Use umask() to set file and UNIX socket permissions without race conditions.

[tinc] / src / control.c

diff --git a/src/control.c b/src/control.c
index 83a9d79..84098be 100644 (file)
--- a/src/control.c
+++ b/src/control.c
@@ -1,6 +1,6 @@
 /*
     control.c -- Control socket handling.
-    Copyright (C) 2012 Guus Sliepen <guus@tinc-vpn.org>
+    Copyright (C) 2013 Guus Sliepen <guus@tinc-vpn.org>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -25,6 +25,7 @@
 #include "graph.h"
 #include "logger.h"
 #include "meta.h"
+#include "names.h"
 #include "net.h"
 #include "netutl.h"
 #include "protocol.h"
@@ -33,7 +34,6 @@
 #include "xalloc.h"
 
 char controlcookie[65];
-extern char *pidfilename;
 
 static bool control_return(connection_t *c, int type, int error) {
        return send_request(c, "%d %d %d", CONTROL, type, error);
@@ -137,17 +137,16 @@ bool init_control(void) {
        randomize(controlcookie, sizeof controlcookie / 2);
        bin2hex(controlcookie, controlcookie, sizeof controlcookie / 2);
 
+       mode_t mask = umask(0);
+       umask(mask | 077);
        FILE *f = fopen(pidfilename, "w");
+       umask(mask);
+
        if(!f) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Cannot write control socket cookie file %s: %s", pidfilename, strerror(errno));
                return false;
        }
 
-#ifdef HAVE_FCHMOD
-       fchmod(fileno(f), 0600);
-#else
-       chmod(pidfilename, 0600);
-#endif
        // Get the address and port of the first listening socket
 
        char *localhost = NULL;
@@ -157,7 +156,7 @@ bool init_control(void) {
        // Make sure we have a valid address, and map 0.0.0.0 and :: to 127.0.0.1 and ::1.
 
        if(getsockname(listen_socket[0].tcp.fd, (struct sockaddr *)&sa, &len)) {
-               xasprintf(&localhost, "127.0.0.1 port %d", myport);
+               xasprintf(&localhost, "127.0.0.1 port %s", myport);
        } else {
                if(sa.sa.sa_family == AF_INET) {
                        if(sa.in.sin_addr.s_addr == 0)