[fisim/crypto] Add instruction skip simulator

This only works for a debug enabled FPGA/chip and is only been tested on a CW340!

Add a script to load the pentest framework, connect to OpenOCD, and connect to GDB.
Generate a trace file of a called function.
Use the trace file to insert instruction skips in order to simulate fault attacks and test countermeasures.

Signed-off-by: Siemen Dhooghe <[email protected]>

Author: siemen11

sw/device/tests/penetrationtests/BUILD

@@ -295,6 +295,17 @@ pentest_cryptolib_fi_asym(
     test_vectors = [],
 )
 
+pentest_cryptolib_fi_asym(
+    name = "fi_asym_cryptolib_python_gdb_test",
+    tags = [
+        "manual",
+        "skip_in_ci",
+    ],
+    test_args = "",
+    test_harness = "//sw/host/penetrationtests/python/fi:fi_asym_cryptolib_python_gdb_test",
+    test_vectors = [],
+)
+
 CRYPTOLIB_SCA_SYM_TESTVECTOR_TARGETS = [
     "//sw/host/penetrationtests/testvectors/data:sca_sym_cryptolib",
 ]

sw/host/penetrationtests/python/fi/BUILD

@@ -168,6 +168,27 @@ py_binary(
     ],
 )
 
+py_binary(
+    name = "fi_asym_cryptolib_python_gdb_test",
+    testonly = True,
+    srcs = ["gdb_testing/fi_asym_cryptolib_python_gdb_test.py"],
+    data = [
+        "//sw/host/opentitantool",
+        "//third_party/openocd:openocd_bin",
+        "//util/openocd/board:cw340_ftdi.cfg",
+        "//util/openocd/target:lowrisc-earlgrey.cfg",
+        "@lowrisc_rv32imcb_toolchain//:bin/riscv32-unknown-elf-gdb",
+    ],
+    deps = [
+        "//sw/host/penetrationtests/python/fi:fi_asym_cryptolib_commands",
+        "//sw/host/penetrationtests/python/util:common_library",
+        "//sw/host/penetrationtests/python/util:gdb_controller",
+        "//sw/host/penetrationtests/python/util:targets",
+        "@rules_python//python/runfiles",
+        requirement("pycryptodome"),
+    ],
+)
+
 py_library(
     name = "fi_ibex_functions",
     srcs = ["host_scripts/fi_ibex_functions.py"],

sw/host/penetrationtests/python/fi/gdb_testing/fi_asym_cryptolib_python_gdb_test.py

@@ -0,0 +1,324 @@
+# Copyright lowRISC contributors (OpenTitan project).
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+
+from sw.host.penetrationtests.python.fi.communication.fi_asym_cryptolib_commands import (
+    OTFIAsymCrypto,
+)
+from python.runfiles import Runfiles
+from sw.host.penetrationtests.python.util import targets
+from sw.host.penetrationtests.python.util import common_library
+from sw.host.penetrationtests.python.util.gdb_controller import GDBController
+import json
+import argparse
+import sys
+import os
+import time
+from Crypto.PublicKey import ECC
+from Crypto.Signature import DSS
+from Crypto.Hash import SHA384
+
+ignored_keys_set = set(["status"])
+opentitantool_path = ""
+
+target = None
+asymfi = None
+
+# Read in the extra arguments from the opentitan_test.
+parser = argparse.ArgumentParser()
+parser.add_argument("--bitstream", type=str)
+parser.add_argument("--bootstrap", type=str)
+
+args, config_args = parser.parse_known_args()
+
+BITSTREAM = args.bitstream
+BOOTSTRAP = args.bootstrap
+
+
+# Preparing the input for an invalid signature
+key = ECC.generate(curve="P-384")
+pubx = [x for x in key.pointQ.x.to_bytes(48, "little")]
+puby = [x for x in key.pointQ.y.to_bytes(48, "little")]
+message = [i for i in range(16)]
+h = SHA384.new(bytes(message))
+signer = DSS.new(key, "fips-186-3")
+signature = [x for x in signer.sign(h)]
+# Corrupt the signature for FiSim Testing
+signature[0] ^= 0x1
+r_bytes = signature[:48]
+s_bytes = signature[48:]
+r_bytes.reverse()
+s_bytes.reverse()
+cfg = 0
+trigger = 1
+h = SHA384.new(bytes(message))
+message_digest = [x for x in h.digest()]
+
+
+def trigger_testos_init(print_output=True):
+    # Initializing the testOS (setting up the alerts and accelerators)
+    (device_id, _, _, _, _, _, _) = asymfi.init(
+        alert_config=common_library.no_escalation_alert_config
+    )
+    if print_output:
+        print("Output from init ", device_id)
+
+
+def trigger_p384_verify():
+    asymfi.handle_p384_verify(pubx, puby, r_bytes, s_bytes, message_digest, cfg, trigger)
+
+
+def read_testos_output():
+    # Read the output from the operation
+    response = target.read_response(max_tries=500)
+    return response
+
+
+if __name__ == "__main__":
+    r = Runfiles.Create()
+    # Get the openocd path.
+    openocd_path = r.Rlocation("lowrisc_opentitan/third_party/openocd/build_openocd/bin/openocd")
+    # Get the openocd config files.
+    # The first file is on the cw340 (this is specific to the cw340)
+    CONFIG_FILE_CHIP = r.Rlocation("lowrisc_opentitan/util/openocd/board/cw340_ftdi.cfg")
+    # The config for the earlgrey design
+    CONFIG_FILE_DESIGN = r.Rlocation("lowrisc_opentitan/util/openocd/target/lowrisc-earlgrey.cfg")
+    # Get the opentitantool path.
+    opentitantool_path = r.Rlocation("lowrisc_opentitan/sw/host/opentitantool/opentitantool")
+    # The path for GDB and the default port (set up by OpenOCD)
+    GDB_PATH = r.Rlocation("lowrisc_rv32imcb_toolchain/bin/riscv32-unknown-elf-gdb")
+    GDB_PORT = 3333
+    # Directory for the trace log files
+    log_dir = os.environ.get("TEST_UNDECLARED_OUTPUTS_DIR")
+    pc_trace_file = os.path.join(log_dir, "pc_trace.log")
+    # Directory for the output results
+    test_results_file = os.path.join(log_dir, "test_results.log")
+    # Program the bitstream for FPGAs.
+    bitstream_path = None
+    if BITSTREAM:
+        bitstream_path = r.Rlocation("lowrisc_opentitan/" + BITSTREAM)
+    # Get the firmware path.
+    firmware_path = r.Rlocation("lowrisc_opentitan/" + BOOTSTRAP)
+    # Get the disassembly path.
+    dis_path = firmware_path.replace(".img", ".dis")
+    # And the path for the elf.
+    elf_path = firmware_path.replace(".img", ".elf")
+
+    if "fpga" in BOOTSTRAP:
+        target_type = "fpga"
+    else:
+        target_type = "chip"
+
+    target_cfg = targets.TargetConfig(
+        target_type=target_type,
+        interface_type="hyperdebug",
+        fw_bin=firmware_path,
+        opentitantool=opentitantool_path,
+        bitstream=bitstream_path,
+        tool_args=config_args,
+        openocd=openocd_path,
+        openocd_chip_config=CONFIG_FILE_CHIP,
+        openocd_design_config=CONFIG_FILE_DESIGN,
+    )
+
+    target = targets.Target(target_cfg)
+    asymfi = OTFIAsymCrypto(target)
+    successful_faults = 0
+    total_attacks = 0
+
+    # How to read outputs in this script:
+    # To view the UART output from the testOS or the chip in general, use:
+    # target.print_all() or print(read_testos_output())
+    # In order to print the OpenOCD output use print(target.read_openocd())
+    # In order to print the output from GDB use print(gdb.read_output()) or
+    # when you want to know the output from a gdb.send_command() print it:
+    # print(gdb.send_command())
+
+    # What to do when running into errors:
+    # - If device is busy or seeing "rejected 'gdb' connection, no more connections allowed",
+    # cut the USB connection, e.g., sudo fuser /dev/ttyUSB0 and kill the PID
+    # - If the port is busy check sudo lsof -i :3333 and then kill the PID
+
+    try:
+        # Program the bitstream, flash the target, and set up OpenOCD
+        target.initialize_target()
+
+        # Initialize the testOS
+        trigger_testos_init()
+
+        # Connect to GDB
+        gdb = GDBController(gdb_path=GDB_PATH, gdb_port=GDB_PORT, elf_file=elf_path)
+
+        # Provide the function name and extract the start and end address from the dis file
+        function_name = "p384_scalar_write"
+        # otcrypto_ecdsa_p384_verify (second one)
+        # OUTLINED_FUNCTION_22 (second one)
+        # hardened_memeq (not working yet)
+        # p384_scalar_write (any one)
+        # Gives back an array of hits where the function is called
+        trace_addresses = gdb.get_function_addresses(dis_path, function_name)
+        print("Start and stop addresses of ", function_name, ": ", trace_addresses)
+
+        p384_observation_addresses = gdb.get_function_addresses(
+            dis_path, "otcrypto_ecdsa_p384_verify"
+        )
+        crash_observation_address = gdb.get_function_start_address(
+            dis_path, "ottf_exception_handler"
+        )
+
+        # Start the tracing
+        # We set a short timeout to detect whether GDB has connected properly
+        # and a long timeout for the entire tracing
+        initial_timeout = 2
+        total_timeout = 60 * 30
+
+        # We pick the second address hit
+        # TODO: Find a way to pick the correct one
+        gdb.setup_pc_trace(pc_trace_file, trace_addresses[1][0], trace_addresses[1][1])
+        gdb.send_command("c", check_response=False)
+
+        # Trigger the p384 verify from the testOS (we do not read its output)
+        trigger_p384_verify()
+
+        start_time = time.time()
+        initial_timeout_stopped = False
+        total_timeout_stopped = False
+
+        # Run the tracing to get the trace log
+        # Sometimes the tracing fails due to race conditions,
+        # we have a quick initial timeout to catch this
+        while time.time() - start_time < initial_timeout:
+            output = gdb.read_output()
+            if "Breakpoint 1, " in output:
+                initial_timeout_stopped = True
+                break
+        if not initial_timeout_stopped:
+            print("No initial break point found, can be a misfire, try again")
+            sys.exit(1)
+        while time.time() - start_time < total_timeout:
+            output = gdb.read_output()
+            if "PC trace complete" in output:
+                print("\nTrace complete")
+                total_timeout_stopped = True
+                break
+        if not total_timeout_stopped:
+            print("Final tracing timeout reached")
+            sys.exit(1)
+
+        # Parse and truncate the trace log to get all PCs in a list
+        pc_list = gdb.parse_pc_trace_file(pc_trace_file)
+        # Get the unique PCs out
+        pc_list = list(set(pc_list))
+
+        # TODO: Make this truncate for wait cycles and identify the instance count ...
+        print("Tracing has a total of", len(pc_list), "PCs", flush=True)
+
+        if len(pc_list) <= 0:
+            print("Found no tracing, stopping")
+            sys.exit(1)
+
+        # Reset the target, flush the output, and close gdb
+        gdb.reset_target()
+        target.dump_all()
+        trigger_testos_init(print_output=False)
+        gdb.close_gdb()
+        gdb = GDBController(gdb_path=GDB_PATH, gdb_port=GDB_PORT, elf_file=elf_path)
+
+        # Open the results file
+        test_results = open(test_results_file, "w")
+
+        idx = 0
+        while idx < len(pc_list):
+            print("-" * 80)
+            print("Applying instruction skip in ", pc_list[idx])
+            print("-" * 80)
+
+            prefix_observation = "fisim_result:"
+            function_output_observation = "function output detected"
+            crash_observation = "crash detected"
+
+            try:
+                # TODO Adding the observation points creates issues in the flow of the instructions
+                # The observation points
+                # observations = {
+                #     # Function output
+                #     p384_observation_addresses[1][1]: f"{function_output_observation}",
+                #     # Crash check
+                #     crash_observation_address: f"{crash_observation}",
+                # }
+                # gdb.add_observation(observations)
+
+                # TODO Handle multiple same addresses
+                gdb.apply_instruction_skip(
+                    pc_list[idx], gdb.parse_next_instruction(pc_list[idx], dis_path)
+                )
+                gdb.send_command("c", check_response=False)
+
+                # The instruction skip loop
+                trigger_p384_verify()
+                time.sleep(0.02)
+                testos_response = read_testos_output()
+
+                gdb_response = gdb.read_output()
+                if (
+                    'stopped,reason="breakpoint-hit"' in gdb_response
+                    and "instruction skip applied" in gdb_response
+                ):
+                    idx += 1
+                    total_attacks += 1
+                    testos_response_json = json.loads(testos_response)
+                    print("Output:", testos_response_json, flush=True)
+                    verification_result = testos_response_json["result"]
+                    if verification_result:
+                        successful_faults += 1
+                        print("-" * 80)
+                        print("Successful FI attack!")
+                        print("Location:", pc_list[idx - 1])
+                        print(gdb_response)
+                        print("Response:", testos_response_json)
+                        print("-" * 80)
+                        test_results.write(f"{pc_list[idx - 1]}: {testos_response_json}\n")
+
+                    # Reset GDB by closing and opening again
+                    gdb.close_gdb()
+                    gdb = GDBController(gdb_path=GDB_PATH, gdb_port=GDB_PORT, elf_file=elf_path)
+                    # We do not need to reset the target since it returned an output
+                else:
+                    print("No break point found, something went wrong", flush=True)
+                    gdb.close_gdb()
+                    gdb = GDBController(gdb_path=GDB_PATH, gdb_port=GDB_PORT, elf_file=elf_path)
+                    gdb.reset_target()
+                    target.dump_all()
+                    trigger_testos_init(print_output=False)
+                    # Reset again
+                    gdb.close_gdb()
+                    gdb = GDBController(gdb_path=GDB_PATH, gdb_port=GDB_PORT, elf_file=elf_path)
+
+            except json.JSONDecodeError:
+                print("Error: JSON decoding failed. Invalid response format", flush=True)
+                gdb.close_gdb()
+                gdb = GDBController(gdb_path=GDB_PATH, gdb_port=GDB_PORT, elf_file=elf_path)
+                gdb.reset_target()
+                target.dump_all()
+                trigger_testos_init(print_output=False)
+                # Reset again
+                gdb.close_gdb()
+                gdb = GDBController(gdb_path=GDB_PATH, gdb_port=GDB_PORT, elf_file=elf_path)
+
+            except TimeoutError:
+                print("Timeout error, retrying", flush=True)
+                gdb.close_gdb()
+                target.close_openocd()
+                target.initialize_target()
+                trigger_testos_init()
+                target.dump_all()
+                gdb = GDBController(gdb_path=GDB_PATH, gdb_port=GDB_PORT, elf_file=elf_path)
+
+    finally:
+        print("-" * 80)
+        print("Trace data is logged in ", pc_trace_file)
+        print("Instruction skip results are logged in ", test_results_file)
+        print(f"Total attacks {total_attacks}, successful attacks {successful_faults}")
+        print("You can find the dissassembly in ", dis_path)
+        # Close the OpenOCD and GDB connection at the end
+        target.close_openocd()

sw/host/penetrationtests/python/util/BUILD

@@ -30,3 +30,8 @@ py_library(
     name = "hyperdebug",
     srcs = ["hyperdebug.py"],
 )
+
+py_library(
+    name = "gdb_controller",
+    srcs = ["gdb_controller.py"],
+)