Fix a race in soclose() where connections could be queued to the

listening socket after the pass that cleans those queues. This
results in these connections being orphaned (and leaked). The fix
is to clean up the so queues after detaching the socket from the
protocol. Thanks to ups and jhb for discussions and a thorough code
review.

1 files changed, 26 insertions, 22 deletions

diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index 635a2bf..f1690df 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -592,6 +592,10 @@ sofree(so)
 	    (so->so_qstate & SQ_INCOMP) == 0,
 	    ("sofree: so_head == NULL, but still SQ_COMP(%d) or SQ_INCOMP(%d)",
 	    so->so_qstate & SQ_COMP, so->so_qstate & SQ_INCOMP));
+	if (so->so_options & SO_ACCEPTCONN) {
+		KASSERT((TAILQ_EMPTY(&so->so_comp)), ("sofree: so_comp populated"));
+		KASSERT((TAILQ_EMPTY(&so->so_incomp)), ("sofree: so_comp populated"));
+	}
 	SOCK_UNLOCK(so);
 	ACCEPT_UNLOCK();
 
@@ -640,6 +644,28 @@ soclose(so)
 	KASSERT(!(so->so_state & SS_NOFDREF), ("soclose: SS_NOFDREF on enter"));
 
 	funsetown(&so->so_sigio);
+	if (so->so_state & SS_ISCONNECTED) {
+		if ((so->so_state & SS_ISDISCONNECTING) == 0) {
+			error = sodisconnect(so);
+			if (error)
+				goto drop;
+		}
+		if (so->so_options & SO_LINGER) {
+			if ((so->so_state & SS_ISDISCONNECTING) &&
+			    (so->so_state & SS_NBIO))
+				goto drop;
+			while (so->so_state & SS_ISCONNECTED) {
+				error = tsleep(&so->so_timeo,
+				    PSOCK | PCATCH, "soclos", so->so_linger * hz);
+				if (error)
+					break;
+			}
+		}
+	}
+
+drop:
+	if (so->so_proto->pr_usrreqs->pru_close != NULL)
+		(*so->so_proto->pr_usrreqs->pru_close)(so);
 	if (so->so_options & SO_ACCEPTCONN) {
 		struct socket *sp;
 		ACCEPT_LOCK();
@@ -663,28 +689,6 @@ soclose(so)
 		}
 		ACCEPT_UNLOCK();
 	}
-	if (so->so_state & SS_ISCONNECTED) {
-		if ((so->so_state & SS_ISDISCONNECTING) == 0) {
-			error = sodisconnect(so);
-			if (error)
-				goto drop;
-		}
-		if (so->so_options & SO_LINGER) {
-			if ((so->so_state & SS_ISDISCONNECTING) &&
-			    (so->so_state & SS_NBIO))
-				goto drop;
-			while (so->so_state & SS_ISCONNECTED) {
-				error = tsleep(&so->so_timeo,
-				    PSOCK | PCATCH, "soclos", so->so_linger * hz);
-				if (error)
-					break;
-			}
-		}
-	}
-
-drop:
-	if (so->so_proto->pr_usrreqs->pru_close != NULL)
-		(*so->so_proto->pr_usrreqs->pru_close)(so);
 	ACCEPT_LOCK();
 	SOCK_LOCK(so);
 	KASSERT((so->so_state & SS_NOFDREF) == 0, ("soclose: NOFDREF"));