Commit 5121700b authored by Daniel Borkmann's avatar Daniel Borkmann Committed by Alexei Starovoitov

bpf, sockmap: fix bpf_tcp_sendmsg sock error handling

While working on bpf_tcp_sendmsg() code, I noticed that when a
sk->sk_err is set we error out with err = sk->sk_err. However
this is problematic since sk->sk_err is a positive error value
and therefore we will neither go into sk_stream_error() nor will
we report an error back to user space. I had this case with EPIPE
and user space was thinking sendmsg() succeeded since EPIPE is
a positive value, thinking we submitted 32 bytes. Fix it by
negating the sk->sk_err value.

Fixes: 4f738adb ("bpf: create tcp_bpf_ulp allowing BPF to monitor socket TX/RX data")
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 74682128
...@@ -1053,7 +1053,7 @@ static int bpf_tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) ...@@ -1053,7 +1053,7 @@ static int bpf_tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
int copy; int copy;
if (sk->sk_err) { if (sk->sk_err) {
err = sk->sk_err; err = -sk->sk_err;
goto out_err; goto out_err;
} }
......
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