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| author | Dmitry Safonov <dima@arista.com> | 2020-04-06 19:13:42 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-04-07 12:37:21 +0200 |
| commit | eeec26d5da8248ea4e240b8795bb4364213d3247 (patch) | |
| tree | 2e1aef9815026c6d771813a7216a531c8cba33cd | |
| parent | time/namespace: Fix time_for_children symlink (diff) | |
| download | linux-eeec26d5da8248ea4e240b8795bb4364213d3247.tar.xz linux-eeec26d5da8248ea4e240b8795bb4364213d3247.zip | |
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
| -rw-r--r-- | Documentation/admin-guide/sysctl/user.rst | 6 | ||||
| -rw-r--r-- | kernel/ucount.c | 1 |
2 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/admin-guide/sysctl/user.rst b/Documentation/admin-guide/sysctl/user.rst index 650eaa03f15e..c45824589339 100644 --- a/Documentation/admin-guide/sysctl/user.rst +++ b/Documentation/admin-guide/sysctl/user.rst @@ -65,6 +65,12 @@ max_pid_namespaces The maximum number of pid namespaces that any user in the current user namespace may create. +max_time_namespaces +=================== + + The maximum number of time namespaces that any user in the current + user namespace may create. + max_user_namespaces =================== 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"), |