diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/fork.c | 52 | ||||
| -rw-r--r-- | kernel/ptrace.c | 3 | ||||
| -rw-r--r-- | kernel/signal.c | 4 |
3 files changed, 55 insertions, 4 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index a4ec2d1e25ee..55a6906d3014 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2029,6 +2029,41 @@ __latent_entropy struct task_struct *copy_process( return ERR_PTR(-EINVAL); } + if (clone_flags & CLONE_AUTOREAP) { + if (clone_flags & CLONE_THREAD) + return ERR_PTR(-EINVAL); + if (clone_flags & CLONE_PARENT) + return ERR_PTR(-EINVAL); + if (args->exit_signal) + return ERR_PTR(-EINVAL); + } + + if ((clone_flags & CLONE_PARENT) && current->signal->autoreap) + return ERR_PTR(-EINVAL); + + if (clone_flags & CLONE_NNP) { + if (clone_flags & CLONE_THREAD) + return ERR_PTR(-EINVAL); + } + + if (clone_flags & CLONE_PIDFD_AUTOKILL) { + if (!(clone_flags & CLONE_PIDFD)) + return ERR_PTR(-EINVAL); + if (!(clone_flags & CLONE_AUTOREAP)) + return ERR_PTR(-EINVAL); + if (clone_flags & CLONE_THREAD) + return ERR_PTR(-EINVAL); + /* + * Without CLONE_NNP the child could escalate privileges + * after being spawned, so require CAP_SYS_ADMIN. + * With CLONE_NNP the child can't gain new privileges, + * so allow unprivileged usage. + */ + if (!(clone_flags & CLONE_NNP) && + !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) + return ERR_PTR(-EPERM); + } + /* * Force any signals received before this point to be delivered * before the fork happens. Collect up signals sent to multiple @@ -2251,13 +2286,18 @@ __latent_entropy struct task_struct *copy_process( * if the fd table isn't shared). */ if (clone_flags & CLONE_PIDFD) { - int flags = (clone_flags & CLONE_THREAD) ? PIDFD_THREAD : 0; + unsigned flags = PIDFD_STALE; + + if (clone_flags & CLONE_THREAD) + flags |= PIDFD_THREAD; + if (clone_flags & CLONE_PIDFD_AUTOKILL) + flags |= PIDFD_AUTOKILL; /* * Note that no task has been attached to @pid yet indicate * that via CLONE_PIDFD. */ - retval = pidfd_prepare(pid, flags | PIDFD_STALE, &pidfile); + retval = pidfd_prepare(pid, flags, &pidfile); if (retval < 0) goto bad_fork_free_pid; pidfd = retval; @@ -2413,6 +2453,9 @@ __latent_entropy struct task_struct *copy_process( */ copy_seccomp(p); + if (clone_flags & CLONE_NNP) + task_set_no_new_privs(p); + init_task_pid_links(p); if (likely(p->pid)) { ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace); @@ -2436,6 +2479,8 @@ __latent_entropy struct task_struct *copy_process( */ p->signal->has_child_subreaper = p->real_parent->signal->has_child_subreaper || p->real_parent->signal->is_child_subreaper; + if (clone_flags & CLONE_AUTOREAP) + p->signal->autoreap = 1; list_add_tail(&p->sibling, &p->real_parent->children); list_add_tail_rcu(&p->tasks, &init_task.tasks); attach_pid(p, PIDTYPE_TGID); @@ -2897,7 +2942,8 @@ static bool clone3_args_valid(struct kernel_clone_args *kargs) { /* Verify that no unknown flags are passed along. */ if (kargs->flags & - ~(CLONE_LEGACY_FLAGS | CLONE_CLEAR_SIGHAND | CLONE_INTO_CGROUP)) + ~(CLONE_LEGACY_FLAGS | CLONE_CLEAR_SIGHAND | CLONE_INTO_CGROUP | + CLONE_AUTOREAP | CLONE_NNP | CLONE_PIDFD_AUTOKILL)) return false; /* diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 392ec2f75f01..68c17daef8d4 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -549,7 +549,8 @@ static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) if (!dead && thread_group_empty(p)) { if (!same_thread_group(p->real_parent, tracer)) dead = do_notify_parent(p, p->exit_signal); - else if (ignoring_children(tracer->sighand)) { + else if (ignoring_children(tracer->sighand) || + p->signal->autoreap) { __wake_up_parent(p, tracer); dead = true; } diff --git a/kernel/signal.c b/kernel/signal.c index d65d0fe24bfb..e61f39fa8c8a 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2251,6 +2251,10 @@ bool do_notify_parent(struct task_struct *tsk, int sig) if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) sig = 0; } + if (!tsk->ptrace && tsk->signal->autoreap) { + autoreap = true; + sig = 0; + } /* * Send with __send_signal as si_pid and si_uid are in the * parent's namespaces. |