summary refs log tree commit diff
path: root/kernel/ucount.c
diff options
context:
space:
mode:
authorDmitry Safonov <dima@arista.com>2020-04-06 18:13:42 +0100
committerThomas Gleixner <tglx@linutronix.de>2020-04-07 12:37:21 +0200
commiteeec26d5da8248ea4e240b8795bb4364213d3247 (patch)
tree2e1aef9815026c6d771813a7216a531c8cba33cd /kernel/ucount.c
parentb801f1e22c23c259d6a2c955efddd20370de19a6 (diff)
downloadlinux-eeec26d5da8248ea4e240b8795bb4364213d3247.tar.gz
time/namespace: Add max_time_namespaces ucount
Michael noticed that userns limit for number of time namespaces is missing.

Furthermore, time namespace introduced UCOUNT_TIME_NAMESPACES, but didn't
introduce an array member in user_table[]. It would make array's
initialisation OOB write, but by luck the user_table array has an excessive
empty member (all accesses to the array are limited with UCOUNT_COUNTS - so
it silently reuses the last free member.

Fixes user-visible regression: max_inotify_instances by reason of the
missing UCOUNT_ENTRY() has limited max number of namespaces instead of the
number of inotify instances.

Fixes: 769071ac9f20 ("ns: Introduce Time Namespace")
Reported-by: Michael Kerrisk (man-pages) <mtk.manpages@gmail.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andrei Vagin <avagin@gmail.com>
Acked-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: stable@kernel.org
Link: https://lkml.kernel.org/r/20200406171342.128733-1-dima@arista.com

Diffstat (limited to 'kernel/ucount.c')
-rw-r--r--kernel/ucount.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/ucount.c b/kernel/ucount.c
index a53cc2b4179c..29c60eb4ec9b 100644
--- a/kernel/ucount.c
+++ b/kernel/ucount.c
@@ -69,6 +69,7 @@ static struct ctl_table user_table[] = {
 	UCOUNT_ENTRY("max_net_namespaces"),
 	UCOUNT_ENTRY("max_mnt_namespaces"),
 	UCOUNT_ENTRY("max_cgroup_namespaces"),
+	UCOUNT_ENTRY("max_time_namespaces"),
 #ifdef CONFIG_INOTIFY_USER
 	UCOUNT_ENTRY("max_inotify_instances"),
 	UCOUNT_ENTRY("max_inotify_watches"),