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long-cbor decode fix #119

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long-cbor decode fix #119

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9 changes: 8 additions & 1 deletion Sources/CBORDecoder.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -60,9 +60,16 @@ public class CBORDecoder {
throw CBORError.tooLongSequence
}

/// Application-safe limit here
let MAX_REASONABLE_LENGTH = 200_000
guard n <= MAX_REASONABLE_LENGTH else {
throw CBORError.tooLongSequence
}

return Int(n)
}


private func readN(_ n: Int) throws -> [CBOR] {
return try (0..<n).map { _ in
guard let r = try decodeItem() else { throw CBORError.unfinishedSequence }
Expand Down Expand Up @@ -197,7 +204,7 @@ public class CBORDecoder {
return CBOR.double(try readBinaryNumber(Float64.self))

case 0xff: return CBOR.break
default: return nil
default: throw CBORError.unfinishedSequence
}
}
}
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32 changes: 32 additions & 0 deletions Tests/CBORDecoderTests.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -201,8 +201,40 @@ class CBORDecoderTests: XCTestCase {
_ = try? CBOR.decode(randomData, options: CBOROptions(maximumDepth: 512))
}
}

func testDecodeFailsForAbsurdlyBigArrayOrMapLength() {

let hugeArrayHeader: [UInt8] = [
0x9b,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
]

XCTAssertThrowsError(try CBORDecoder(input: hugeArrayHeader).decodeItem()) { error in
XCTAssertEqual(error as? CBORError, CBORError.tooLongSequence)
}

let hugeMapHeader: [UInt8] = [
0xbb,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
]

XCTAssertThrowsError(try CBORDecoder(input: hugeMapHeader).decodeItem()) { error in
XCTAssertEqual(error as? CBORError, CBORError.tooLongSequence)
}
}

func testDecodeFailsForEmptyInput() {
let emptyInput: [UInt8] = []
XCTAssertThrowsError(try CBORDecoder(input: emptyInput).decodeItem()) { error in
XCTAssertEqual(error as? CBORError, CBORError.unfinishedSequence)
}
}


}



#if os(Android)

extension XCTestCase {
Expand Down