Never call load_dh_param(NULL) because this leads to an illegal

fopen(NULL).

CHANGES

@@ -4,6 +4,9 @@
 
  Changes between 0.9.6 and 0.9.7  [xx XXX 2000]
 
+  *) Never call load_dh_param(NULL) in s_server.
+     [Bodo Moeller]
+
   *) Add engine application.  It can currently list engines by name and
      identity, and test if they are actually available.
      [Richard Levitte]

apps/s_server.c

@@ -416,9 +416,6 @@ int MAIN(int argc, char *argv[])
 	int state=0;
 	SSL_METHOD *meth=NULL;
 	ENGINE *e=NULL;
-#ifndef NO_DH
-	DH *dh=NULL;
-#endif
 
 #if !defined(NO_SSL2) && !defined(NO_SSL3)
 	meth=SSLv23_server_method();
@@ -682,7 +679,13 @@ bad:
 #ifndef NO_DH
 	if (!no_dhe)
 		{
-		dh=load_dh_param(dhfile ? dhfile : s_cert_file);
+		DH *dh=NULL;
+
+		if (dhfile)
+			dh = load_dh_param(dhfile);
+		else if (s_cert_file)
+			dh = load_dh_param(s_cert_file);
+
 		if (dh != NULL)
 			{
 			BIO_printf(bio_s_out,"Setting temp DH parameters\n");