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

[Jiri Slaby]

On 02/11/2016, 06:32 PM, Willy Tarreau wrote:
> 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.

Hi,

yes definitely. Thanks for noting.

For reference:
http://article.gmane.org/gmane.linux.kernel/2142236

thanks,
-- 
js
suse labs