Commit Message
Greg KH
Oct. 22, 2022, 7:22 a.m. UTC
From: Lee Jones <lee@kernel.org> [ Upstream commit 83c10cc362d91c0d8d25e60779ee52fdbbf3894d ] The documentation for find_vpid() clearly states: "Must be called with the tasklist_lock or rcu_read_lock() held." Presently we do neither for find_vpid() instance in bpf_task_fd_query(). Add proper rcu_read_lock/unlock() to fix the issue. Fixes: 41bdc4b40ed6f ("bpf: introduce bpf subcommand BPF_TASK_FD_QUERY") Signed-off-by: Lee Jones <lee@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20220912133855.1218900-1-lee@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org> --- kernel/bpf/syscall.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 7a3444988c84..494ba88054e8 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -4361,7 +4361,9 @@ static int bpf_task_fd_query(const union bpf_attr *attr, if (attr->task_fd_query.flags != 0) return -EINVAL; + rcu_read_lock(); task = get_pid_task(find_vpid(pid), PIDTYPE_PID); + rcu_read_unlock(); if (!task) return -ENOENT;