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authorSabrina Dubroca <sd@queasysnail.net>2020-06-10 12:19:43 +0200
committerAlexei Starovoitov <ast@kernel.org>2020-06-12 15:10:12 -0700
commit2c7269b231194aae23fb90ab65842573a91acbc9 (patch)
tree8b85edb1c7f094125445f5cea4e5d574c0d783e7
parent2c4779eff837f1035f6f9650d246905daadd9528 (diff)
downloadlinux-2c7269b231194aae23fb90ab65842573a91acbc9.tar.gz
bpf: tcp: Recv() should return 0 when the peer socket is closed
If the peer is closed, we will never get more data, so tcp_bpf_wait_data will get stuck forever. In case we passed MSG_DONTWAIT to recv(), we get EAGAIN but we should actually get 0. >From man 2 recv: RETURN VALUE When a stream socket peer has performed an orderly shutdown, the return value will be 0 (the traditional "end-of-file" return). This patch makes tcp_bpf_wait_data always return 1 when the peer socket has been shutdown. Either we have data available, and it would have returned 1 anyway, or there isn't, in which case we'll call tcp_recvmsg which does the right thing in this situation. Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Sabrina Dubroca <sd@queasysnail.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Jakub Sitnicki <jakub@cloudflare.com> Link: https://lore.kernel.org/bpf/26038a28c21fea5d04d4bd4744c5686d3f2e5504.1591784177.git.sd@queasysnail.net
-rw-r--r--net/ipv4/tcp_bpf.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index 2b915aa..7aa68f4 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -245,6 +245,9 @@ static int tcp_bpf_wait_data(struct sock *sk, struct sk_psock *psock,
DEFINE_WAIT_FUNC(wait, woken_wake_function);
int ret = 0;
+ if (sk->sk_shutdown & RCV_SHUTDOWN)
+ return 1;
+
if (!timeo)
return ret;