From 3d1c455f9a898e7427b642800644ae7142dc7557 Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Sat, 5 Sep 2015 12:56:04 +0200 Subject: [PATCH] login: fix NULL-deref on wall_message We treat an empty wall-message equal to a NULL wall-message since: commit 5744f59a3ee883ef3a78214bd5236157acdc35ba Author: Lennart Poettering 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 --- src/login/logind-dbus.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/src/login/logind-dbus.c b/src/login/logind-dbus.c index 7cc68d4865dda..e433549cb94a4 100644 --- a/src/login/logind-dbus.c +++ b/src/login/logind-dbus.c @@ -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);