linux/security
Davidlohr Bueso 23c8cec8cf ipc/msg: introduce msgctl(MSG_STAT_ANY)
There is a permission discrepancy when consulting msq ipc object
metadata between /proc/sysvipc/msg (0444) and the MSG_STAT shmctl
command.  The later does permission checks for the object vs S_IRUGO.
As such there can be cases where EACCESS is returned via syscall but the
info is displayed anyways in the procfs files.

While this might have security implications via info leaking (albeit no
writing to the msq metadata), this behavior goes way back and showing
all the objects regardless of the permissions was most likely an
overlook - so we are stuck with it.  Furthermore, modifying either the
syscall or the procfs file can cause userspace programs to break (ie
ipcs).  Some applications require getting the procfs info (without root
privileges) and can be rather slow in comparison with a syscall -- up to
500x in some reported cases for shm.

This patch introduces a new MSG_STAT_ANY command such that the msq ipc
object permissions are ignored, and only audited instead.  In addition,
I've left the lsm security hook checks in place, as if some policy can
block the call, then the user has no other choice than just parsing the
procfs file.

Link: http://lkml.kernel.org/r/20180215162458.10059-4-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reported-by: Robert Kettler <robert.kettler@outlook.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11 10:28:37 -07:00
..
apparmor Merge branch 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2018-04-07 11:11:41 -07:00
integrity ima: Fallback to the builtin hash algorithm 2018-03-25 07:26:32 -04:00
keys headers: untangle kmemleak.h from mm.h 2018-04-05 21:36:27 -07:00
loadpin get rid of pointless includes of fs_struct.h 2018-02-22 14:28:50 -05:00
selinux ipc/msg: introduce msgctl(MSG_STAT_ANY) 2018-04-11 10:28:37 -07:00
smack ipc/msg: introduce msgctl(MSG_STAT_ANY) 2018-04-11 10:28:37 -07:00
tomoyo net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
yama pids: introduce find_get_task_by_vpid() helper 2018-02-06 18:32:46 -08:00
commoncap.c
device_cgroup.c
inode.c
Kconfig Currently, hardened usercopy performs dynamic bounds checking on slab 2018-02-03 16:25:42 -08:00
lsm_audit.c
Makefile
min_addr.c
security.c New features: 2018-04-10 11:27:30 -07:00