stun

commit f278e9f47d626981d26f061adec552581a03b7d9
parent 98118c6d6e5219ebae7c239e9ca55fad38daef86
Author: sin <sin@2f30.org>
Date:   Tue, 29 Mar 2016 10:42:25 +0100

revoke privs later so bind can succeed on low ports

Diffstat:
M
stun.c
 | 
31
++++++++++++++++---------------

1 file changed, 16 insertions(+), 15 deletions(-)
diff --git a/stun.c b/stun.c
@@ -155,6 +155,20 @@ logerr(char *msg, ...)
 	exit(1);
 }
 
+void
+revokeprivs(void)
+{
+	struct passwd *pw;
+
+	pw = getpwnam(NOPRIVUSER);
+	if (!pw)
+		logerr("no %s user", NOPRIVUSER);
+	if (setgroups(1, &pw->pw_gid) ||
+	    setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
+	    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
+		logerr("failed to revoke privs");
+}
+
 int
 padto(int len, int blocksize)
 {
@@ -641,6 +655,7 @@ serversetup(int devfd)
 	if (ret < 0)
 		logerr("listen failed");
 
+	revokeprivs();
 	for (;;) {
 		netfd = accept(listenfd, (struct sockaddr *)&remote,
 		               (socklen_t []){sizeof(remote)});
@@ -761,20 +776,6 @@ daemonize(void)
 }
 
 void
-revokeprivs(void)
-{
-	struct passwd *pw;
-
-	pw = getpwnam(NOPRIVUSER);
-	if (!pw)
-		logerr("no %s user", NOPRIVUSER);
-	if (setgroups(1, &pw->pw_gid) ||
-	    setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
-	    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
-		logerr("failed to revoke privs");
-}
-
-void
 usage(void)
 {
 	fprintf(stderr, "usage: stun [-df] -s [-p port] [-t type] interface\n");
@@ -825,7 +826,6 @@ main(int argc, char *argv[])
 	openlog("stun", LOG_PID | LOG_NDELAY, LOG_DAEMON);
 
 	devfd = opendev(argv[0]);
-	revokeprivs();
 
 	pw = getenv("STUNPW");
 	if (!pw)
@@ -836,6 +836,7 @@ main(int argc, char *argv[])
 	if (sflag)
 		return serversetup(devfd);
 	/* auto-reconnect client */
+	revokeprivs();
 	for (;;) {
 		clientsetup(devfd);
 		sleep(RECONNECTTIMEO);