Willy Tarreau dcaffd537f pipe: limit the per-user amount of pages allocated in pipes ... On no-so-small systems, it is possible for a single process to cause an OOM condition by filling large pipes with data that are never read. A typical process filling 4000 pipes with 1 MB of data will use 4 GB of memory. On small systems it may be tricky to set the pipe max size to prevent this from happening. This patch makes it possible to enforce a per-user soft limit above which new pipes will be limited to a single page, effectively limiting them to 4 kB each, as well as a hard limit above which no new pipes may be created for this user. This has the effect of protecting the system against memory abuse without hurting other users, and still allowing pipes to work correctly though with less data at once. The limit are controlled by two new sysctls : pipe-user-pages-soft, and pipe-user-pages-hard. Both may be disabled by setting them to zero. The default soft limit allows the default number of FDs per process (1024) to create pipes of the default size (64kB), thus reaching a limit of 64MB before starting to create only smaller pipes. With 256 processes limited to 1024 FDs each, this results in 1024*64kB + (256*1024 - 1024) * 4kB = 1084 MB of memory allocated for a user. The hard limit is disabled by default to avoid breaking existing applications that make intensive use of pipes (eg: for splicing). 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> Signed-off-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Conflicts: Documentation/sysctl/fs.txt fs/pipe.c include/linux/sched.h Change-Id: Ic7c678af18129943e16715fdaa64a97a7f0854be		2016-10-29 23:12:35 +08:00
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acpi
asm-generic	crypto: create generic version of ablk_helper	2016-10-29 23:12:13 +08:00
crypto	crypto: sha512 - Expose generic sha512 routine to be callable from other modules	2016-10-29 23:12:14 +08:00
drm
keys	KEYS: Permit in-place link replacement in keyring list	2016-10-29 23:12:12 +08:00
linux	pipe: limit the per-user amount of pages allocated in pipes	2016-10-29 23:12:35 +08:00
math-emu
media	Fix header list when building with Android	2016-10-29 23:12:09 +08:00
misc
mtd
net	ipv6: clean up anycast when an interface is destroyed	2016-10-29 23:12:33 +08:00
pcmcia
rdma
rxrpc
scsi
sound
target
trace	f2fs: trace old block address for CoWed page	2016-10-29 23:12:32 +08:00
video
xen
Kbuild