Currently, a sock_ops BPF program can write the op field and all the
reply fields (reply and replylong). This is a bug. The op field should
not have been writeable and there is currently no way to use replylong
field for indices >= 1. This patch enforces that only the reply field
(which equals replylong[0]) is writeable.
Fixes: 40304b2a1567 ("bpf: BPF support for sock_ops")
Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
{
if (type == BPF_WRITE) {
switch (off) {
- case offsetof(struct bpf_sock_ops, op) ...
- offsetof(struct bpf_sock_ops, replylong[3]):
+ case offsetof(struct bpf_sock_ops, reply):
break;
default:
return false;