Perform (partial) server initialization before dropping privileges.

Some operations during backend creation (e.g. becoming DRM master)
require CAP_SYS_ADMIN privileges. At this point, sway has dropped them
already, though. This patch splits the privileged part of server_init
into its own function and calls it before dropping its privileges.
This fixes the bug with minimal security implications.
This commit is contained in:
Tobias Blass 2018-06-13 00:39:24 +02:00
parent 202ee51150
commit a5c091e302
3 changed files with 15 additions and 3 deletions

View file

@ -47,6 +47,8 @@ struct sway_server {
struct sway_server server;
/* Prepares an unprivileged server_init by performing all privileged operations in advance */
bool server_privileged_prepare(struct sway_server *server);
bool server_init(struct sway_server *server);
void server_fini(struct sway_server *server);
void server_run(struct sway_server *server);

View file

@ -359,6 +359,11 @@ int main(int argc, char **argv) {
executable_sanity_check();
bool suid = false;
if (!server_privileged_prepare(&server)) {
return 1;
}
#ifdef __linux__
if (getuid() != geteuid() || getgid() != getegid()) {
// Retain capabilities after setuid()

View file

@ -25,9 +25,8 @@
#include "sway/tree/layout.h"
bool server_init(struct sway_server *server) {
wlr_log(L_DEBUG, "Initializing Wayland server");
bool server_privileged_prepare(struct sway_server *server) {
wlr_log(L_DEBUG, "Preparing Wayland server initialization");
server->wl_display = wl_display_create();
server->wl_event_loop = wl_display_get_event_loop(server->wl_display);
server->backend = wlr_backend_autocreate(server->wl_display, NULL);
@ -36,6 +35,12 @@ bool server_init(struct sway_server *server) {
wlr_log(L_ERROR, "Unable to create backend");
return false;
}
return true;
}
bool server_init(struct sway_server *server) {
wlr_log(L_DEBUG, "Initializing Wayland server");
struct wlr_renderer *renderer = wlr_backend_get_renderer(server->backend);
assert(renderer);