Add Eric. OK, I agree, it seems we need a simple fix.
Acked-by: Oleg Nesterov <[email protected]> ------------------------------------------------------------------------- But let me add some "offtopic" notes... Why do we actually need this fix? kill_something_info(). But at first glance sys_kill/kill_something_info can simply use SEND_SIG_NOINFO? If yes, this makes sense anyway, I will re-check... do_pidfd_send_signal(PIDFD_SIGNAL_PROCESS_GROUP) allows to call kill_pgrp_info() if si_code < 0... Not that I think this would be better, but we could move this "rewrite" logic into __kill_pgrp_info()... Anything else needs this change? Most probably yes, but after the quick grep I don't see other group senders with !is_si_special(info). Eric, what do you think? Oleg. On 06/22, Bradley Morgan wrote: > > send_signal_locked() rewrites sender ids for the target namespace. > Group sends reuse the same siginfo, so one recipient can affect the > next. > > Copy the siginfo before changing it. > > Fixes: 7a0cf094944e ("signal: Correct namespace fixups of si_pid and si_uid") > Cc: [email protected] > Signed-off-by: Bradley Morgan <[email protected]> > --- > Changes since v1: > - No code changes in this patch. > - Add patch 2 for Oleg's const suggestion. > - Link to v1: > > https://lore.kernel.org/all/[email protected]/T/#m89955d13f10807c316d34cc76680d690a2d95b31 > > kernel/signal.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/kernel/signal.c b/kernel/signal.c > index b9fc7be1a169..d72d9be3a992 100644 > --- a/kernel/signal.c > +++ b/kernel/signal.c > @@ -1181,6 +1181,7 @@ static inline bool has_si_pid_and_uid(struct > kernel_siginfo *info) > int send_signal_locked(int sig, struct kernel_siginfo *info, > struct task_struct *t, enum pid_type type) > { > + struct kernel_siginfo rewritten; > /* Should SIGKILL or SIGSTOP be received by a pid namespace init? */ > bool force = false; > > @@ -1194,6 +1195,9 @@ int send_signal_locked(int sig, struct kernel_siginfo > *info, > /* SIGKILL and SIGSTOP is special or has ids */ > struct user_namespace *t_user_ns; > > + rewritten = *info; > + info = &rewritten; > + > rcu_read_lock(); > t_user_ns = task_cred_xxx(t, user_ns); > if (current_user_ns() != t_user_ns) { > -- > 2.53.0 >
