From: Ludwig Nussel <ludwig.nussel@suse.de>
Date: Mon, 7 Feb 2022 10:50:12 +0000 (+0100)
Subject: logind: increase max wall message length to 4096
X-Git-Tag: v251-rc1~298^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1831759a705b85c3486a79fb98a20474bbe6bae4;p=thirdparty%2Fsystemd.git

logind: increase max wall message length to 4096
---

diff --git a/src/login/logind-dbus.c b/src/login/logind-dbus.c
index ef31ec654ec..8fcdf6e936b 100644
--- a/src/login/logind-dbus.c
+++ b/src/login/logind-dbus.c
@@ -54,6 +54,15 @@
 #include "utmp-wtmp.h"
 #include "virt.h"
 
+/* As a random fun fact sysvinit had a 252 (256-(strlen(" \r\n")+1))
+ * character limit for the wall message.
+ * https://git.savannah.nongnu.org/cgit/sysvinit.git/tree/src/shutdown.c#n72
+ * There is no real technical need for that but doesn't make sense
+ * to store arbitrary amounts either. As we are not stingy here, we
+ * allow 4k.
+ */
+#define WALL_MESSAGE_MAX 4096
+
 static void reset_scheduled_shutdown(Manager *m);
 
 static int get_sender_session(
@@ -3116,14 +3125,10 @@ static int method_set_wall_message(
         if (r < 0)
                 return r;
 
-        /* sysvinit has a 252 (256-(strlen(" \r\n")+1)) character
-         * limit for the wall message. There is no real technical
-         * need for that but doesn't make sense to store arbitrary
-         * amounts either.
-         * https://git.savannah.nongnu.org/cgit/sysvinit.git/tree/src/shutdown.c#n72)
-        */
-        if (strlen(wall_message) > 252)
-                return -EMSGSIZE;
+        if (strlen(wall_message) > WALL_MESSAGE_MAX)
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS,
+                        "Wall message too long, maximum permitted length is %u characters.",
+                        WALL_MESSAGE_MAX);
 
         /* Short-circuit the operation if the desired state is already in place, to
          * avoid an unnecessary polkit permission check. */