From c62a93bbda1e2807a59b743757391f567df2c09a Mon Sep 17 00:00:00 2001
From: Simon Warta <simon@kullo.net>
Date: Thu, 29 Nov 2018 15:18:57 +0100
Subject: [PATCH 1/3] Improve error messages for imuln argument range

---
 lib/bn.js               | 2 +-
 test/arithmetic-test.js | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/bn.js b/lib/bn.js
index 0854c1c..b775150 100644
--- a/lib/bn.js
+++ b/lib/bn.js
@@ -1919,7 +1919,7 @@
     if (isNegNum) num = -num;
 
     assert(typeof num === 'number');
-    assert(num < 0x4000000);
+    assert(num < 0x4000000, 'Argument not in supported range -0x4000000 < num < 0x4000000');
 
     // Carry
     var carry = 0;
diff --git a/test/arithmetic-test.js b/test/arithmetic-test.js
index 67956ff..df2545a 100644
--- a/test/arithmetic-test.js
+++ b/test/arithmetic-test.js
@@ -288,7 +288,7 @@ describe('BN.js/Arithmetic', function () {
     it('should throw error with num eq 0x4000000', function () {
       assert.throws(function () {
         new BN(0).imuln(0x4000000);
-      }, /^Error: Assertion failed$/);
+      }, /^Error: Argument not in supported range -0x4000000 < num < 0x4000000$/);
     });
 
     it('should negate number if number is negative', function () {

From 1d299e55d909b8f1213e0f59619dce7575ce8fb7 Mon Sep 17 00:00:00 2001
From: Simon Warta <simon@kullo.net>
Date: Thu, 29 Nov 2018 15:24:17 +0100
Subject: [PATCH 2/3] Improve error message and add test for imuln argument
 type

---
 lib/bn.js               |  2 +-
 test/arithmetic-test.js | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/lib/bn.js b/lib/bn.js
index b775150..7fe0dd0 100644
--- a/lib/bn.js
+++ b/lib/bn.js
@@ -1918,7 +1918,7 @@
     var isNegNum = num < 0;
     if (isNegNum) num = -num;
 
-    assert(typeof num === 'number');
+    assert(typeof num === 'number', 'Argument num must be a number');
     assert(num < 0x4000000, 'Argument not in supported range -0x4000000 < num < 0x4000000');
 
     // Carry
diff --git a/test/arithmetic-test.js b/test/arithmetic-test.js
index df2545a..1603a36 100644
--- a/test/arithmetic-test.js
+++ b/test/arithmetic-test.js
@@ -285,6 +285,16 @@ describe('BN.js/Arithmetic', function () {
       assert.equal(a.muln(0xdead).toString(16), c.toString(16));
     });
 
+    it('should throw error with num of type other than number', function () {
+      assert.throws(function () {
+        new BN(0).imuln('1');
+      }, /^Error: Argument num must be a number$/);
+
+      assert.throws(function () {
+        new BN(0).imuln(new BN(1));
+      }, /^Error: Argument num must be a number$/);
+    });
+
     it('should throw error with num eq 0x4000000', function () {
       assert.throws(function () {
         new BN(0).imuln(0x4000000);

From c8766d653129e4f5679a4375f36ac4bd7a092b07 Mon Sep 17 00:00:00 2001
From: Simon Warta <simon@kullo.net>
Date: Thu, 29 Nov 2018 15:38:14 +0100
Subject: [PATCH 3/3] Ensure argument of imuln is an integer

---
 lib/bn.js               |  9 +++++++++
 test/arithmetic-test.js | 22 ++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/lib/bn.js b/lib/bn.js
index 7fe0dd0..67c7b42 100644
--- a/lib/bn.js
+++ b/lib/bn.js
@@ -6,6 +6,14 @@
     if (!val) throw new Error(msg || 'Assertion failed');
   }
 
+  // compatibility replacement for Number.isInteger
+  // https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Global_Objects/Number/isInteger#Polyfill
+  function isInteger (value) {
+    return typeof value === 'number' &&
+      isFinite(value) &&
+      Math.floor(value) === value;
+  }
+
   // Could use `inherits` module, but don't want to move from single file
   // architecture yet.
   function inherits (ctor, superCtor) {
@@ -1919,6 +1927,7 @@
     if (isNegNum) num = -num;
 
     assert(typeof num === 'number', 'Argument num must be a number');
+    assert(isInteger(num), 'Argument must be an integer');
     assert(num < 0x4000000, 'Argument not in supported range -0x4000000 < num < 0x4000000');
 
     // Carry
diff --git a/test/arithmetic-test.js b/test/arithmetic-test.js
index 1603a36..b45f3ec 100644
--- a/test/arithmetic-test.js
+++ b/test/arithmetic-test.js
@@ -295,6 +295,28 @@ describe('BN.js/Arithmetic', function () {
       }, /^Error: Argument num must be a number$/);
     });
 
+    it('should throw error with num eq 1.5, -1.5 and NaN', function () {
+      assert.throws(function () {
+        new BN(0).imuln(1.5);
+      }, /^Error: Argument must be an integer$/);
+
+      assert.throws(function () {
+        new BN(0).imuln(-1.5);
+      }, /^Error: Argument must be an integer$/);
+
+      assert.throws(function () {
+        new BN(0).imuln(Infinity);
+      }, /^Error: Argument must be an integer$/);
+
+      assert.throws(function () {
+        new BN(0).imuln(-Infinity);
+      }, /^Error: Argument must be an integer$/);
+
+      assert.throws(function () {
+        new BN(0).imuln(NaN);
+      }, /^Error: Argument must be an integer$/);
+    });
+
     it('should throw error with num eq 0x4000000', function () {
       assert.throws(function () {
         new BN(0).imuln(0x4000000);