diff options
| author | Adin Scannell <ascannell@google.com> | 2019-06-24 17:28:46 -0700 |
|---|---|---|
| committer | gVisor bot <gvisor-bot@google.com> | 2019-06-24 17:30:01 -0700 |
| commit | 7f5d0afe525af4728ed5ec75193e9e4560d9558c (patch) | |
| tree | f721f563a477325e4addfadca979fa3c406b4a85 | |
| parent | 94a6bfab5d0a2a1950915d7db9cd5e1502de8c13 (diff) | |
Add O_EXITKILL to ptrace options.
This prevents a race before PDEATH_SIG can take effect during
a sentry crash.
Discovered and solution by avagin@.
PiperOrigin-RevId: 254871534
| -rw-r--r-- | pkg/sentry/platform/ptrace/subprocess.go | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/pkg/sentry/platform/ptrace/subprocess.go b/pkg/sentry/platform/ptrace/subprocess.go index 3656611ed..f15b3415a 100644 --- a/pkg/sentry/platform/ptrace/subprocess.go +++ b/pkg/sentry/platform/ptrace/subprocess.go @@ -370,13 +370,16 @@ func (t *thread) destroy() { // init initializes trace options. func (t *thread) init() { - // Set our TRACESYSGOOD option to differeniate real SIGTRAP. + // Set our TRACESYSGOOD option to differeniate real SIGTRAP. We also + // set PTRACE_O_EXITKILL to ensure that the unexpected exit of the + // sentry will immediately kill the associated stubs. + const PTRACE_O_EXITKILL = 0x100000 _, _, errno := syscall.RawSyscall6( syscall.SYS_PTRACE, syscall.PTRACE_SETOPTIONS, uintptr(t.tid), 0, - syscall.PTRACE_O_TRACESYSGOOD|syscall.PTRACE_O_TRACEEXIT, + syscall.PTRACE_O_TRACESYSGOOD|syscall.PTRACE_O_TRACEEXIT|PTRACE_O_EXITKILL, 0, 0) if errno != 0 { panic(fmt.Sprintf("ptrace set options failed: %v", errno)) |