Messages in this thread | | | Date | Thu, 20 Sep 2018 15:12:58 +0200 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH] signal/GenWQE: Fix sending of SIGKILL |
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On Thu, Sep 13, 2018 at 12:48:43PM +0200, Eric W. Biederman wrote: > > The genweq_add_file and genwqe_del_file by caching current without > using reference counting embed the assumption that a file descriptor > will never be passed from one process to another. It even embeds the > assumption that the the thread that opened the file will be in > existence when the process terminates. Neither of which are > guaranteed to be true. > > Therefore replace caching the task_struct of the opener with > pid of the openers thread group id. All the knowledge of the > opener is used for is as the target of SIGKILL and a SIGKILL > will kill the entire process group. > > Rename genwqe_force_sig to genwqe_terminate, remove it's unncessary > signal argument, update it's ownly caller, and use kill_pid > instead of force_sig. > > The work force_sig does in changing signal handling state is not > relevant to SIGKILL sent as SEND_SIG_PRIV. The exact same processess > will be killed just with less work, and less confusion. The work done > by force_sig is really only needed for handling syncrhonous > exceptions. > > It will still be possible to cause genwqe_device_remove to wait 8 > seconds by passing a file descriptor to another process but the possible > user after free is fixed. > > Fixes: eaf4722d4645 ("GenWQE Character device and DDCB queue") > Cc: stable@vger.kernel.org > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: Frank Haverkamp <haver@linux.vnet.ibm.com> > Cc: Joerg-Stephan Vogt <jsvogt@de.ibm.com> > Cc: Michael Jung <mijung@gmx.net> > Cc: Michael Ruettger <michael@ibmra.de> > Cc: Kleber Sacilotto de Souza <klebers@linux.vnet.ibm.com> > Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> > Cc: Eberhard S. Amann <esa@linux.vnet.ibm.com> > Cc: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com> > Cc: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com> > Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> > --- > > Greg I intend to take this through my signal tree, but if you would > rather take this through your driver tree please feel free.
No objection from me for you to take it through your tree:
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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