On 02/19, Eric W. Biederman wrote: > > Oleg Nesterov <oleg@xxxxxxxxxx> writes: > > > > SI_FROMUSER() == T, unless we have more (hopefully not) in-kernel > > users which send SI_FROMUSER() signals, .si_pid must be valid? > > So the argument is that while things such as force_sig_info(SIGSEGV) > don't have a si_pid we don't care because from_ancestor_ns == 0. > > Interesting. Then I don't know if we have any kernel senders > that cross the namespace boundaries. > > That said I still object to this code. > > sys_kill(-pgrp, SIGUSR1) > kill_something_info(SIGUSR1, &info, 0) > __kill_pgrp_info(SIGUSR1, &info task_pgrp(current)) > group_send_sig_info(SIGUSR1, &info, tsk) > __group_send_sig_info(SIGUSR1, &info, tsk) > send_signal(SIGUSR1, &info, tsk, 1) > __send_signal(SIGUSR1, &info, tsk, 1) > > > Process groups and sessions can have processes in multiple pid > namespaces, which is very useful for not messing up your controlling > terminal. > > In which case sys_kill cannot possibly set the si_pid value correct > and from_ancestor_ns is not enough either. (I know, I shouldn't reply today because I am already sleeping ;) Why? send_signal() should calculate the correct value of from_parent and pass it to __send_signal(). If it is true, then we clear .si_pid in the copied siginfo (which was already queued). We don't mangle the original siginfo. This happens for each process we send the signal. Or I misunderstood you? Oleg. _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
