[Pkg-javascript-commits] [node-asn1.js] 71/202: der: fix nonegative integers with 80 bit set

[Bastien Roucariès]

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rouca pushed a commit to branch master
in repository node-asn1.js.

commit 0bccdb465c9846c07e7e167292927d0f0226bdd5
Author: Ilya Petrov <ilya.muromec at gmail.com>
Date:   Sat Nov 15 14:44:15 2014 +0700

    der: fix nonegative integers with 80 bit set
    
    Nonegative integers can have highest bit (0x80) which
    makes them interpreted as negative numbers.
    
    When encoding such integers, prepend 00 byte before first byte
    to force positive number detection.
---
 lib/asn1/encoders/der.js | 21 ++++++++++++++++-----
 test/der-encode-test.js  | 13 +++++++++++++
 2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/lib/asn1/encoders/der.js b/lib/asn1/encoders/der.js
index f56cdfa..f22a35e 100644
--- a/lib/asn1/encoders/der.js
+++ b/lib/asn1/encoders/der.js
@@ -169,8 +169,13 @@ DERNode.prototype._encodeInt = function encodeInt(num, values) {
   }
 
   // Bignum, assume big endian
-  if (bignum !== null && num instanceof bignum)
-    num = new Buffer(num.toArray());
+  if (bignum !== null && num instanceof bignum) {
+    var numArray = num.toArray();
+    if(num.sign === false && numArray[0] & 0x80) {
+      numArray.unshift(0);
+    }
+    num = new Buffer(numArray);
+  }
 
   if (Buffer.isBuffer(num)) {
     var size = num.length;
@@ -184,20 +189,26 @@ DERNode.prototype._encodeInt = function encodeInt(num, values) {
     return this._createEncoderBuffer(out);
   }
 
-  if (num < 0x100)
+  if (num < 0x80)
     return this._createEncoderBuffer(num);
 
+  if (num < 0x100)
+    return this._createEncoderBuffer([0, num]);
+
   var size = 1;
   for (var i = num; i >= 0x100; i >>= 8)
     size++;
 
-  var out = new Buffer(size);
+  var out = new Array(size);
   for (var i = out.length - 1; i >= 0; i--) {
     out[i] = num & 0xff;
     num >>= 8;
   }
+  if(out[0] & 0x80) {
+    out.unshift(0);
+  }
 
-  return this._createEncoderBuffer(out);
+  return this._createEncoderBuffer(new Buffer(out));
 };
 
 DERNode.prototype._encodeBool = function encodeBool(value) {
diff --git a/test/der-encode-test.js b/test/der-encode-test.js
index 8652707..a490f23 100644
--- a/test/der-encode-test.js
+++ b/test/der-encode-test.js
@@ -1,5 +1,6 @@
 var assert = require('assert');
 var asn1 = require('..');
+var BN = require('bn.js');
 
 var Buffer = require('buffer').Buffer;
 
@@ -49,4 +50,16 @@ describe('asn1.js DER encoder', function() {
     this.explicit(0).seqof(Int);
   }, [ 1 ], 'A0053003020101' );
 
+  test('should encode BN(128) properly', function() {
+    this.int();
+  }, new BN(128), '02020080');
+
+  test('should encode int 128 properly', function() {
+    this.int();
+  }, 128, '02020080');
+
+  test('should encode 0x8011 properly', function() {
+    this.int();
+  }, 0x8011, '0203008011');
+
 });

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