svn commit: r249263 - head/sys/rpc

[John Baldwin]

Author: jhb
Date: Mon Apr  8 19:03:01 2013
New Revision: 249263
URL: http://svnweb.freebsd.org/changeset/base/249263

Log:
  Fix a potential socket leak in the NFS server.  If a client closes its
  connection after it was accepted by the userland nfsd process but before
  it was handled off to svc_vc_create() in the kernel, then svc_vc_create()
  would see it as a new listen socket and try to listen on it leaving a
  dangling reference to the socket.  Instead, check for disconnected sockets
  and treat them like a connected socket.  The call to pru_getaddr() should
  fail and cause svc_vc_create() to fail.  Note that we need to lock the
  socket to get a consistent snapshot of so_state since there is a window
  in soisdisconnected() where both flags are clear.
  
  Reviewed by:	dfr, rmacklem
  MFC after:	1 week

Modified:
  head/sys/rpc/svc_vc.c

Modified: head/sys/rpc/svc_vc.c
==============================================================================
--- head/sys/rpc/svc_vc.c	Mon Apr  8 18:46:35 2013	(r249262)
+++ head/sys/rpc/svc_vc.c	Mon Apr  8 19:03:01 2013	(r249263)
@@ -146,7 +146,9 @@ svc_vc_create(SVCPOOL *pool, struct sock
 	struct sockaddr* sa;
 	int error;
 
-	if (so->so_state & SS_ISCONNECTED) {
+	SOCK_LOCK(so);
+	if (so->so_state & (SS_ISCONNECTED|SS_ISDISCONNECTED)) {
+		SOCK_UNLOCK(so);
 		error = so->so_proto->pr_usrreqs->pru_peeraddr(so, &sa);
 		if (error)
 			return (NULL);
@@ -154,6 +156,7 @@ svc_vc_create(SVCPOOL *pool, struct sock
 		free(sa, M_SONAME);
 		return (xprt);
 	}
+	SOCK_UNLOCK(so);
 
 	xprt = svc_xprt_alloc();
 	sx_init(&xprt->xp_lock, "xprt->xp_lock");