Merge pull request #119 from ZJONSSON/crx

Crx

README.md

@@ -27,6 +27,7 @@ There are no added compiled dependencies - inflation is handled by node.js's bui
 
 Please note:  Methods that use the Central Directory instead of parsing entire file can be found under [`Open`](#open)
 
+Chrome extension files (.crx) are zipfiles with an [extra header](http://www.adambarth.com/experimental/crx/docs/crx.html) at the start of the file.  Unzipper will parse .crx file with the streaming methods (`Parse` and `ParseOne`).  The `Open` methods will check for `crx` headers and parse crx files, but only if you provide `crx: true` in options.  
 
 ## Installation
 
@@ -194,7 +195,7 @@ Previous methods rely on the entire zipfile being received through a pipe.  The
 If the file is encrypted you will have to supply a password to decrypt, otherwise you can leave blank.
 Unlike `adm-zip` the Open methods will never read the entire zipfile into buffer.
 
-The last argument is optional `options` object where you can specify `tailSize` (default 80 bytes), i.e. how many bytes should we read at the end of the zipfile to locate the endOfCentralDirectory.  This location can be variable depending on zip64 extensible data sector size.
+The last argument is optional `options` object where you can specify `tailSize` (default 80 bytes), i.e. how many bytes should we read at the end of the zipfile to locate the endOfCentralDirectory.  This location can be variable depending on zip64 extensible data sector size.   Additionally you can supply option `crx: true` which will check for a crx header and parse the file accordingly by shifting all file offsets by the length of the crx header.
 
 ### Open.file([path], [options])
 Returns a Promise to the central directory information with methods to extract individual files.   `start` and `end` options are used to avoid reading the whole file.

lib/Open/directory.js

@@ -9,21 +9,53 @@ var Buffer = require('../Buffer');
 var signature = Buffer.alloc(4);
 signature.writeUInt32LE(0x06054b50,0);
 
+function getCrxHeader(source) {
+  var sourceStream = source.stream(0).pipe(PullStream());
+
+  return sourceStream.pull(4).then(function(data) {
+    var signature = data.readUInt32LE(0);
+    if (signature === 0x34327243) {
+      var crxHeader;
+      return sourceStream.pull(12).then(function(data) {
+        crxHeader = binary.parse(data)
+          .word32lu('version')
+          .word32lu('pubKeyLength')
+          .word32lu('signatureLength')
+          .vars;
+      }).then(function() {
+        return sourceStream.pull(crxHeader.pubKeyLength +crxHeader.signatureLength);
+      }).then(function(data) {
+        crxHeader.publicKey = data.slice(0,crxHeader.pubKeyLength);
+        crxHeader.signature = data.slice(crxHeader.pubKeyLength);
+        crxHeader.size = 16 + crxHeader.pubKeyLength +crxHeader.signatureLength;
+        return crxHeader;
+      });
+    }
+  });
+}
+
 module.exports = function centralDirectory(source, options) {
   var endDir = PullStream(),
       records = PullStream(),
       tailSize = (options && options.tailSize) || 80,
+      crxHeader,
       vars;
 
+  if (options && options.crx)
+    crxHeader = getCrxHeader(source);
+
   return source.size()
     .then(function(size) {
       source.stream(Math.max(0,size-tailSize)).pipe(endDir);
       return endDir.pull(signature);
     })
     .then(function() {
-      return endDir.pull(22);
+      return Promise.props({directory: endDir.pull(22), crxHeader: crxHeader});
     })
-    .then(function(data) {
+    .then(function(d) {
+      var data = d.directory;
+      var startOffset = d.crxHeader && d.crxHeader.size || 0;
+
       vars = binary.parse(data)
         .word32lu('signature')
         .word16lu('diskNumber')
@@ -35,6 +67,8 @@ module.exports = function centralDirectory(source, options) {
         .word16lu('commentLength')
         .vars;
 
+      vars.offsetToStartOfCentralDirectory += startOffset;
+
       source.stream(vars.offsetToStartOfCentralDirectory).pipe(records);
 
       vars.files = Promise.mapSeries(Array(vars.numberOfRecords),function() {
@@ -59,6 +93,8 @@ module.exports = function centralDirectory(source, options) {
             .word32lu('offsetToLocalFileHeader')
             .vars;
 
+        vars.offsetToLocalFileHeader += startOffset;
+
         return records.pull(vars.fileNameLength).then(function(fileNameBuffer) {
           vars.pathBuffer = fileNameBuffer;
           vars.path = fileNameBuffer.toString('utf8');

lib/extract.js

@@ -34,6 +34,9 @@ function Extract (opts) {
   };
 
   var extract = duplexer2(parser,outStream);
+  parser.once('crx-header', function(crxHeader) {
+    extract.crxHeader = crxHeader;
+  });
 
   parser
     .pipe(outStream)

lib/parse.js

@@ -43,6 +43,9 @@ Parse.prototype._readRecord = function () {
 
     var signature = data.readUInt32LE(0);
 
+    if (signature === 0x34327243) {
+      return self._readCrxHeader();
+    }
     if (signature === 0x04034b50) {
       return self._readFile();
     }
@@ -63,6 +66,23 @@ Parse.prototype._readRecord = function () {
   });
 };
 
+Parse.prototype._readCrxHeader = function() {
+  var self = this;
+  return self.pull(12).then(function(data) {
+    self.crxHeader = binary.parse(data)
+      .word32lu('version')
+      .word32lu('pubKeyLength')
+      .word32lu('signatureLength')
+      .vars;  
+    return self.pull(self.crxHeader.pubKeyLength + self.crxHeader.signatureLength);
+  }).then(function(data) {
+    self.crxHeader.publicKey = data.slice(0,self.crxHeader.pubKeyLength);
+    self.crxHeader.signature = data.slice(self.crxHeader.pubKeyLength);
+    self.emit('crx-header',self.crxHeader);
+    return self._readRecord();
+  });
+};
+
 Parse.prototype._readFile = function () {
   var self = this;
   return self.pull(26).then(function(data) {
@@ -79,6 +99,8 @@ Parse.prototype._readFile = function () {
       .word16lu('extraFieldLength')
       .vars;
 
+    if (self.crxHeader) vars.crxHeader = self.crxHeader;
+
     return self.pull(vars.fileNameLength).then(function(fileNameBuffer) {
       var fileName = fileNameBuffer.toString('utf8');
       var entry = Stream.PassThrough();

test/compressed-crx.js

@@ -0,0 +1,78 @@
+'use strict';
+
+var test = require('tap').test;
+var fs = require('fs');
+var path = require('path');
+var temp = require('temp');
+var dirdiff = require('dirdiff');
+var unzip = require('../');
+
+test('parse/extract crx archive', function (t) {
+  var archive = path.join(__dirname, '../testData/compressed-standard-crx/archive.crx');
+
+  temp.mkdir('node-unzip-', function (err, dirPath) {
+    if (err) {
+      throw err;
+    }
+    var unzipExtractor = unzip.Extract({ path: dirPath });
+    unzipExtractor.on('error', function(err) {
+      throw err;
+    });
+    unzipExtractor.on('close', testExtractionResults);
+
+    fs.createReadStream(archive).pipe(unzipExtractor);
+
+    function testExtractionResults() {
+      t.same(unzipExtractor.crxHeader.version,2);
+      dirdiff(path.join(__dirname, '../testData/compressed-standard/inflated'), dirPath, {
+        fileContents: true
+      }, function (err, diffs) {
+        if (err) {
+          throw err;
+        }
+        t.equal(diffs.length, 0, 'extracted directory contents');
+        t.end();
+      });
+    }
+  });
+});
+
+test('open methods', function(t) {
+  var archive = path.join(__dirname, '../testData/compressed-standard-crx/archive.crx');
+  var buffer = fs.readFileSync(archive);
+  var request = require('request');
+  var AWS = require('aws-sdk');
+  var s3 = new AWS.S3({region: 'us-east-1'});
+
+  // We have to modify the `getObject` and `headObject` to use makeUnauthenticated
+  s3.getObject = function(params,cb) {
+    return s3.makeUnauthenticatedRequest('getObject',params,cb);
+  };
+
+  s3.headObject = function(params,cb) {
+    return s3.makeUnauthenticatedRequest('headObject',params,cb);
+  };
+
+  var tests = [
+    {name: 'buffer',args: [buffer]},
+    {name: 'file', args: [archive]},
+    {name: 'url', args: [request, 'https://s3.amazonaws.com/unzipper/archive.crx']},
+    {name: 's3', args: [s3, { Bucket: 'unzipper', Key: 'archive.crx'}]}
+  ];
+
+  tests.forEach(function(test) {
+    t.test(test.name, function(t) {
+      t.test('opening with crx option', function(t) {
+        var method = unzip.Open[test.name];
+        method.apply(method, test.args.concat({crx:true}))
+        .then(function(d) {
+          return d.files[1].buffer();
+        })
+        .then(function(d) {
+          t.same(String(d), '42\n', test.name + ' content matches');
+          t.end();
+        });
+      });
+    });
+  });
+});

testData/compressed-standard-crx/crxmake.sh

@@ -0,0 +1,31 @@
+#!/bin/bash -e
+#
+# Purpose: Pack a Chromium extension directory into crx format
+
+crx="archive.crx"
+pub="publickey.tmp"
+sig="signature.tmp"
+zip="../compressed-standard/archive.zip"
+key="./key"
+
+# signature
+openssl sha1 -sha1 -binary -sign key.pem < "$zip" > "$sig"
+
+# public key
+openssl rsa -pubout -outform DER < key.pem > "$pub" 2>/dev/null
+
+byte_swap () {
+  # Take "abcdefgh" and return it as "ghefcdab"
+  echo "${1:6:2}${1:4:2}${1:2:2}${1:0:2}"
+}
+
+crmagic_hex="4372 3234" # Cr24
+version_hex="0200 0000" # 2
+pub_len_hex=$(byte_swap $(printf '%08x\n' $(ls -l "$pub" | awk '{print $5}')))
+sig_len_hex=$(byte_swap $(printf '%08x\n' $(ls -l "$sig" | awk '{print $5}')))
+(
+  echo "$crmagic_hex $version_hex $pub_len_hex $sig_len_hex" | xxd -r -p
+  cat "$pub" "$sig" "$zip"
+) > "$crx"
+rm *.tmp
+echo "Wrote $crx"

testData/compressed-standard-crx/key.pem

@@ -0,0 +1,28 @@
+-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----