fix: restore description_length cap in V2 register_application and register_context

The DLTv2 IPC registration handlers have their description_length
sanity guards commented out, while the equivalent V1 code paths apply
them correctly. This allows an attacker-controlled description_length
(uint32) to be passed directly to dlt_receiver_check_and_get, which
calls memcpy into a 257-byte stack buffer (description[DLT_DAEMON_DESCSIZE + 1]),
causing a stack buffer overflow.

Uncomment the existing guards in both V2 code paths to clamp
description_length to DLT_DAEMON_DESCSIZE (256).

Affected functions:
- dlt_daemon_process_user_message_register_application (V2 branch, ~line 4012)
- dlt_daemon_process_user_message_register_context (V2 branch, ~line 4301)

Signed-off-by: Ian Chu <ian_chu@vicone.com>

Author: IanYHChu

src/daemon/dlt-daemon.c

@@ -4009,10 +4009,10 @@ int dlt_daemon_process_user_message_register_application(DltDaemon *daemon,
 
         len = usercontext.description_length;
 
-        // if (len > DLT_DAEMON_DESCSIZE) {
-        //     len = DLT_DAEMON_DESCSIZE;
-        //     dlt_log(LOG_WARNING, "Application description exceeds limit\n");
-        // }
+        if (len > DLT_DAEMON_DESCSIZE) {
+            len = DLT_DAEMON_DESCSIZE;
+            dlt_log(LOG_WARNING, "Application description exceeds limit\n");
+        }
 
         /* adjust buffer pointer */
         rec->buf += to_remove + sizeof(DltUserHeader);
@@ -4298,10 +4298,10 @@ int dlt_daemon_process_user_message_register_context(DltDaemon *daemon,
 
         len = usercontext.description_length;
 
-        // if (len > DLT_DAEMON_DESCSIZE) {
-        //     dlt_vlog(LOG_WARNING, "Context description exceeds limit: %u\n", len);
-        //     len = DLT_DAEMON_DESCSIZE;
-        // }
+        if (len > DLT_DAEMON_DESCSIZE) {
+            dlt_vlog(LOG_WARNING, "Context description exceeds limit: %u\n", len);
+            len = DLT_DAEMON_DESCSIZE;
+        }
 
         /* adjust buffer pointer */
         rec->buf += to_remove + sizeof(DltUserHeader);