From 20fb10aa4c3d5b265c54bfb07924d12695525d04 Mon Sep 17 00:00:00 2001 From: Lee Jones Date: Mon, 12 Sep 2022 14:38:55 +0100 Subject: [PATCH] UPSTREAM: 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. Bug: 232939090 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 Signed-off-by: Lee Jones Change-Id: I517b52d97a22b92be1a479279067ddb7b84efbba --- kernel/bpf/syscall.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 9ebdcdaa5f16..de788761b708 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2787,7 +2787,9 @@ 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;