Re: [PATCH 3.12 32/64] unix: properly account for FDs passed over unix sockets

[Willy Tarreau]

Hi Jiri,

On Thu, Feb 11, 2016 at 02:59:08PM +0100, Jiri Slaby wrote:
> From: willy tarreau <w@xxxxxx>
> 
> 3.12-stable review patch.  If anyone has any objections, please let me know.
> 
> ===============
> 
> [ Upstream commit 712f4aad406bb1ed67f3f98d04c044191f0ff593 ]
> 
> It is possible for a process to allocate and accumulate far more FDs than
> the process' limit by sending them over a unix socket then closing them
> to keep the process' fd count low.
> 
> This change addresses this problem by keeping track of the number of FDs
> in flight per user and preventing non-privileged processes from having
> more FDs in flight than their configured FD limit.
> 
> Reported-by: socketpair@xxxxxxxxx
> Reported-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
> Mitigates: CVE-2013-4312 (Linux 2.0+)
> Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Acked-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Willy Tarreau <w@xxxxxx>
> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>

A possible issue was reported regarding this patch, and Hannes
implemented a fix that's not yet in mainline. I guess it's
preferable to postpone this patch for now.

Thanks,
Willy