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

[Greg KH <greg@kroah.com>]

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@gmail.com>
> 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@gmail.com>
> 
> 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