oss-security - Re: CVE request - kernel: nfsd4: bug in read

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Date: Thu, 8 Jul 2010 20:05:01 -0400 (EDT)
From: Josh Bressers <bressers@...hat.com>
To: oss-security@...ts.openwall.com
Cc: "Steven M. Christey" <coley@...us.mitre.org>
Subject: Re: CVE request - kernel: nfsd4: bug in read_buf

Please use CVE-2010-2521

Thanks.

-- 
    JB


----- "Eugene Teo" <eugeneteo@...nel.sg> wrote:

> 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);
> }

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