mirror of
https://github.com/opencontainers/runc.git
synced 2026-07-11 22:37:14 +08:00
Kir Kolyshkin
8491d33482
Since commit 957d97bcf4 was made to fix issue [7],
a few things happened:
- a similar functionality appeared in go 1.20 [1], so the issue
mentioned in the comment (being removed) is no longer true;
- a bug in runc was found [2], which also affects go [3];
- the bug was fixed in go 1.21 [4] and 1.20.2 [5];
- a similar fix was made to x/sys/unix.Faccessat [6].
The essense of [2] is, even if a (non-root) user that the container is
run as does not have execute permission bit set for the executable, it
should still work in case runc has the CAP_DAC_OVERRIDE capability set.
To fix this [2] without reintroducing the older bug [7]:
- drop own Eaccess implementation;
- use the one from x/sys/unix for Go 1.19 (depends on [6]);
- do not use anything when Go 1.20+ is used.
NOTE it is virtually impossible to fix the bug [2] when Go 1.20 or Go
1.20.1 is used because of [3].
A test case is added by a separate commit.
Fixes: #3715.
[1] https://go-review.googlesource.com/c/go/+/414824
[2] https://github.com/opencontainers/runc/issues/3715
[3] https://go.dev/issue/58552
[4] https://go-review.googlesource.com/c/go/+/468735
[5] https://go-review.googlesource.com/c/go/+/469956
[6] https://go-review.googlesource.com/c/sys/+/468877
[7] https://github.com/opencontainers/runc/issues/3520
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
105 lines
2.0 KiB
Go
105 lines
2.0 KiB
Go
//go:build linux
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// +build linux
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package system
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import (
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"os"
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"os/exec"
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"unsafe"
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"golang.org/x/sys/unix"
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)
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type ParentDeathSignal int
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func (p ParentDeathSignal) Restore() error {
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if p == 0 {
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return nil
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}
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current, err := GetParentDeathSignal()
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if err != nil {
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return err
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}
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if p == current {
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return nil
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}
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return p.Set()
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}
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func (p ParentDeathSignal) Set() error {
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return SetParentDeathSignal(uintptr(p))
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}
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func Execv(cmd string, args []string, env []string) error {
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name, err := exec.LookPath(cmd)
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if err != nil {
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return err
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}
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return Exec(name, args, env)
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}
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func Exec(cmd string, args []string, env []string) error {
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for {
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err := unix.Exec(cmd, args, env)
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if err != unix.EINTR { //nolint:errorlint // unix errors are bare
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return &os.PathError{Op: "exec", Path: cmd, Err: err}
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}
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}
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}
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func SetParentDeathSignal(sig uintptr) error {
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if err := unix.Prctl(unix.PR_SET_PDEATHSIG, sig, 0, 0, 0); err != nil {
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return err
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}
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return nil
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}
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func GetParentDeathSignal() (ParentDeathSignal, error) {
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var sig int
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if err := unix.Prctl(unix.PR_GET_PDEATHSIG, uintptr(unsafe.Pointer(&sig)), 0, 0, 0); err != nil {
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return -1, err
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}
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return ParentDeathSignal(sig), nil
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}
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func SetKeepCaps() error {
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if err := unix.Prctl(unix.PR_SET_KEEPCAPS, 1, 0, 0, 0); err != nil {
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return err
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}
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return nil
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}
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func ClearKeepCaps() error {
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if err := unix.Prctl(unix.PR_SET_KEEPCAPS, 0, 0, 0, 0); err != nil {
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return err
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}
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return nil
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}
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func Setctty() error {
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if err := unix.IoctlSetInt(0, unix.TIOCSCTTY, 0); err != nil {
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return err
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}
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return nil
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}
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// SetSubreaper sets the value i as the subreaper setting for the calling process
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func SetSubreaper(i int) error {
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return unix.Prctl(unix.PR_SET_CHILD_SUBREAPER, uintptr(i), 0, 0, 0)
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}
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// GetSubreaper returns the subreaper setting for the calling process
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func GetSubreaper() (int, error) {
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var i uintptr
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if err := unix.Prctl(unix.PR_GET_CHILD_SUBREAPER, uintptr(unsafe.Pointer(&i)), 0, 0, 0); err != nil {
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return -1, err
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}
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return int(i), nil
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}
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