v1.1.8: bugfix increase incorrect loop limit for eager parsing

README.md

@@ -1,29 +1,31 @@
-# BlueCrypt ASN.1 Parser
+# Bluecrypt ASN.1 Parser
 
-An ASN.1 parser in less than 100 lines of Vanilla JavaScript,
-part of the BlueCrypt suite.
+An ASN.1 decoder in less than 100 lines of Vanilla JavaScript,
+part of the Bluecrypt suite.
 <br>
 <small>(< 150 with newlines and comments)</small>
 
-| < 100 lines of code | 1.1k gzipped | 2.5k minified | 4.7k with comments |
-
 # Features
 
+| <100 lines of code | 1.1k gzipped | 2.5k minified | 4.7k with comments |
+
 * [x] Complete ASN.1 parser
   * [x] Parses x.509 certificates
   * [x] PEM (base64-encoded DER)
 * [x] VanillaJS, Zero Dependencies
-  * [x] Browsers (back to ES5.1)
+  * [x] Browsers (even old ones)
+  * [x] Online [Demo](https://coolaj86.com/demos/asn1-parser/)
   * [ ] Node.js (built, publishing soon)
-  * [ ] Online Demo (built, publishing soon)
 
-![](https://i.imgur.com/gV7w7bM.png)
+### Need an ASN.1 Builder too?
+
+Check out https://git.coolaj86.com/coolaj86/asn1-packer.js/
 
-<!--
 # Demo
 
 <https://coolaj86.com/demos/asn1-parser/>
--->
+
+<img border="1" src="https://i.imgur.com/gV7w7bM.png" />
 
 # Usage
 
@@ -32,7 +34,7 @@ part of the BlueCrypt suite.
 ```
 
 ```js
-'use strict";
+'use strict';
 
 var ASN1 = window.ASN1  // 62 lines
 var Enc = window.Enc    // 27 lines
@@ -51,13 +53,13 @@ var json = ASN1.parse(der);
 console.log(json);
 ```
 
-```json
+```js
 { "type": 48 /*0x30*/, "lengthSize": 0, "length": 89
 , "children": [
     { "type": 48 /*0x30*/, "lengthSize": 0, "length": 19
 		, "children": [
-        { "type": 6, "lengthSize": 0, "length": 7, "value": <0x2a8648ce3d0201> },
-        { "type": 6, "lengthSize": 0, "length": 8, "value": <0x2a8648ce3d030107> }
+        { "type": 6, "lengthSize": 0, "length": 7, "value": "<0x2a8648ce3d0201>" },
+        { "type": 6, "lengthSize": 0, "length": 8, "value": "<0x2a8648ce3d030107>" }
       ]
     },
     { "type": 3, "lengthSize": 0, "length": 66,
@@ -71,14 +73,22 @@ Note: `value` will be a `Uint8Array`, not a hex string.
 
 ### Optimistic Parsing
 
-This is a dumbed-down, minimal ASN1 parser.
+This is a dumbed-down, minimal ASN1 parser
+(though quite clever in its simplicity).
 
-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).
+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.
 
-It is possible that it will produce false positives, but not likely
-in real-world scenarios (PEM, x509, CSR, etc).
+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).
 
 I'd be interested to hear if you encounter such a case.
 
@@ -92,5 +102,5 @@ to produce a small, focused file that does exactly what it needs to do.
 
 # Legal
 
-[BlueCrypt VanillaJS ASN.1 Parser](https://git.coolaj86.com/coolaj86/asn1-parser.js) |
+[Bluecrypt VanillaJS ASN.1 Parser](https://git.coolaj86.com/coolaj86/asn1-parser.js) |
 MPL-2.0

asn1-parser.js

@@ -1,3 +1,7 @@
+// 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';
 
@@ -13,91 +17,106 @@ var PEM = exports.PEM;
 // Parser
 //
 
-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,
+// 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
 // Sometimes Bit String is used as a container (RSA Pub Spki)
 ASN1.CTYPES = [ 0x30, 0x31, 0xa0, 0xa1 ];
-ASN1.parse = function parseAsn1(buf, depth, ws) {
-  if (!ws) { ws = ''; }
-  if (!depth) { depth = 0; }
-  if (depth >= 20) { throw new Error(ASN1.EDEEP); }
+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); }
 
-  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] };
-  var child;
-  var iters = 0;
-  var adjust = 0;
-  var adjustedLen;
+    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] };
+    var child;
+    var iters = 0;
+    var adjust = 0;
+    var adjustedLen;
 
-  // Determine how many bytes the length uses, and what it is
-  if (0x80 & asn1.length) {
-    asn1.lengthSize = 0x7f & asn1.length;
-    // I think that buf->hex->int solves the problem of Endianness... not sure
-    asn1.length = parseInt(Enc.bufToHex(buf.slice(index, index + asn1.lengthSize)), 16);
-    index += asn1.lengthSize;
-  }
-
-  // High-order bit Integers have a leading 0x00 to signify that they are positive.
-  // Bit Streams use the first byte to signify padding, which x.509 doesn't use.
-  if (0x00 === buf[index] && (0x02 === asn1.type || 0x03 === asn1.type)) {
-    // However, 0x00 on its own is a valid number
-    if (asn1.length > 1) {
-      index += 1;
-      adjust = -1;
+    // Determine how many bytes the length uses, and what it is
+    if (0x80 & asn1.length) {
+      asn1.lengthSize = 0x7f & asn1.length;
+      // I think that buf->hex->int solves the problem of Endianness... not sure
+      asn1.length = parseInt(Enc.bufToHex(buf.slice(index, index + asn1.lengthSize)), 16);
+      index += asn1.lengthSize;
     }
-  }
-  adjustedLen = asn1.length + adjust;
 
-  //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 < 15 && index < (2 + asn1.length + asn1.lengthSize)) {
-      iters += 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);
-      //console.warn('2 len:', (2 + asn1.lengthSize + asn1.length), 'idx:', index, 'clen:', (2 + child.lengthSize + child.length));
-      if (index > (2 + asn1.lengthSize + asn1.length)) {
-        if (!eager) { console.error(JSON.stringify(asn1, ASN1._replacer, 2)); }
-        throw new Error("Parse error: child value length (" + child.length
-          + ") is greater than remaining parent length (" + (asn1.length - index)
-          + " = " + asn1.length + " - " + index + ")");
+    // High-order bit Integers have a leading 0x00 to signify that they are positive.
+    // Bit Streams use the first byte to signify padding, which x.509 doesn't use.
+    if (0x00 === buf[index] && (0x02 === asn1.type || 0x03 === asn1.type)) {
+      // However, 0x00 on its own is a valid number
+      if (asn1.length > 1) {
+        index += 1;
+        adjust = -1;
       }
-      asn1.children.push(child);
-      //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");
+    adjustedLen = asn1.length + adjust;
+
+    //console.warn(depth.join(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)) {
+        iters += 1;
+        depth.length += 1;
+        child = parseAsn1(buf.slice(index, index + adjustedLen), depth, eager);
+        depth.length -= 1;
+        // 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);
+        //console.warn('2 len:', (2 + asn1.lengthSize + asn1.length), 'idx:', index, 'clen:', (2 + child.lengthSize + child.length));
+        if (index > (2 + asn1.lengthSize + asn1.length)) {
+          if (!eager) { console.error(JSON.stringify(asn1, ASN1._replacer, 2)); }
+          throw new Error("Parse error: child value length (" + child.length
+            + ") is greater than remaining parent length (" + (asn1.length - index)
+            + " = " + asn1.length + " - " + index + ")");
+        }
+        asn1.children.push(child);
+        //console.warn(depth.join(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); }
+
+      delete asn1.value;
+      return asn1;
     }
-    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); }
+
+    // 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; }
   }
 
-  // We want to fail if we know for sure that it's bad
-  if (-1 !== ASN1.CTYPES.indexOf(asn1.type)) {
-    return parseChildren();
-  }
-
-  asn1.value = buf.slice(index, index + adjustedLen);
-  try {
-    return parseChildren(true);
-  } catch(e) {
-    // leaving iterable array as a matter of convenience
-    asn1.children = [];
-    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.");
   }
+  return asn1;
 };
 ASN1._replacer = function (k, v) {
   if ('type' === k) { return '0x' + Enc.numToHex(v); }
-  if ('value' === k) { return '0x' + Enc.bufToHex(v.data || v); }
+  if (v && 'value' === k) { return '0x' + Enc.bufToHex(v.data || v); }
   return v;
 };
 

index.html

@@ -1,7 +1,7 @@
 <!DOCTYPE html>
 <html>
 <head>
-  <title>ASN.1 Parser - BlueCrypt</title>
+  <title>ASN.1 Parser - Bluecrypt</title>
   <style>
     textarea {
       width: 42em;
@@ -10,30 +10,57 @@
   </style>
 </head>
 <body>
-  <h1>BlueCrypt ASN.1 Parser</h1>
+  <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('change');
-      var pem = PEM.parseBlock(document.querySelector('.js-input').value);
-      var hex = Enc.bufToHex(pem.der);
-      console.log(hex);
-      document.querySelector('.js-hex').innerText = hex
-        .match(/.{2}/g).join(' ').match(/.{1,24}/g).join(' ').match(/.{1,50}/g).join('\n');
-      var json = ASN1.parse(pem.der);
+      console.log('keyup');
+      var json;
+
+      try {
+        var pem = PEM.parseBlock(document.querySelector('.js-input').value);
+        var hex = Enc.bufToHex(pem.der);
+        var arr = [];
+        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 } };
+      }
+
       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

@@ -1,9 +1,12 @@
 {
   "name": "asn1-parser",
-  "version": "1.0.0",
-  "description": "An ASN.1 parser in less than 100 lines of Vanilla JavaScript, part of the BlueCrypt suite.",
+  "version": "1.1.8",
+  "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"
   },