Re: [stable] [PATCH] kernel 2.6.24.1 still vulnerable to the vmsplice local root exploit

[Oliver Pinter]

simple len and base check is already in kernel:

2.6.22.17 @ 1176,2-16 - fs/splice.c

                /*
                 * Sanity check this iovec. 0 read succeeds.
                 */
                if (unlikely(!len))
                        break;
                error = -EFAULT;
                if (unlikely(!base))
                        break;



On 2/10/08, Greg KH <greg@xxxxxxxxx> wrote:
> On Sun, Feb 10, 2008 at 02:02:27PM +0100, Oliver Pinter wrote:
> > thx it fixed for 2.6.22
> >
> > >>>>>>>
> >
> > commit f6e993b835393543bab2d917f9dea75218473edd
> > Author: Oliver Pinter <oliver.pntr@xxxxxxxxx>
> > Date:   Sun Feb 10 14:03:46 2008 +0100
> >
> >     [PATCH] vm: splice local root exploit fix for 2.6.22.y
> >
> >     Based on Bastian Blank's patch
> >
> >     Fix for CVE_2008_0009 and CVE_2008-0010
> >
> >     ----->8-----
> >
> >     oliver@pancs:/tmp$ ./2617_26241_root_exploit
> >     -----------------------------------
> >      Linux vmsplice Local Root Exploit
> >       By qaaz
> >       -----------------------------------
> >       [+] mmap: 0x0 .. 0x1000
> >       [+] page: 0x0
> >       [+] page: 0x20
> >       [+] mmap: 0x4000 .. 0x5000
> >       [+] page: 0x4000
> >       [+] page: 0x4020
> >       [+] mmap: 0x1000 .. 0x2000
> >       [+] page: 0x1000
> >       [+] mmap: 0xb7f1a000 .. 0xb7f4c000
> >       [-] vmsplice: Bad address
> >
> >     -----8<-----
> >
> >     Signed-off-by: Oliver Pinter <oliver.pntr@xxxxxxxxx>
> >
> > diff --git a/fs/splice.c b/fs/splice.c
> > index e263d3b..d8b106e 100644
> > --- a/fs/splice.c
> > +++ b/fs/splice.c
> > @@ -1182,6 +1182,12 @@ static int get_iovec_page_array(const struct
> > iovec __user *iov,
> >  		if (unlikely(!base))
> >  			break;
> >
> > +		/* CVE-2008-0009, CVE-2008-0010 fix */
>
> No, this is a different CVE, as it is a different problem from the
> original 09 and 10 report.
>
> It has been given CVE-2008-0600 to address this issue (09 and 10 only
> affect .23 and .24 kernels, and have been fixed.)
>
> > +		if(!access_ok(VERIFY_READ, base, len)) {
> > +			error = -EFAULT;
> > +			break;
> > +		}
>
> Hm, perhaps we should just properly check the len field instead?  That's
> what is being overflowed here...
>
> thanks,
>
> greg k-h
>


-- 
Thanks,
Oliver
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