Re: CVE request - kernel: cifs: Fix a kernel BUG with remote OS/2 server

[Josh Bressers <bressers () redhat com>]

Please use CVE-2010-2248

Thanks.

-- 
    JB


----- "Eugene Teo" <eugeneteo () kernel sg> wrote:

> "This was known to trigger with a OS/2 server. The server sets 
> pSMBr->CountHigh to a incorrect value even in case of normal writes. 
> This results in 'nbytes' being computed wrongly and triggers a kernel
>
> BUG at mm/filemap.c.
>
>      void iov_iter_advance(struct iov_iter *i, size_t bytes)
>      {
>              BUG_ON(i->count < bytes);    <--- BUG here
>
> Why the server is setting 'CountHigh' is not clear but only does so 
> after writing 64k bytes. Though this looks like the server bug, the 
> client side crash may not be acceptable.
>
> The workaround is to mask off high 16 bits if the number of bytes 
> written as returned by the server is greater than the bytes requested
> by 
> the client."
>
> https://bugzilla.redhat.com/show_bug.cgi?id=608583
> http://git.kernel.org/linus/6513a81e9325d712f1bfb9a1d7b750134e49ff18
>
> -- 
> main(i) { putchar(182623909 >> (i-1) * 5&31|!!(i<7)<<6) && main(++i);
> }