CVE request - kernel: nfsd4: bug in read_buf

[Eugene Teo <eugeneteo () kernel sg>]

https://bugzilla.redhat.com/show_bug.cgi?id=612028
Upstream commit: http://git.kernel.org/linus/2bc3c117

Introduced in commit 89fc0a31 ( v2.5.49) and 099e99f0 (v2.6.0-test3). 
Fixed in v2.6.34-rc6.

"When read_buf is called to move over to the next page in the pagelist 
of an NFSv4 request, it sets argp->end to essentially a random number, 
certainly not an address within the page which argp->p now points to. 
So subsequent calls to READ_BUF will think there is much more than a 
page of spare space (the cast to u32 ensures an unsigned comparison) so 
we can expect to fall off the end of the second page."

There's a possibility of triggering this with a specially crafted NFS 
WRITE request (if accepted by the server).

Thanks, Eugene
--
main(i) { putchar(182623909 >> (i-1) * 5&31|!!(i<7)<<6) && main(++i); }