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|
package helper
import (
"flag"
"io"
"os"
"os/exec"
"strconv"
"strings"
"syscall"
"testing"
"git.ophivana.moe/security/fortify/helper/bwrap"
"git.ophivana.moe/security/fortify/internal/fmsg"
)
// InternalChildStub is an internal function but exported because it is cross-package;
// it is part of the implementation of the helper stub.
func InternalChildStub() {
// this test mocks the helper process
if os.Getenv(FortifyHelper) != "1" ||
os.Getenv(FortifyStatus) == "-1" { // this indicates the stub is being invoked as a bwrap child without pipes
return
}
argsFD := flag.Int("args", -1, "")
statFD := flag.Int("fd", -1, "")
_ = flag.CommandLine.Parse(os.Args[4:])
switch os.Args[3] {
case "bwrap":
bwrapStub(argsFD, statFD)
default:
genericStub(argsFD, statFD)
}
fmsg.Exit(0)
}
// InternalReplaceExecCommand is an internal function but exported because it is cross-package;
// it is part of the implementation of the helper stub.
func InternalReplaceExecCommand(t *testing.T) {
t.Cleanup(func() {
execCommand = exec.Command
})
// replace execCommand to have the resulting *exec.Cmd launch TestHelperChildStub
execCommand = func(name string, arg ...string) *exec.Cmd {
// pass through nonexistent path
if name == "/nonexistent" && len(arg) == 0 {
return exec.Command(name)
}
return exec.Command(os.Args[0], append([]string{"-test.run=TestHelperChildStub", "--", name}, arg...)...)
}
}
func genericStub(argsFD, statFD *int) {
// simulate args pipe behaviour
func() {
if *argsFD == -1 {
panic("attempted to start helper without passing args pipe fd")
}
f := os.NewFile(uintptr(*argsFD), "|0")
if f == nil {
panic("attempted to start helper without args pipe")
}
if _, err := io.Copy(os.Stdout, f); err != nil {
panic("cannot read args: " + err.Error())
}
}()
var wait chan struct{}
// simulate status pipe behaviour
if os.Getenv(FortifyStatus) == "1" {
if *statFD == -1 {
panic("attempted to start helper with status reporting without passing status pipe fd")
}
wait = make(chan struct{})
go func() {
f := os.NewFile(uintptr(*statFD), "|1")
if f == nil {
panic("attempted to start with status reporting without status pipe")
}
if _, err := f.Write([]byte{'x'}); err != nil {
panic("cannot write to status pipe: " + err.Error())
}
// wait for status pipe close
var epoll int
if fd, err := syscall.EpollCreate1(0); err != nil {
panic("cannot open epoll fd: " + err.Error())
} else {
defer func() {
if err = syscall.Close(fd); err != nil {
panic("cannot close epoll fd: " + err.Error())
}
}()
epoll = fd
}
if err := syscall.EpollCtl(epoll, syscall.EPOLL_CTL_ADD, int(f.Fd()), &syscall.EpollEvent{}); err != nil {
panic("cannot add status pipe to epoll: " + err.Error())
}
events := make([]syscall.EpollEvent, 1)
if _, err := syscall.EpollWait(epoll, events, -1); err != nil {
panic("cannot poll status pipe: " + err.Error())
}
if events[0].Events != syscall.EPOLLERR {
panic(strconv.Itoa(int(events[0].Events)))
}
close(wait)
}()
}
if wait != nil {
<-wait
}
}
func bwrapStub(argsFD, statFD *int) {
// the bwrap launcher does not ever launch with sync fd
if *statFD != -1 {
panic("attempted to launch bwrap with status monitoring")
}
// test args pipe behaviour
func() {
if *argsFD == -1 {
panic("attempted to start bwrap without passing args pipe fd")
}
f := os.NewFile(uintptr(*argsFD), "|0")
if f == nil {
panic("attempted to start helper without args pipe")
}
got, want := new(strings.Builder), new(strings.Builder)
if _, err := io.Copy(got, f); err != nil {
panic("cannot read args: " + err.Error())
}
// hardcoded bwrap configuration used by test
if _, err := MustNewCheckedArgs((&bwrap.Config{
Unshare: nil,
Net: true,
UserNS: false,
Hostname: "localhost",
Chdir: "/nonexistent",
Clearenv: true,
NewSession: true,
DieWithParent: true,
AsInit: true,
}).Args()).WriteTo(want); err != nil {
panic("cannot read want: " + err.Error())
}
if len(flag.CommandLine.Args()) > 0 && flag.CommandLine.Args()[0] == "crash-test-dummy" && got.String() != want.String() {
panic("bad bwrap args\ngot: " + got.String() + "\nwant: " + want.String())
}
}()
if err := syscall.Exec(
os.Args[0],
append([]string{os.Args[0], "-test.run=TestHelperChildStub", "--"}, flag.CommandLine.Args()...),
os.Environ()); err != nil {
panic("cannot start general stub: " + err.Error())
}
}
|
