Support Tar with large entry size

[ivanjx]

Description

Currently i cannot use TarReader.GetNextEntryAsync whenever it sees a tar entry file with more than 8GB of size (my case is 9GB). In the entry header itself, instead of writing size of the file in octal, the size header is constructed like this:
[0x80, 0, 0, 0, <size in bytes big endian>]

Reproduction Steps

using TarReader tar = new TarReader(tarStream, true);
List<TarEntry> entries = new List<TarEntry>();

while (true)
{
    TarEntry? entry = await tar.GetNextEntryAsync();

    if (entry == null)
    {
        break;
    }

    entries.Add(entry);
}
...

Expected behavior

Not error

Actual behavior

error:

Unable to parse number.
   at System.Formats.Tar.TarHelpers.ThrowInvalidNumber()
   at System.Formats.Tar.TarHelpers.ParseOctal[T](ReadOnlySpan`1 buffer)
   at System.Formats.Tar.TarHeader.TryReadCommonAttributes(Span`1 buffer, TarEntryFormat initialFormat)
   at System.Formats.Tar.TarHeader.TryReadAttributes(TarEntryFormat initialFormat, Span`1 buffer)
   at System.Formats.Tar.TarHeader.<TryGetNextHeaderAsync>d__48.MoveNext()
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Formats.Tar.TarReader.<TryGetNextEntryHeaderAsync>d__15.MoveNext()
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Formats.Tar.TarReader.<GetNextEntryInternalAsync>d__13.MoveNext()
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at xxxxx.<GetEntriesAsync>d__0.MoveNext() in [redacted]

Regression?

No response

Known Workarounds

this is currently my own tar parser implementation:

public async Task<TarEntry[]> GetEntriesAsync(Stream tarStream, CancellationToken cancellationToken)
    {
        byte[] entryHeaderBuff = new byte[512];
        List<TarEntry> entries = new List<TarEntry>();

        while (true)
        {
            cancellationToken.ThrowIfCancellationRequested();
            entryHeaderBuff[0] = 0; // Reset flag.
            int read = await tarStream.ReadAsync(
                entryHeaderBuff,
                cancellationToken);

            if (read < entryHeaderBuff.Length ||
                entryHeaderBuff[0] == 0)
            {
                // No more entries.
                break;
            }

            string fileName = Encoding.ASCII.GetString(entryHeaderBuff, 0, 100).Trim('\0');
            long fileSize;

            if (entryHeaderBuff[124] == 0x80)
            {
                byte[] sizeBuff = new byte[8];
                entryHeaderBuff
                    .AsSpan()
                    .Slice(124 + 4, 8)
                    .CopyTo(sizeBuff);
                Array.Reverse(sizeBuff);
                fileSize = BitConverter.ToInt64(sizeBuff);
            }
            else
            {
                string sizeStr = Encoding.UTF8.GetString(entryHeaderBuff, 124, 12).Trim('\0');
                fileSize = Convert.ToInt64(sizeStr, 8);
            }

            entries.Add(new TarEntry(fileName, fileSize));

            // Next.
            tarStream.Seek((fileSize + 511) / 512 * 512, SeekOrigin.Current);
        }

        return entries.ToArray();
    }

Configuration

No response

Other information

No response

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Issue Details

---

Description

Currently i cannot use TarReader.GetNextEntryAsync whenever it sees a tar entry file with more than 8GB of size (my case is 9GB). In the entry header itself, instead of writing size of the file in octal, the size header is constructed like this:
[0x80, 0, 0, 0, <size in bytes big endian>]

Reproduction Steps

using TarReader tar = new TarReader(tarStream, true);
List<TarEntry> entries = new List<TarEntry>();

while (true)
{
    TarEntry? entry = await tar.GetNextEntryAsync();

    if (entry == null)
    {
        break;
    }

    entries.Add(entry);
}
...

Expected behavior

Not error

Actual behavior

error:

Unable to parse number.
   at System.Formats.Tar.TarHelpers.ThrowInvalidNumber()
   at System.Formats.Tar.TarHelpers.ParseOctal[T](ReadOnlySpan`1 buffer)
   at System.Formats.Tar.TarHeader.TryReadCommonAttributes(Span`1 buffer, TarEntryFormat initialFormat)
   at System.Formats.Tar.TarHeader.TryReadAttributes(TarEntryFormat initialFormat, Span`1 buffer)
   at System.Formats.Tar.TarHeader.<TryGetNextHeaderAsync>d__48.MoveNext()
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Formats.Tar.TarReader.<TryGetNextEntryHeaderAsync>d__15.MoveNext()
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at System.Formats.Tar.TarReader.<GetNextEntryInternalAsync>d__13.MoveNext()
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at xxxxx.<GetEntriesAsync>d__0.MoveNext() in [redacted]

Regression?

No response

Known Workarounds

this is currently my own tar parser implementation:

public async Task<TarEntry[]> GetEntriesAsync(Stream tarStream, CancellationToken cancellationToken)
    {
        byte[] entryHeaderBuff = new byte[512];
        List<TarEntry> entries = new List<TarEntry>();

        while (true)
        {
            cancellationToken.ThrowIfCancellationRequested();
            entryHeaderBuff[0] = 0; // Reset flag.
            int read = await tarStream.ReadAsync(
                entryHeaderBuff,
                cancellationToken);

            if (read < entryHeaderBuff.Length ||
                entryHeaderBuff[0] == 0)
            {
                // No more entries.
                break;
            }

            string fileName = Encoding.ASCII.GetString(entryHeaderBuff, 0, 100).Trim('\0');
            long fileSize;

            if (entryHeaderBuff[124] == 0x80)
            {
                byte[] sizeBuff = new byte[8];
                entryHeaderBuff
                    .AsSpan()
                    .Slice(124 + 4, 8)
                    .CopyTo(sizeBuff);
                Array.Reverse(sizeBuff);
                fileSize = BitConverter.ToInt64(sizeBuff);
            }
            else
            {
                string sizeStr = Encoding.UTF8.GetString(entryHeaderBuff, 124, 12).Trim('\0');
                fileSize = Convert.ToInt64(sizeStr, 8);
            }

            entries.Add(new TarEntry(fileName, fileSize));

            // Next.
            tarStream.Seek((fileSize + 511) / 512 * 512, SeekOrigin.Current);
        }

        return entries.ToArray();
    }

Configuration

No response

Other information

No response

Author:	ivanjx
Assignees:	-
Labels:	untriaged, area-System.Formats.Tar
Milestone:	-

[ivanjx]

closing in favor of #93763