From 7de3297a9239dbcadd7c52eaab3b75cb6cf522e4 Mon Sep 17 00:00:00 2001 From: Lee Jones Date: Mon, 12 Sep 2022 14:38:55 +0100 Subject: [PATCH] bpf: Ensure correct locking around vulnerable function find_vpid() [ 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 Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20220912133855.1218900-1-lee@kernel.org Signed-off-by: Sasha Levin --- kernel/bpf/syscall.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 7a3444988c84b..494ba88054e81 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; -- 2.47.2