fix https://syzkaller.appspot.com/bug?id=910c84220f7ed55f124919cf54980c617e5fed76

fix-tcp-panic.diff

commit a0b8622b34a7a865eee497dbb8e844f0e39383dd
Author: Ryota Ozaki <ozaki.ryota@gmail.com>
Date:   Tue Aug 13 12:04:03 2019 +0900

    fix tcp panic

diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index c89dc0f4d57..fc0a7a3fd9d 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -886,6 +886,7 @@ sosend(struct socket *so, struct sockaddr *addr, struct uio *uio,
 	long space, len, resid, clen, mlen;
 	int error, s, dontroute, atomic;
 	short wakeup_state = 0;
+	bool need_connect = false;
 
 	clen = 0;
 
@@ -937,6 +938,7 @@ sosend(struct socket *so, struct sockaddr *addr, struct uio *uio,
 					error = ENOTCONN;
 					goto release;
 				}
+				need_connect = true;
 			} else if (addr == NULL) {
 				error = EDESTADDRREQ;
 				goto release;
@@ -1051,6 +1053,23 @@ sosend(struct socket *so, struct sockaddr *addr, struct uio *uio,
 				so->so_options |= SO_DONTROUTE;
 			if (resid > 0)
 				so->so_state |= SS_MORETOCOME;
+
+			if (need_connect) {
+				if (addr == NULL) {
+					error = EDESTADDRREQ;
+					goto release;
+				}
+				if (addr->sa_family !=
+				    so->so_proto->pr_domain->dom_family) {
+					error = EAFNOSUPPORT;
+					goto release;
+				}
+				error = (*so->so_proto->pr_usrreqs->pr_connect)(
+				    so, addr, l);
+				if (error != 0)
+					goto release;
+			}
+
 			if (flags & MSG_OOB) {
 				error = (*so->so_proto->pr_usrreqs->pr_sendoob)(
 				    so, top, control);