Fix issue when ZIP64 extra field has different size than expected fro…

…m Central directory file header
weichsel · Jan 23, 2024 · fa7be46 · fa7be46
1 parent cbd9900
commit fa7be46
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Showing 2 changed files with 6 additions and 3 deletions.
diff --git a/Sources/ZIPFoundation/Entry+ZIP64.swift b/Sources/ZIPFoundation/Entry+ZIP64.swift
@@ -104,7 +104,10 @@ extension Entry.ZIP64ExtendedInformation {
 
     init?(data: Data, fields: [Field]) {
         let headerLength = 4
-        guard fields.reduce(0, { $0 + $1.size }) + headerLength == data.count else { return nil }
+        let tmpDataSize:UInt16 = data.scanValue(start: 2)
+        guard Int(tmpDataSize) + headerLength == data.count else {
+            return nil
+        }
         var readOffset = headerLength
         func value<T>(of field: Field) throws -> T where T: BinaryInteger {
             if fields.contains(field) {
@@ -120,7 +123,7 @@ extension Entry.ZIP64ExtendedInformation {
             }
         }
         do {
-            dataSize = data.scanValue(start: 2)
+            dataSize = tmpDataSize
             uncompressedSize = try value(of: .uncompressedSize)
             compressedSize = try value(of: .compressedSize)
             relativeOffsetOfLocalHeader = try value(of: .relativeOffsetOfLocalHeader)

diff --git a/Tests/ZIPFoundationTests/ZIPFoundationEntryTests+ZIP64.swift b/Tests/ZIPFoundationTests/ZIPFoundationEntryTests+ZIP64.swift
@@ -132,7 +132,7 @@ extension ZIPFoundationTests {
         let invalidExtraField2 = ZIP64ExtendedInformation(data: Data(extraFieldBytesMissingByte),
                                                           fields: [.compressedSize, .uncompressedSize])
         XCTAssertNil(invalidExtraField2)
-        let extraFieldBytesWithWrongFields: [UInt8] = [0x01, 0x00, 0x10, 0x00, 0x0a, 0x00, 0x00, 0x00,
+        let extraFieldBytesWithWrongFields: [UInt8] = [0x01, 0x00, 0x0a, 0x00, 0x0a, 0x00, 0x00, 0x00,
                                                        0x00, 0x00, 0x00, 0x00, 0x0a, 0x00, 0x00, 0x00,
                                                        0x00, 0x00, 0x00, 0x00]
         let invalidExtraField3 = ZIP64ExtendedInformation(data: Data(extraFieldBytesWithWrongFields),