Messages in this thread | | | Date | Tue, 26 Feb 2013 09:24:41 -0800 | From | Matt Helsley <> | Subject | Re: [PATCH] proc connector: reject unprivileged listener bumps |
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On Mon, Feb 25, 2013 at 11:32:25PM -0800, Kees Cook wrote: > While PROC_CN_MCAST_LISTEN/IGNORE is entirely advisory, it was possible > for an unprivileged user to turn off notifications for all listeners by > sending PROC_CN_MCAST_IGNORE. Instead, require the same privileges as > required for a multicast bind. > > Signed-off-by: Kees Cook <keescook@chromium.org> > Cc: Evgeniy Polyakov <zbr@ioremap.net> > Cc: Matt Helsley <matthltc@us.ibm.com> > Cc: stable@vger.kernel.org > --- > drivers/connector/cn_proc.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c > index fce2000..1110478 100644 > --- a/drivers/connector/cn_proc.c > +++ b/drivers/connector/cn_proc.c > @@ -313,6 +313,12 @@ static void cn_proc_mcast_ctl(struct cn_msg *msg, > (task_active_pid_ns(current) != &init_pid_ns)) > return; > > + /* Can only change if privileged. */
I think this comment doesn't tell us anything above and beyond the what capability check already tells us. I think you could improve it by noting that since the connector is multicast and not namespace-safe it's not yet appropriate to use ns_capable() here.
Acked-by: Matt Helsley <matthltc@us.ibm.com>
> + if (!capable(CAP_NET_ADMIN)) { > + err = EPERM; > + goto out; > + }
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