From: Al Viro <viro@zeniv.linux.org.uk> stable inclusion from stable-v4.19.321 commit fa5bfdf6cb5846a00e712d630a43e3cf55ccb411 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=... -------------------------------- 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 f6b6a6c4b491..778e1b5bf80a 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4578,9 +4578,12 @@ 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) -- 2.34.1