[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20240216-albern-aufwiegen-1de327c7dafd@brauner>
Date: Fri, 16 Feb 2024 13:28:24 +0100
From: Christian Brauner <brauner@...nel.org>
To: Oleg Nesterov <oleg@...hat.com>
Cc: Andy Lutomirski <luto@...capital.net>,
"Eric W. Biederman" <ebiederm@...ssion.com>, Tycho Andersen <tycho@...ho.pizza>, linux-api@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] pidfd: change pidfd_send_signal() to respect
PIDFD_THREAD
On Wed, Feb 14, 2024 at 01:36:56PM +0100, Oleg Nesterov wrote:
> On 02/10, Oleg Nesterov wrote:
> >
> > On 02/10, Christian Brauner wrote:
> > >
> > > + if (type == PIDFD_SIGNAL_PROCESS_GROUP)
> > > + ret = kill_pgrp_info(sig, &kinfo, pid);
> >
> > I guess you meant
> >
> > if (type == PIDTYPE_PGID)
> >
> > other than that,
> >
> > Reviewed-by: Oleg Nesterov <oleg@...hat.com>
>
> Yes, but there is another thing I hadn't thought of...
>
> sys_pidfd_send_signal() does
>
> /* Only allow sending arbitrary signals to yourself. */
> ret = -EPERM;
> if ((task_pid(current) != pid) &&
> (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
> goto err;
>
> and I am not sure that task_pid(current) == pid should allow
> the "arbitrary signals" if PIDFD_SIGNAL_PROCESS_GROUP.
>
> Perhaps
>
> /* Only allow sending arbitrary signals to yourself. */
> ret = -EPERM;
> if ((task_pid(current) != pid || type == PIDTYPE_PGID) &&
> (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL)
> goto err;
Honestly, we should probably just do:
if (kinfo->si_code != SI_USER)
goto err
and be done with it. If we get regressions reports about this then it's
easy to fix that up. But I find that unlikely. So why not try to get
away with something much simpler. What do you think?
View attachment "0001-signal-disallow-non-SI_USER-signals-in-pidfd_send_si.patch" of type "text/x-diff" (1741 bytes)
Powered by blists - more mailing lists