From: Al Viro viro@zeniv.linux.org.uk

stable inclusion from stable-v5.10.225 commit ad149f5585345e383baa65f1539d816cd715fd3b category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAQOJK CVE: CVE-2024-45021

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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commit 046667c4d3196938e992fba0dfcde570aa85cd0e upstream.

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 akpm@linux-foundation.org Acked-by: Michal Hocko mhocko@suse.com Signed-off-by: Al Viro viro@zeniv.linux.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Jinjiang Tu tujinjiang@huawei.com --- mm/memcontrol.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c index aefaa33147b1..ac365005f7a1 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5436,9 +5436,12 @@ 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)