예제 #1
0
        // For AES the method in the entry is 99, and the real compression method is in the extradata
        //
        private void ProcessAESExtraData(ZipExtraData extraData)
        {
#if !NET_1_1 && !NETCF_2_0
            if (extraData.Find(0x9901))
            {
                // Set version and flag for Zipfile.CreateAndInitDecryptionStream
                versionToExtract = ZipConstants.VERSION_AES;                    // Ver 5.1 = AES see "Version" getter
                // Set StrongEncryption flag for ZipFile.CreateAndInitDecryptionStream
                Flags = Flags | (int)GeneralBitFlags.StrongEncryption;
                //
                // Unpack AES extra data field see http://www.winzip.com/aes_info.htm
                int length = extraData.ValueLength;                     // Data size currently 7
                if (length < 7)
                {
                    throw new ZipException("AES Extra Data Length " + length + " invalid.");
                }
                int ver            = extraData.ReadShort(); // Version number (1=AE-1 2=AE-2)
                int vendorId       = extraData.ReadShort(); // 2-character vendor ID 0x4541 = "AE"
                int encrStrength   = extraData.ReadByte();  // encryption strength 1 = 128 2 = 192 3 = 256
                int actualCompress = extraData.ReadShort(); // The actual compression method used to compress the file
                _aesEncryptionStrength = encrStrength;
                method = (CompressionMethod)actualCompress;
            }
            else
            {
                throw new ZipException("AES Extra Data missing");
            }
#else
            throw new ZipException("AES unsupported");
#endif
        }
예제 #2
0
        /// <summary>
        /// Process extra data fields updating the entry based on the contents.
        /// </summary>
        /// <param name="localHeader">True if the extra data fields should be handled
        /// for a local header, rather than for a central header.
        /// </param>
        internal void ProcessExtraData(bool localHeader)
        {
            ZipExtraData extraData = new ZipExtraData(extra);

            if (extraData.Find(0x0001))
            {
                // Version required to extract is ignored here as some archivers dont set it correctly
                // in theory it should be version 45 or higher

                // The recorded size will change but remember that this is zip64.
                forceZip64_ = true;

                if (extraData.ValueLength < 4)
                {
                    throw new ZipException("Extra data extended Zip64 information length is invalid");
                }

                if (localHeader || (size == uint.MaxValue))
                {
                    size = (ulong)extraData.ReadLong();
                }

                if (localHeader || (compressedSize == uint.MaxValue))
                {
                    compressedSize = (ulong)extraData.ReadLong();
                }

                if (!localHeader && (offset == uint.MaxValue))
                {
                    offset = extraData.ReadLong();
                }

                // Disk number on which file starts is ignored
            }
            else
            {
                if (
                    ((versionToExtract & 0xff) >= ZipConstants.VersionZip64) &&
                    ((size == uint.MaxValue) || (compressedSize == uint.MaxValue))
                    )
                {
                    throw new ZipException("Zip64 Extended information required but is missing.");
                }
            }

            if (extraData.Find(10))
            {
                // No room for any tags.
                if (extraData.ValueLength < 4)
                {
                    throw new ZipException("NTFS Extra data invalid");
                }

                extraData.ReadInt(); // Reserved

                while (extraData.UnreadCount >= 4)
                {
                    int ntfsTag    = extraData.ReadShort();
                    int ntfsLength = extraData.ReadShort();
                    if (ntfsTag == 1)
                    {
                        if (ntfsLength >= 24)
                        {
                            long lastModification = extraData.ReadLong();
                            long lastAccess       = extraData.ReadLong();
                            long createTime       = extraData.ReadLong();

                            DateTime = DateTime.FromFileTime(lastModification);
                        }
                        break;
                    }
                    // An unknown NTFS tag so simply skip it.
                    extraData.Skip(ntfsLength);
                }
            }
            else if (extraData.Find(0x5455))
            {
                int length   = extraData.ValueLength;
                int readByte = extraData.ReadByte();

                // Can include other times but these are ignored.  Length of data should
                // actually be 1 + 4 * no of bits in flags.
                if (((readByte & 1) != 0) && (length >= 5))
                {
                    int iTime = extraData.ReadInt();

                    DateTime = (new DateTime(1970, 1, 1, 0, 0, 0).ToUniversalTime() +
                                new TimeSpan(0, 0, 0, iTime, 0)).ToLocalTime();
                }
            }
            if (method == CompressionMethod.WinZipAES)
            {
                ProcessAESExtraData(extraData);
            }
        }