[PATCH 5.1 25/46] selinux: do not report error on connect(AF_UNSPEC)

From: Greg Kroah-Hartman
Date: Wed May 15 2019 - 07:37:54 EST

From: Paolo Abeni <pabeni@xxxxxxxxxx>

[ Upstream commit c7e0d6cca86581092cbbf2cd868b3601495554cf ]

calling connect(AF_UNSPEC) on an already connected TCP socket is an
established way to disconnect() such socket. After commit 68741a8adab9
("selinux: Fix ltp test connect-syscall failure") it no longer works
and, in the above scenario connect() fails with EAFNOSUPPORT.

Fix the above falling back to the generic/old code when the address family
is not AF_INET{4,6}, but leave the SCTP code path untouched, as it has
specific constraints.

Fixes: 68741a8adab9 ("selinux: Fix ltp test connect-syscall failure")
Reported-by: Tom Deseyn <tdeseyn@xxxxxxxxxx>
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
security/selinux/hooks.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4572,7 +4572,7 @@ static int selinux_socket_connect_helper
struct lsm_network_audit net = {0,};
struct sockaddr_in *addr4 = NULL;
struct sockaddr_in6 *addr6 = NULL;
- unsigned short snum;
+ unsigned short snum = 0;
u32 sid, perm;

/* sctp_connectx(3) calls via selinux_sctp_bind_connect()
@@ -4595,12 +4595,12 @@ static int selinux_socket_connect_helper
/* Note that SCTP services expect -EINVAL, whereas
- * others expect -EAFNOSUPPORT.
+ * others must handle this at the protocol level:
+ * connect(AF_UNSPEC) on a connected socket is
+ * a documented way disconnect the socket.
if (sksec->sclass == SECCLASS_SCTP_SOCKET)
return -EINVAL;
- else

err = sel_netport_sid(sk->sk_protocol, snum, &sid);