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Fix NFC card actions #182

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Merged
martenrebane merged 1 commit into from
Mar 26, 2026
Merged

Fix NFC card actions #182

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36 changes: 33 additions & 3 deletions Modules/IdCardLib/Sources/IdCardLib/CardActions/CardReaderNFC.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -67,8 +67,8 @@ class CardReaderNFC: @unchecked CardReader, Loggable {
typealias TLV = TKBERTLVRecord

let tag: SendableISO7816Tag
var ksEnc: Bytes
var ksMac: Bytes
var ksEnc: Bytes = AES.Zero
var ksMac: Bytes = AES.Zero
var SSC: Bytes = AES.Zero

init(_ tag: NFCISO7816Tag, CAN: String) async throws {
Expand All @@ -78,8 +78,9 @@ class CardReaderNFC: @unchecked CardReader, Loggable {
_ = try await self.tag.sendCommand(cls: 0x00, ins: 0xA4, p1Byte: 0x02, p2Byte: 0x0C, data: Data([0x01, 0x1C]))
CardReaderNFC.logger().debug("Read CardAccess")
let data = try await self.tag.sendCommand(cls: 0x00, ins: 0xB0, p1Byte: 0x00, p2Byte: 0x00, leByte: 256)
let sanitizedData = sanitizedTLV(data)

guard let (mappingType, parameterId) = TLV.sequenceOfRecords(from: data)?
guard let (mappingType, parameterId) = TLV.sequenceOfRecords(from: sanitizedData)?
.flatMap({ cardAccess in TLV.sequenceOfRecords(from: cardAccess.value) ?? [] })
.compactMap({ tlv in
if let records = TLV.sequenceOfRecords(from: tlv.value),
Expand Down Expand Up @@ -201,6 +202,35 @@ class CardReaderNFC: @unchecked CardReader, Loggable {
}
}

private func sanitizedTLV(_ data: Data) -> Data {
guard data.count >= 2 else { return data }

var index = 1
let firstLengthByte = data[index]
index += 1

let valueLength: Int

if firstLengthByte & 0x80 == 0 {
valueLength = Int(firstLengthByte)
} else {
let lengthByteCount = Int(firstLengthByte & 0x7F)

guard data.count >= index + lengthByteCount else {
return data
}

valueLength = data[index..<(
index + lengthByteCount
)].reduce(0) { ($0 << 8) | Int($1) }

index += lengthByteCount
}

let totalLength = index + valueLength
return data.prefix(min(totalLength, data.count))
}

private func getDO87(_ apdu: NFCISO7816APDU) throws -> Data {
if let data = apdu.data, !data.isEmpty {
let ivValue = try AES.CBC(key: ksEnc).encrypt(SSC)
Expand Down
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