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 539ff36..84098be 100644 (file)
--- a/src/control.c
+++ b/src/control.c
@@ -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)