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    SubjectRe: [PATCH] wireless: fix 64K kernel heap content leak via ioctl
    On Fri, Aug 27, 2010 at 2:22 PM, Jean Tourrilhes <jt@hpl.hp.com> 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@kernel.org [2.6.32+]

    Luis
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