From: Vincent Whitchurch vincent.whitchurch@axis.com
[ Upstream commit f9390b249c90a15a4d9e69fbfb7a53c860b1fcaf ]
On kernels before v5.15, calling read() on a unix socket after shutdown(SHUT_RD) or shutdown(SHUT_RDWR) would return the data previously written or EOF. But now, while read() after shutdown(SHUT_RD) still behaves the same way, read() after shutdown(SHUT_RDWR) always fails with -EINVAL.
This behaviour change was apparently inadvertently introduced as part of a bug fix for a different regression caused by the commit adding sockmap support to af_unix, commit 94531cfcbe79c359 ("af_unix: Add unix_stream_proto for sockmap"). Those commits, for unclear reasons, started setting the socket state to TCP_CLOSE on shutdown(SHUT_RDWR), while this state change had previously only been done in unix_release_sock().
Restore the original behaviour. The sockmap tests in tests/selftests/bpf continue to pass after this patch.
Fixes: d0c6416bd7091647f60 ("unix: Fix an issue in unix_shutdown causing the other end read/write failures") Link: https://lore.kernel.org/lkml/20211111140000.GA10779@axis.com/ Signed-off-by: Vincent Whitchurch vincent.whitchurch@axis.com Tested-by: Casey Schaufler casey@schaufler-ca.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/unix/af_unix.c | 3 --- 1 file changed, 3 deletions(-)
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 78e08e82c08c4..b0bfc78e421ce 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -2882,9 +2882,6 @@ static int unix_shutdown(struct socket *sock, int mode)
unix_state_lock(sk); sk->sk_shutdown |= mode; - if ((sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) && - mode == SHUTDOWN_MASK) - sk->sk_state = TCP_CLOSE; other = unix_peer(sk); if (other) sock_hold(other);