compositor: Drop setuid when launching clients

src/compositor.c

@@ -96,6 +96,9 @@ child_client_exec(int sockfd, const char *path)
 	sigfillset(&allsigs);
 	sigprocmask(SIG_UNBLOCK, &allsigs, NULL);
 
+	/* Launch clients as the user. */
+	seteuid(getuid());
+
 	/* SOCK_CLOEXEC closes both ends, so we dup the fd to get a
 	 * non-CLOEXEC fd to pass through exec. */
 	clientfd = dup(sockfd);