feat(magic): port of nfc-tools/libnfc#461

Author: maitredede

magic/magic.go

@@ -0,0 +1,72 @@
+package magic
+
+import (
+	"github.com/maitredede/gonfc"
+	"go.uber.org/zap"
+)
+
+const (
+	MAX_FRAME_LEN          int  = 264
+	SAK_FLAG_ATS_SUPPORTED byte = 0x20
+	CASCADE_BIT            byte = 0x04
+)
+
+// ISO14443A Anti-Collision Commands
+var (
+	abtReqa      = []byte{0x26}
+	strangeWupa  = []byte{0x40}
+	backdoorTest = []byte{0x43}
+	abtSelectAll = []byte{0x93, 0x20}
+	abtSelectTag = []byte{0x93, 0x70, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
+	abtRats      = []byte{0xe0, 0x50, 0x00, 0x00}
+	abtHalt      = []byte{0x50, 0x00, 0x00, 0x00}
+)
+
+// IsMagicCard is an implementation of https://github.com/nfc-tools/libnfc/pull/461
+func IsMagicCard(device gonfc.Device) (bool, error) {
+	l := device.Logger().Named("magic")
+
+	// Configure the CRC
+	if err := device.SetPropertyBool(gonfc.NP_HANDLE_CRC, false); err != nil {
+		return false, err
+	}
+
+	// Use raw send/receive methods
+	if err := device.SetPropertyBool(gonfc.NP_EASY_FRAMING, false); err != nil {
+		return false, err
+	}
+
+	// Disable 14443-4 autoswitching
+	if err := device.SetPropertyBool(gonfc.NP_AUTO_ISO14443_4, false); err != nil {
+		return false, err
+	}
+
+	if err := transmitBits(l, device, strangeWupa, 7); err != nil {
+		l.Debugf("This is NOT a backdoored rewritable UID card")
+		return false, nil
+	}
+	if err := transmitBytes(l, device, backdoorTest); err != nil {
+		l.Debugf("This is backdoored rewritable UID card")
+		return true, nil
+	}
+	l.Debugf("This is NOT a backdoored rewritable UID card")
+	return false, nil
+}
+
+func transmitBits(l *zap.SugaredLogger, device gonfc.Device, pbtx []byte, szTxBits int) error {
+	abtRx := make([]byte, 264)
+	_ /*n*/, err := device.InitiatorTransceiveBits(pbtx, szTxBits, nil, abtRx, nil)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func transmitBytes(l *zap.SugaredLogger, device gonfc.Device, pbtx []byte) error {
+	abtRx := make([]byte, 264)
+	_ /*n*/, err := device.InitiatorTransceiveBytes(pbtx, abtRx, 0)
+	if err != nil {
+		return err
+	}
+	return nil
+}