Extraction of password-protected Zip files failed.

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
csharp
Domain
backend

Research direction

Start by reproducing the issue with a password-protected Zip created by Bandizip and follow the extraction loop shown in the report, especially the read after the ZipEntry is fully consumed. Done means extracting the entry succeeds and a subsequent read returns 0 instead of throwing “Data descriptor signature not found”.

Written by the indexing model from the issue text.

Description

*no response* bug
Describe the bug

When other programs (such as Bandizip) compress files into password-protected Zip files, using this library to extract them will throw an exception.
When the 'ZipEntry' is fully read, an exception will be thrown on the next read attempt.
ICSharpCode.SharpZipLib.Zip.ZipException: Data descriptor signature not found

`
// An exception will be thrown here.
while ((ze = zis.GetNextEntry()) != null) {
string filePath = Path.Combine(targetFolderPath, ze.Name);
string directoryPath = Path.GetDirectoryName(filePath) ?? string.Empty;

if (!string.IsNullOrEmpty(directoryPath) && !Directory.Exists(directoryPath)) {
    Directory.CreateDirectory(directoryPath);
}

if (File.Exists(filePath)) {
    File.Delete(filePath);
}

if (!ze.IsDirectory) {
    long nCur = 0; 
    long nLength = zis.Length;
    OnUnZipEntryStart(ze.Name);
    OnUnZipEntryProgress(0, nLength);
    using (FileStream fs = File.Create(filePath)) {
        int sourceBytes;
        do {
            //An exception will be thrown here.
            sourceBytes = zis.Read(data, 0, data.Length);
            nCur += sourceBytes;
            fs.Write(data, 0, sourceBytes);
        } while (sourceBytes > 0);
    }
}

}
`

Reproduction Code

No response

Steps to reproduce

When the 'ZipEntry' is fully read
On subsequent reads, it is theoretically expected to return 0.
But throw ICSharpCode.SharpZipLib.Zip.ZipException: Data descriptor signature not found

Expected behavior

None

Operating System

Windows

Framework Version

.NET Framework 4.x

Tags

No response

Additional context

No response

Dominant language
C#
Stars
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Forks
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PR merge metrics
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