Messages in this thread Patch in this message | | | Date | Tue, 07 Apr 2020 10:41:59 -0000 | From | "tip-bot2 for Dmitry Safonov" <> | Subject | [tip: timers/urgent] time/namespace: Add max_time_namespaces ucount |
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The following commit has been merged into the timers/urgent branch of tip:
Commit-ID: eeec26d5da8248ea4e240b8795bb4364213d3247 Gitweb: https://git.kernel.org/tip/eeec26d5da8248ea4e240b8795bb4364213d3247 Author: Dmitry Safonov <dima@arista.com> AuthorDate: Mon, 06 Apr 2020 18:13:42 +01:00 Committer: Thomas Gleixner <tglx@linutronix.de> CommitterDate: Tue, 07 Apr 2020 12:37:21 +02:00
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
--- Documentation/admin-guide/sysctl/user.rst | 6 ++++++ kernel/ucount.c | 1 + 2 files changed, 7 insertions(+)
diff --git a/Documentation/admin-guide/sysctl/user.rst b/Documentation/admin-guide/sysctl/user.rst index 650eaa0..c458245 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 a53cc2b..29c60eb 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"),
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