From 006dccd14fb24f7621d6e9143a7550fdc73feced Mon Sep 17 00:00:00 2001 From: Joe Stringer Date: Tue, 7 Apr 2020 20:35:40 -0700 Subject: [PATCH] UPSTREAM: bpf: Fix use of sk->sk_reuseport from sk_assign 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") Change-Id: Ifbbc44ec070a0766b189f589ee7808bc38c520db Signed-off-by: Joe Stringer Signed-off-by: Daniel Borkmann Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/20200408033540.10339-1-joe@wand.net.nz --- net/core/filter.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/filter.c b/net/core/filter.c index 2e45f4973a64..14126ffedad0 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -6035,7 +6035,7 @@ 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)))