| Date | Wed, 30 Mar 2011 23:33:38 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH] [226/275] Prevent rt_sigqueueinfo and rt_tgsigqueueinfo from spoofing the signal code |
| |
On 03/30, Andi Kleen wrote: > > --- linux-2.6.35.y.orig/kernel/signal.c 2011-03-29 22:50:25.616602954 -0700 > +++ linux-2.6.35.y/kernel/signal.c 2011-03-29 23:03:02.941224912 -0700 > @@ -2410,9 +2410,13 @@ > 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;
Oh, please don't.
Quoting Roland:
Commit da48524eb206 ("Prevent rt_sigqueueinfo and rt_tgsigqueueinfo from spoofing the signal code") made the check on si_code too strict: glibc's aio implementation wants to queue signals with SI_ASYNCIO, and indeed glibc's tst-aio4 fails with the patched kernel.
If stable needs this change, then it probably needs
Relax si_code check in rt_sigqueueinfo and rt_tgsigqueueinfo commit 243b422af9ea9af4ead07a8ad54c90d4f9b6081a
as well.
Oleg.
|