644
--- a/src/crypto/bn/add.c
+++ b/src/crypto/bn/add.c
@@ -56,6 +56,8 @@
 
 #include <openssl/bn.h>
 
+#include <string.h>
+
 #include <openssl/err.h>
 #include <openssl/mem.h>
 
@@ -311,27 +313,8 @@ int BN_usub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b) {
     }
   }
 
-  if (rp != ap) {
-    for (;;) {
-      if (!dif--) {
-        break;
-      }
-      rp[0] = ap[0];
-      if (!dif--) {
-        break;
-      }
-      rp[1] = ap[1];
-      if (!dif--) {
-        break;
-      }
-      rp[2] = ap[2];
-      if (!dif--) {
-        break;
-      }
-      rp[3] = ap[3];
-      rp += 4;
-      ap += 4;
-    }
+  if (dif > 0 && rp != ap) {
+    memcpy(rp, ap, sizeof(*rp) * dif);
   }
 
   r->top = max;