mqueue: revert bump up DFLT_*MAX

Mqueue limitation is slightly naieve parameter likes other ipcs because
unprivileged user can consume kernel memory by using ipcs.

Thus, too aggressive raise bring us security issue.  Example, current
setting allow evil unprivileged user use 256GB (= 256 * 1024 * 1024*1024)
and it's enough large to system will belome unresponsive.  Don't do that.

Instead, every admin should adjust the knobs for their own systems.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Doug Ledford <dledford@redhat.com>
Acked-by: Joe Korty <joe.korty@ccur.com>
Cc: Amerigo Wang <amwang@redhat.com>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index 6e1dd08194fd..2488535a32a3 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -118,12 +118,12 @@ extern int mq_init_ns(struct ipc_namespace *ns);
 #define DFLT_QUEUESMAX                256
 #define HARD_QUEUESMAX               1024
 #define MIN_MSGMAX                      1
-#define DFLT_MSG                       64U
-#define DFLT_MSGMAX                  1024
+#define DFLT_MSG                       10U
+#define DFLT_MSGMAX                    10
 #define HARD_MSGMAX                 65536
 #define MIN_MSGSIZEMAX                128
 #define DFLT_MSGSIZE                 8192U
-#define DFLT_MSGSIZEMAX        (1024*1024)
+#define DFLT_MSGSIZEMAX              8192
 #define HARD_MSGSIZEMAX     (16*1024*1024)
 #else
 static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }