[PATCH] weston-launch: make sure we are launched as root

[Armin K]

If running as normal user, it will check if
binary is setuid root and fail if it is not.

Running as root or through sudo when binary
is not setuid root isn't affected and works
as it always worked.
---
 src/weston-launch.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/weston-launch.c b/src/weston-launch.c
index a111812..bd9d6ce 100644
--- a/src/weston-launch.c
+++ b/src/weston-launch.c
@@ -106,6 +106,7 @@ static int
 weston_launch_allowed(struct weston_launch *wl)
 {
 	struct group *gr;
+	struct stat s;
 	gid_t *groups;
 	int i;
 #ifdef HAVE_SYSTEMD_LOGIN
@@ -116,6 +117,16 @@ weston_launch_allowed(struct weston_launch *wl)
 	if (getuid() == 0)
 		return 1;
 
+        if (stat(BINDIR "/weston-launch", &s) < 0) {
+                fprintf(stderr, "failed to get weston-launch binary information\n");
+                return 0;
+        }
+
+        if(s.st_uid != 0 || s.st_gid != 0 || !(s.st_mode & S_ISUID)) {
+                fprintf(stderr, "weston-launch binary must be setuid root\n");
+                return 0;
+        }
+
 	gr = getgrnam("weston-launch");
 	if (gr) {
 		groups = read_groups();
-- 
1.8.3.4