README.md

@@ -1,31 +1,29 @@
 # Bluecrypt ASN.1 Parser
 
-An ASN.1 decoder in less than 100 lines of Vanilla JavaScript,
+An ASN.1 parser in less than 100 lines of Vanilla JavaScript,
 part of the Bluecrypt suite.
 <br>
 <small>(< 150 with newlines and comments)</small>
 
-# Features
+| < 100 lines of code | 1.1k gzipped | 2.5k minified | 4.7k with comments |
 
-| <100 lines of code | 1.1k gzipped | 2.5k minified | 4.7k with comments |
+# Features
 
 * [x] Complete ASN.1 parser
   * [x] Parses x.509 certificates
   * [x] PEM (base64-encoded DER)
 * [x] VanillaJS, Zero Dependencies
-  * [x] Browsers (even old ones)
-  * [x] Online [Demo](https://coolaj86.com/demos/asn1-parser/)
+  * [x] Browsers (back to ES5.1)
   * [ ] Node.js (built, publishing soon)
+  * [ ] Online Demo (built, publishing soon)
 
-### Need an ASN.1 Builder too?
-
-Check out https://git.coolaj86.com/coolaj86/asn1-packer.js/
+![](https://i.imgur.com/gV7w7bM.png)
 
+<!--
 # Demo
 
 <https://coolaj86.com/demos/asn1-parser/>
-
-<img border="1" src="https://i.imgur.com/gV7w7bM.png" />
+-->
 
 # Usage
 
@@ -73,22 +71,14 @@ Note: `value` will be a `Uint8Array`, not a hex string.
 
 ### Optimistic Parsing
 
-This is a dumbed-down, minimal ASN1 parser
-(though quite clever in its simplicity).
+This is a dumbed-down, minimal ASN1 parser.
 
-There are some ASN.1 types (at least Bit String and Octet String,
-possibly others) that can be treated either as primitive values or
-as container types base on the schema being used.
+Rather than incorporating knowledge of each possible x509 schema
+to know whether to traverse deeper into a value container,
+it always tries to dive in (and backs out when parsing fails).
 
-Rather than incorporating knowledge of each possible x509 schema,
-this parser will return values for types that are _always_ values,
-it recurse on types that are _always_ containers and, for ambigiuous
-types, it will first try to recurse and, on error, will fall back to
-returning a value.
-
-In theory, it is possible that it will produce false positives,
-but that would be highly unlikely in real-world scenarios
-(PEM, x509, PKCS#1, SEC1, PKCS#8, SPKI, PKIX, CSR, etc).
+It is possible that it will produce false positives, but not likely
+in real-world scenarios (PEM, x509, CSR, etc).
 
 I'd be interested to hear if you encounter such a case.
 

asn1-parser.js

@@ -1,7 +1,3 @@
-// Copyright 2018 AJ ONeal. All rights reserved
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 ;(function (exports) {
 'use strict';
 
@@ -17,23 +13,16 @@ var PEM = exports.PEM;
 // Parser
 //
 
-// Although I've only seen 9 max in https certificates themselves,
-// but each domain list could have up to 100
-ASN1.ELOOPN = 102;
-ASN1.ELOOP = "uASN1.js Error: iterated over " + ASN1.ELOOPN + "+ elements (probably a malformed file)";
-// I've seen https certificates go 29 deep
-ASN1.EDEEPN = 60;
-ASN1.EDEEP = "uASN1.js Error: element nested " + ASN1.EDEEPN + "+ layers deep (probably a malformed file)";
-// Container Types are Sequence 0x30, Container Array? (0xA0, 0xA1)
-// Value Types are Boolean 0x01, Integer 0x02, Null 0x05, Object ID 0x06, String 0x0C, 0x16, 0x13, 0x1e Value Array? (0x82)
-// Bit String (0x03) and Octet String (0x04) may be values or containers
+ASN1.ELOOP = "uASN1.js Error: iterated over 15+ elements (probably a malformed file)";
+ASN1.EDEEP = "uASN1.js Error: element nested 20+ layers deep (probably a malformed file)";
+// Container Types are Sequence 0x30, Octect String 0x04, Array? (0xA0, 0xA1)
+// Value Types are Integer 0x02, Bit String 0x03, Null 0x05, Object ID 0x06,
 // Sometimes Bit String is used as a container (RSA Pub Spki)
 ASN1.CTYPES = [ 0x30, 0x31, 0xa0, 0xa1 ];
-ASN1.VTYPES = [ 0x01, 0x02, 0x05, 0x06, 0x0c, 0x82 ];
-ASN1.parse = function parseAsn1Helper(buf) {
-  //var ws = '  ';
-  function parseAsn1(buf, depth, eager) {
-    if (depth.length >= ASN1.EDEEPN) { throw new Error(ASN1.EDEEP); }
+ASN1.parse = function parseAsn1(buf, depth, ws) {
+  if (!ws) { ws = ''; }
+  if (!depth) { depth = 0; }
+  if (depth >= 20) { throw new Error(ASN1.EDEEP); }
 
   var index = 2; // we know, at minimum, data starts after type (0) and lengthSize (1)
   var asn1 = { type: buf[0], lengthSize: 0, length: buf[1] };
@@ -61,16 +50,14 @@ ASN1.parse = function parseAsn1Helper(buf) {
   }
   adjustedLen = asn1.length + adjust;
 
-    //console.warn(depth.join(ws) + '0x' + Enc.numToHex(asn1.type), index, 'len:', asn1.length, asn1);
+  //console.warn(ws + '0x' + Enc.numToHex(asn1.type), index, 'len:', asn1.length, asn1);
 
   function parseChildren(eager) {
     asn1.children = [];
     //console.warn('1 len:', (2 + asn1.lengthSize + asn1.length), 'idx:', index, 'clen:', 0);
-      while (iters < ASN1.ELOOPN && index < (2 + asn1.length + asn1.lengthSize)) {
+    while (iters < 15 && index < (2 + asn1.length + asn1.lengthSize)) {
       iters += 1;
-        depth.length += 1;
-        child = parseAsn1(buf.slice(index, index + adjustedLen), depth, eager);
-        depth.length -= 1;
+      child = ASN1.parse(buf.slice(index, index + adjustedLen), (depth || 0) + 1, ws + '  ');
       // The numbers don't match up exactly and I don't remember why...
       // probably something with adjustedLen or some such, but the tests pass
       index += (2 + child.lengthSize + child.length);
@@ -82,41 +69,35 @@ ASN1.parse = function parseAsn1Helper(buf) {
           + " = " + asn1.length + " - " + index + ")");
       }
       asn1.children.push(child);
-        //console.warn(depth.join(ws) + '0x' + Enc.numToHex(asn1.type), index, 'len:', asn1.length, asn1);
+      //console.warn(ws + '0x' + Enc.numToHex(asn1.type), index, 'len:', asn1.length, asn1);
     }
     if (index !== (2 + asn1.lengthSize + asn1.length)) {
       //console.warn('index:', index, 'length:', (2 + asn1.lengthSize + asn1.length));
       throw new Error("premature end-of-file");
     }
-      if (iters >= ASN1.ELOOPN) { throw new Error(ASN1.ELOOP); }
+    if (iters >= 15) { throw new Error(ASN1.ELOOP); }
 
     delete asn1.value;
     return asn1;
   }
 
-    // Recurse into types that are _always_ containers
-    if (-1 !== ASN1.CTYPES.indexOf(asn1.type)) { return parseChildren(eager); }
+  // We want to fail if we know for sure that it's bad
+  if (-1 !== ASN1.CTYPES.indexOf(asn1.type)) {
+    return parseChildren();
+  }
 
-    // Return types that are _always_ values
   asn1.value = buf.slice(index, index + adjustedLen);
-    if (-1 !== ASN1.VTYPES.indexOf(asn1.type)) { return asn1; }
-
-    // For ambigious / unknown types, recurse and return on failure
-    // (and return child array size to zero)
-    try { return parseChildren(true); }
-    catch(e) { asn1.children.length = 0; return asn1; }
-  }
-
-  var asn1 = parseAsn1(buf, []);
-  var len = buf.byteLength || buf.length;
-  if (len !== 2 + asn1.lengthSize + asn1.length) {
-    throw new Error("Length of buffer does not match length of ASN.1 sequence.");
-  }
+  try {
+    return parseChildren(true);
+  } catch(e) {
+    // leaving iterable array as a matter of convenience
+    asn1.children = [];
     return asn1;
+  }
 };
 ASN1._replacer = function (k, v) {
   if ('type' === k) { return '0x' + Enc.numToHex(v); }
-  if (v && 'value' === k) { return '0x' + Enc.bufToHex(v.data || v); }
+  if ('value' === k) { return '0x' + Enc.bufToHex(v.data || v); }
   return v;
 };
 

index.html

@@ -12,55 +12,28 @@
 <body>
   <h1>Bluecrypt ASN.1 Parser</h1>
 
-  <h2>PEM (base64-encoded DER)</h2>
   <textarea class="js-input" placeholder="Paste a PEM here">-----BEGIN PUBLIC KEY-----
 MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEIT1SWLxsacPiE5Z16jkopAn8/+85
 rMjgyCokrnjDft6Y/YnA4A50yZe7CnFsqeDcpnPbubP6cpYiVcnevNIYyg==
 -----END PUBLIC KEY-----</textarea>
 
-  <h2>Hex</h2>
   <pre><code class="js-hex"> </code></pre>
 
-  <h2>ASN.1 Array</h2>
-  <pre><code class="js-array"> </code></pre>
-
-  <h2>ASN.1 Object</h2>
   <pre><code class="js-json"> </code></pre>
 
-  <br>
-  <p>Made with <a href="https://git.coolaj86.com/coolaj86/asn1-parser.js/">asn1-parser.js</a></p>
-
   <script src="./asn1-parser.js"></script>
   <script>
     var $input = document.querySelector('.js-input');
 
-    function toArray(next) {
-      console.log(next);
-      if (next.value) {
-        return [next.type, Enc.bufToHex(next.value)];
-      }
-      return [next.type, next.children.map(function (child) {
-        return toArray(child);
-      })];
-    }
-
     function convert() {
-      console.log('keyup');
-      var json;
-
-      try {
+      console.log('change');
       var pem = PEM.parseBlock(document.querySelector('.js-input').value);
       var hex = Enc.bufToHex(pem.der);
-        var arr = [];
+      console.log(hex);
       document.querySelector('.js-hex').innerText = hex
         .match(/.{2}/g).join(' ').match(/.{1,24}/g).join(' ').match(/.{1,50}/g).join('\n');
-        json = ASN1.parse(pem.der);
-      } catch(e) {
-        json = { error: { message: e.message } };
-      }
-
+      var json = ASN1.parse(pem.der);
       document.querySelector('.js-json').innerText = JSON.stringify(json, ASN1._replacer, 2);
-      document.querySelector('.js-array').innerText = JSON.stringify(toArray(json), null, 2);
     }
 
     $input.addEventListener('keyup', convert);

package.json

@@ -1,12 +1,9 @@
 {
   "name": "asn1-parser",
-  "version": "1.1.8",
+  "version": "1.0.2",
   "description": "An ASN.1 parser in less than 100 lines of Vanilla JavaScript, part of the Bluecrypt suite.",
   "homepage": "https://git.coolaj86.com/coolaj86/asn1-parser.js",
   "main": "asn1-parser.js",
-  "scripts": {
-    "prepare": "uglifyjs asn1-parser.js > asn1-parser.min.js"
-  },
   "directories": {
     "lib": "lib"
   },