The patch titled signals: protect cinit from unblocked SIG_DFL signals has been added to the -mm tree. Its filename is signals-protect-cinit-from-unblocked-sig_dfl-signals.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: signals: protect cinit from unblocked SIG_DFL signals From: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx> Drop early any SIG_DFL or SIG_IGN signals to container-init from within the same container. But queue SIGSTOP and SIGKILL to the container-init if they are from an ancestor container. Blocked, fatal signals (i.e when SIG_DFL is to terminate) from within the container can still terminate the container-init. That will be addressed in the next patch. Note: To be bisect-safe, SIGNAL_UNKILLABLE will be set for container-inits in a follow-on patch. Until then, this patch is just a preparatory step. Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Roland McGrath <roland@xxxxxxxxxx> Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> Cc: Daniel Lezcano <daniel.lezcano@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/signal.c | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-) diff -puN kernel/signal.c~signals-protect-cinit-from-unblocked-sig_dfl-signals kernel/signal.c --- a/kernel/signal.c~signals-protect-cinit-from-unblocked-sig_dfl-signals +++ a/kernel/signal.c @@ -55,20 +55,21 @@ static int sig_handler_ignored(void __us (handler == SIG_DFL && sig_kernel_ignore(sig)); } -static int sig_task_ignored(struct task_struct *t, int sig) +static int sig_task_ignored(struct task_struct *t, int sig, + int from_ancestor_ns) { void __user *handler; handler = sig_handler(t, sig); if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) && - handler == SIG_DFL) + handler == SIG_DFL && !from_ancestor_ns) return 1; return sig_handler_ignored(handler, sig); } -static int sig_ignored(struct task_struct *t, int sig) +static int sig_ignored(struct task_struct *t, int sig, int from_ancestor_ns) { /* * Blocked signals are never ignored, since the @@ -78,7 +79,7 @@ static int sig_ignored(struct task_struc if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) return 0; - if (!sig_task_ignored(t, sig)) + if (!sig_task_ignored(t, sig, from_ancestor_ns)) return 0; /* @@ -634,7 +635,7 @@ static int check_kill_permission(int sig * Returns true if the signal should be actually delivered, otherwise * it should be dropped. */ -static int prepare_signal(int sig, struct task_struct *p) +static int prepare_signal(int sig, struct task_struct *p, int from_ancestor_ns) { struct signal_struct *signal = p->signal; struct task_struct *t; @@ -718,7 +719,7 @@ static int prepare_signal(int sig, struc } } - return !sig_ignored(p, sig); + return !sig_ignored(p, sig, from_ancestor_ns); } /* @@ -832,7 +833,8 @@ static int __send_signal(int sig, struct trace_sched_signal_send(sig, t); assert_spin_locked(&t->sighand->siglock); - if (!prepare_signal(sig, t)) + + if (!prepare_signal(sig, t, from_ancestor_ns)) return 0; pending = group ? &t->signal->shared_pending : &t->pending; @@ -902,7 +904,15 @@ out_set: static int send_signal(int sig, struct siginfo *info, struct task_struct *t, int group) { - return __send_signal(sig, info, t, group, 0); + int from_ancestor_ns = 0; + +#ifdef CONFIG_PID_NS + if (!is_si_special(info) && SI_FROMUSER(info) && + task_pid_nr_ns(current, task_active_pid_ns(t)) <= 0) + from_ancestor_ns = 1; +#endif + + return __send_signal(sig, info, t, group, from_ancestor_ns); } int print_fatal_signals; @@ -1336,7 +1346,7 @@ int send_sigqueue(struct sigqueue *q, st goto ret; ret = 1; /* the signal is ignored */ - if (!prepare_signal(sig, t)) + if (!prepare_signal(sig, t, 0)) goto out; ret = 0; _ Patches currently in -mm which might be from sukadev@xxxxxxxxxxxxxxxxxx are vfs-simple_set_mnt-should-return-void.patch devpts-must-release-s_umount-on-error.patch signals-remove-handler-parameter-to-tracehook-functions.patch signals-protect-init-from-unwanted-signals-more.patch signals-add-from_ancestor_ns-parameter-to-send_signal.patch signals-protect-cinit-from-unblocked-sig_dfl-signals.patch signals-zap_pid_ns_process-should-use-force_sig.patch signals-protect-cinit-from-blocked-fatal-signals.patch signals-si_user-masquerade-si_pid-when-crossing-pid-ns-boundary.patch pids-document-task_pgrp-task_session-is-not-safe-without-tasklist-rcu.patch pids-document-task_pgrp-task_session-is-not-safe-without-tasklist-rcu-fix.patch pids-improve-get_task_pid-to-fix-the-unsafe-sys_wait4-task_pgrp.patch pids-refactor-vnr-nr_ns-helpers-to-make-them-safe.patch pids-kill-now-unused-signal_struct-__pgrp-__session-and-friends.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html