| Message ID | 20200408033540.10339-1-joe@wand.net.nz |
|---|---|
| State | Accepted |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | [bpf] bpf: Fix use of sk->sk_reuseport from sk_assign | expand |
On Tue, Apr 07, 2020 at 08:35:40PM -0700, Joe Stringer wrote: > In testing, we found that for request sockets the sk->sk_reuseport field > may yet be uninitialized, which caused bpf_sk_assign() to randomly > succeed or return -ESOCKTNOSUPPORT when handling the forward ACK in a > three-way handshake. > > Fix it by only applying the reuseport check for full sockets. Acked-by: Martin KaFai Lau <kafai@fb.com>
On 4/8/20 5:35 AM, Joe Stringer wrote: > In testing, we found that for request sockets the sk->sk_reuseport field > may yet be uninitialized, which caused bpf_sk_assign() to randomly > succeed or return -ESOCKTNOSUPPORT when handling the forward ACK in a > three-way handshake. > > Fix it by only applying the reuseport check for full sockets. > > Fixes: cf7fbe660f2d ("bpf: Add socket assign support") > Signed-off-by: Joe Stringer <joe@wand.net.nz> Applied, thanks!
diff --git a/net/core/filter.c b/net/core/filter.c index 7628b947dbc3..7d6ceaa54d21 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -5925,7 +5925,7 @@ BPF_CALL_3(bpf_sk_assign, struct sk_buff *, skb, struct sock *, sk, u64, flags) return -EOPNOTSUPP; if (unlikely(dev_net(skb->dev) != sock_net(sk))) return -ENETUNREACH; - if (unlikely(sk->sk_reuseport)) + if (unlikely(sk_fullsock(sk) && sk->sk_reuseport)) return -ESOCKTNOSUPPORT; if (sk_is_refcounted(sk) && unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
In testing, we found that for request sockets the sk->sk_reuseport field may yet be uninitialized, which caused bpf_sk_assign() to randomly succeed or return -ESOCKTNOSUPPORT when handling the forward ACK in a three-way handshake. Fix it by only applying the reuseport check for full sockets. Fixes: cf7fbe660f2d ("bpf: Add socket assign support") Signed-off-by: Joe Stringer <joe@wand.net.nz> --- net/core/filter.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)