diff options
Diffstat (limited to 'pkg/sentry/syscalls')
| -rw-r--r-- | pkg/sentry/syscalls/linux/sys_signal.go | 16 |
1 files changed, 7 insertions, 9 deletions
diff --git a/pkg/sentry/syscalls/linux/sys_signal.go b/pkg/sentry/syscalls/linux/sys_signal.go index 93b3f531a..66ecb1299 100644 --- a/pkg/sentry/syscalls/linux/sys_signal.go +++ b/pkg/sentry/syscalls/linux/sys_signal.go @@ -315,25 +315,23 @@ func Sigaltstack(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.S setaddr := args[0].Pointer() oldaddr := args[1].Pointer() + alt := t.SignalStack() if oldaddr != 0 { - alt := t.SignalStack() - if t.OnSignalStack(alt) { - alt.Flags |= arch.SignalStackFlagOnStack - } if err := t.CopyOutSignalStack(oldaddr, &alt); err != nil { return 0, nil, err } } if setaddr != 0 { - if t.OnSignalStack(t.SignalStack()) { - return 0, nil, syserror.EPERM - } alt, err := t.CopyInSignalStack(setaddr) if err != nil { return 0, nil, err } - if err := t.SetSignalStack(alt); err != nil { - return 0, nil, err + // The signal stack cannot be changed if the task is currently + // on the stack. This is enforced at the lowest level because + // these semantics apply to changing the signal stack via a + // ucontext during a signal handler. + if !t.SetSignalStack(alt) { + return 0, nil, syserror.EPERM } } |