login: fix NULL-deref on wall_message

We treat an empty wall-message equal to a NULL wall-message since:

        commit 5744f59a3e
        Author: Lennart Poettering <lennart@poettering.net>
        Date:   Fri Sep 4 10:34:47 2015 +0200

            logind: treat an empty wall message like a NULL one

Fix the shutdown scheduler to not deref a NULL pointer, but properly
check for an empty wall-message.

Fixes: #1120
This commit is contained in:
David Herrmann 2015-09-05 12:56:04 +02:00
parent c9912c5eaf
commit 3d1c455f9a

View file

@ -1796,9 +1796,11 @@ static int update_schedule_file(Manager *m) {
if (r < 0)
return log_error_errno(r, "Failed to create shutdown subdirectory: %m");
t = cescape(m->wall_message);
if (!t)
return log_oom();
if (!isempty(m->wall_message)) {
t = cescape(m->wall_message);
if (!t)
return log_oom();
}
r = fopen_temporary("/run/systemd/shutdown/scheduled", &f, &temp_path);
if (r < 0)
@ -1814,7 +1816,7 @@ static int update_schedule_file(Manager *m) {
m->enable_wall_messages,
m->scheduled_shutdown_type);
if (!isempty(m->wall_message))
if (t)
fprintf(f, "WALL_MESSAGE=%s\n", t);
r = fflush_and_check(f);