0d134522d8
By using the shm file when sending the keymap to all clients, we effectively allows any client to change the keymap, as any client has the ability to change the content of the file. Sending a read-only file descriptor, or making the file itself read-only before unlinking, can be worked around by the client by using chmod(2) and open(2) on /proc/<pid>/<fd>. Using memfd could potentially solve this issue, but as the usage of mmap with MAP_SHARED is wide spread among clients, such a change can not be introduced without causing wide spread compatibility issues. So, to avoid allowing clients to interfere with each other, create a separate shm file for each wl_keyboard resource when sending the keymap. We could eventually do this per client, but in most cases, there will only be one wl_keyboard resource per client anyway. https://bugzilla.gnome.org/show_bug.cgi?id=784206