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// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package bpf_test
import (
"net"
"testing"
"golang.org/x/net/bpf"
"golang.org/x/net/ipv4"
)
func TestVMLoadAbsoluteOffsetOutOfBounds(t *testing.T) {
pkt := []byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0, 1, 2, 3,
}
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: uint32(len(pkt)),
Size: 1,
},
// Out of bounds should return 0, return 1 to tell if execution continued
bpf.RetConstant{Val: 1},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run(pkt)
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 0, out; want != got {
t.Fatalf("unexpected result:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMLoadAbsoluteOffsetPlusSizeOutOfBounds(t *testing.T) {
pkt := []byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0,
}
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Off: uint32(len(pkt) - 1),
Size: 2,
},
// Out of bounds should return 0, return 1 to tell if execution continued
bpf.RetConstant{Val: 1},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run(pkt)
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 0, out; want != got {
t.Fatalf("unexpected result:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMLoadAbsoluteBadInstructionSize(t *testing.T) {
_, _, err := testVM(t, []bpf.Instruction{
bpf.LoadAbsolute{
Size: 5,
},
bpf.RetA{},
})
if errStr(err) != "assembling instruction 1: invalid load byte length 0" {
t.Fatalf("unexpected error: %v", err)
}
}
func TestVMLoadConstantOK(t *testing.T) {
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadConstant{
Dst: bpf.RegX,
Val: 9,
},
bpf.TXA{},
bpf.RetA{},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0,
})
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 1, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMLoadIndirectOutOfBounds(t *testing.T) {
pkt := []byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0,
}
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadIndirect{
Off: uint32(len(pkt)),
Size: 1,
},
// Out of bounds should return 0, return 1 to tell if execution continued
bpf.RetConstant{Val: 1},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run(pkt)
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 0, out; want != got {
t.Fatalf("unexpected result:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMLoadMemShiftOutOfBounds(t *testing.T) {
pkt := []byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
0,
}
vm, done, err := testVM(t, []bpf.Instruction{
bpf.LoadMemShift{
Off: uint32(len(pkt)),
},
// Out of bounds should return 0, return 1 to tell if execution continued
bpf.RetConstant{Val: 1},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
defer done()
out, err := vm.Run(pkt)
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 0, out; want != got {
t.Fatalf("unexpected result:\n- want: %d\n- got: %d",
want, got)
}
}
const (
dhcp4Port = 53
)
func TestVMLoadMemShiftLoadIndirectNoResult(t *testing.T) {
vm, in, done := testDHCPv4(t)
defer done()
// Append mostly empty UDP header with incorrect DHCPv4 port
in = append(in, []byte{
0, 0,
0, dhcp4Port + 1,
0, 0,
0, 0,
}...)
out, err := vm.Run(in)
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := 0, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func TestVMLoadMemShiftLoadIndirectOK(t *testing.T) {
vm, in, done := testDHCPv4(t)
defer done()
// Append mostly empty UDP header with correct DHCPv4 port
in = append(in, []byte{
0, 0,
0, dhcp4Port,
0, 0,
0, 0,
}...)
out, err := vm.Run(in)
if err != nil {
t.Fatalf("unexpected error while running program: %v", err)
}
if want, got := len(in)-8, out; want != got {
t.Fatalf("unexpected number of output bytes:\n- want: %d\n- got: %d",
want, got)
}
}
func testDHCPv4(t *testing.T) (virtualMachine, []byte, func()) {
// DHCPv4 test data courtesy of David Anderson:
// https://github.com/google/netboot/blob/master/dhcp4/conn_linux.go#L59-L70
vm, done, err := testVM(t, []bpf.Instruction{
// Load IPv4 packet length
bpf.LoadMemShift{Off: 8},
// Get UDP dport
bpf.LoadIndirect{Off: 8 + 2, Size: 2},
// Correct dport?
bpf.JumpIf{Cond: bpf.JumpEqual, Val: dhcp4Port, SkipFalse: 1},
// Accept
bpf.RetConstant{Val: 1500},
// Ignore
bpf.RetConstant{Val: 0},
})
if err != nil {
t.Fatalf("failed to load BPF program: %v", err)
}
// Minimal requirements to make a valid IPv4 header
h := &ipv4.Header{
Len: ipv4.HeaderLen,
Src: net.IPv4(192, 168, 1, 1),
Dst: net.IPv4(192, 168, 1, 2),
}
hb, err := h.Marshal()
if err != nil {
t.Fatalf("failed to marshal IPv4 header: %v", err)
}
hb = append([]byte{
0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff,
}, hb...)
return vm, hb, done
}
|
