Eric W. Biederman [ebiederm@xxxxxxxxxxxx] wrote: | Oleg Nesterov <oleg@xxxxxxxxxx> writes: | | >> I was going through the ->si_pid assignments to try and fix them at | >> source (like the mqueue patch I sent last week). | > | > OK. | | Note. When a signal goes to a process group (or similar) we can't fix | si_pid at the source. We have to fix it when only a single destination | process is known. It doesn't mean that fixing it at the source | is hopeless but... Right. Most calls to kill_pgrp_info() and __kill_pgrp_info() use SEND_SIG_PRIV or SEND_SIG_NOINFO, so their ->si_pid is set. The only place seems to be the sys_kill()/sys_tkill(). | | >> The two cases that don't fit the model are sys_kill() and sys_tkill(). | >> For that I was hoping we could use siginfo_from_user() again. i.e | >> | >> if (siginfo_from_user()) | >> masquerade_si_pid() | >> | >> in the default: case of send_signal(). To be safe, masquerade_si_pid() | >> could do it only iff si_code is either SI_USER or SI_TKILL. | >> | >> IOW, with some tweaks, I am trying to see if we can use siginfo_from_user() | >> in place of the SIG_FROM_USER. | > | > sys_rt_sigqueueinfo(). | > | > But, perhaps we can just ignore the problems with sigqueueinfo() (and | > document them). Yes, thats one reason I was thinking of checking si_code == SI_USER or SI_TKILL, but rt_sigqueueinfo() could still use those values too. In fact it could use SI_ASYNCIO :-) and mess with sig_from_user() (i.e if rt_sigqueueinfo() sets si_code to SI_ASYNCIO and sends SIGKILL/SIGSTOP to a descendant cinit, SIGKILL/SIGSTOP will be ignored). We could/should warn if rt_sigqueueinfo() sets si_code to SI_ASYNCIO. One more reason to make SI_ASYNCIO a kernel signal I guess. | | Yes. I don't think si_pid is valid in that case anyway. It is the | kernel signals where si_pid is a reliable field that are important. | | Eric Sukadev _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
