tailscale/net/stun/fuzz_test.go

// Copyright (c) Tailscale Inc & contributors
// SPDX-License-Identifier: BSD-3-Clause

package stun

import "testing"

// A STUN message is 20 bytes: 2-byte type, 2-byte length, 4-byte magic
// cookie at offsets 4–7, then a 12-byte transaction ID.
var minimalValidSTUN = []byte{
	0x00, 0x01, // message type: Binding request (STUN method + class)
	0x00, 0x00, // message length: 0
	0x21, 0x12, 0xa4, 0x42, // fixed STUN magic cookie
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // transaction ID (12 bytes)
}

func FuzzParseResponse(f *testing.F) {
	f.Add(minimalValidSTUN)
	// seeds from test cases
	f.Add([]byte{0x1, 0x1, 0x0, 0x14, 0x21, 0x12, 0xa4, 0x42, 0xeb, 0xc2, 0xd3,
		0x6e, 0xf4, 0x71, 0x21, 0x7c, 0x4f, 0x3e, 0x30, 0x8e, 0x80, 0x22, 0x0, 0x3, 0x61,
		0x62, 0x63, 0x0, 0x0, 0x20, 0x0, 0x8, 0x0, 0x1, 0xce, 0x66, 0x5e, 0x12, 0xa4,
		0x43})
	f.Add([]byte{0x1, 0x1, 0x0, 0xc, 0x21, 0x12, 0xa4, 0x42, 0x23, 0x60, 0xb1, 0x1e,
		0x3e, 0xc6, 0x8f, 0xfa, 0x93, 0xe0, 0x80, 0x7, 0x0, 0x20, 0x0, 0x8, 0x0, 0x1,
		0xc7, 0x86, 0x69, 0x57, 0x85, 0x6f})
	f.Add([]byte{0x1, 0x1, 0x0, 0x24, 0x21, 0x12, 0xa4, 0x42, 0x7e, 0x57, 0x96,
		0x68, 0x29, 0xf4, 0x44, 0x60, 0x9d, 0x1d, 0xea, 0xa6, 0x0, 0x1, 0x0, 0x8, 0x0,
		0x1, 0xe9, 0xd3, 0x48, 0x45, 0x21, 0x2d, 0x0, 0x4, 0x0, 0x8, 0x0, 0x1, 0xd, 0x96,
		0x4d, 0x48, 0xa9, 0xd4, 0x0, 0x5, 0x0, 0x8, 0x0, 0x1, 0xd, 0x97, 0x4d, 0x48,
		0xa9, 0xd5})
	f.Add([]byte{0x1, 0x1, 0x0, 0x24, 0x21, 0x12, 0xa4, 0x42, 0xeb, 0xc2, 0xd3,
		0x6e, 0xf4, 0x71, 0x21, 0x7c, 0x4f, 0x3e, 0x30, 0x8e, 0x80, 0x22, 0x0, 0xa, 0x65,
		0x6e, 0x64, 0x70, 0x6f, 0x69, 0x6e, 0x74, 0x65, 0x72, 0x0, 0x0, 0x0, 0x20, 0x0,
		0x8, 0x0, 0x1, 0xce, 0x66, 0x5e, 0x12, 0xa4, 0x43, 0x80, 0x28, 0x0, 0x4, 0xb6,
		0x99, 0xbb, 0x2, 0x1, 0x1, 0x0, 0x24, 0x21, 0x12, 0xa4, 0x42})
	f.Add([]byte{0x1, 0x1, 0x0, 0x44, 0x21, 0x12, 0xa4, 0x42, 0x48, 0x2e, 0xb6,
		0x47, 0x15, 0xe8, 0xb2, 0x8e, 0xae, 0xad, 0x64, 0x44, 0x0, 0x1, 0x0, 0x8, 0x0,
		0x1, 0xe4, 0xab, 0x48, 0x45, 0x21, 0x2d, 0x0, 0x4, 0x0, 0x8, 0x0, 0x1, 0x27,
		0x10, 0xd9, 0xa, 0x44, 0x98, 0x0, 0x5, 0x0, 0x8, 0x0, 0x1, 0x27, 0x11, 0xd9,
		0x74, 0x7a, 0x8a, 0x80, 0x20, 0x0, 0x8, 0x0, 0x1, 0xc5, 0xb9, 0x69, 0x57, 0x85,
		0x6f, 0x80, 0x22, 0x0, 0x10, 0x56, 0x6f, 0x76, 0x69, 0x64, 0x61, 0x2e, 0x6f,
		0x72, 0x67, 0x20, 0x30, 0x2e, 0x39, 0x36, 0x0})
	f.Add([]byte{0x1, 0x1, 0x0, 0x48, 0x21, 0x12, 0xa4, 0x42, 0x6, 0xf5, 0x66, 0x85,
		0xd2, 0x8a, 0xf3, 0xe6, 0x9c, 0xe3, 0x41, 0xe2, 0x0, 0x1, 0x0, 0x14, 0x0, 0x2,
		0x90, 0xce, 0x26, 0x2, 0x0, 0xd1, 0xb4, 0xcf, 0xc1, 0x0, 0x38, 0xb2, 0x31, 0xff,
		0xfe, 0xef, 0x96, 0xf6, 0x80, 0x2b, 0x0, 0x14, 0x0, 0x2, 0xd, 0x96, 0x26, 0x4,
		0xa8, 0x80, 0x0, 0x2, 0x0, 0xd1, 0x0, 0x0, 0x0, 0x0, 0x0, 0xc5, 0x70, 0x1, 0x0,
		0x20, 0x0, 0x14, 0x0, 0x2, 0xb1, 0xdc, 0x7, 0x10, 0xa4, 0x93, 0xb2, 0x3a, 0xa7,
		0x85, 0xea, 0x38, 0xc2, 0x19, 0x62, 0xc, 0xd7, 0x14})
	f.Add([]byte{0x1, 0x1, 0x0, 0xc, 0x21, 0x12, 0xa4, 0x42, 0xf9, 0xf1, 0x21, 0xcb,
		0xde, 0x7d, 0x7c, 0x75, 0x92, 0x3c, 0xe2, 0x71, 0x0, 0x20, 0x0, 0x8, 0x0, 0x1,
		0xc7, 0x87, 0x69, 0x57, 0x85, 0x6f})
	f.Add([]byte{0x1, 0x1, 0x0, 0x18, 0x21, 0x12, 0xa4, 0x42, 0x4f, 0xd5, 0xd2, 0x2,
		0xdc, 0xb3, 0x7d, 0x31, 0xfc, 0x77, 0x33, 0x6, 0x0, 0x20, 0x0, 0x14, 0x0, 0x2,
		0xcd, 0x3d, 0x21, 0x12, 0xa4, 0x42, 0x4f, 0xd5, 0xd2, 0x2, 0xdc, 0xb3, 0x82,
		0xce, 0x2d, 0xc3, 0xfc, 0xc7})
	f.Add([]byte{0x1, 0x1, 0x0, 0x14, 0x21, 0x12, 0xa4, 0x42, 0xeb, 0xc2, 0xd3,
		0x6e, 0xf4, 0x71, 0x21, 0x7c, 0x4f, 0x3e, 0x30, 0x8e, 0x80, 0x22, 0x0, 0x1, 0x61,
		0x0, 0x0, 0x0, 0x0, 0x20, 0x0, 0x8, 0x0, 0x1, 0xce, 0x66, 0x5e, 0x12, 0xa4, 0x43})

	f.Fuzz(func(t *testing.T, data []byte) {
		_, _, _ = ParseResponse(data)
	})
}

func FuzzParseBindingRequest(f *testing.F) {
	f.Add(minimalValidSTUN)
	f.Add(Request(NewTxID()))

	f.Fuzz(func(t *testing.T, data []byte) {
		_, _ = ParseBindingRequest(data)
	})
}

func FuzzMappedAddress(f *testing.F) {
	f.Add([]byte{0x0, 0x1, 0xe4, 0xab, 0x48, 0x45, 0x21, 0x2d})
	f.Add([]byte{0x0, 0x1, 0x21, 0x12, 0xa4, 0x42, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
		0x0, 0x0})
	f.Add([]byte{0x0, 0x1, 0xe9, 0xd3, 0x48, 0x45, 0x21, 0x2d})
	f.Add([]byte{0x0, 0x2, 0x90, 0xce, 0x26, 0x2, 0x0, 0xd1, 0xb4, 0xcf, 0xc1, 0x0,
		0x38, 0xb2, 0x31, 0xff, 0xfe, 0xef, 0x96, 0xf6})

	f.Fuzz(func(t *testing.T, data []byte) {
		_, _, _ = mappedAddress(data)
	})
}

func FuzzForeachAttr(f *testing.F) {
	// Single MAPPED-ADDRESS attribute (IPv4): type 0x0001
	f.Add([]byte{0x00, 0x01, 0x00, 0x08, 0x00, 0x01, 0xe9, 0xd3,
		0x48, 0x45, 0x21, 0x2d})
	// Single MAPPED-ADDRESS attribute (IPv6): type 0x0001
	f.Add([]byte{0x00, 0x01, 0x00, 0x14, 0x00, 0x02, 0x90, 0xce, 0x26, 0x02, 0x00, 0xd1, 0xb4, 0xcf, 0xc1, 0x00, 0x38, 0xb2,
		0x31, 0xff, 0xfe, 0xef, 0x96, 0xf6})

	f.Fuzz(func(t *testing.T, data []byte) {
		_ = foreachAttr(data, func(_ uint16, _ []byte) error {
			return nil
		})
	})
}

func FuzzXorMappedAddress(f *testing.F) {
	f.Add([]byte{0x00, 0x01, 0xe4, 0xab, 0x48, 0x45, 0x21, 0x2d})
	f.Add([]byte{0x02, 0x90, 0xce, 0x26, 0x1, 0x0, 0xd1, 0xb4, 0xcf, 0xc1, 0x38, 0xb2})

	f.Fuzz(func(t *testing.T, data []byte) {
		var tx TxID
		_, _, _ = xorMappedAddress(tx, data)
	})
}