Cannot extract shared runtime tar-ball with TarFile.ExtractToDirectory

[ericstj]

Description

Hit a FormatException when extracting a .tar.gz file. I ran into this using the work item extraction I recently added to runfo: jaredpar/runfo#152

Reproduction Steps

Download https://dotnetcli.azureedge.net/dotnet/Runtime/6.0.5-servicing.22213.9/dotnet-runtime-6.0.5-osx-x64.tar.gz.
Pass this to TarFile.ExtractToDirectory, eg:

TarFile.ExtractToDirectory(@"c:\scratch\aspnetrepro\correlation-payload\dotnet-runtime-6.0.5-osx-x64.tar.gz", @".\", true);

Expected behavior

Successfully extracts tar file

Actual behavior

Unhandled exception. System.FormatException: Could not find any recognizable digits.
   at System.ParseNumbers.StringToInt(ReadOnlySpan`1 s, Int32 radix, Int32 flags, Int32& currPos)
   at System.Convert.ToInt32(String value, Int32 fromBase)
   at System.Formats.Tar.TarHelpers.GetTenBaseNumberFromOctalAsciiChars(Span`1 buffer)
   at System.Formats.Tar.TarHeader.TryReadCommonAttributes(Span`1 buffer)
   at System.Formats.Tar.TarHeader.TryGetNextHeader(Stream archiveStream, Boolean copyData)
   at System.Formats.Tar.TarReader.TryGetNextEntryHeader(TarHeader& header, Boolean copyData)
   at System.Formats.Tar.TarReader.GetNextEntry(Boolean copyData)
   at System.Formats.Tar.TarFile.ExtractToDirectoryInternal(Stream source, String destinationDirectoryPath, Boolean overwriteFiles, Boolean leaveOpen)
   at System.Formats.Tar.TarFile.ExtractToDirectory(String sourceFileName, String destinationDirectoryName, Boolean overwriteFiles)

Regression?

No

Known Workarounds

No response

Configuration

.NET 7.0 preview 5, windows 11

Other information

No response

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Issue Details

---

Description

Hit a FormatException when extracting a .tar.gz file. I ran into this using the work item extraction I recently added to runfo: jaredpar/runfo#152

Reproduction Steps

Download https://dotnetcli.azureedge.net/dotnet/Runtime/6.0.5-servicing.22213.9/dotnet-runtime-6.0.5-osx-x64.tar.gz.
Pass this to TarFile.ExtractToDirectory, eg:

TarFile.ExtractToDirectory(@"c:\scratch\aspnetrepro\correlation-payload\dotnet-runtime-6.0.5-osx-x64.tar.gz", @".\", true);

Expected behavior

Successfully extracts tar file

Actual behavior

Unhandled exception. System.FormatException: Could not find any recognizable digits.
   at System.ParseNumbers.StringToInt(ReadOnlySpan`1 s, Int32 radix, Int32 flags, Int32& currPos)
   at System.Convert.ToInt32(String value, Int32 fromBase)
   at System.Formats.Tar.TarHelpers.GetTenBaseNumberFromOctalAsciiChars(Span`1 buffer)
   at System.Formats.Tar.TarHeader.TryReadCommonAttributes(Span`1 buffer)
   at System.Formats.Tar.TarHeader.TryGetNextHeader(Stream archiveStream, Boolean copyData)
   at System.Formats.Tar.TarReader.TryGetNextEntryHeader(TarHeader& header, Boolean copyData)
   at System.Formats.Tar.TarReader.GetNextEntry(Boolean copyData)
   at System.Formats.Tar.TarFile.ExtractToDirectoryInternal(Stream source, String destinationDirectoryPath, Boolean overwriteFiles, Boolean leaveOpen)
   at System.Formats.Tar.TarFile.ExtractToDirectory(String sourceFileName, String destinationDirectoryName, Boolean overwriteFiles)

Regression?

No

Known Workarounds

No response

Configuration

.NET 7.0 preview 5, windows 11

Other information

No response

Author:	ericstj
Assignees:	-
Labels:	area-System.IO.Compression, untriaged
Milestone:	-

[carlossanlop]

Thanks for reporting, Eric.

The first argument is passing the compressed archive. The tar APIs only handle uncompressed archives.

using FileStream compressedStream = File.OpenRead(@"c:\scratch\aspnetrepro\correlation-payload\dotnet-runtime-6.0.5-osx-x64.tar.gz");
using GZipStream decompressor = new(compressedStream, CompressionMode.Decompress);
TarFile.ExtractToDirectory(source: decompressor, destinationDirectoryName: @".\", overwriteFiles: true);

But I did find another bug: The archive you provided contains entries whose paths begin with ./, including an initial entry with the root folder literally named ./. I will open another issue to get this addressed ASAP.

[ericstj]

Do you have an issue tracking the addition of APIs to support extracting a compressed tar.gz?

[carlossanlop]

Do you have an issue tracking the addition of APIs to support extracting a compressed tar.gz?

I do not, I'll open one too. Thanks @ericstj.

[carlossanlop]

Do you have an issue tracking the addition of APIs to support extracting a compressed tar.gz?

Opened #70517

[danmoseley]

Presumbly it's going to be common to attempt to open a .tar.gz with this API. Can we provide a better message than "Unhandled exception. System.FormatException: Could not find any recognizable digits." ? Even @ericstj apparently didn't realize the problem. If the repro is that simple, it is guaranteed that customers will be confused.

edit: Presumably compressed file could fail .tar validation in almost any way, but I'm guessing that it will generally fail in just about the very start of attempting to parse it. So we could special case that first failure message. Or, we could add a line or two of code to look for the signature of a compressed file - at least of .gz, and give a custom message.