extra x11 hardening

1 files changed, 8 insertions, 11 deletions

diff --git a/src/firejail/x11.c b/src/firejail/x11.c
index 74de24b47..98ac184d9 100644
--- a/src/firejail/x11.c
+++ b/src/firejail/x11.c
@@ -1235,16 +1235,15 @@ void x11_xorg(void) {
 
         // move the temporary file in RUN_XAUTHORITY_SEC_FILE in order to have it deleted
         // automatically when the sandbox is closed (rename doesn't work)
-                                                  // root needed
-        if (copy_file(tmpfname, RUN_XAUTHORITY_SEC_FILE, getuid(), getgid(), 0600)) {
-                fprintf(stderr, "Error: cannot create the new .Xauthority file\n");
-                exit(1);
-        }
+        if (arg_debug)
+                printf("Copying the new .Xauthority file\n");
+        copy_file_from_user_to_root(tmpfname, RUN_XAUTHORITY_SEC_FILE, getuid(), getgid(), 0600);
+        
         /* coverity[toctou] */
         unlink(tmpfname);
         umount("/tmp");
 
-        // remount RUN_XAUTHORITY_SEC_FILE noexec, nodev, nosuid
+        // mount RUN_XAUTHORITY_SEC_FILE noexec, nodev, nosuid
         fs_remount(RUN_XAUTHORITY_SEC_FILE, MOUNT_NOEXEC, 0);
 
         // Ensure there is already a file in the usual location, so that bind-mount below will work.
@@ -1354,19 +1353,17 @@ void fs_x11(void) {
         if (mount("/tmp/.X11-unix", RUN_WHITELIST_X11_DIR, 0, MS_BIND|MS_REC, 0) < 0)
                 errExit("mount bind");
 
-        // This directory must be mode 1777, or Xlib will barf.
+        // This directory must be mode 1777
         if (mount("tmpfs", "/tmp/.X11-unix", "tmpfs",
                 MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_STRICTATIME,
                 "mode=1777,uid=0,gid=0") < 0)
                 errExit("mounting tmpfs on /tmp/.X11-unix");
         fs_logger("tmpfs /tmp/.X11-unix");
 
-        // create an empty file which will have the desired socket bind-mounted over it
-        int fd = open(x11file, O_RDWR|O_CREAT|O_EXCL, x11stat.st_mode & ~S_IFMT);
+        // create an empty root-owned file which will have the desired socket bind-mounted over it
+        int fd = open(x11file, O_RDONLY|O_CREAT|O_EXCL, S_IRUSR | S_IWUSR);
         if (fd < 0)
                 errExit(x11file);
-        if (fchown(fd, x11stat.st_uid, x11stat.st_gid))
-                errExit("fchown");
         close(fd);
 
         // the mount source is under control of the user, so be careful and