inaban

commit: eacb154d166531eebf7682b6af8041529c044bdc
parent: fd988723948cc946481a66ab5256339c20982609
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date:   Mon,  1 Jul 2019 06:20:52 +0200

inaban: Forbid running as root, drop permission if setuid

Diffstat:
M
inaban.c
28
++++++++++++++++++++++++++++

1 file changed, 28 insertions(+), 0 deletions(-)
diff --git a/inaban.c b/inaban.c
@@ -853,9 +853,35 @@ server_new_xdg_surface(struct wl_listener *listener, void *data)
 	wl_list_insert(&server->views, &view->link);
 }
 
+static bool
+drop_permissions(void)
+{
+	if(getuid() != geteuid() || getgid() != getegid())
+	{
+		if(setuid(getuid()) != 0 || setgid(getgid()) != 0)
+		{
+			wlr_log(WLR_ERROR, "Unable to drop root, refusing to continue");
+			return false;
+		}
+		if(geteuid() == 0 && getegid() == 0)
+		{
+			wlr_log(WLR_ERROR,
+			        "Still effectively running as root after dropping permissions, refusing to continue");
+			return false;
+		}
+	}
+
+	return true;
+}
+
 int
 main(int argc, char *argv[])
 {
+	if(geteuid() == 0 && getegid() == 0)
+	{
+		wlr_log(WLR_ERROR, "Running as root is unsupported, refusing to continue");
+		return false;
+	}
 	wlr_log_init(WLR_DEBUG, NULL);
 	char *startup_cmd = NULL;
 
@@ -888,6 +914,8 @@ main(int argc, char *argv[])
 	 * don't). */
 	server.backend = wlr_backend_autocreate(server.wl_display, NULL);
 
+	if(!drop_permissions()) abort();
+
 	/* If we don't provide a renderer, autocreate makes a GLES2 renderer for us.
 	 * The renderer is responsible for defining the various pixel formats it
 	 * supports for shared memory, this configures that for clients. */