unix: properly account for FDs passed over unix sockets

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[ Upstream commit 712f4aad40 ]

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@gmail.com
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Mitigates: CVE-2013-4312 (Linux 2.0+)
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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willy tarreau 2016-01-10 07:54:56 +01:00 • committed by Greg Kroah-Hartman

parent 3767d554c0

commit 5e226f9689

3 changed files with 29 additions and 9 deletions

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1

include/linux/sched.h

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24

net/unix/af_unix.c

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13

net/unix/garbage.c

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