From f1b9bbf593051c6b1d7220758d9f1953f1ce9600 Mon Sep 17 00:00:00 2001
From: Karel Miko <karel.miko@gmail.com>
Date: Sat, 30 Jun 2018 15:48:40 +0200
Subject: [PATCH] bn_fast_mp_invmod fix related to #118

---
 bn_fast_mp_invmod.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/bn_fast_mp_invmod.c b/bn_fast_mp_invmod.c
index 91b5bf6..be1a810 100644
--- a/bn_fast_mp_invmod.c
+++ b/bn_fast_mp_invmod.c
@@ -138,6 +138,14 @@ top:
          goto LBL_ERR;
       }
    }
+
+   /* too big */
+   while (mp_cmp_mag(&D, b) != MP_LT) {
+      if ((res = mp_sub(&D, b, &D)) != MP_OKAY) {
+         goto LBL_ERR;
+      }
+   }
+
    mp_exch(&D, c);
    c->sign = neg;
    res = MP_OKAY;