From d0b9aeed0e64cff42ad4f3d87ccd13ace476cd4b Mon Sep 17 00:00:00 2001
From: DavidKorczynski <david@adalogics.com>
Date: Thu, 19 Oct 2023 17:27:27 +0100
Subject: [PATCH] decode: fix possible NULL dereference (#189)

---
 src/cmt_decode_msgpack.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/cmt_decode_msgpack.c b/src/cmt_decode_msgpack.c
index 2e1cf31..4ede1bd 100644
--- a/src/cmt_decode_msgpack.c
+++ b/src/cmt_decode_msgpack.c
@@ -977,8 +977,11 @@ static int unpack_basic_type_meta(mpack_reader_t *reader, size_t index, void *co
     result = cmt_mpack_unpack_map(reader, callbacks, context);
 
     if (CMT_DECODE_MSGPACK_SUCCESS == result) {
-        decode_context->map->label_count = cfl_list_size(&decode_context->map->label_keys);
+	if (decode_context->map == NULL || decode_context->map->parent == NULL) {
+            return CMT_DECODE_MSGPACK_INVALID_ARGUMENT_ERROR;
+	}
 
+        decode_context->map->label_count = cfl_list_size(&decode_context->map->label_keys);
         if (decode_context->map->type == CMT_HISTOGRAM) {
             histogram = (struct cmt_histogram *) decode_context->map->parent;