From 96961f1beb172d155389ea9be31c6aeff212a6a7 Mon Sep 17 00:00:00 2001
From: David Korczynski <david@adalogics.com>
Date: Mon, 26 Jun 2023 06:39:38 -0700
Subject: [PATCH] tests: internal: fuzzers: add cmetrics decoder fuzzer

Signed-off-by: David Korczynski <david@adalogics.com>
---
 tests/internal/fuzzers/CMakeLists.txt         |  1 +
 tests/internal/fuzzers/cmetrics_decode_fuzz.c | 57 +++++++++++++++++++
 2 files changed, 58 insertions(+)
 create mode 100644 tests/internal/fuzzers/cmetrics_decode_fuzz.c

diff --git a/tests/internal/fuzzers/CMakeLists.txt b/tests/internal/fuzzers/CMakeLists.txt
index 721b957e35f..0ace2db9898 100644
--- a/tests/internal/fuzzers/CMakeLists.txt
+++ b/tests/internal/fuzzers/CMakeLists.txt
@@ -3,6 +3,7 @@ set(UNIT_TESTS_FILES
   aws_credentials_fuzzer.c
   base64_fuzzer.c
   engine_fuzzer.c
+  cmetrics_decode_fuzz.c
   config_fuzzer.c
   config_random_fuzzer.c
   ctrace_fuzzer.c
diff --git a/tests/internal/fuzzers/cmetrics_decode_fuzz.c b/tests/internal/fuzzers/cmetrics_decode_fuzz.c
new file mode 100644
index 00000000000..78f2bc03111
--- /dev/null
+++ b/tests/internal/fuzzers/cmetrics_decode_fuzz.c
@@ -0,0 +1,57 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+
+/*  Fluent Bit
+ *  ==========
+ *  Copyright (C) 2015-2023 The Fluent Bit Authors
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+#include <cmetrics/cmt_decode_opentelemetry.h>
+
+
+int
+LLVMFuzzerTestOneInput(const uint8_t * data, size_t size)
+{
+    struct cfl_list decoded_contexts;
+    struct cmt *cmt = NULL;
+    size_t off = 0;
+    int result;
+
+    /* At least one byte is needed for deciding which decoder to use */
+    if (size < 1) {
+        return 0;
+    }
+
+    uint8_t decider = data[0] % 2;
+
+    /* Adjust data pointer since the first byte is used */
+    data += 1;
+    size -= 1;
+
+    /* Fuzz a given decoder */
+    if (decider == 0) {
+        result = cmt_decode_opentelemetry_create(&decoded_contexts, data, size,
+                                                 &off);
+        if (result == CMT_DECODE_OPENTELEMETRY_SUCCESS) {
+            cmt_decode_opentelemetry_destroy (&decoded_contexts);
+        }
+    }
+    else if (decider == 1) {
+        result = cmt_decode_msgpack_create(&cmt, (char *) data, size, &off);
+        if (result == 0) {
+            cmt_destroy(cmt);
+        }
+    }
+    return 0;
+}