From 2bc7712f57af22058770d1ef131ad3da79a0c764 Mon Sep 17 00:00:00 2001
From: Jonathan Hui <jonhui@google.com>
Date: Fri, 8 Aug 2025 22:54:35 -0700
Subject: [PATCH] [fuzz] add fuzzer for `otPlatTrelHandleReceived` (#11779)

---
 tests/fuzz/CMakeLists.txt |   3 +
 tests/fuzz/trel.cpp       | 136 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 139 insertions(+)
 create mode 100644 tests/fuzz/trel.cpp

diff --git a/tests/fuzz/CMakeLists.txt b/tests/fuzz/CMakeLists.txt
index c5b28972a..f8cb57939 100644
--- a/tests/fuzz/CMakeLists.txt
+++ b/tests/fuzz/CMakeLists.txt
@@ -47,6 +47,8 @@ set(COMMON_LIBS
     ot-config
 )
 
+target_compile_definitions(ot-config INTERFACE "OPENTHREAD_CONFIG_RADIO_LINK_TREL_ENABLE=1")
+
 #----------------------------------------------------------------------------------------------------------------------
 
 macro(ot_nexus_test name)
@@ -83,3 +85,4 @@ ot_nexus_test(icmp6)
 ot_nexus_test(ip6)
 ot_nexus_test(mdns)
 ot_nexus_test(radio-one-node)
+ot_nexus_test(trel)
diff --git a/tests/fuzz/trel.cpp b/tests/fuzz/trel.cpp
new file mode 100644
index 000000000..6601059dc
--- /dev/null
+++ b/tests/fuzz/trel.cpp
@@ -0,0 +1,136 @@
+/*
+ *  Copyright (c) 2025, The OpenThread Authors.
+ *  All rights reserved.
+ *
+ *  Redistribution and use in source and binary forms, with or without
+ *  modification, are permitted provided that the following conditions are met:
+ *  1. Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *  3. Neither the name of the copyright holder nor the
+ *     names of its contributors may be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ *  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ *  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ *  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ *  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ *  POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <openthread/platform/trel.h>
+
+#include "platform/nexus_core.hpp"
+#include "platform/nexus_node.hpp"
+
+namespace ot {
+namespace Nexus {
+
+class FuzzDataProvider
+{
+public:
+    FuzzDataProvider(const uint8_t *aData, size_t aSize)
+        : mData(aData)
+        , mSize(aSize)
+    {
+    }
+
+    void ConsumeData(void *aBuf, size_t aLength)
+    {
+        assert(aLength <= mSize);
+        memcpy(aBuf, mData, aLength);
+        mData += aLength;
+        mSize -= aLength;
+    }
+
+    uint8_t *ConsumeRemainingBytes(void)
+    {
+        uint8_t *buf = static_cast<uint8_t *>(malloc(mSize));
+        memcpy(buf, mData, mSize);
+        mSize = 0;
+        return buf;
+    }
+
+    size_t RemainingBytes(void) { return mSize; }
+
+private:
+    const uint8_t *mData;
+    size_t         mSize;
+};
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+{
+    const uint16_t kMaxMessageSize = 2048;
+
+    FuzzDataProvider fdp(data, size);
+
+    unsigned int seed;
+    uint8_t     *buffer;
+    uint16_t     bufferLength;
+    otSockAddr   senderAddr;
+
+    if (size < sizeof(seed) + sizeof(senderAddr))
+    {
+        return 0;
+    }
+
+    if (size > sizeof(seed) + sizeof(senderAddr) + kMaxMessageSize)
+    {
+        return 0;
+    }
+
+    fdp.ConsumeData(&seed, sizeof(seed));
+    srand(seed);
+
+    Core nexus;
+
+    Node &node = nexus.CreateNode();
+
+    node.GetInstance().SetLogLevel(kLogLevelInfo);
+
+    node.GetInstance().Get<BorderRouter::RoutingManager>().Init(/* aInfraIfIndex */ 1, /* aInfraIfIsRunning */ true);
+    node.GetInstance().Get<BorderRouter::RoutingManager>().SetEnabled(true);
+    node.GetInstance().Get<Srp::Server>().SetAutoEnableMode(true);
+    node.GetInstance().Get<BorderRouter::RoutingManager>().SetDhcp6PdEnabled(true);
+    node.GetInstance().Get<BorderRouter::RoutingManager>().SetNat64PrefixManagerEnabled(true);
+    node.GetInstance().Get<Nat64::Translator>().SetEnabled(true);
+
+    Log("---------------------------------------------------------------------------------------");
+    Log("Form network");
+
+    node.Form();
+    nexus.AdvanceTime(60 * 1000);
+    VerifyOrQuit(node.Get<Mle::Mle>().IsLeader());
+    VerifyOrQuit(node.Get<Srp::Server>().GetState() == Srp::Server::kStateRunning);
+
+    Log("---------------------------------------------------------------------------------------");
+    Log("Fuzz");
+
+    fdp.ConsumeData(&senderAddr, sizeof(senderAddr));
+    bufferLength = fdp.RemainingBytes();
+    buffer       = fdp.ConsumeRemainingBytes();
+
+    otPlatTrelHandleReceived(&node.GetInstance(), buffer, bufferLength, &senderAddr);
+
+    nexus.AdvanceTime(10 * 1000);
+
+    free(buffer);
+
+    return 0;
+}
+
+} // namespace Nexus
+} // namespace ot