ZipArchive does not indicate in any way if file length specified in central directory does not match the actual file length. #27741
Description
>dotnet --version
2.1.500-preview-009335
The following zip archive: tttt.zip has corrupted central directory entry making it report the length of the compressed file tttt.txt to be 256 bytes. All zip archivers I tried so far fail to extract that file one way or another. But ZipArchive seem to completely ignore the discrepancy:
using System;
using System.IO;
using System.IO.Compression;
namespace BrokenZipCoreTest
{
class Program
{
static void Main(string[] args)
{
using (var za = ZipFile.OpenRead(@"E:\dev\tttt.zip"))
{
var e = za.GetEntry("tttt.txt");
Console.WriteLine("entry length: {0}", e.Length);
using (var ms = new MemoryStream())
{
using (var source = e.Open())
{
source.CopyTo(ms);
}
Console.WriteLine("actual length: {0}", ms.Length);
}
}
}
}
}produces the following output:
entry length: 256
actual length: 39208160
No exceptions thrown.
I'm not 100% sure, but I think the library should detect it, instead of proceeding silently.