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Force write of local file header when "version needed to extract" changes #112032

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merged 4 commits into from
Feb 10, 2025
Merged

Force write of local file header when "version needed to extract" changes #112032

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fcbc4e1
Add failing test
edwardneal Jan 31, 2025
8999361
Force local file headers to be rewritten if the version to extract is…
edwardneal Jan 31, 2025
63a1fac
Code review
edwardneal Jan 31, 2025
056cf91
Merge branch 'main' into issue-112017
carlossanlop Jan 31, 2025
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9 changes: 6 additions & 3 deletions src/libraries/System.IO.Compression/src/System/IO/Compression/ZipArchiveEntry.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -60,7 +60,6 @@ internal ZipArchiveEntry(ZipArchive archive, ZipCentralDirectoryFileHeader cd)
_versionToExtract = (ZipVersionNeededValues)cd.VersionNeededToExtract;
_generalPurposeBitFlag = (BitFlagValues)cd.GeneralPurposeBitFlag;
_isEncrypted = (_generalPurposeBitFlag & BitFlagValues.IsEncrypted) != 0;
CompressionMethod = (CompressionMethodValues)cd.CompressionMethod;
_lastModified = new DateTimeOffset(ZipHelper.DosTimeToDateTime(cd.LastModified));
_compressedSize = cd.CompressedSize;
_uncompressedSize = cd.UncompressedSize;
Expand All @@ -87,9 +86,11 @@ internal ZipArchiveEntry(ZipArchive archive, ZipCentralDirectoryFileHeader cd)

_fileComment = cd.FileComment;

_compressionLevel = MapCompressionLevel(_generalPurposeBitFlag, CompressionMethod);

Changes = ZipArchive.ChangeState.Unchanged;

// Setting CompressionMethod can change the _versionToExtract variable, which can change the value of Changes
CompressionMethod = (CompressionMethodValues)cd.CompressionMethod;
_compressionLevel = MapCompressionLevel(_generalPurposeBitFlag, CompressionMethod);
}

// Initializes a ZipArchiveEntry instance for a new archive entry with a specified compression level.
Expand Down Expand Up @@ -1243,10 +1244,12 @@ private void VersionToExtractAtLeast(ZipVersionNeededValues value)
if (_versionToExtract < value)
{
_versionToExtract = value;
Changes |= ZipArchive.ChangeState.FixedLengthMetadata;
}
if (_versionMadeBySpecification < value)
{
_versionMadeBySpecification = value;
Changes |= ZipArchive.ChangeState.FixedLengthMetadata;
}
}

Expand Down
139 changes: 139 additions & 0 deletions src/libraries/System.IO.Compression/tests/ZipArchive/zip_InvalidParametersAndStrangeFiles.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -907,6 +907,145 @@ public static async Task ZipArchive_InvalidHuffmanData()
}
}

[Fact]
public static void ZipArchive_InvalidVersionToExtract()
{
using (MemoryStream updatedStream = new MemoryStream())
{
int originalLocalVersionToExtract = s_inconsistentVersionToExtract[4];
int originalCentralDirectoryVersionToExtract = s_inconsistentVersionToExtract[57];

// The existing archive will have a "version to extract" of 0.0, but will contain entries
// with deflate compression (which has a minimum version to extract of 2.0.)
Assert.Equal(0x00, originalLocalVersionToExtract);
Assert.Equal(0x00, originalCentralDirectoryVersionToExtract);

updatedStream.Write(s_inconsistentVersionToExtract);
updatedStream.Seek(0, SeekOrigin.Begin);

using (ZipArchive originalArchive = new ZipArchive(updatedStream, ZipArchiveMode.Read, true))
{
Assert.Equal(1, originalArchive.Entries.Count);

ZipArchiveEntry firstEntry = originalArchive.Entries[0];

Assert.Equal("first.bin", firstEntry.Name);
Assert.Equal(10, firstEntry.Length);

using (Stream entryStream = firstEntry.Open())
{
Assert.Equal(10, firstEntry.Length);

byte[] uncompressedBytes = new byte[firstEntry.Length];
int bytesRead = entryStream.Read(uncompressedBytes);

Assert.Equal(10, bytesRead);

Assert.Equal(new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09 }, uncompressedBytes);
}
}

updatedStream.Seek(0, SeekOrigin.Begin);

// Create a new entry, forcing the central directory headers to be rewritten. The local file header
// for first.bin would normally be skipped (because it hasn't changed) but it needs to be rewritten
// because the central directory headers will be rewritten with a valid value and the local file header
// needs to match.
using (ZipArchive updatedArchive = new ZipArchive(updatedStream, ZipArchiveMode.Update))
{
ZipArchiveEntry newEntry = updatedArchive.CreateEntry("second.bin", CompressionLevel.NoCompression);
}

byte[] updatedContents = updatedStream.ToArray();
int updatedLocalVersionToExtract = updatedContents[4];
int updatedCentralDirectoryVersionToExtract = updatedContents[97];

Assert.Equal(20, updatedCentralDirectoryVersionToExtract);
Assert.Equal(20, updatedLocalVersionToExtract);
}
}

private static readonly byte[] s_inconsistentVersionToExtract =
{
// ===== Local file header signature 0x04034b50
0x50, 0x4b, 0x03, 0x04,
// version to extract 0.0 (invalid - this should be at least 2.0 to make use of deflate compression)
0x00, 0x00,
// general purpose flags
0x02, 0x00, // 0000_0002 'for maximum-compression deflating'
// Deflate
0x08, 0x00,
// Last mod file time
0x3b, 0x33,
// Last mod date
0x3f, 0x5a,
// CRC32
0x46, 0xd7, 0x6c, 0x45,
// compressed size
0x0c, 0x00, 0x00, 0x00,
// UNcompressed size
0x0a, 0x00, 0x00, 0x00,
// file name length
0x09, 0x00,
// extra field length
0x00, 0x00,
// filename
0x66, 0x69, 0x72, 0x73, 0x74, 0x2e, 0x62, 0x69, 0x6e,
// -------------
// Data!
0x63, 0x60, 0x64, 0x62, 0x66, 0x61, 0x65, 0x63, 0xe7, 0xe0, 0x04, 0x00,
// -------- Central directory signature 0x02014b50
0x50, 0x4b, 0x01, 0x02,
// version made by 2.0
0x14, 0x00,
// version to extract 0.0 (invalid - this should be at least 2.0 to make use of deflate compression)
0x00, 0x00,
// general purpose flags
0x02, 0x00,
// Deflate
0x08, 0x00,
// Last mod file time
0x3b, 0x33,
// Last mod date
0x3f, 0x5a,
// CRC32
0x46, 0xd7, 0x6c, 0x45,
// compressed size
0x0c, 0x00, 0x00, 0x00,
// UNcompressed size
0x0a, 0x00, 0x00, 0x00,
// file name length
0x09, 0x00,
// extra field length
0x00, 0x00,
// file comment length
0x00, 0x00,
// disk number start
0x00, 0x00,
// internal file attributes
0x00, 0x00,
// external file attributes
0x00, 0x00, 0x00, 0x00,
// relative offset of local header
0x00, 0x00, 0x00, 0x00,
// file name
0x66, 0x69, 0x72, 0x73, 0x74, 0x2e, 0x62, 0x69, 0x6e,
// == 'end of CD' signature 0x06054b50
0x50, 0x4b, 0x05, 0x06,
// disk number, disk number with CD
0x00, 0x00,
0x00, 0x00,
// total number of entries in CD on this disk, and overall
0x01, 0x00,
0x01, 0x00,
// size of CD
0x37, 0x00, 0x00, 0x00,
// offset of start of CD wrt start disk
0x33, 0x00, 0x00, 0x00,
// comment length
0x00, 0x00
};

private static readonly byte[] s_slightlyIncorrectZip64 =
{
// ===== Local file header signature 0x04034b50
Expand Down
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