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package sandbox
import (
"encoding/gob"
"fmt"
"math"
"os"
"path"
"syscall"
"unsafe"
)
func init() { gob.Register(new(BindMount)) }
// BindMount bind mounts host path Source on container path Target.
type BindMount struct {
Source, Target string
Flags int
}
func (b *BindMount) apply(*Params) error {
if !path.IsAbs(b.Source) || !path.IsAbs(b.Target) {
return msg.WrapErr(syscall.EBADE,
"path is not absolute")
}
return bindMount(b.Source, b.Target, b.Flags)
}
func (b *BindMount) Is(op Op) bool { vb, ok := op.(*BindMount); return ok && *b == *vb }
func (*BindMount) prefix() string { return "mounting" }
func (b *BindMount) String() string {
if b.Source == b.Target {
return fmt.Sprintf("%q flags %#x", b.Source, b.Flags)
}
return fmt.Sprintf("%q on %q flags %#x", b.Source, b.Target, b.Flags&BindWritable)
}
func (f *Ops) Bind(source, target string, flags int) *Ops {
*f = append(*f, &BindMount{source, target, flags | BindRecursive})
return f
}
func init() { gob.Register(new(MountProc)) }
// MountProc mounts a private instance of proc.
type MountProc string
func (p MountProc) apply(*Params) error {
v := string(p)
if !path.IsAbs(v) {
return msg.WrapErr(syscall.EBADE,
fmt.Sprintf("path %q is not absolute", v))
}
target := toSysroot(v)
if err := os.MkdirAll(target, 0755); err != nil {
return msg.WrapErr(err, err.Error())
}
return wrapErrSuffix(syscall.Mount("proc", target, "proc",
syscall.MS_NOSUID|syscall.MS_NOEXEC|syscall.MS_NODEV, ""),
fmt.Sprintf("cannot mount proc on %q:", v))
}
func (p MountProc) Is(op Op) bool { vp, ok := op.(MountProc); return ok && p == vp }
func (MountProc) prefix() string { return "mounting" }
func (p MountProc) String() string { return fmt.Sprintf("proc on %q", string(p)) }
func (f *Ops) Proc(dest string) *Ops {
*f = append(*f, MountProc(dest))
return f
}
func init() { gob.Register(new(MountDev)) }
// MountDev mounts part of host dev.
type MountDev string
func (d MountDev) apply(params *Params) error {
v := string(d)
if !path.IsAbs(v) {
return msg.WrapErr(syscall.EBADE,
fmt.Sprintf("path %q is not absolute", v))
}
target := toSysroot(v)
if err := mountTmpfs("devtmpfs", v, 0, 0755); err != nil {
return err
}
for _, name := range []string{"null", "zero", "full", "random", "urandom", "tty"} {
if err := bindMount(
"/dev/"+name, path.Join(v, name),
BindSource|BindDevice,
); err != nil {
return err
}
}
for i, name := range []string{"stdin", "stdout", "stderr"} {
if err := os.Symlink(
"/proc/self/fd/"+string(rune(i+'0')),
path.Join(target, name),
); err != nil {
return msg.WrapErr(err, err.Error())
}
}
for _, pair := range [][2]string{
{"/proc/self/fd", "fd"},
{"/proc/kcore", "core"},
{"pts/ptmx", "ptmx"},
} {
if err := os.Symlink(pair[0], path.Join(target, pair[1])); err != nil {
return msg.WrapErr(err, err.Error())
}
}
devPtsPath := path.Join(target, "pts")
for _, name := range []string{path.Join(target, "shm"), devPtsPath} {
if err := os.Mkdir(name, 0755); err != nil {
return msg.WrapErr(err, err.Error())
}
}
if err := syscall.Mount("devpts", devPtsPath, "devpts",
syscall.MS_NOSUID|syscall.MS_NOEXEC,
"newinstance,ptmxmode=0666,mode=620"); err != nil {
return wrapErrSuffix(err,
fmt.Sprintf("cannot mount devpts on %q:", devPtsPath))
}
if params.Flags&FAllowTTY != 0 {
var buf [8]byte
if _, _, errno := syscall.Syscall(
syscall.SYS_IOCTL, 1, syscall.TIOCGWINSZ,
uintptr(unsafe.Pointer(&buf[0])),
); errno == 0 {
if err := bindMount("/proc/self/fd/1", path.Join(v, "console"), BindDevice); err != nil {
return err
}
}
}
return nil
}
func (d MountDev) Is(op Op) bool { vd, ok := op.(MountDev); return ok && d == vd }
func (MountDev) prefix() string { return "mounting" }
func (d MountDev) String() string { return fmt.Sprintf("dev on %q", string(d)) }
func (f *Ops) Dev(dest string) *Ops {
*f = append(*f, MountDev(dest))
return f
}
func init() { gob.Register(new(MountMqueue)) }
// MountMqueue mounts a private mqueue instance on container Path.
type MountMqueue string
func (m MountMqueue) apply(*Params) error {
v := string(m)
if !path.IsAbs(v) {
return msg.WrapErr(syscall.EBADE,
fmt.Sprintf("path %q is not absolute", v))
}
target := toSysroot(v)
if err := os.MkdirAll(target, 0755); err != nil {
return msg.WrapErr(err, err.Error())
}
return wrapErrSuffix(syscall.Mount("mqueue", target, "mqueue",
syscall.MS_NOSUID|syscall.MS_NOEXEC|syscall.MS_NODEV, ""),
fmt.Sprintf("cannot mount mqueue on %q:", v))
}
func (m MountMqueue) Is(op Op) bool { vm, ok := op.(MountMqueue); return ok && m == vm }
func (MountMqueue) prefix() string { return "mounting" }
func (m MountMqueue) String() string { return fmt.Sprintf("mqueue on %q", string(m)) }
func (f *Ops) Mqueue(dest string) *Ops {
*f = append(*f, MountMqueue(dest))
return f
}
func init() { gob.Register(new(MountTmpfs)) }
// MountTmpfs mounts tmpfs on container Path.
type MountTmpfs struct {
Path string
Size int
Perm os.FileMode
}
func (t *MountTmpfs) apply(*Params) error {
if !path.IsAbs(t.Path) {
return msg.WrapErr(syscall.EBADE,
fmt.Sprintf("path %q is not absolute", t.Path))
}
if t.Size < 0 || t.Size > math.MaxUint>>1 {
return msg.WrapErr(syscall.EBADE,
fmt.Sprintf("size %d out of bounds", t.Size))
}
return mountTmpfs("tmpfs", t.Path, t.Size, t.Perm)
}
func (t *MountTmpfs) Is(op Op) bool { vt, ok := op.(*MountTmpfs); return ok && *t == *vt }
func (*MountTmpfs) prefix() string { return "mounting" }
func (t *MountTmpfs) String() string { return fmt.Sprintf("tmpfs on %q size %d", t.Path, t.Size) }
func (f *Ops) Tmpfs(dest string, size int, perm os.FileMode) *Ops {
*f = append(*f, &MountTmpfs{dest, size, perm})
return f
}
func init() { gob.Register(new(Symlink)) }
// Symlink creates a symlink in the container filesystem.
type Symlink [2]string
func (l *Symlink) apply(*Params) error {
// symlink target is an arbitrary path value, so only validate link name here
if !path.IsAbs(l[1]) {
return msg.WrapErr(syscall.EBADE,
fmt.Sprintf("path %q is not absolute", l[1]))
}
if err := os.Symlink(l[0], toSysroot(l[1])); err != nil {
return msg.WrapErr(err, err.Error())
}
return nil
}
func (l *Symlink) Is(op Op) bool { vl, ok := op.(*Symlink); return ok && *l == *vl }
func (*Symlink) prefix() string { return "creating" }
func (l *Symlink) String() string { return fmt.Sprintf("symlink on %q target %q", l[1], l[0]) }
func (f *Ops) Link(target, linkName string) *Ops {
*f = append(*f, &Symlink{target, linkName})
return f
}
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