On Fri, Aug 27, 2010 at 2:22 PM, Jean Tourrilhes <jt@xxxxxxxxxx> wrote: > On Fri, Aug 27, 2010 at 02:02:41PM -0700, Kees Cook wrote: >> This problem was originally tracked down by Brad Spengler. >> >> When calling wireless ioctls, if a driver does not correctly >> validate/shrink iwp->length, the resulting copy_to_user can leak up to >> 64K of kernel heap contents. >> >> It seems that this is triggerable[1] in 2.6.32 at least on ath5k, but >> I was not able to track down how. The twisty maze of ioctl handlers >> stumped me. :) > > You can always ask. > >> Other drivers I checked did not appear to have any problems, >> but the potential remains. I'm not sure if this patch is the right approach; >> it was fixed differently[2] in grsecurity. > > Did you tried your patch for real ? With large scan request ? > I ask because at first glance, it looks incorrect, asI believe > it kills large request. But someone would need to test, for sure. > >> [1] http://forums.grsecurity.net/viewtopic.php?f=3&t=2290&start=0 >> [2] http://grsecurity.net/~spender/wireless-infoleak-fix2.patch > > I believe this patch would make the situation worse. > > Would you mind validating the following patch ? I've just > verified that it compiles and I believe it does what you are asking in > a much more predictable way. > Regards, > > Jean > > diff -u -p wext.j2.c wext.c > --- wext.j2.c 2010-08-27 14:17:26.000000000 -0700 > +++ wext.c 2010-08-27 14:19:33.000000000 -0700 > @@ -800,9 +800,12 @@ static int ioctl_standard_iw_point(struc > goto out; > } > > - if (copy_to_user(iwp->pointer, extra, > - iwp->length * > - descr->token_size)) { > + /* Verify how much we should return. Some driver > + * may abuse iwp->length... */ > + if((iwp->length * descr->token_size) < extra_size) > + extra_size = iwp->length * descr->token_size; > + > + if (copy_to_user(iwp->pointer, extra, extra_size)) { > err = -EFAULT; > goto out; > } Jean, can you submit in a new thread and right before the SOB add in the commit log Cc: stable@xxxxxxxxxx [2.6.32+] Luis -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
