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Do not set the StrongEncryption flag for WinZipAes encrypted entries #329

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Merged
piksel merged 1 commit into from
Jun 15, 2019
Merged

Do not set the StrongEncryption flag for WinZipAes encrypted entries #329

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5 changes: 2 additions & 3 deletions src/ICSharpCode.SharpZipLib/Zip/ZipEntry.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -1131,10 +1131,9 @@ private void ProcessAESExtraData(ZipExtraData extraData)
{
if (extraData.Find(0x9901))
{
// Set version and flag for Zipfile.CreateAndInitDecryptionStream
// Set version 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
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40 changes: 24 additions & 16 deletions src/ICSharpCode.SharpZipLib/Zip/ZipFile.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -3542,23 +3542,9 @@ private Stream CreateAndInitDecryptionStream(Stream baseStream, ZipEntry entry)
{
CryptoStream result = null;

if ((entry.Version < ZipConstants.VersionStrongEncryption)
|| (entry.Flags & (int)GeneralBitFlags.StrongEncryption) == 0)
{
var classicManaged = new PkzipClassicManaged();

OnKeysRequired(entry.Name);
if (HaveKeys == false)
{
throw new ZipException("No password available for encrypted stream");
}

result = new CryptoStream(baseStream, classicManaged.CreateDecryptor(key, null), CryptoStreamMode.Read);
CheckClassicPassword(result, entry);
}
else
if (entry.CompressionMethodForHeader == CompressionMethod.WinZipAES)
{
if (entry.Version == ZipConstants.VERSION_AES)
if (entry.Version >= ZipConstants.VERSION_AES)
{
//
OnKeysRequired(entry.Name);
Expand Down Expand Up @@ -3587,6 +3573,28 @@ private Stream CreateAndInitDecryptionStream(Stream baseStream, ZipEntry entry)
throw new ZipException("Decryption method not supported");
}
}
else
{
if ((entry.Version < ZipConstants.VersionStrongEncryption)
|| (entry.Flags & (int)GeneralBitFlags.StrongEncryption) == 0)
{
var classicManaged = new PkzipClassicManaged();

OnKeysRequired(entry.Name);
if (HaveKeys == false)
{
throw new ZipException("No password available for encrypted stream");
}

result = new CryptoStream(baseStream, classicManaged.CreateDecryptor(key, null), CryptoStreamMode.Read);
CheckClassicPassword(result, entry);
}
else
{
// We don't support PKWare strong encryption
throw new ZipException("Decryption method not supported");
}
}

return result;
}
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