EAP-FAST: Allow empty PAC file to be used

Even if the PAC file does not start with the proper header line, allow
the file to be used if it is empty. [Bug 423]

Signed-hostap: Jouni Malinen <j@w1.fi>

src/eap_peer/eap_fast_pac.c

@@ -422,8 +422,12 @@ int eap_fast_load_pac(struct eap_sm *sm, struct eap_fast_pac **pac_root,
 	if (eap_fast_init_pac_data(sm, pac_file, &rc) < 0)
 		return 0;
 
-	if (eap_fast_read_line(&rc, &pos) < 0 ||
-	    os_strcmp(pac_file_hdr, rc.buf) != 0)
+	if (eap_fast_read_line(&rc, &pos) < 0) {
+		/* empty file - assume it is fine to overwrite */
+		eap_fast_deinit_pac_data(&rc);
+		return 0;
+	}
+	if (os_strcmp(pac_file_hdr, rc.buf) != 0)
 		err = "Unrecognized header line";
 
 	while (!err && eap_fast_read_line(&rc, &pos) == 0) {