From 38867ae2bf5b1fcdfb17bdcc7f2337e61935d6a6 Mon Sep 17 00:00:00 2001
From: John Safranek <john@wolfssl.com>
Date: Thu, 12 Nov 2020 10:15:55 -0800
Subject: [PATCH] Scan-Build Fixes 1. Added a check to see if the "d" in
 sp_div() ended up with a negative used length. Return error if so.

To recreate:
    $ scan-build ./configure --enable-sp --enable-sp-asm --enable-sp-math
---
 wolfcrypt/src/sp_int.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/wolfcrypt/src/sp_int.c b/wolfcrypt/src/sp_int.c
index 9f9012cb0..ab1bd6dcc 100644
--- a/wolfcrypt/src/sp_int.c
+++ b/wolfcrypt/src/sp_int.c
@@ -927,6 +927,9 @@ static int sp_div(sp_int* a, sp_int* d, sp_int* r, sp_int* rem)
             d = sd;
         }
 
+        if (d->used < 0)
+            err = MP_VAL;
+
         tr->used = sa->used - d->used + 1;
         sp_clear(tr);
         tr->used = sa->used - d->used + 1;