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|
//go:build testtool
/*
Package sandbox provides utilities for checking sandbox outcome.
This package must never be used outside integration tests, there is a much better native implementation of mountinfo
in the public sandbox/vfs package. Files in this package are excluded by the build system to prevent accidental misuse.
*/
package sandbox
import (
"crypto/sha512"
"encoding/hex"
"encoding/json"
"errors"
"io/fs"
"log"
"os"
"syscall"
)
var (
assert = log.New(os.Stderr, "sandbox: ", 0)
printfFunc = assert.Printf
fatalfFunc = assert.Fatalf
)
func printf(format string, v ...any) { printfFunc(format, v...) }
func fatalf(format string, v ...any) { fatalfFunc(format, v...) }
type TestCase struct {
Env []string `json:"env"`
FS *FS `json:"fs"`
Mount []*MountinfoEntry `json:"mount"`
Seccomp bool `json:"seccomp"`
}
type T struct {
FS fs.FS
MountsPath string
}
func (t *T) MustCheckFile(wantFilePath string) {
var want *TestCase
mustDecode(wantFilePath, &want)
t.MustCheck(want)
}
func (t *T) MustCheck(want *TestCase) {
if want.Env != nil {
var (
fail bool
i int
got string
)
for i, got = range os.Environ() {
if i == len(want.Env) {
fatalf("got more than %d environment variables", len(want.Env))
}
if got != want.Env[i] {
fail = true
printf("[FAIL] %s", got)
} else {
printf("[ OK ] %s", got)
}
}
i++
if i != len(want.Env) {
fatalf("got %d environment variables, want %d", i, len(want.Env))
}
if fail {
fatalf("[FAIL] some environment variables did not match")
}
} else {
printf("[SKIP] skipping environ check")
}
if want.FS != nil && t.FS != nil {
if err := want.FS.Compare(".", t.FS); err != nil {
fatalf("%v", err)
}
} else {
printf("[SKIP] skipping fs check")
}
if want.Mount != nil {
var fail bool
m := mustParseMountinfo(t.MountsPath)
i := 0
for ent := range m.Entries() {
if i == len(want.Mount) {
fatalf("got more than %d entries", i)
}
if !ent.EqualWithIgnore(want.Mount[i], "//ignore") {
fail = true
printf("[FAIL] %s", ent)
} else {
printf("[ OK ] %s", ent)
}
i++
}
if err := m.Err(); err != nil {
fatalf("%v", err)
}
if i != len(want.Mount) {
fatalf("got %d entries, want %d", i, len(want.Mount))
}
if fail {
fatalf("[FAIL] some mount points did not match")
}
} else {
printf("[SKIP] skipping mounts check")
}
if want.Seccomp {
if trySyscalls() != nil {
os.Exit(1)
}
} else {
printf("[SKIP] skipping seccomp check")
}
}
func MustCheckFilter(pid int, want string) {
err := CheckFilter(pid, want)
if err == nil {
return
}
var perr *ptraceError
if !errors.As(err, &perr) {
fatalf("%s", err)
}
switch perr.op {
case "PTRACE_ATTACH":
fatalf("cannot attach to process %d: %v", pid, err)
case "PTRACE_SECCOMP_GET_FILTER":
if perr.errno == syscall.ENOENT {
fatalf("seccomp filter not installed for process %d", pid)
}
fatalf("cannot get filter: %v", err)
default:
fatalf("cannot check filter: %v", err)
}
*(*int)(nil) = 0 // not reached
}
func CheckFilter(pid int, want string) error {
if err := ptraceAttach(pid); err != nil {
return err
}
defer func() {
if err := ptraceDetach(pid); err != nil {
printf("cannot detach from process %d: %v", pid, err)
}
}()
h := sha512.New()
if buf, err := getFilter[[8]byte](pid, 0); err != nil {
return err
} else {
for _, b := range buf {
h.Write(b[:])
}
}
if got := hex.EncodeToString(h.Sum(nil)); got != want {
printf("[FAIL] %s", got)
return syscall.ENOTRECOVERABLE
} else {
printf("[ OK ] %s", got)
return nil
}
}
func mustDecode(wantFilePath string, v any) {
if f, err := os.Open(wantFilePath); err != nil {
fatalf("cannot open %q: %v", wantFilePath, err)
} else if err = json.NewDecoder(f).Decode(v); err != nil {
fatalf("cannot decode %q: %v", wantFilePath, err)
} else if err = f.Close(); err != nil {
fatalf("cannot close %q: %v", wantFilePath, err)
}
}
func mustParseMountinfo(name string) *Mountinfo {
m := NewMountinfo(name)
if err := m.Parse(); err != nil {
fatalf("%v", err)
panic("unreachable")
}
return m
}
|
