Messages in this thread | | | From | (Eric W. Biederman) | Date | Tue, 21 Apr 2020 09:57:09 -0500 | Subject | Re: [PATCH] signal: Avoid corrupting si_pid and si_uid in do_notify_parent |
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Christian Brauner <christian.brauner@ubuntu.com> writes:
> On Mon, Apr 20, 2020 at 12:05:38PM -0500, Eric W. Biederman wrote: >> diff --git a/kernel/signal.c b/kernel/signal.c >> index 9899c5f91ee1..a88a89422227 100644 >> --- a/kernel/signal.c >> +++ b/kernel/signal.c >> @@ -1993,8 +1993,12 @@ bool do_notify_parent(struct task_struct *tsk, int sig) >> if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) >> sig = 0; >> } >> + /* >> + * Bypass send_signal as the si_pid and si_uid values have >> + * been generated in the parent's namespaces. >> + */ > > At first I misread that comment as saying that we're skipping sending a > signal not that it relates to a specific function (and I won't admit that > I wrote a whole long paragraph on why I'm confused we're skipping > sending signals on invalid si_pid and si_uid...).
I have updated the comment to read: + /* + * Send with __send_signal as si_pid and si_uid are in the + * parent's namespaces. + */
That should be enough of a hint for someone to read the code and figure out what is going on.
Eric
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