Added ZipCrypto decrypting ability

Author: 5saviahv

adm-zip.js

@@ -63,9 +63,9 @@ module.exports = function (/**String*/input) {
 		 *
 		 * @return Buffer or Null in case of error
 		 */
-		readFile: function (/**Object*/entry) {
+		readFile: function (/**Object*/entry, /*String, Buffer*/pass) {
 			var item = getEntry(entry);
-			return item && item.getData() || null;
+			return item && item.getData(pass) || null;
 		},
 
 		/**
@@ -482,7 +482,7 @@ module.exports = function (/**String*/input) {
 		 * Test the archive
 		 *
 		 */
-		test: function () {
+		test: function (pass) {
 			if (!_zip) {
 				return false;
 			}
@@ -492,7 +492,7 @@ module.exports = function (/**String*/input) {
 					if (entry.isDirectory) {
 						continue;
 					}
-					var content = _zip.entries[entry].getData();
+					var content = _zip.entries[entry].getData(pass);
 					if (!content) {
 						return false;
 					}
@@ -510,7 +510,7 @@ module.exports = function (/**String*/input) {
 		 * @param overwrite If the file already exists at the target path, the file will be overwriten if this is true.
 		 *                  Default is FALSE
 		 */
-		extractAllTo: function (/**String*/targetPath, /**Boolean*/overwrite) {
+		extractAllTo: function (/**String*/targetPath, /**Boolean*/overwrite, /*String, Buffer*/pass) {
 			overwrite = overwrite || false;
 			if (!_zip) {
 				throw new Error(Utils.Errors.NO_ZIP);
@@ -521,7 +521,7 @@ module.exports = function (/**String*/input) {
 					Utils.makeDir(entryName);
 					return;
 				}
-				var content = entry.getData();
+				var content = entry.getData(pass);
 				if (!content) {
 					throw new Error(Utils.Errors.CANT_EXTRACT_FILE);
 				}

methods/index.js

@@ -1,2 +1,3 @@
 exports.Deflater = require("./deflater");
-exports.Inflater = require("./inflater");
+exports.Inflater = require("./inflater");
+exports.ZipCrypto = require("./zipcrypto");

methods/zipcrypto.js

@@ -0,0 +1,77 @@
+// generate CRC32 lookup table
+const crctable = (new Uint32Array(256)).map((t,crc)=>{
+    for(let j=0;j<8;j++){
+        if (0 !== (crc & 1)){
+            crc = (crc >>> 1) ^ 0xEDB88320
+        }else{
+            crc >>>= 1    
+        }
+    }
+    return crc>>>0;
+});
+
+function make_decrypter(/*Buffer*/pwd){
+    // C-style uInt32 Multiply
+    const uMul = (a,b) => Math.imul(a, b) >>> 0;
+    // Initialize keys with default values
+    const keys = new Uint32Array([0x12345678, 0x23456789, 0x34567890]);
+    // crc32 byte update 
+    const crc32update = (pCrc32, bval) => {
+        return crctable[(pCrc32 ^ bval) & 0xff] ^ (pCrc32 >>> 8);
+    }
+    // update keys with byteValues
+    const updateKeys = (byteValue) => {
+        keys[0] = crc32update(keys[0], byteValue);
+        keys[1] += keys[0] & 0xff; 
+        keys[1] = uMul(keys[1], 134775813) + 1;
+        keys[2] = crc32update(keys[2], keys[1] >>> 24);
+    }
+
+    // 1. Stage initialize key
+    const pass = (Buffer.isBuffer(pwd)) ? pwd :  Buffer.from(pwd);
+    for(let i=0; i< pass.length; i++){
+        updateKeys(pass[i]);
+    }
+
+    // return decrypter function
+    return function (/*Buffer*/data){
+        if (!Buffer.isBuffer(data)){
+            throw 'decrypter needs Buffer'
+        }
+        // result - we create new Buffer for results
+        const result = Buffer.alloc(data.length);
+        let pos = 0;
+        // process input data
+        for(let c of data){
+            const k = (keys[2] | 2) >>> 0;      // key
+            c ^= (uMul(k, k^1) >> 8) & 0xff;    // decode
+            result[pos++] = c;                  // Save Value
+            updateKeys(c);                      // update keys with decoded byte
+        }
+        return result;
+    }
+}
+
+function decrypt(/*Buffer*/ data, /*Object*/header, /*String, Buffer*/ pwd){
+    if (!data || !Buffer.isBuffer(data) || data.length < 12) {
+        return Buffer.alloc(0);
+    }
+    
+    // We Initialize and generate decrypting function
+    const decrypter = make_decrypter(pwd);
+
+    // check - for testing password
+    const check = header.crc >>> 24;
+    // decrypt salt what is always 12 bytes and is a part of file content
+    const testbyte = decrypter(data.slice(0, 12))[11];
+
+    // does password meet expectations
+    if (check !== testbyte){
+        throw 'ADM-ZIP: Wrong Password';
+    }
+
+    // decode content
+    return decrypter(data.slice(12));
+}
+
+module.exports = {decrypt};

zipEntry.js

@@ -34,7 +34,7 @@ module.exports = function (/*Buffer*/input) {
         return true;
     }
 
-    function decompress(/*Boolean*/async, /*Function*/callback, /*String*/pass) {
+    function decompress(/*Boolean*/async, /*Function*/callback, /*String, Buffer*/pass) {
         if(typeof callback === 'undefined' && typeof async === 'string') {
             pass=async;
             async=void 0;
@@ -55,8 +55,10 @@ module.exports = function (/*Buffer*/input) {
         }
 
         if (_entryHeader.encripted){
-            if (async && callback) callback(Buffer.alloc(0), Utils.Errors.UNKNOWN_METHOD);
-            throw new Error(Utils.Errors.UNKNOWN_METHOD);
+            if ('string' !== typeof pass && !Buffer.isBuffer(pass)){
+                throw new Error('ADM-ZIP: Incompatible password parameter');
+            }
+            compressedData = Methods.ZipCrypto.decrypt(compressedData, _entryHeader, pass);
         }
 
         var data = Buffer.alloc(_entryHeader.size);