From 882c68117122d9a86f0dc61870ec4752fb6fb608 Mon Sep 17 00:00:00 2001
From: Daniel Cousens <github@dcousens.com>
Date: Thu, 30 Nov 2017 14:07:31 +1100
Subject: [PATCH 1/3] check unexpected high bits for invalid characters

---
 lib/bn.js | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/bn.js b/lib/bn.js
index 57c5bb9..944259b 100644
--- a/lib/bn.js
+++ b/lib/bn.js
@@ -186,6 +186,7 @@
   function parseHex (str, start, end) {
     var r = 0;
     var len = Math.min(str.length, end);
+    var z = 0;
     for (var i = start; i < len; i++) {
       var c = str.charCodeAt(i) - 48;
 
@@ -206,9 +207,11 @@
         b = c;
       }
 
-      assert(c >= 0 && b <= 0xf, 'Invalid character');
       r |= b;
+      z |= b;
     }
+
+    assert(!(z & 0xf0), 'Invalid character in ' + str);
     return r;
   }
 

From 8f9f971e21f7f428d1928a918cc8ceb8c7fbcd64 Mon Sep 17 00:00:00 2001
From: Daniel Cousens <github@dcousens.com>
Date: Thu, 30 Nov 2017 14:16:13 +1100
Subject: [PATCH 2/3] add more invalid hex tests

---
 test/constructor-test.js | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/test/constructor-test.js b/test/constructor-test.js
index 9f27203..385634b 100644
--- a/test/constructor-test.js
+++ b/test/constructor-test.js
@@ -108,6 +108,22 @@ describe('BN.js/Constructor', function () {
         res;
       }, /Invalid character/);
     });
+
+    it('should not accept non-hex characters', function () {
+      [
+        '0000000z',
+        '000000gg',
+        '0000gg00',
+        'ffffggff',
+        'ffffggff',
+        'hexadecimal'
+      ].forEach(function (str) {
+        assert.throws(function () {
+          var res = new BN(str, 16);
+          res;
+        }, /Invalid character in /);
+      });
+    })
   });
 
   describe('with Array input', function () {

From 4b7109dc4b69a917fafe4f10a9f8eb48bf693ef2 Mon Sep 17 00:00:00 2001
From: Daniel Cousens <github@dcousens.com>
Date: Thu, 30 Nov 2017 14:34:38 +1100
Subject: [PATCH 3/3] add ./- tests

---
 test/constructor-test.js | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/test/constructor-test.js b/test/constructor-test.js
index 385634b..0356b79 100644
--- a/test/constructor-test.js
+++ b/test/constructor-test.js
@@ -114,8 +114,10 @@ describe('BN.js/Constructor', function () {
         '0000000z',
         '000000gg',
         '0000gg00',
-        'ffffggff',
-        'ffffggff',
+        'fffggfff',
+        '/0000000',
+        '0-000000', // if -, is first, that is OK
+        'ff.fffff',
         'hexadecimal'
       ].forEach(function (str) {
         assert.throws(function () {
@@ -123,7 +125,7 @@ describe('BN.js/Constructor', function () {
           res;
         }, /Invalid character in /);
       });
-    })
+    });
   });
 
   describe('with Array input', function () {