fuzz: Add support for fuzzing

Adds support for fuzzing with basic cdc fuzzer.

14 files changed, 1269 insertions, 0 deletions

diff --git a/fuzz/dcd_fuzz.cc b/fuzz/dcd_fuzz.cc
new file mode 100644
index 000000000..94d504a2c
--- /dev/null
+++ b/fuzz/dcd_fuzz.cc
@@ -0,0 +1,202 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2022 Nathaniel Brough
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+#include "device/dcd.h"
+#include "fuzz/fuzz_private.h"
+#include <assert.h>
+#include <cstdint>
+#include <limits>
+
+#define UNUSED(x) (void)(x)
+
+//--------------------------------------------------------------------+
+// State tracker
+//--------------------------------------------------------------------+
+struct State {
+  bool interrupts_enabled;
+  bool sof_enabled;
+  uint8_t address;
+};
+
+static State state = {false, 0, 0};
+
+//--------------------------------------------------------------------+
+// Controller API
+// All no-ops as we are fuzzing.
+//--------------------------------------------------------------------+
+extern "C" {
+void dcd_init(uint8_t rhport) {
+  UNUSED(rhport);
+  return;
+}
+
+void dcd_int_handler(uint8_t rhport) {
+  assert(_fuzz_data_provider.has_value());
+
+  if (!state.interrupts_enabled) {
+    return;
+  }
+
+  // Choose if we want to generate a signal based on the fuzzed data.
+  if (_fuzz_data_provider->ConsumeBool()) {
+    dcd_event_bus_signal(
+        rhport,
+        // Choose a random event based on the fuzz data.
+        (dcd_eventid_t)_fuzz_data_provider->ConsumeIntegralInRange<uint8_t>(
+            DCD_EVENT_INVALID + 1, DCD_EVENT_COUNT - 1),
+        // Identify trigger as either an interrupt or a syncrhonous call
+        // depending on fuzz data.
+        _fuzz_data_provider->ConsumeBool());
+  }
+
+  if (_fuzz_data_provider->ConsumeBool()) {
+    constexpr size_t kSetupFrameLength = 8;
+    std::vector<uint8_t> setup =
+        _fuzz_data_provider->ConsumeBytes<uint8_t>(kSetupFrameLength);
+    // Fuzz consumer may return less than requested. If this is the case
+    // we want to make sure that at least that length is allocated and available
+    // to the signal handler.
+    if (setup.size() != kSetupFrameLength) {
+      setup.resize(kSetupFrameLength);
+    }
+    dcd_event_setup_received(rhport, setup.data(),
+                             // Identify trigger as either an interrupt or a
+                             // syncrhonous call depending on fuzz data.
+                             _fuzz_data_provider->ConsumeBool());
+  }
+}
+
+void dcd_int_enable(uint8_t rhport) {
+  state.interrupts_enabled = true;
+  UNUSED(rhport);
+  return;
+}
+
+void dcd_int_disable(uint8_t rhport) {
+  state.interrupts_enabled = false;
+  UNUSED(rhport);
+  return;
+}
+
+void dcd_set_address(uint8_t rhport, uint8_t dev_addr) {
+  UNUSED(rhport);
+  state.address = dev_addr;
+  // Respond with status.
+  dcd_edpt_xfer(rhport, tu_edpt_addr(0, TUSB_DIR_IN), NULL, 0);
+  return;
+}
+
+void dcd_remote_wakeup(uint8_t rhport) {
+  UNUSED(rhport);
+  return;
+}
+
+void dcd_connect(uint8_t rhport) {
+  UNUSED(rhport);
+  return;
+}
+
+void dcd_disconnect(uint8_t rhport) {
+  UNUSED(rhport);
+  return;
+}
+
+void dcd_sof_enable(uint8_t rhport, bool en) {
+  state.sof_enabled = en;
+  UNUSED(rhport);
+  return;
+}
+
+//--------------------------------------------------------------------+
+// Endpoint API
+//--------------------------------------------------------------------+
+
+// Configure endpoint's registers according to descriptor
+bool dcd_edpt_open(uint8_t rhport, tusb_desc_endpoint_t const *desc_ep) {
+  UNUSED(rhport);
+  UNUSED(desc_ep);
+  return _fuzz_data_provider->ConsumeBool();
+}
+
+// Close all non-control endpoints, cancel all pending transfers if any.
+// Invoked when switching from a non-zero Configuration by SET_CONFIGURE
+// therefore required for multiple configuration support.
+void dcd_edpt_close_all(uint8_t rhport) {
+  UNUSED(rhport);
+  return;
+}
+
+// Close an endpoint.
+// Since it is weak, caller must TU_ASSERT this function's existence before
+// calling it.
+void dcd_edpt_close(uint8_t rhport, uint8_t ep_addr) {
+  UNUSED(rhport);
+  UNUSED(ep_addr);
+  return;
+}
+
+// Submit a transfer, When complete dcd_event_xfer_complete() is invoked to
+// notify the stack
+bool dcd_edpt_xfer(uint8_t rhport, uint8_t ep_addr, uint8_t *buffer,
+                   uint16_t total_bytes) {
+  UNUSED(rhport);
+  UNUSED(buffer);
+  UNUSED(total_bytes);
+
+  uint8_t const dir = tu_edpt_dir(ep_addr);
+
+  if (dir == TUSB_DIR_IN) {
+    std::vector<uint8_t> temp =
+        _fuzz_data_provider->ConsumeBytes<uint8_t>(total_bytes);
+    std::copy(temp.begin(), temp.end(), buffer);
+  }
+  // Ignore output data as it's not useful for fuzzing without a more
+  // complex fuzzed backend.
+
+  return _fuzz_data_provider->ConsumeBool();
+}
+
+/* TODO: implement a fuzzed version of this.
+bool dcd_edpt_xfer_fifo(uint8_t rhport, uint8_t ep_addr, tu_fifo_t *ff,
+                        uint16_t total_bytes) {} 
+*/
+
+// Stall endpoint, any queuing transfer should be removed from endpoint
+void dcd_edpt_stall(uint8_t rhport, uint8_t ep_addr) {
+
+  UNUSED(rhport);
+  UNUSED(ep_addr);
+  return;
+}
+
+// clear stall, data toggle is also reset to DATA0
+// This API never calls with control endpoints, since it is auto cleared when
+// receiving setup packet
+void dcd_edpt_clear_stall(uint8_t rhport, uint8_t ep_addr) {
+
+  UNUSED(rhport);
+  UNUSED(ep_addr);
+  return;
+}
+}
\ No newline at end of file
diff --git a/fuzz/device/cdc/CMakeLists.txt b/fuzz/device/cdc/CMakeLists.txt
new file mode 100644
index 000000000..fa6e83b7e
--- /dev/null
+++ b/fuzz/device/cdc/CMakeLists.txt
@@ -0,0 +1,29 @@
+cmake_minimum_required(VERSION 3.5)
+
+include(${CMAKE_CURRENT_SOURCE_DIR}/../../../hw/bsp/family_support.cmake)
+
+# gets PROJECT name for the example (e.g. <BOARD>-<DIR_NAME>)
+family_get_project_name(PROJECT ${CMAKE_CURRENT_LIST_DIR})
+
+project(${PROJECT})
+
+# Checks this example is valid for the family and initializes the project
+family_initialize_project(${PROJECT} ${CMAKE_CURRENT_LIST_DIR})
+
+add_executable(${PROJECT})
+
+# Example source
+target_sources(${PROJECT} PUBLIC
+        ${CMAKE_CURRENT_SOURCE_DIR}/src/main.c
+        ${CMAKE_CURRENT_SOURCE_DIR}/src/msc_disk.c
+        ${CMAKE_CURRENT_SOURCE_DIR}/src/usb_descriptors.c
+        )
+
+# Example include
+target_include_directories(${PROJECT} PUBLIC
+        ${CMAKE_CURRENT_SOURCE_DIR}/src
+        )
+
+# Configure compilation flags and libraries for the example... see the corresponding function
+# in hw/bsp/FAMILY/family.cmake for details.
+family_configure_device_example(${PROJECT})
\ No newline at end of file
diff --git a/fuzz/device/cdc/Makefile b/fuzz/device/cdc/Makefile
new file mode 100644
index 000000000..76a43923f
--- /dev/null
+++ b/fuzz/device/cdc/Makefile
@@ -0,0 +1,12 @@
+include ../../../tools/top.mk
+include ../../make.mk
+
+INC += \
+	src \
+	$(TOP)/hw \
+
+# Example source
+SRC_C += $(addprefix $(CURRENT_PATH)/, $(wildcard src/*.c))
+SRC_CXX += $(addprefix $(CURRENT_PATH)/, $(wildcard src/*.cc))
+
+include ../../rules.mk
diff --git a/fuzz/device/cdc/skip.txt b/fuzz/device/cdc/skip.txt
new file mode 100644
index 000000000..d844feae8
--- /dev/null
+++ b/fuzz/device/cdc/skip.txt
@@ -0,0 +1 @@
+mcu:SAMD11
\ No newline at end of file
diff --git a/fuzz/device/cdc/src/fuzz.cc b/fuzz/device/cdc/src/fuzz.cc
new file mode 100644
index 000000000..f783125f9
--- /dev/null
+++ b/fuzz/device/cdc/src/fuzz.cc
@@ -0,0 +1,174 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2022 Nathaniel Brough
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+
+#include <cassert>
+#include <fuzzer/FuzzedDataProvider.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "class/cdc/cdc_device.h"
+#include "fuzz/fuzz.h"
+#include "tusb.h"
+#include <cstdint>
+#include <string>
+#include <vector>
+
+extern "C" {
+
+#define FUZZ_ITERATIONS 500
+
+//--------------------------------------------------------------------+
+// MACRO CONSTANT TYPEDEF PROTYPES
+//--------------------------------------------------------------------+
+
+void cdc_task(FuzzedDataProvider *provider);
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  FuzzedDataProvider provider(Data, Size);
+  std::vector<uint8_t> callback_data = provider.ConsumeBytes<uint8_t>(
+      provider.ConsumeIntegralInRange<size_t>(0, Size));
+  fuzz_init(callback_data.data(), callback_data.size());
+  // init device stack on configured roothub port
+  tud_init(BOARD_TUD_RHPORT);
+
+  for (int i = 0; i < FUZZ_ITERATIONS; i++) {
+    if (provider.remaining_bytes() == 0) {
+      return 0;
+    }
+    tud_int_handler(provider.ConsumeIntegral<uint8_t>());
+    tud_task(); // tinyusb device task
+    cdc_task(&provider);
+  }
+
+  return 0;
+}
+
+//--------------------------------------------------------------------+
+// USB CDC
+//--------------------------------------------------------------------+
+enum CdcApiFuncs {
+  kCdcNConnected,
+  kCdcNGetLineState,
+  kCdcNGetLineCoding,
+  kCdcNSetWantedChar,
+  kCdcNAvailable,
+  kCdcNRead,
+  kCdcNReadChar,
+  kCdcNReadFlush,
+  kCdcNPeek,
+  kCdcNWrite,
+  kCdcNWriteChar,
+  kCdcNWriteStr,
+  kCdcNWriteFlush,
+  kCdcNWriteAvailable,
+  kCdcNWriteClear,
+  // We don't need to fuzz tud_cdc_<not n>* as they are just wrappers
+  // calling with n==0.
+  kMaxValue,
+};
+
+void cdc_task(FuzzedDataProvider *provider) {
+
+  assert(provider != NULL);
+  const int kMaxBufferSize = 4096;
+  switch (provider->ConsumeEnum<CdcApiFuncs>()) {
+  case kCdcNConnected:
+    // TODO: Fuzz interface number
+    (void)tud_cdc_n_connected(0);
+    break;
+  case kCdcNGetLineState:
+    // TODO: Fuzz interface number
+    (void)tud_cdc_n_get_line_state(0);
+    break;
+  case kCdcNGetLineCoding: {
+    cdc_line_coding_t coding;
+    // TODO: Fuzz interface number
+    (void)tud_cdc_n_get_line_coding(0, &coding);
+  } break;
+  case kCdcNSetWantedChar:
+    // TODO: Fuzz interface number
+    (void)tud_cdc_n_set_wanted_char(0, provider->ConsumeIntegral<char>());
+    break;
+  case kCdcNAvailable:
+    // TODO: Fuzz interface number
+    (void)tud_cdc_n_available(0);
+    break;
+  case kCdcNRead: {
+    std::vector<uint8_t> buffer;
+    buffer.resize(provider->ConsumeIntegralInRange<size_t>(0, kMaxBufferSize));
+    // TODO: Fuzz interface number
+    (void)tud_cdc_n_read(0, buffer.data(), buffer.size());
+    break;
+  }
+  case kCdcNReadChar:
+    // TODO: Fuzz interface number
+    tud_cdc_n_read_char(0);
+    break;
+  case kCdcNReadFlush:
+    // TODO: Fuzz interface number
+    tud_cdc_n_read_flush(0);
+    break;
+  case kCdcNPeek: {
+    uint8_t peak = 0;
+    tud_cdc_n_peek(0, &peak);
+    break;
+  }
+  case kCdcNWrite: {
+    std::vector<uint8_t> buffer = provider->ConsumeBytes<uint8_t>(
+        provider->ConsumeIntegralInRange<size_t>(0, kMaxBufferSize));
+
+    // TODO: Fuzz interface number
+    (void)tud_cdc_n_write(0, buffer.data(), buffer.size());
+    break;
+  }
+  case kCdcNWriteChar:
+    // TODO: Fuzz interface number
+    (void)tud_cdc_n_write_char(0, provider->ConsumeIntegral<char>());
+    break;
+  case kCdcNWriteStr: {
+    std::string str = provider->ConsumeRandomLengthString(kMaxBufferSize);
+    // TODO: Fuzz interface number
+    (void)tud_cdc_n_write_str(0, str.c_str());
+    break;
+  }
+  case kCdcNWriteFlush:
+    // TODO: Fuzz interface number
+    (void)tud_cdc_n_write_flush(0);
+    break;
+  case kCdcNWriteAvailable:
+    // TODO: Fuzz interface number
+    (void)tud_cdc_n_write_available(0);
+    break;
+  case kCdcNWriteClear:
+    // TODO: Fuzz interface number
+    (void)tud_cdc_n_write_clear(0);
+    break;
+  case kMaxValue:
+    // Noop.
+    break;
+  }
+}
+}
\ No newline at end of file
diff --git a/fuzz/device/cdc/src/tusb_config.h b/fuzz/device/cdc/src/tusb_config.h
new file mode 100644
index 000000000..10a8a825a
--- /dev/null
+++ b/fuzz/device/cdc/src/tusb_config.h
@@ -0,0 +1,114 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2022 Nathaniel Brough
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+
+#ifndef _TUSB_CONFIG_H_
+#define _TUSB_CONFIG_H_
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+//--------------------------------------------------------------------+
+// Board Specific Configuration
+//--------------------------------------------------------------------+
+
+// RHPort number used for device can be defined by board.mk, default to port 0
+#ifndef BOARD_TUD_RHPORT
+#define BOARD_TUD_RHPORT      0
+#endif
+
+// RHPort max operational speed can defined by board.mk
+#ifndef BOARD_TUD_MAX_SPEED
+#define BOARD_TUD_MAX_SPEED   OPT_MODE_DEFAULT_SPEED
+#endif
+
+//--------------------------------------------------------------------
+// Common Configuration
+//--------------------------------------------------------------------
+
+// defined by compiler flags for flexibility
+#ifndef CFG_TUSB_MCU
+#error CFG_TUSB_MCU must be defined
+#endif
+
+#ifndef CFG_TUSB_OS
+#define CFG_TUSB_OS           OPT_OS_NONE
+#endif
+
+#ifndef CFG_TUSB_DEBUG
+#define CFG_TUSB_DEBUG        0
+#endif
+
+// Enable Device stack
+#define CFG_TUD_ENABLED       1
+
+// Default is max speed that hardware controller could support with on-chip PHY
+#define CFG_TUD_MAX_SPEED     BOARD_TUD_MAX_SPEED
+
+/* USB DMA on some MCUs can only access a specific SRAM region with restriction on alignment.
+ * Tinyusb use follows macros to declare transferring memory so that they can be put
+ * into those specific section.
+ * e.g
+ * - CFG_TUSB_MEM SECTION : __attribute__ (( section(".usb_ram") ))
+ * - CFG_TUSB_MEM_ALIGN   : __attribute__ ((aligned(4)))
+ */
+#ifndef CFG_TUSB_MEM_SECTION
+#define CFG_TUSB_MEM_SECTION
+#endif
+
+#ifndef CFG_TUSB_MEM_ALIGN
+#define CFG_TUSB_MEM_ALIGN    __attribute__ ((aligned(4)))
+#endif
+
+//--------------------------------------------------------------------
+// DEVICE CONFIGURATION
+//--------------------------------------------------------------------
+
+#ifndef CFG_TUD_ENDPOINT0_SIZE
+#define CFG_TUD_ENDPOINT0_SIZE    64
+#endif
+
+//------------- CLASS -------------//
+#define CFG_TUD_CDC              1
+#define CFG_TUD_MSC              0
+#define CFG_TUD_HID              0
+#define CFG_TUD_MIDI             0
+#define CFG_TUD_VENDOR           0
+
+// CDC FIFO size of TX and RX
+#define CFG_TUD_CDC_RX_BUFSIZE   (TUD_OPT_HIGH_SPEED ? 512 : 64)
+#define CFG_TUD_CDC_TX_BUFSIZE   (TUD_OPT_HIGH_SPEED ? 512 : 64)
+
+// CDC Endpoint transfer buffer size, more is faster
+#define CFG_TUD_CDC_EP_BUFSIZE   (TUD_OPT_HIGH_SPEED ? 512 : 64)
+
+// MSC Buffer size of Device Mass storage
+#define CFG_TUD_MSC_EP_BUFSIZE   512
+
+#ifdef __cplusplus
+ }
+#endif
+
+#endif /* _TUSB_CONFIG_H_ */
diff --git a/fuzz/device/cdc/src/usb_descriptors.cc b/fuzz/device/cdc/src/usb_descriptors.cc
new file mode 100644
index 000000000..0f636f05d
--- /dev/null
+++ b/fuzz/device/cdc/src/usb_descriptors.cc
@@ -0,0 +1,229 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2022 Nathaniel Brough
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+
+#include "tusb.h"
+
+/* A combination of interfaces must have a unique product id, since PC will save
+ * device driver after the first plug.
+ * Auto ProductID layout's Bitmap:
+ *   [MSB]         HID | CDC          [LSB]
+ */
+#define _PID_MAP(itf, n) ((CFG_TUD_##itf) << (n))
+#define USB_PID                                                                \
+  (0x4000 | _PID_MAP(CDC, 0) | _PID_MAP(HID, 2) | _PID_MAP(MIDI, 3) |          \
+   _PID_MAP(VENDOR, 4))
+
+#define USB_VID 0xCafe
+#define USB_BCD 0x0200
+
+//--------------------------------------------------------------------+
+// Device Descriptors
+//--------------------------------------------------------------------+
+
+// Invoked when received GET DEVICE DESCRIPTOR
+// Application return pointer to descriptor
+uint8_t const *tud_descriptor_device_cb(void) {
+  static tusb_desc_device_t const desc_device = {
+      .bLength = sizeof(tusb_desc_device_t),
+      .bDescriptorType = TUSB_DESC_DEVICE,
+      .bcdUSB = USB_BCD,
+
+      // Use Interface Association Descriptor (IAD) for CDC
+      // As required by USB Specs IAD's subclass must be common class (2) and
+      // protocol must be IAD (1)
+      .bDeviceClass = TUSB_CLASS_MISC,
+      .bDeviceSubClass = MISC_SUBCLASS_COMMON,
+      .bDeviceProtocol = MISC_PROTOCOL_IAD,
+
+      .bMaxPacketSize0 = CFG_TUD_ENDPOINT0_SIZE,
+
+      .idVendor = USB_VID,
+      .idProduct = USB_PID,
+      .bcdDevice = 0x0100,
+
+      .iManufacturer = 0x01,
+      .iProduct = 0x02,
+      .iSerialNumber = 0x03,
+
+      .bNumConfigurations = 0x01};
+
+  return (uint8_t const *)&desc_device;
+}
+
+//--------------------------------------------------------------------+
+// Configuration Descriptor
+//--------------------------------------------------------------------+
+
+enum { ITF_NUM_CDC = 0, ITF_NUM_CDC_DATA, ITF_NUM_TOTAL };
+
+#define EPNUM_CDC_NOTIF 0x81
+#define EPNUM_CDC_OUT 0x02
+#define EPNUM_CDC_IN 0x82
+
+#define CONFIG_TOTAL_LEN (TUD_CONFIG_DESC_LEN + TUD_CDC_DESC_LEN)
+
+// full speed configuration
+uint8_t const desc_fs_configuration[] = {
+    // Config number, interface count, string index, total length, attribute,
+    // power in mA
+    TUD_CONFIG_DESCRIPTOR(1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, 0x00, 100),
+
+    // Interface number, string index, EP notification address and size, EP data
+    // address (out, in) and size.
+    TUD_CDC_DESCRIPTOR(ITF_NUM_CDC, 4, EPNUM_CDC_NOTIF, 8, EPNUM_CDC_OUT,
+                       EPNUM_CDC_IN, 64),
+};
+
+#if TUD_OPT_HIGH_SPEED
+// Per USB specs: high speed capable device must report device_qualifier and
+// other_speed_configuration
+
+// high speed configuration
+uint8_t const desc_hs_configuration[] = {
+    // Config number, interface count, string index, total length, attribute,
+    // power in mA
+    TUD_CONFIG_DESCRIPTOR(1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, 0x00, 100),
+
+    // Interface number, string index, EP notification address and size, EP data
+    // address (out, in) and size.
+    TUD_CDC_DESCRIPTOR(ITF_NUM_CDC, 4, EPNUM_CDC_NOTIF, 8, EPNUM_CDC_OUT,
+                       EPNUM_CDC_IN, 512),
+};
+
+// other speed configuration
+uint8_t desc_other_speed_config[CONFIG_TOTAL_LEN];
+
+// device qualifier is mostly similar to device descriptor since we don't change
+// configuration based on speed
+tusb_desc_device_qualifier_t const desc_device_qualifier = {
+    .bLength = sizeof(tusb_desc_device_qualifier_t),
+    .bDescriptorType = TUSB_DESC_DEVICE_QUALIFIER,
+    .bcdUSB = USB_BCD,
+
+    .bDeviceClass = TUSB_CLASS_MISC,
+    .bDeviceSubClass = MISC_SUBCLASS_COMMON,
+    .bDeviceProtocol = MISC_PROTOCOL_IAD,
+
+    .bMaxPacketSize0 = CFG_TUD_ENDPOINT0_SIZE,
+    .bNumConfigurations = 0x01,
+    .bReserved = 0x00};
+
+// Invoked when received GET DEVICE QUALIFIER DESCRIPTOR request
+// Application return pointer to descriptor, whose contents must exist long
+// enough for transfer to complete. device_qualifier descriptor describes
+// information about a high-speed capable device that would change if the device
+// were operating at the other speed. If not highspeed capable stall this
+// request.
+uint8_t const *tud_descriptor_device_qualifier_cb(void) {
+  return (uint8_t const *)&desc_device_qualifier;
+}
+
+// Invoked when received GET OTHER SEED CONFIGURATION DESCRIPTOR request
+// Application return pointer to descriptor, whose contents must exist long
+// enough for transfer to complete Configuration descriptor in the other speed
+// e.g if high speed then this is for full speed and vice versa
+uint8_t const *tud_descriptor_other_speed_configuration_cb(uint8_t index) {
+  (void)index; // for multiple configurations
+
+  // if link speed is high return fullspeed config, and vice versa
+  // Note: the descriptor type is OHER_SPEED_CONFIG instead of CONFIG
+  memcpy(desc_other_speed_config,
+         (tud_speed_get() == TUSB_SPEED_HIGH) ? desc_fs_configuration
+                                              : desc_hs_configuration,
+         CONFIG_TOTAL_LEN);
+
+  desc_other_speed_config[1] = TUSB_DESC_OTHER_SPEED_CONFIG;
+
+  return desc_other_speed_config;
+}
+
+#endif // highspeed
+
+// Invoked when received GET CONFIGURATION DESCRIPTOR
+// Application return pointer to descriptor
+// Descriptor contents must exist long enough for transfer to complete
+uint8_t const *tud_descriptor_configuration_cb(uint8_t index) {
+  (void)index; // for multiple configurations
+
+#if TUD_OPT_HIGH_SPEED
+  // Although we are highspeed, host may be fullspeed.
+  return (tud_speed_get() == TUSB_SPEED_HIGH) ? desc_hs_configuration
+                                              : desc_fs_configuration;
+#else
+  return desc_fs_configuration;
+#endif
+}
+
+//--------------------------------------------------------------------+
+// String Descriptors
+//--------------------------------------------------------------------+
+
+// array of pointer to string descriptors
+char const *string_desc_arr[] = {
+    (const char[]){0x09, 0x04}, // 0: is supported language is English (0x0409)
+    "TinyUSB",                  // 1: Manufacturer
+    "TinyUSB Device",           // 2: Product
+    "123456789012",             // 3: Serials, should use chip ID
+    "TinyUSB CDC",              // 4: CDC Interface
+};
+
+static uint16_t _desc_str[32];
+
+// Invoked when received GET STRING DESCRIPTOR request
+// Application return pointer to descriptor, whose contents must exist long
+// enough for transfer to complete
+uint16_t const *tud_descriptor_string_cb(uint8_t index, uint16_t langid) {
+  (void)langid;
+
+  uint8_t chr_count;
+
+  if (index == 0) {
+    memcpy(&_desc_str[1], string_desc_arr[0], 2);
+    chr_count = 1;
+  } else {
+    // Note: the 0xEE index string is a Microsoft OS 1.0 Descriptors.
+    // https://docs.microsoft.com/en-us/windows-hardware/drivers/usbcon/microsoft-defined-usb-descriptors
+
+    if (!(index < sizeof(string_desc_arr) / sizeof(string_desc_arr[0])))
+      return NULL;
+
+    const char *str = string_desc_arr[index];
+
+    // Cap at max char
+    chr_count = (uint8_t)strlen(str);
+    if (chr_count > 31)
+      chr_count = 31;
+
+    // Convert ASCII string into UTF-16
+    for (uint8_t i = 0; i < chr_count; i++) {
+      _desc_str[1 + i] = str[i];
+    }
+  }
+
+  // first byte is length (including header), second byte is string type
+  _desc_str[0] = (uint16_t)((TUSB_DESC_STRING << 8) | (2 * chr_count + 2));
+
+  return _desc_str;
+}
diff --git a/fuzz/dicts/cdc.dict b/fuzz/dicts/cdc.dict
new file mode 100644
index 000000000..138775cdc
--- /dev/null
+++ b/fuzz/dicts/cdc.dict
@@ -0,0 +1,74 @@
+# List of supported OIDs
+RNDIS_OID_GEN_SUPPORTED_LIST="\x00\x01\x01\x01"
+# Hardware status
+RNDIS_OID_GEN_HARDWARE_STATUS="\x00\x01\x01\x02"
+# Media types supported (encoded)
+RNDIS_OID_GEN_MEDIA_SUPPORTED="\x00\x01\x01\x03"
+# Media types in use (encoded)
+RNDIS_OID_GEN_MEDIA_IN_USE="\x00\x01\x01\x04"
+RNDIS_OID_GEN_MAXIMUM_LOOKAHEAD="\x00\x01\x01\x05"
+# Maximum frame size in bytes
+RNDIS_OID_GEN_MAXIMUM_FRAME_SIZE="\x00\x01\x01\x06"
+# Link speed in units of 100 bps
+RNDIS_OID_GEN_LINK_SPEED="\x00\x01\x01\x07"
+# Transmit buffer space
+RNDIS_OID_GEN_TRANSMIT_BUFFER_SPACE="\x00\x01\x01\x08"
+# Receive buffer space
+RNDIS_OID_GEN_RECEIVE_BUFFER_SPACE="\x00\x01\x01\x09"
+# NDIS version number used by the driver
+RNDIS_OID_GEN_DRIVER_VERSION="\x00\x01\x01\x10"
+# Maximum total packet length in bytes
+RNDIS_OID_GEN_MAXIMUM_TOTAL_SIZE="\x00\x01\x01\x11"
+# Optional protocol flags (encoded)
+RNDIS_OID_GEN_PROTOCOL_OPTIONS="\x00\x01\x01\x12"
+# Optional NIC flags (encoded)
+RNDIS_OID_GEN_MAC_OPTIONS="\x00\x01\x01\x13"
+# Whether the NIC is connected to the network
+RNDIS_OID_GEN_MEDIA_CONNECT_STATUS="\x00\x01\x01\x14"
+# The maximum number of send packets the driver can accept per call to its MiniportSendPacketsfunction
+RNDIS_OID_GEN_MAXIMUM_SEND_PACKETS="\x00\x01\x01\x15"
+# Vendor-assigned version number of the driver
+RNDIS_OID_GEN_VENDOR_DRIVER_VERSION="\x00\x01\x01\x16"
+# The custom GUIDs (Globally Unique Identifier) supported by the miniport driver
+RNDIS_OID_GEN_SUPPORTED_GUIDS="\x00\x01\x01\x17"
+# List of network-layer addresses associated with the binding between a transport and the driver
+RNDIS_OID_GEN_NETWORK_LAYER_ADDRESSES="\x00\x01\x01\x18"
+# Size of packets' additional headers
+RNDIS_OID_GEN_TRANSPORT_HEADER_OFFSET="\x00\x01\x01\x19"
+RNDIS_OID_GEN_MEDIA_CAPABILITIES="\x00\x01\x02\x01"
+# Physical media supported by the miniport driver (encoded)
+RNDIS_OID_GEN_PHYSICAL_MEDIUM="\x00\x01\x02\x02"
+# Permanent station address
+RNDIS_OID_802_3_PERMANENT_ADDRESS="\x01\x01\x01\x01"
+# Current station address
+RNDIS_OID_802_3_CURRENT_ADDRESS="\x01\x01\x01\x02"
+# Current multicast address list
+RNDIS_OID_802_3_MULTICAST_LIST="\x01\x01\x01\x03"
+# Maximum size of multicast address list
+RNDIS_OID_802_3_MAXIMUM_LIST_SIZE="\x01\x01\x01\x04"
+# Directed packets. Directed packets contain a destination address equal to the station address of the NIC.
+RNDIS_PACKET_TYPE_DIRECTED="\x00\x00\x00\x01"
+# Multicast address packets sent to addresses in the multicast address list.
+RNDIS_PACKET_TYPE_MULTICAST="\x00\x00\x00\x02"
+# All multicast address packets, not just the ones enumerated in the multicast address list.
+RNDIS_PACKET_TYPE_ALL_MULTICAST="\x00\x00\x00\x04"
+# Broadcast packets.
+RNDIS_PACKET_TYPE_BROADCAST="\x00\x00\x00\x08"
+# All source routing packets. If the protocol driver sets this bit, the NDIS library attempts to act as a source routing bridge.
+RNDIS_PACKET_TYPE_SOURCE_ROUTING="\x00\x00\x00\x10"
+# Specifies all packets regardless of whether VLAN filtering is enabled or not and whether the VLAN identifier matches or not.
+RNDIS_PACKET_TYPE_PROMISCUOUS="\x00\x00\x00\x20"
+# SMT packets that an FDDI NIC receives.
+RNDIS_PACKET_TYPE_SMT="\x00\x00\x00\x40"
+# All packets sent by installed protocols and all packets indicated by the NIC that is identified by a given NdisBindingHandle.
+RNDIS_PACKET_TYPE_ALL_LOCAL="\x00\x00\x00\x80"
+# Packets sent to the current group address.
+RNDIS_PACKET_TYPE_GROUP="\x00\x00\x10\x00"
+# All functional address packets, not just the ones in the current functional address.
+RNDIS_PACKET_TYPE_ALL_FUNCTIONAL="\x00\x00\x20\x00"
+# Functional address packets sent to addresses included in the current functional address.
+RNDIS_PACKET_TYPE_FUNCTIONAL="\x00\x00\x40\x00"
+# NIC driver frames that a Token Ring NIC receives.
+RNDIS_PACKET_TYPE_MAC_FRAME="\x00\x00\x80\x00"
+RNDIS_PACKET_TYPE_NO_LOCAL="\x00\x01\x00\x00"
+
diff --git a/fuzz/fuzz.cc b/fuzz/fuzz.cc
new file mode 100644
index 000000000..2e4186f1a
--- /dev/null
+++ b/fuzz/fuzz.cc
@@ -0,0 +1,34 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2022 Nathaniel Brough
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+
+#include "fuzzer/FuzzedDataProvider.h"
+#include <optional>
+
+std::optional<FuzzedDataProvider> _fuzz_data_provider;
+
+extern "C" int fuzz_init(const uint8_t *data, size_t size) {
+  _fuzz_data_provider.emplace(data, size);
+  return 0;
+}
diff --git a/fuzz/fuzz.h b/fuzz/fuzz.h
new file mode 100644
index 000000000..6aa4949a1
--- /dev/null
+++ b/fuzz/fuzz.h
@@ -0,0 +1,37 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2022 Nathaniel Brough
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+
+#pragma once
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int fuzz_init(const uint8_t *data, size_t size);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/fuzz/fuzz_private.h b/fuzz/fuzz_private.h
new file mode 100644
index 000000000..0d791fcdc
--- /dev/null
+++ b/fuzz/fuzz_private.h
@@ -0,0 +1,30 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2022 Nathaniel Brough
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+
+#pragma once
+#include "fuzzer/FuzzedDataProvider.h"
+#include <optional>
+
+extern std::optional<FuzzedDataProvider> _fuzz_data_provider;
diff --git a/fuzz/make.mk b/fuzz/make.mk
new file mode 100644
index 000000000..0921fc8f3
--- /dev/null
+++ b/fuzz/make.mk
@@ -0,0 +1,100 @@
+# ---------------------------------------
+# Common make definition for all examples
+# ---------------------------------------
+
+# Build directory
+BUILD := _build
+PROJECT := $(notdir $(CURDIR))
+
+# Handy check parameter function
+check_defined = \
+    $(strip $(foreach 1,$1, \
+    $(call __check_defined,$1,$(strip $(value 2)))))
+__check_defined = \
+    $(if $(value $1),, \
+    $(error Undefined make flag: $1$(if $2, ($2))))
+
+#-------------- Fuzz harness compiler  ------------
+
+CC ?=  clang
+CXX ?= clang++
+GDB ?= gdb
+OBJCOPY = objcopy
+SIZE = size
+MKDIR = mkdir
+
+ifeq ($(CMDEXE),1)
+  CP = copy
+  RM = del
+  PYTHON = python
+else
+  SED = sed
+  CP = cp
+  RM = rm
+  PYTHON = python3
+endif
+
+#-------------- Source files and compiler flags --------------
+
+
+INC   += $(TOP)/$(FAMILY_PATH)
+
+# Compiler Flags
+CFLAGS += \
+  -ggdb \
+  -fsanitize=fuzzer \
+  -fdata-sections \
+  -ffunction-sections \
+  -fno-strict-aliasing \
+  -Wall \
+  -Wextra \
+  -Werror \
+  -Wfatal-errors \
+  -Wdouble-promotion \
+  -Wstrict-prototypes \
+  -Wstrict-overflow \
+  -Werror-implicit-function-declaration \
+  -Wfloat-equal \
+  -Wundef \
+  -Wshadow \
+  -Wwrite-strings \
+  -Wsign-compare \
+  -Wmissing-format-attribute \
+  -Wunreachable-code \
+  -Wcast-align \
+  -Wcast-qual \
+  -Wnull-dereference \
+  -Wuninitialized \
+  -Wunused \
+  -Wredundant-decls
+
+CFLAGS += \
+  -DOPT_MCU_FUZZ=1 \
+  -DCFG_TUSB_MCU=OPT_MCU_FUZZ 
+
+CXXFLAGS += \
+  -xc++ \
+  -Wno-c++11-narrowing \
+  -fno-implicit-templates
+
+# conversion is too strict for most mcu driver, may be disable sign/int/arith-conversion
+#  -Wconversion
+  
+# Debugging/Optimization
+ifeq ($(DEBUG), 1)
+  CFLAGS += -Og
+else
+  CFLAGS += $(CFLAGS_OPTIMIZED)
+endif
+
+# Log level is mapped to TUSB DEBUG option
+ifneq ($(LOG),)
+  CMAKE_DEFSYM +=	-DLOG=$(LOG)
+  CFLAGS += -DCFG_TUSB_DEBUG=$(LOG)
+endif
+
+# Logger: default is uart, can be set to rtt or swo
+ifneq ($(LOGGER),)
+	CMAKE_DEFSYM +=	-DLOGGER=$(LOGGER)
+endif
+
diff --git a/fuzz/rules.mk b/fuzz/rules.mk
new file mode 100644
index 000000000..aedc7fe83
--- /dev/null
+++ b/fuzz/rules.mk
@@ -0,0 +1,160 @@
+# ---------------------------------------
+# Common make rules for all examples
+# ---------------------------------------
+
+# Set all as default goal
+.DEFAULT_GOAL := all
+
+# ---------------------------------------
+# Compiler Flags
+# ---------------------------------------
+
+LIBS_GCC ?=  -lm
+
+# libc
+LIBS += $(LIBS_GCC)
+
+ifneq ($(BOARD), spresense)
+LIBS += -lc -Wl,-Bstatic -lc++ -lc++abi -Wl,-Bdynamic
+endif
+
+# TinyUSB Stack source
+SRC_C += \
+	src/tusb.c \
+	src/common/tusb_fifo.c \
+	src/device/usbd.c \
+	src/device/usbd_control.c \
+	src/class/audio/audio_device.c \
+	src/class/cdc/cdc_device.c \
+	src/class/dfu/dfu_device.c \
+	src/class/dfu/dfu_rt_device.c \
+	src/class/hid/hid_device.c \
+	src/class/midi/midi_device.c \
+	src/class/msc/msc_device.c \
+	src/class/net/ecm_rndis_device.c \
+	src/class/net/ncm_device.c \
+	src/class/usbtmc/usbtmc_device.c \
+	src/class/video/video_device.c \
+	src/class/vendor/vendor_device.c
+
+
+# Fuzzers are c++
+SRC_CXX += \
+	fuzz/dcd_fuzz.cc \
+	fuzz/fuzz.cc \
+	fuzz/msc_fuzz.cc \
+	fuzz/usbd_fuzz.cc
+
+# TinyUSB stack include
+INC += $(TOP)/src
+
+CFLAGS += $(addprefix -I,$(INC))
+CXXFLAGS += -std=c++17
+
+# LTO makes it difficult to analyze map file for optimizing size purpose
+# We will run this option in ci
+ifeq ($(NO_LTO),1)
+CFLAGS := $(filter-out -flto,$(CFLAGS))
+endif
+
+ifneq ($(LD_FILE),)
+LDFLAGS_LD_FILE ?= -Wl,-T,$(TOP)/$(LD_FILE)
+endif
+
+LDFLAGS += $(CFLAGS) $(LDFLAGS_LD_FILE) -fuse-ld=lld -Wl,[email protected] -Wl,--cref -Wl,-gc-sections
+ifneq ($(SKIP_NANOLIB), 1)
+endif
+
+ASFLAGS += $(CFLAGS)
+
+# Assembly files can be name with upper case .S, convert it to .s
+SRC_S := $(SRC_S:.S=.s)
+
+# Due to GCC LTO bug https://bugs.launchpad.net/gcc-arm-embedded/+bug/1747966
+# assembly file should be placed first in linking order
+# '_asm' suffix is added to object of assembly file
+OBJ += $(addprefix $(BUILD)/obj/, $(SRC_S:.s=_asm.o))
+OBJ += $(addprefix $(BUILD)/obj/, $(SRC_C:.c=.o))
+OBJ += $(addprefix $(BUILD)/obj/, $(SRC_CXX:.cc=_cxx.o))
+
+# Verbose mode
+ifeq ("$(V)","1")
+$(info CFLAGS  $(CFLAGS) ) $(info )
+$(info LDFLAGS $(LDFLAGS)) $(info )
+$(info ASFLAGS $(ASFLAGS)) $(info )
+endif
+
+# ---------------------------------------
+# Rules
+# ---------------------------------------
+
+all: $(BUILD)/$(PROJECT) 
+
+OBJ_DIRS = $(sort $(dir $(OBJ)))
+$(OBJ): | $(OBJ_DIRS)
+$(OBJ_DIRS):
+ifeq ($(CMDEXE),1)
+	@$(MKDIR) $(subst /,\,$@)
+else
+	@$(MKDIR) -p $@
+endif
+
+$(BUILD)/$(PROJECT): $(OBJ)
+	@echo LINK $@
+	@ $(CXX) -o $@  $(LIB_FUZZING_ENGINE) $^ $(LIBS) $(LDFLAGS)
+
+# We set vpath to point to the top of the tree so that the source files
+# can be located. By following this scheme, it allows a single build rule
+# to be used to compile all .c files.
+vpath %.c . $(TOP)
+$(BUILD)/obj/%.o: %.c
+	@echo CC $(notdir $@)
+	@$(CC) $(CFLAGS) -c -MD -o $@ $<
+	
+# All cpp srcs
+vpath %.cc . $(TOP)
+$(BUILD)/obj/%_cxx.o: %.cc
+	@echo CXX $(notdir $@)
+	@$(CXX) $(CFLAGS) $(CXXFLAGS) -c -MD -o $@ $<
+
+# ASM sources lower case .s
+vpath %.s . $(TOP)
+$(BUILD)/obj/%_asm.o: %.s
+	@echo AS $(notdir $@)
+	@$(CC) -x assembler-with-cpp $(ASFLAGS) -c -o $@ $<
+
+# ASM sources upper case .S
+vpath %.S . $(TOP)
+$(BUILD)/obj/%_asm.o: %.S
+	@echo AS $(notdir $@)
+	@$(CC) -x assembler-with-cpp $(ASFLAGS) -c -o $@ $<
+
+.PHONY: clean
+clean:
+ifeq ($(CMDEXE),1)
+	rd /S /Q $(subst /,\,$(BUILD))
+else
+	$(RM) -rf $(BUILD)
+endif
+# ---------------- GNU Make End -----------------------
+
+# get depenecies
+.PHONY: get-deps
+get-deps:
+  ifdef DEPS_SUBMODULES
+	git -C $(TOP) submodule update --init $(DEPS_SUBMODULES)
+  endif
+
+size: $(BUILD)/$(PROJECT)
+	-@echo ''
+	@$(SIZE) $<
+	-@echo ''
+
+# linkermap must be install previously at https://github.com/hathach/linkermap
+linkermap: $(BUILD)/$(PROJECT)
+	@linkermap -v $<.map
+
+# Print out the value of a make variable.
+# https://stackoverflow.com/questions/16467718/how-to-print-out-a-variable-in-makefile
+print-%:
+	@echo $* = $($*)
\ No newline at end of file
diff --git a/fuzz/usbd_fuzz.cc b/fuzz/usbd_fuzz.cc
new file mode 100644
index 000000000..45c5fd7ea
--- /dev/null
+++ b/fuzz/usbd_fuzz.cc
@@ -0,0 +1,73 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2022 Nathaniel Brough
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+
+#include "fuzz/fuzz_private.h"
+#include "tusb.h"
+// #include "usb_descriptors.h"
+
+#ifndef CFG_FUZZ_MAX_STRING_LEN
+#define CFG_FUZZ_MAX_STRING_LEN 1000
+#endif
+
+extern "C" {
+
+/* TODO: Implement a fuzzed version of this.
+uint8_t const *tud_descriptor_bos_cb(void) {  }
+*/
+
+/* TODO: Implement a fuzzed version of this.
+uint8_t const *tud_descriptor_device_qualifier_cb(void) {}
+*/
+
+/* TODO: Implement a fuzzed version of this.
+uint8_t const *tud_descriptor_other_speed_configuration_cb(uint8_t index) {}
+*/
+
+void tud_mount_cb(void) {
+  // NOOP
+}
+
+void tud_umount_cb(void) {
+  // NOOP
+}
+
+void tud_suspend_cb(bool remote_wakeup_en) {
+  (void)remote_wakeup_en;
+  // NOOP
+}
+
+void tud_resume_cb(void) {
+  // NOOP
+}
+
+/* TODO: Implement a fuzzed version of this.
+bool tud_vendor_control_xfer_cb(uint8_t rhport, uint8_t stage,
+                                tusb_control_request_t const *request) {}
+*/
+
+/* TODO: Implement a fuzzed version of this.
+uint16_t const *tud_descriptor_string_cb(uint8_t index, uint16_t langid) {}
+*/
+}