From f7a4c40c50f544191339b358e7418e72b0134fe4 Mon Sep 17 00:00:00 2001
From: Thomas Arts <thomas.arts@robuster.software>
Date: Wed, 29 May 2019 08:21:25 +0200
Subject: [PATCH] Only decode correctly encoded negative binaries

---
 src/aeb_fate_encoding.erl | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/aeb_fate_encoding.erl b/src/aeb_fate_encoding.erl
index 1a73809..22603b2 100644
--- a/src/aeb_fate_encoding.erl
+++ b/src/aeb_fate_encoding.erl
@@ -318,7 +318,12 @@ deserialize2(<<?POS_BIG_INT, Rest/binary>>) ->
      Rest2};
 deserialize2(<<?NEG_BITS, Rest/binary>>) ->
     {Bint, Rest2} = aeser_rlp:decode_one(Rest),
-    {?FATE_BITS(-binary:decode_unsigned(Bint)), Rest2};
+    case binary:decode_unsigned(Bint) of
+        Pos when Pos > 0 ->
+            {?FATE_BITS(-Pos), Rest2};
+        N ->
+            error({illegal_parameter, neg_bits, N})
+    end;
 deserialize2(<<?POS_BITS, Rest/binary>>) ->
     {Bint, Rest2} = aeser_rlp:decode_one(Rest),
     {?FATE_BITS(binary:decode_unsigned(Bint)), Rest2};