From: Linus Torvalds <torvalds@linux-foundation.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Jürg Billeter" <j@bitron.ch>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Oleg Nesterov" <oleg@redhat.com>,
"Michael Kerrisk" <mtk.manpages@gmail.com>,
"Filipe Brandenburger" <filbranden@google.com>,
"David Wilcox" <davidvsthegiant@gmail.com>,
hansecke@gmail.com,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
Subject: Re: [RESEND PATCH] prctl: add PR_[GS]ET_PDEATHSIG_PROC
Date: Tue, 3 Oct 2017 09:10:04 -0700 [thread overview]
Message-ID: <CA+55aFz4FBarZhrbbASHcrS7SUgoiHh5A6t865XvA0SZyjxxnQ@mail.gmail.com> (raw)
In-Reply-To: <878tgse1c5.fsf@xmission.com>
On Tue, Oct 3, 2017 at 7:46 AM, Eric W. Biederman <ebiederm@xmission.com> wrote:
>
> The process that requests the signal be sent is the process that is
> receiving the signal. I can see a theoretical need for a permission
> check in there somewhere (especially as this persists over fork).
Note that it also persists over not just fork, but execve() too.
Yes, the signal is cleared if the e[ug]id/fs[ug]id is changed by exec,
but not (for example) if just uid is changed.
Does that matter? Probably not. But signal handling does actually
check uid, so it does actually affect signal permission checks across
execve.
I'm not entirely convinced about this patch. The parent death signal
has been problematic before, I'm not sure we want to add to the whole
situation without very strong arguments.
Linus
next prev parent reply other threads:[~2017-10-03 16:10 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-09 9:40 [PATCH] prctl: add PR_[GS]ET_PDEATHSIG_PROC Jürg Billeter
2017-09-12 17:05 ` Oleg Nesterov
2017-09-12 18:54 ` Jürg Billeter
2017-09-13 17:11 ` Oleg Nesterov
2017-09-13 17:26 ` Jürg Billeter
2017-09-13 17:48 ` Oleg Nesterov
2017-09-29 12:30 ` [RESEND PATCH] " Jürg Billeter
2017-10-02 23:20 ` Andrew Morton
2017-10-03 3:25 ` Eric W. Biederman
2017-10-03 6:45 ` Jürg Billeter
2017-10-03 14:46 ` Eric W. Biederman
2017-10-03 16:10 ` Linus Torvalds [this message]
2017-10-03 16:36 ` Eric W. Biederman
2017-10-03 17:02 ` Linus Torvalds
2017-10-03 19:30 ` Eric W. Biederman
2017-10-03 20:02 ` Linus Torvalds
2017-10-03 20:32 ` Eric W. Biederman
2017-10-03 17:00 ` Jürg Billeter
2017-10-03 17:40 ` Eric W. Biederman
2017-10-03 17:47 ` Jürg Billeter
2017-10-03 19:05 ` Eric W. Biederman
2017-10-05 16:27 ` Oleg Nesterov
2017-10-08 17:47 ` Jürg Billeter
2017-10-09 16:32 ` Eric W. Biederman
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