On 04/25, Willy Tarreau wrote: > > 2.6.27.59-stable review patch. If anyone has any objections, please let us > know. > > ------------------ > > From: Julien Tinnes <[email protected]> > > commit da48524eb20662618854bb3df2db01fc65f3070c upstream.
This also needs 243b422af9ea9af4ead07a8ad54c90d4f9b6081a > Userland should be able to trust the pid and uid of the sender of a > signal if the si_code is SI_TKILL. > > Unfortunately, the kernel has historically allowed sigqueueinfo() to > send any si_code at all (as long as it was negative - to distinguish it > from kernel-generated signals like SIGILL etc), so it could spoof a > SI_TKILL with incorrect siginfo values. > > Happily, it looks like glibc has always set si_code to the appropriate > SI_QUEUE, so there are probably no actual user code that ever uses > anything but the appropriate SI_QUEUE flag. > > So just tighten the check for si_code (we used to allow any negative > value), and add a (one-time) warning in case there are binaries out > there that might depend on using other si_code values. > > Signed-off-by: Julien Tinnes <[email protected]> > Acked-by: Oleg Nesterov <[email protected]> > Signed-off-by: Linus Torvalds <[email protected]> > Signed-off-by: Greg Kroah-Hartman <[email protected]> > [wt: 2.6.27 does not have do_rt_tgsigqueueinfo()] > > --- > kernel/signal.c | 16 ++++++++++++---- > 1 file changed, 12 insertions(+), 4 deletions(-) > > Index: longterm-2.6.27/kernel/signal.c > =================================================================== > --- longterm-2.6.27.orig/kernel/signal.c 2011-01-23 10:52:37.000000000 > +0100 > +++ longterm-2.6.27/kernel/signal.c 2011-04-25 16:06:27.491278774 +0200 > @@ -2294,9 +2294,13 @@ > return -EFAULT; > > /* Not even root can pretend to send signals from the kernel. > - Nor can they impersonate a kill(), which adds source info. */ > - if (info.si_code >= 0) > + * Nor can they impersonate a kill()/tgkill(), which adds source info. > + */ > + if (info.si_code != SI_QUEUE) { > + /* We used to allow any < 0 si_code */ > + WARN_ON_ONCE(info.si_code < 0); > return -EPERM; > + } > info.si_signo = sig; > > /* POSIX.1b doesn't mention process groups. */ > > _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
