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Code Issues 975 Packages Projects Releases 25 Wiki Activity

Fix Zip headers to support both sync and async reading

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Co-authored-by: adamhathcock <527620+adamhathcock@users.noreply.github.com>
This commit is contained in:
copilot-swe-agent[bot]
2025-12-30 11:47:31 +00:00
parent 39a0b4ce78
commit ec31cb9987
12 changed files with 298 additions and 10 deletions
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6
src/SharpCompress/Archives/Zip/ZipArchive.cs
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@@ -199,7 +199,7 @@ public class ZipArchive : AbstractWritableArchive<ZipArchiveEntry, ZipVolume>
if (stream.CanSeek) //could be multipart. Test for central directory - might not be z64 safe
{
var z = new SeekableZipHeaderFactory(password, new ArchiveEncoding());
var x = z.ReadSeekableHeader(stream).FirstOrDefault();
var x = z.ReadSeekableHeader(stream, useSync: true).FirstOrDefault();
return x?.ZipHeaderType == ZipHeaderType.DirectoryEntry;
}
else
@@ -254,7 +254,9 @@ public class ZipArchive : AbstractWritableArchive<ZipArchiveEntry, ZipVolume>
protected override IEnumerable<ZipArchiveEntry> LoadEntries(IEnumerable<ZipVolume> volumes)
{
var vols = volumes.ToArray();
foreach (var h in headerFactory.NotNull().ReadSeekableHeader(vols.Last().Stream))
foreach (
var h in headerFactory.NotNull().ReadSeekableHeader(vols.Last().Stream, useSync: true)
)
{
if (h != null)
{

15
src/SharpCompress/Common/Zip/Headers/DirectoryEndHeader.cs
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@@ -1,4 +1,5 @@
using System.IO;
using System.Threading.Tasks;
namespace SharpCompress.Common.Zip.Headers;
@@ -7,7 +8,7 @@ internal class DirectoryEndHeader : ZipHeader
public DirectoryEndHeader()
: base(ZipHeaderType.DirectoryEnd) { }
internal override void Read(AsyncBinaryReader reader)
internal override void Read(BinaryReader reader)
{
VolumeNumber = reader.ReadUInt16();
FirstVolumeWithDirectory = reader.ReadUInt16();
@@ -19,6 +20,18 @@ internal class DirectoryEndHeader : ZipHeader
Comment = reader.ReadBytes(CommentLength);
}
internal override async ValueTask Read(AsyncBinaryReader reader)
{
VolumeNumber = await reader.ReadUInt16Async();
FirstVolumeWithDirectory = await reader.ReadUInt16Async();
TotalNumberOfEntriesInDisk = await reader.ReadUInt16Async();
TotalNumberOfEntries = await reader.ReadUInt16Async();
DirectorySize = await reader.ReadUInt32Async();
DirectoryStartOffsetRelativeToDisk = await reader.ReadUInt32Async();
CommentLength = await reader.ReadUInt16Async();
Comment = await reader.ReadBytesAsync(CommentLength);
}
public ushort VolumeNumber { get; private set; }
public ushort FirstVolumeWithDirectory { get; private set; }

33
src/SharpCompress/Common/Zip/Headers/DirectoryEntryHeader.cs
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@@ -1,5 +1,6 @@
using System.IO;
using System.Linq;
using System.Threading.Tasks;
namespace SharpCompress.Common.Zip.Headers;
@@ -31,7 +32,37 @@ internal class DirectoryEntryHeader : ZipFileEntry
var extra = reader.ReadBytes(extraLength);
var comment = reader.ReadBytes(commentLength);
// According to .ZIP File Format Specification
ProcessReadData(name, extra, comment);
}
internal override async ValueTask Read(AsyncBinaryReader reader)
{
Version = await reader.ReadUInt16Async();
VersionNeededToExtract = await reader.ReadUInt16Async();
Flags = (HeaderFlags)await reader.ReadUInt16Async();
CompressionMethod = (ZipCompressionMethod)await reader.ReadUInt16Async();
OriginalLastModifiedTime = LastModifiedTime = await reader.ReadUInt16Async();
OriginalLastModifiedDate = LastModifiedDate = await reader.ReadUInt16Async();
Crc = await reader.ReadUInt32Async();
CompressedSize = await reader.ReadUInt32Async();
UncompressedSize = await reader.ReadUInt32Async();
var nameLength = await reader.ReadUInt16Async();
var extraLength = await reader.ReadUInt16Async();
var commentLength = await reader.ReadUInt16Async();
DiskNumberStart = await reader.ReadUInt16Async();
InternalFileAttributes = await reader.ReadUInt16Async();
ExternalFileAttributes = await reader.ReadUInt32Async();
RelativeOffsetOfEntryHeader = await reader.ReadUInt32Async();
var name = await reader.ReadBytesAsync(nameLength);
var extra = await reader.ReadBytesAsync(extraLength);
var comment = await reader.ReadBytesAsync(commentLength);
ProcessReadData(name, extra, comment);
}
private void ProcessReadData(byte[] name, byte[] extra, byte[] comment)
{
//
// For example: https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT
//

3
src/SharpCompress/Common/Zip/Headers/IgnoreHeader.cs
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@@ -1,4 +1,5 @@
using System.IO;
using System.Threading.Tasks;
namespace SharpCompress.Common.Zip.Headers;
@@ -8,4 +9,6 @@ internal class IgnoreHeader : ZipHeader
: base(type) { }
internal override void Read(BinaryReader reader) { }
internal override ValueTask Read(AsyncBinaryReader reader) => default;
}

27
src/SharpCompress/Common/Zip/Headers/LocalEntryHeader.cs
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@@ -4,8 +4,27 @@ using System.Threading.Tasks;
namespace SharpCompress.Common.Zip.Headers;
internal class LocalEntryHeader(ArchiveEncoding archiveEncoding) : ZipFileEntry(ZipHeaderType.LocalEntry, archiveEncoding)
internal class LocalEntryHeader(ArchiveEncoding archiveEncoding)
: ZipFileEntry(ZipHeaderType.LocalEntry, archiveEncoding)
{
internal override void Read(BinaryReader reader)
{
Version = reader.ReadUInt16();
Flags = (HeaderFlags)reader.ReadUInt16();
CompressionMethod = (ZipCompressionMethod)reader.ReadUInt16();
OriginalLastModifiedTime = LastModifiedTime = reader.ReadUInt16();
OriginalLastModifiedDate = LastModifiedDate = reader.ReadUInt16();
Crc = reader.ReadUInt32();
CompressedSize = reader.ReadUInt32();
UncompressedSize = reader.ReadUInt32();
var nameLength = reader.ReadUInt16();
var extraLength = reader.ReadUInt16();
var name = reader.ReadBytes(nameLength);
var extra = reader.ReadBytes(extraLength);
ProcessReadData(name, extra);
}
internal override async ValueTask Read(AsyncBinaryReader reader)
{
Version = await reader.ReadUInt16Async();
@@ -21,7 +40,11 @@ internal class LocalEntryHeader(ArchiveEncoding archiveEncoding) : ZipFileEntry(
var name = await reader.ReadBytesAsync(nameLength);
var extra = await reader.ReadBytesAsync(extraLength);
// According to .ZIP File Format Specification
ProcessReadData(name, extra);
}
private void ProcessReadData(byte[] name, byte[] extra)
{
//
// For example: https://pkware.cachefly.net/webdocs/casestudies/APPNOTE.TXT
//

4
src/SharpCompress/Common/Zip/Headers/SplitHeader.cs
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@@ -1,5 +1,6 @@
using System;
using System.IO;
using System.Threading.Tasks;
namespace SharpCompress.Common.Zip.Headers;
@@ -9,4 +10,7 @@ internal class SplitHeader : ZipHeader
: base(ZipHeaderType.Split) { }
internal override void Read(BinaryReader reader) => throw new NotImplementedException();
internal override ValueTask Read(AsyncBinaryReader reader) =>
throw new NotImplementedException();
}

20
src/SharpCompress/Common/Zip/Headers/Zip64DirectoryEndHeader.cs
View File

@@ -1,4 +1,5 @@
using System.IO;
using System.Threading.Tasks;
namespace SharpCompress.Common.Zip.Headers;
@@ -26,6 +27,25 @@ internal class Zip64DirectoryEndHeader : ZipHeader
);
}
internal override async ValueTask Read(AsyncBinaryReader reader)
{
SizeOfDirectoryEndRecord = (long)await reader.ReadUInt64Async();
VersionMadeBy = await reader.ReadUInt16Async();
VersionNeededToExtract = await reader.ReadUInt16Async();
VolumeNumber = await reader.ReadUInt32Async();
FirstVolumeWithDirectory = await reader.ReadUInt32Async();
TotalNumberOfEntriesInDisk = (long)await reader.ReadUInt64Async();
TotalNumberOfEntries = (long)await reader.ReadUInt64Async();
DirectorySize = (long)await reader.ReadUInt64Async();
DirectoryStartOffsetRelativeToDisk = (long)await reader.ReadUInt64Async();
DataSector = await reader.ReadBytesAsync(
(int)(
SizeOfDirectoryEndRecord
- SIZE_OF_FIXED_HEADER_DATA_EXCEPT_SIGNATURE_AND_SIZE_FIELDS
)
);
}
private const int SIZE_OF_FIXED_HEADER_DATA_EXCEPT_SIGNATURE_AND_SIZE_FIELDS = 44;
public long SizeOfDirectoryEndRecord { get; private set; }

9
src/SharpCompress/Common/Zip/Headers/Zip64DirectoryEndLocatorHeader.cs
View File

@@ -5,7 +5,14 @@ namespace SharpCompress.Common.Zip.Headers;
internal class Zip64DirectoryEndLocatorHeader() : ZipHeader(ZipHeaderType.Zip64DirectoryEndLocator)
{
internal override async ValueTask Read(AsyncBinaryReader reader)
internal override void Read(BinaryReader reader)
{
FirstVolumeWithDirectory = reader.ReadUInt32();
RelativeOffsetOfTheEndOfDirectoryRecord = (long)reader.ReadUInt64();
TotalNumberOfVolumes = reader.ReadUInt32();
}
internal override async ValueTask Read(AsyncBinaryReader reader)
{
FirstVolumeWithDirectory = await reader.ReadUInt32Async();
RelativeOffsetOfTheEndOfDirectoryRecord = (long)await reader.ReadUInt64Async();

3
src/SharpCompress/Common/Zip/Headers/ZipFileEntry.cs
View File

@@ -5,7 +5,8 @@ using System.IO;
namespace SharpCompress.Common.Zip.Headers;
internal abstract class ZipFileEntry(ZipHeaderType type, ArchiveEncoding archiveEncoding) : ZipHeader(type)
internal abstract class ZipFileEntry(ZipHeaderType type, ArchiveEncoding archiveEncoding)
: ZipHeader(type)
{
internal bool IsDirectory
{

2
src/SharpCompress/Common/Zip/Headers/ZipHeader.cs
View File

@@ -1,3 +1,4 @@
using System.IO;
using System.Threading.Tasks;
namespace SharpCompress.Common.Zip.Headers;
@@ -6,6 +7,7 @@ internal abstract class ZipHeader(ZipHeaderType type)
{
internal ZipHeaderType ZipHeaderType { get; } = type;
internal abstract void Read(BinaryReader reader);
internal abstract ValueTask Read(AsyncBinaryReader reader);
internal bool HasData { get; set; } = true;

108
src/SharpCompress/Common/Zip/SeekableZipHeaderFactory.cs
View File

@@ -27,7 +27,7 @@ internal sealed class SeekableZipHeaderFactory : ZipHeaderFactory
var eocd_location = stream.Position;
var entry = new DirectoryEndHeader();
entry.Read(reader);
await entry.Read(reader);
if (entry.IsZip64)
{
@@ -86,6 +86,73 @@ internal sealed class SeekableZipHeaderFactory : ZipHeaderFactory
}
}
internal IEnumerable<ZipHeader> ReadSeekableHeader(Stream stream, bool useSync)
{
var reader = new BinaryReader(stream);
SeekBackToHeader(stream, reader);
var eocd_location = stream.Position;
var entry = new DirectoryEndHeader();
entry.Read(reader);
if (entry.IsZip64)
{
_zip64 = true;
// ZIP64_END_OF_CENTRAL_DIRECTORY_LOCATOR should be before the EOCD
stream.Seek(eocd_location - ZIP64_EOCD_LENGTH - 4, SeekOrigin.Begin);
var zip64_locator = reader.ReadUInt32();
if (zip64_locator != ZIP64_END_OF_CENTRAL_DIRECTORY_LOCATOR)
{
throw new ArchiveException("Failed to locate the Zip64 Directory Locator");
}
var zip64Locator = new Zip64DirectoryEndLocatorHeader();
zip64Locator.Read(reader);
stream.Seek(zip64Locator.RelativeOffsetOfTheEndOfDirectoryRecord, SeekOrigin.Begin);
var zip64Signature = reader.ReadUInt32();
if (zip64Signature != ZIP64_END_OF_CENTRAL_DIRECTORY)
{
throw new ArchiveException("Failed to locate the Zip64 Header");
}
var zip64Entry = new Zip64DirectoryEndHeader();
zip64Entry.Read(reader);
stream.Seek(zip64Entry.DirectoryStartOffsetRelativeToDisk, SeekOrigin.Begin);
}
else
{
stream.Seek(entry.DirectoryStartOffsetRelativeToDisk, SeekOrigin.Begin);
}
var position = stream.Position;
while (true)
{
stream.Position = position;
var signature = reader.ReadUInt32();
var nextHeader = ReadHeader(signature, reader, _zip64);
position = stream.Position;
if (nextHeader is null)
{
yield break;
}
if (nextHeader is DirectoryEntryHeader entryHeader)
{
//entry could be zero bytes so we need to know that.
entryHeader.HasData = entryHeader.CompressedSize != 0;
yield return entryHeader;
}
else if (nextHeader is DirectoryEndHeader endHeader)
{
yield return endHeader;
}
}
}
private static bool IsMatch(byte[] haystack, int position, byte[] needle)
{
for (var i = 0; i < needle.Length; i++)
@@ -138,6 +205,45 @@ internal sealed class SeekableZipHeaderFactory : ZipHeaderFactory
throw new ArchiveException("Failed to locate the Zip Header");
}
private static void SeekBackToHeader(Stream stream, BinaryReader reader)
{
// Minimum EOCD length
if (stream.Length < MINIMUM_EOCD_LENGTH)
{
throw new ArchiveException(
"Could not find Zip file Directory at the end of the file. File may be corrupted."
);
}
var len =
stream.Length < MAX_SEARCH_LENGTH_FOR_EOCD
? (int)stream.Length
: MAX_SEARCH_LENGTH_FOR_EOCD;
// We search for marker in reverse to find the first occurance
byte[] needle = { 0x06, 0x05, 0x4b, 0x50 };
stream.Seek(-len, SeekOrigin.End);
var seek = reader.ReadBytes(len);
// Search in reverse
Array.Reverse(seek);
// don't exclude the minimum eocd region, otherwise you fail to locate the header in empty zip files
var max_search_area = len; // - MINIMUM_EOCD_LENGTH;
for (var pos_from_end = 0; pos_from_end < max_search_area; ++pos_from_end)
{
if (IsMatch(seek, pos_from_end, needle))
{
stream.Seek(-pos_from_end, SeekOrigin.End);
return;
}
}
throw new ArchiveException("Failed to locate the Zip Header");
}
internal LocalEntryHeader GetLocalHeader(
Stream stream,
DirectoryEntryHeader directoryEntryHeader

78
src/SharpCompress/Common/Zip/ZipHeaderFactory.cs
View File

@@ -35,7 +35,11 @@ internal class ZipHeaderFactory
_archiveEncoding = archiveEncoding;
}
protected async ValueTask<ZipHeader?> ReadHeader(uint headerBytes, AsyncBinaryReader reader, bool zip64 = false)
protected async ValueTask<ZipHeader?> ReadHeader(
uint headerBytes,
AsyncBinaryReader reader,
bool zip64 = false
)
{
switch (headerBytes)
{
@@ -49,6 +53,78 @@ internal class ZipHeaderFactory
return entryHeader;
}
case DIRECTORY_START_HEADER_BYTES:
{
var entry = new DirectoryEntryHeader(_archiveEncoding);
await entry.Read(reader);
return entry;
}
case POST_DATA_DESCRIPTOR:
{
if (
_lastEntryHeader != null
&& FlagUtility.HasFlag(
_lastEntryHeader.NotNull().Flags,
HeaderFlags.UsePostDataDescriptor
)
)
{
_lastEntryHeader.Crc = await reader.ReadUInt32Async();
_lastEntryHeader.CompressedSize = zip64
? (long)await reader.ReadUInt64Async()
: await reader.ReadUInt32Async();
_lastEntryHeader.UncompressedSize = zip64
? (long)await reader.ReadUInt64Async()
: await reader.ReadUInt32Async();
}
else
{
await reader.ReadBytesAsync(zip64 ? 20 : 12);
}
return null;
}
case DIGITAL_SIGNATURE:
return null;
case DIRECTORY_END_HEADER_BYTES:
{
var entry = new DirectoryEndHeader();
await entry.Read(reader);
return entry;
}
case SPLIT_ARCHIVE_HEADER_BYTES:
{
return new SplitHeader();
}
case ZIP64_END_OF_CENTRAL_DIRECTORY:
{
var entry = new Zip64DirectoryEndHeader();
await entry.Read(reader);
return entry;
}
case ZIP64_END_OF_CENTRAL_DIRECTORY_LOCATOR:
{
var entry = new Zip64DirectoryEndLocatorHeader();
await entry.Read(reader);
return entry;
}
default:
return null;
}
}
protected ZipHeader? ReadHeader(uint headerBytes, BinaryReader reader, bool zip64 = false)
{
switch (headerBytes)
{
case ENTRY_HEADER_BYTES:
{
var entryHeader = new LocalEntryHeader(_archiveEncoding);
entryHeader.Read(reader);
LoadHeader(entryHeader, reader.BaseStream);
_lastEntryHeader = entryHeader;
return entryHeader;
}
case DIRECTORY_START_HEADER_BYTES:
{
var entry = new DirectoryEntryHeader(_archiveEncoding);
entry.Read(reader);