linux/ipc
Manfred Spraul 39cfffd774 ipc/util.c: use ipc_rcu_putref() for failues in ipc_addid()
ipc_addid() is impossible to use:
- for certain failures, the caller must not use ipc_rcu_putref(),
  because the reference counter is not yet initialized.
- for other failures, the caller must use ipc_rcu_putref(),
  because parallel operations could be ongoing already.

The patch cleans that up, by initializing the refcount early, and by
modifying all callers.

The issues is related to the finding of
syzbot+2827ef6b3385deb07eaf@syzkaller.appspotmail.com: syzbot found an
issue with reading kern_ipc_perm.seq, here both read and write to already
released memory could happen.

Link: http://lkml.kernel.org/r/20180712185241.4017-4-manfred@colorfullife.com
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22 10:52:51 -07:00
..
compat.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ipc_sysctl.c
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mq_sysctl.c
mqueue.c y2038: ipc: Enable COMPAT_32BIT_TIME 2018-04-20 16:20:27 +02:00
msg.c ipc/util.c: use ipc_rcu_putref() for failues in ipc_addid() 2018-08-22 10:52:51 -07:00
msgutil.c ipc: convert ipc_namespace.count from atomic_t to refcount_t 2017-09-08 18:26:51 -07:00
namespace.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sem.c ipc/util.c: use ipc_rcu_putref() for failues in ipc_addid() 2018-08-22 10:52:51 -07:00
shm.c ipc/util.c: use ipc_rcu_putref() for failues in ipc_addid() 2018-08-22 10:52:51 -07:00
syscall.c y2038: ipc: Redirect ipc(SEMTIMEDOP, ...) to compat_ksys_semtimedop 2018-04-20 16:20:30 +02:00
util.c ipc/util.c: use ipc_rcu_putref() for failues in ipc_addid() 2018-08-22 10:52:51 -07:00
util.h y2038: ipc: Enable COMPAT_32BIT_TIME 2018-04-20 16:20:27 +02:00