login: fix NULL-deref on wall_message

[elogind.git] / src / login / logind-dbus.c

diff --git a/src/login/logind-dbus.c b/src/login/logind-dbus.c
index 768aa1a3190607f14a67465316c834453b04d6a2..def9f3927474a212495bee9aaf41faca053b8f91 100644 (file)
--- a/src/login/logind-dbus.c
+++ b/src/login/logind-dbus.c
@@ -1340,8 +1340,7 @@ static int bus_manager_log_shutdown(
                 InhibitWhat w,
                 const char *unit_name) {
 
-        const char *p;
-        const char *q;
+        const char *p, *q;
 
         assert(m);
         assert(unit_name);
@@ -1366,8 +1365,8 @@ static int bus_manager_log_shutdown(
                 q = NULL;
         }
 
-        if (m->wall_message)
-                p = strjoina(p, " (", m->wall_message, ")", NULL);
+        if (!isempty(m->wall_message))
+                p = strjoina(p, " (", m->wall_message, ")");
 
         return log_struct(LOG_NOTICE,
                           LOG_MESSAGE_ID(SD_MESSAGE_SHUTDOWN),
@@ -1784,9 +1783,11 @@ 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)
@@ -1802,7 +1803,7 @@ 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);
@@ -2276,7 +2277,7 @@ static int method_set_wall_message(
         int r;
         Manager *m = userdata;
         char *wall_message;
-        bool enable_wall_messages;
+        int enable_wall_messages;
 
         assert(message);
         assert(m);
@@ -2292,15 +2293,19 @@ static int method_set_wall_message(
                                     UID_INVALID,
                                     &m->polkit_registry,
                                     error);
-
         if (r < 0)
                 return r;
         if (r == 0)
                 return 1; /* Will call us back */
 
-        r = free_and_strdup(&m->wall_message, wall_message);
-        if (r < 0)
-                return log_oom();
+        if (isempty(wall_message))
+                m->wall_message = mfree(m->wall_message);
+        else {
+                r = free_and_strdup(&m->wall_message, wall_message);
+                if (r < 0)
+                        return log_oom();
+        }
+
         m->enable_wall_messages = enable_wall_messages;
 
         return sd_bus_reply_method_return(message, NULL);