From: Joe Stringer <joe@wand.net.nz>
To: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org, daniel@iogearbox.net, ast@kernel.org
Subject: [PATCH bpf] bpf: Fix use of sk->sk_reuseport from sk_assign
Date: Tue, 7 Apr 2020 20:35:40 -0700 [thread overview]
Message-ID: <20200408033540.10339-1-joe@wand.net.nz> (raw)
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(-)
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)))
--
2.20.1
next reply other threads:[~2020-04-08 3:35 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-08 3:35 Joe Stringer [this message]
2020-04-08 18:12 ` [PATCH bpf] bpf: Fix use of sk->sk_reuseport from sk_assign Martin KaFai Lau
2020-04-08 23:14 ` Daniel Borkmann
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