From: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx> Date: Wed, 24 Dec 2008 13:46:02 -0800 Subject: [PATCH 4/7][v6] Define siginfo_from_ancestor_ns() Determine if sender of a signal is from an ancestor namespace. This function will be used in a follow-on patch. This is based on discussions on the patch from Oleg Nesterov and me http://lkml.org/lkml/2008/11/25/462. Changelog[v6]: - (Oleg Nesterov) Simplify/correct comments - (Oleg Nesterov) Remove 'ns == NULL' check since task_active_pid_ns() will return a valid ns for the target. - (Roland Mcgrath) Remove incorrect SI_ASYNCIO check in siginfo_from_user(). Changelog[v5]: - (Oleg Nesterov) Put siginfo_from_ancestor_ns() back under CONFIG_PID_NS. - (Oleg Nesterov) Remove the warning in rt_sigqueueinfo(). Changelog[v4]: - siginfo_from_ancestor_ns() is fairly clean and it does not need to be under CONFIG_PID_NS. Only siginfo_from_user() needs to be. - Warn if rt_sigqueueinfo() uses SI_ASYNCIO. - Added a check for pid-ns of receiver being NULL (in case it is exiting). Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx> --- kernel/signal.c | 37 +++++++++++++++++++++++++++++++++++++ 1 files changed, 37 insertions(+), 0 deletions(-) diff --git a/kernel/signal.c b/kernel/signal.c index bb3b6f5..d0dfa0d 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -820,6 +820,43 @@ static inline int legacy_queue(struct sigpending *signals, int sig) { return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); } +/* + * Return 1 if this signal originated directly from a user process (i.e via + * kill(), tkill(), sigqueue()). Return 0 otherwise. + */ +#ifdef CONFIG_PID_NS +static inline int siginfo_from_user(siginfo_t *info) +{ + if (!is_si_special(info) && SI_FROMUSER(info)) + return 1; + + return 0; +} + +static inline int siginfo_from_ancestor_ns(struct task_struct *t, + siginfo_t *info) +{ + /* + * If we do not have a pid in the receiver's namespace, + * we must be from an ancestor namespace. + */ + if (siginfo_from_user(info) && + task_pid_nr_ns(current, task_active_pid_ns(t)) <= 0) { + return 1; + } + + return 0; +} + +#else + +static inline int siginfo_from_ancestor_ns(struct task_struct *t, + siginfo_t *info) +{ + return 0; +} + +#endif static int __send_signal(int sig, struct siginfo *info, struct task_struct *t, int group, int from_ancestor_ns) -- 1.5.2.5 _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers