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Fix ZIP64 handling for Outlook OLM and other low-version producers #378

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Fix ZIP64 handling for Outlook OLM and other low-version producers #378

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5 changes: 3 additions & 2 deletions Sources/ZIPFoundation/Archive+ZIP64.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -80,8 +80,9 @@ extension Archive.ZIP64EndOfCentralDirectoryRecord {
self.sizeOfZIP64EndOfCentralDirectoryRecord = data.scanValue(start: 4)
self.versionMadeBy = data.scanValue(start: 12)
self.versionNeededToExtract = data.scanValue(start: 14)
// Version Needed to Extract: 4.5 - File uses ZIP64 format extensions
guard self.versionNeededToExtract >= Archive.Version.v45.rawValue else { return nil }
// Note: The ZIP spec recommends versionNeededToExtract >= 4.5 for ZIP64,
// but some producers (e.g. Microsoft Outlook OLM export) write valid ZIP64
// structures with a lower version. We accept the record if the signature matches.
self.numberOfDisk = data.scanValue(start: 16)
self.numberOfDiskStart = data.scanValue(start: 20)
self.totalNumberOfEntriesOnDisk = data.scanValue(start: 24)
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9 changes: 6 additions & 3 deletions Sources/ZIPFoundation/Entry.swift
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Expand Up @@ -297,19 +297,22 @@ extension Entry.CentralDirectoryStructure {
extension Entry.CentralDirectoryStructure {

var effectiveCompressedSize: UInt64 {
if self.isZIP64, let compressedSize = self.zip64ExtendedInformation?.compressedSize, compressedSize > 0 {
if self.isZIP64, self.compressedSize == .max,
let compressedSize = self.zip64ExtendedInformation?.compressedSize {
return compressedSize
}
return UInt64(compressedSize)
}
var effectiveUncompressedSize: UInt64 {
if self.isZIP64, let uncompressedSize = self.zip64ExtendedInformation?.uncompressedSize, uncompressedSize > 0 {
if self.isZIP64, self.uncompressedSize == .max,
let uncompressedSize = self.zip64ExtendedInformation?.uncompressedSize {
return uncompressedSize
}
return UInt64(uncompressedSize)
}
var effectiveRelativeOffsetOfLocalHeader: UInt64 {
if self.isZIP64, let offset = self.zip64ExtendedInformation?.relativeOffsetOfLocalHeader, offset > 0 {
if self.isZIP64, self.relativeOffsetOfLocalHeader == .max,
let offset = self.zip64ExtendedInformation?.relativeOffsetOfLocalHeader {
return offset
}
return UInt64(relativeOffsetOfLocalHeader)
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24 changes: 13 additions & 11 deletions Tests/ZIPFoundationTests/ZIPFoundationArchiveTests+ZIP64.swift
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Expand Up @@ -52,17 +52,19 @@ extension ZIPFoundationTests {
additionalDataProvider: {_ -> Data in
return Data() })
XCTAssertNil(invalidEOCDRecord2)
let eocdRecordWithWrongVersion: [UInt8] = [0x50, 0x4b, 0x06, 0x06, 0x2c, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x1e, 0x03, 0x14, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x4c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x5a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
let invalidEOCDRecord3 = Archive.ZIP64EndOfCentralDirectoryRecord(data: Data(eocdRecordWithWrongVersion),
additionalDataProvider: {_ -> Data in
return Data() })
XCTAssertNil(invalidEOCDRecord3)
// Some ZIP producers (e.g. Microsoft Outlook OLM export) write valid ZIP64
// structures with versionNeededToExtract < 4.5. These should be accepted.
let eocdRecordWithLowVersion: [UInt8] = [0x50, 0x4b, 0x06, 0x06, 0x2c, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x1e, 0x03, 0x14, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x4c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x5a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
let lowVersionEOCDRecord = Archive.ZIP64EndOfCentralDirectoryRecord(data: Data(eocdRecordWithLowVersion),
additionalDataProvider: {_ -> Data in
return Data() })
XCTAssertNotNil(lowVersionEOCDRecord)
}

func testArchiveZIP64EOCDLocator() {
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