From 046667c4d3196938e992fba0dfcde570aa85cd0e Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 21 Jul 2024 14:45:08 -0400 Subject: memcg_write_event_control(): fix a user-triggerable oops we are *not* guaranteed that anything past the terminating NUL is mapped (let alone initialized with anything sane). Fixes: 0dea116876ee ("cgroup: implement eventfd-based generic API for notifications") Cc: stable@vger.kernel.org Cc: Andrew Morton Acked-by: Michal Hocko Signed-off-by: Al Viro --- mm/memcontrol-v1.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'mm') diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c index 2aeea4d8bf8e..417c96f2da28 100644 --- a/mm/memcontrol-v1.c +++ b/mm/memcontrol-v1.c @@ -1842,9 +1842,12 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of, buf = endp + 1; cfd = simple_strtoul(buf, &endp, 10); - if ((*endp != ' ') && (*endp != '\0')) + if (*endp == '\0') + buf = endp; + else if (*endp == ' ') + buf = endp + 1; + else return -EINVAL; - buf = endp + 1; event = kzalloc(sizeof(*event), GFP_KERNEL); if (!event) -- cgit v1.2.3