| // Copyright lowRISC contributors. |
| // Licensed under the Apache License, Version 2.0, see LICENSE for details. |
| // SPDX-License-Identifier: Apache-2.0 |
| |
| #include "sw/device/lib/dif/dif_otbn.h" |
| #include "sw/device/lib/runtime/ibex.h" |
| #include "sw/device/lib/runtime/irq.h" |
| #include "sw/device/lib/runtime/log.h" |
| #include "sw/device/lib/testing/entropy_testutils.h" |
| #include "sw/device/lib/testing/otbn_testutils.h" |
| #include "sw/device/lib/testing/rv_plic_testutils.h" |
| #include "sw/device/lib/testing/test_framework/check.h" |
| #include "sw/device/lib/testing/test_framework/ottf_main.h" |
| |
| #include "hw/top_earlgrey/sw/autogen/top_earlgrey.h" |
| |
| /** |
| * ECDSA sign and verify test with the NIST P-256 curve using OTBN. |
| * |
| * IMPORTANT: This test is not a secure, complete, or reusable implementation of |
| * a cryptographic algorithm; it is not even close to being production-ready. |
| * It is only meant as an end-to-end test for OTBN during the bringup phase. |
| * |
| * The test contains constants and expected output, which can be independently |
| * and conveniently verified using a Python script. |
| * |
| * <code> |
| * # Optional: generate a new key |
| * $ openssl ecparam -name prime256v1 -genkey -noout -out \ |
| * otbn_ecdsa_p256_test_private_key.pem |
| * |
| * # Create all constants/variables |
| * $ ./otbn_test_params.py ecc otbn_ecdsa_p256_test_private_key.pem |
| * </code> |
| */ |
| |
| OTBN_DECLARE_APP_SYMBOLS(p256_ecdsa); |
| |
| OTBN_DECLARE_SYMBOL_ADDR(p256_ecdsa, mode); |
| OTBN_DECLARE_SYMBOL_ADDR(p256_ecdsa, msg); |
| OTBN_DECLARE_SYMBOL_ADDR(p256_ecdsa, r); |
| OTBN_DECLARE_SYMBOL_ADDR(p256_ecdsa, s); |
| OTBN_DECLARE_SYMBOL_ADDR(p256_ecdsa, x); |
| OTBN_DECLARE_SYMBOL_ADDR(p256_ecdsa, y); |
| OTBN_DECLARE_SYMBOL_ADDR(p256_ecdsa, d0); |
| OTBN_DECLARE_SYMBOL_ADDR(p256_ecdsa, d1); |
| OTBN_DECLARE_SYMBOL_ADDR(p256_ecdsa, x_r); |
| |
| static const otbn_app_t kOtbnAppP256Ecdsa = OTBN_APP_T_INIT(p256_ecdsa); |
| |
| static const otbn_addr_t kOtbnVarMode = OTBN_ADDR_T_INIT(p256_ecdsa, mode); |
| static const otbn_addr_t kOtbnVarMsg = OTBN_ADDR_T_INIT(p256_ecdsa, msg); |
| static const otbn_addr_t kOtbnVarR = OTBN_ADDR_T_INIT(p256_ecdsa, r); |
| static const otbn_addr_t kOtbnVarS = OTBN_ADDR_T_INIT(p256_ecdsa, s); |
| static const otbn_addr_t kOtbnVarX = OTBN_ADDR_T_INIT(p256_ecdsa, x); |
| static const otbn_addr_t kOtbnVarY = OTBN_ADDR_T_INIT(p256_ecdsa, y); |
| static const otbn_addr_t kOtbnVarD0 = OTBN_ADDR_T_INIT(p256_ecdsa, d0); |
| static const otbn_addr_t kOtbnVarD1 = OTBN_ADDR_T_INIT(p256_ecdsa, d1); |
| static const otbn_addr_t kOtbnVarXR = OTBN_ADDR_T_INIT(p256_ecdsa, x_r); |
| |
| OTTF_DEFINE_TEST_CONFIG(); |
| |
| /** |
| * The plic dif to access the hardware. |
| */ |
| static dif_rv_plic_t plic; |
| |
| /** |
| * The otbn context handler. |
| */ |
| static dif_otbn_t otbn; |
| |
| /** |
| * The peripheral which fired the irq to be filled by the irq handler. |
| */ |
| static volatile top_earlgrey_plic_peripheral_t plic_peripheral; |
| |
| /** |
| * The irq id to be filled by the irq handler. |
| */ |
| static volatile dif_rv_plic_irq_id_t irq_id; |
| |
| /** |
| * The otbn irq to be filled by the irq handler. |
| */ |
| static volatile dif_otbn_irq_t irq; |
| |
| /** |
| * Provides external IRQ handling for otbn tests. |
| * |
| * This function overrides the default OTTF external ISR. |
| * |
| * It performs the following: |
| * 1. Claims the IRQ fired (finds PLIC IRQ index). |
| * 2. Compute the OTBN peripheral. |
| * 3. Compute the otbn irq. |
| * 4. Clears the IRQ at the peripheral. |
| * 5. Completes the IRQ service at PLIC. |
| */ |
| void ottf_external_isr(void) { |
| CHECK_DIF_OK(dif_rv_plic_irq_claim(&plic, kTopEarlgreyPlicTargetIbex0, |
| (dif_rv_plic_irq_id_t *)&irq_id)); |
| |
| plic_peripheral = (top_earlgrey_plic_peripheral_t) |
| top_earlgrey_plic_interrupt_for_peripheral[irq_id]; |
| |
| irq = (dif_otbn_irq_t)(irq_id - |
| (dif_rv_plic_irq_id_t)kTopEarlgreyPlicIrqIdOtbnDone); |
| |
| CHECK_DIF_OK(dif_otbn_irq_acknowledge(&otbn, irq)); |
| |
| // Complete the IRQ by writing the IRQ source to the Ibex specific CC. |
| // register. |
| CHECK_DIF_OK( |
| dif_rv_plic_irq_complete(&plic, kTopEarlgreyPlicTargetIbex0, irq_id)); |
| } |
| |
| static void otbn_wait_for_done_irq(dif_otbn_t *otbn) { |
| // Clear the otbn irq variable: we'll set it in the interrupt handler when |
| // we see the Done interrupt fire. |
| irq = UINT32_MAX; |
| irq_id = UINT32_MAX; |
| plic_peripheral = UINT32_MAX; |
| // Enable Done interrupt. |
| CHECK_DIF_OK( |
| dif_otbn_irq_set_enabled(otbn, kDifOtbnIrqDone, kDifToggleEnabled)); |
| |
| // At this point, OTBN should be running. Wait for an interrupt that says |
| // it's done. |
| while (true) { |
| // This looks a bit odd, but is needed to avoid a race condition where the |
| // OTBN interrupt comes in after we load the otbn_finished flag but before |
| // we run the WFI instruction. The trick is that WFI returns when an |
| // interrupt comes in even if interrupts are globally disabled, which means |
| // that the WFI can actually sit *inside* the critical section. |
| irq_global_ctrl(false); |
| if (plic_peripheral != UINT32_MAX) { |
| break; |
| } |
| wait_for_interrupt(); |
| irq_global_ctrl(true); |
| } |
| irq_global_ctrl(true); |
| |
| CHECK(plic_peripheral == kTopEarlgreyPlicPeripheralOtbn, |
| "Interrupt from incorrect peripheral: (exp: %d, obs: %s)", |
| kTopEarlgreyPlicPeripheralOtbn, plic_peripheral); |
| |
| // Check this is the interrupt we expected. |
| CHECK(irq_id == kTopEarlgreyPlicIrqIdOtbnDone); |
| |
| // Disable Done interrupt. |
| CHECK_DIF_OK( |
| dif_otbn_irq_set_enabled(otbn, kDifOtbnIrqDone, kDifToggleDisabled)); |
| |
| // Acknowledge Done interrupt. This clears INTR_STATE.done back to 0. |
| CHECK_DIF_OK(dif_otbn_irq_acknowledge(otbn, kDifOtbnIrqDone)); |
| } |
| |
| static void otbn_init_irq(void) { |
| mmio_region_t plic_base_addr = |
| mmio_region_from_addr(TOP_EARLGREY_RV_PLIC_BASE_ADDR); |
| // Initialize PLIC and configure OTBN interrupt. |
| CHECK_DIF_OK(dif_rv_plic_init(plic_base_addr, &plic)); |
| |
| // Set interrupt priority to be positive. |
| dif_rv_plic_irq_id_t irq_id = kTopEarlgreyPlicIrqIdOtbnDone; |
| CHECK_DIF_OK(dif_rv_plic_irq_set_priority(&plic, irq_id, 0x1)); |
| |
| CHECK_DIF_OK(dif_rv_plic_irq_set_enabled( |
| &plic, irq_id, kTopEarlgreyPlicTargetIbex0, kDifToggleEnabled)); |
| |
| // Set the threshold for Ibex to 0. |
| CHECK_DIF_OK(dif_rv_plic_target_set_threshold( |
| &plic, kTopEarlgreyPlicTargetIbex0, 0x0)); |
| |
| // Enable the external IRQ (so that we see the interrupt from the PLIC). |
| irq_global_ctrl(true); |
| irq_external_ctrl(true); |
| } |
| |
| /** |
| * Securely wipes OTBN DMEM and waits for Done interrupt. |
| * |
| * @param otbn The OTBN context object. |
| */ |
| static void otbn_wipe_dmem(dif_otbn_t *otbn) { |
| CHECK_DIF_OK(dif_otbn_write_cmd(otbn, kDifOtbnCmdSecWipeDmem)); |
| otbn_wait_for_done_irq(otbn); |
| } |
| |
| /** |
| * CHECK()s that the actual data matches the expected data. |
| * |
| * @param actual The actual data. |
| * @param expected The expected data. |
| * @param size_bytes The size of the actual/expected data. |
| */ |
| static void check_data(const char *msg, const uint8_t *actual, |
| const uint8_t *expected, size_t size_bytes) { |
| for (int i = 0; i < size_bytes; ++i) { |
| CHECK(actual[i] == expected[i], |
| "%s: mismatch at byte %d: 0x%x (actual) != 0x%x (expected)", msg, i, |
| actual[i], expected[i]); |
| } |
| } |
| |
| /** |
| * Starts a profiling section. |
| * |
| * Call this function at the start of a section that should be profiled, and |
| * call `profile_end()` at the end of it to display the results. |
| * |
| * @return The cycle counter when starting the profiling. |
| */ |
| static uint64_t profile_start(void) { return ibex_mcycle_read(); } |
| |
| /** |
| * Ends a profiling section. |
| * |
| * The time since `profile_start()` is printed as log message. |
| * |
| * @param t_start Start timestamp, as returned from profile_start(). |
| * @param msg Name of the operation (for logging purposes). |
| */ |
| static void profile_end(uint64_t t_start, const char *msg) { |
| uint64_t t_end = ibex_mcycle_read(); |
| uint32_t cycles = t_end - t_start; |
| uint32_t time_us = cycles / 100; |
| LOG_INFO("%s took %u cycles or %u us @ 100 MHz.", msg, cycles, time_us); |
| } |
| |
| /** |
| * Signs a message with ECDSA using the P-256 curve. |
| * |
| * @param otbn The OTBN context object. |
| * @param msg The message to sign (32B). |
| * @param private_key_d The private key (32B). |
| * @param[out] signature_r Signature component r (the x-coordinate of R). |
| * Provide a pre-allocated 32B buffer. |
| * @param[out] signature_s Signature component s (the proof). |
| * Provide a pre-allocated 32B buffer. |
| */ |
| static void p256_ecdsa_sign(dif_otbn_t *otbn, const uint8_t *msg, |
| const uint8_t *private_key_d, uint8_t *signature_r, |
| uint8_t *signature_s) { |
| CHECK(otbn != NULL); |
| |
| // Write input arguments. |
| uint32_t mode = 1; // mode 1 => sign |
| otbn_testutils_write_data(otbn, sizeof(mode), &mode, kOtbnVarMode); |
| otbn_testutils_write_data(otbn, /*len_bytes=*/32, msg, kOtbnVarMsg); |
| otbn_testutils_write_data(otbn, /*len_bytes=*/32, private_key_d, kOtbnVarD0); |
| |
| // Write redundant upper bits of d (all-zero for this test). |
| uint8_t d0_high[32] = {0}; |
| otbn_testutils_write_data(otbn, /*len_bytes=*/32, d0_high, kOtbnVarD0 + 32); |
| |
| // Write second share of d (all-zero for this test). |
| uint8_t d1[64] = {0}; |
| otbn_testutils_write_data(otbn, /*len_bytes=*/64, d1, kOtbnVarD1); |
| |
| // Call OTBN to perform operation, and wait for it to complete. |
| otbn_testutils_execute(otbn); |
| otbn_wait_for_done_irq(otbn); |
| |
| // Read back results. |
| otbn_testutils_read_data(otbn, /*len_bytes=*/32, kOtbnVarR, signature_r); |
| otbn_testutils_read_data(otbn, /*len_bytes=*/32, kOtbnVarS, signature_s); |
| } |
| |
| /** |
| * Verifies a message with ECDSA using the P-256 curve. |
| * |
| * @param otbn The OTBN context object. |
| * @param msg The message to verify (32B). |
| * @param signature_r The signature component r (the proof) (32B). |
| * @param signature_s The signature component s (the proof) (32B). |
| * @param public_key_x The public key x-coordinate (32B). |
| * @param public_key_y The public key y-coordinate (32B). |
| * @param[out] signature_x_r Recovered point x_r (== R'.x). Provide a |
| * pre-allocated 32B buffer. |
| */ |
| static void p256_ecdsa_verify(dif_otbn_t *otbn, const uint8_t *msg, |
| const uint8_t *signature_r, |
| const uint8_t *signature_s, |
| const uint8_t *public_key_x, |
| const uint8_t *public_key_y, |
| uint8_t *signature_x_r) { |
| CHECK(otbn != NULL); |
| |
| // Write input arguments. |
| uint32_t mode = 2; // mode 2 => verify |
| otbn_testutils_write_data(otbn, sizeof(mode), &mode, kOtbnVarMode); |
| otbn_testutils_write_data(otbn, /*len_bytes=*/32, msg, kOtbnVarMsg); |
| otbn_testutils_write_data(otbn, /*len_bytes=*/32, signature_r, kOtbnVarR); |
| otbn_testutils_write_data(otbn, /*len_bytes=*/32, signature_s, kOtbnVarS); |
| otbn_testutils_write_data(otbn, /*len_bytes=*/32, public_key_x, kOtbnVarX); |
| otbn_testutils_write_data(otbn, /*len_bytes=*/32, public_key_y, kOtbnVarY); |
| |
| // Call OTBN to perform operation, and wait for it to complete. |
| otbn_testutils_execute(otbn); |
| otbn_wait_for_done_irq(otbn); |
| |
| // Read back results. |
| otbn_testutils_read_data(otbn, /*len_bytes=*/32, kOtbnVarXR, signature_x_r); |
| } |
| |
| /** |
| * Performs a ECDSA roundtrip test using the NIST P-256 curve. |
| * |
| * A roundtrip consists of three steps: Initialize OTBN, sign, and verify. |
| */ |
| static void test_ecdsa_p256_roundtrip(void) { |
| // Message |
| static const uint8_t kIn[32] = {"Hello OTBN."}; |
| |
| // Public key x-coordinate (Q.x) |
| static const uint8_t kPublicKeyQx[32] = { |
| 0x4e, 0xb2, 0x8b, 0x55, 0xeb, 0x88, 0x62, 0x24, 0xf2, 0xbf, 0x1b, |
| 0x9e, 0xd8, 0x4a, 0x09, 0xa7, 0x86, 0x67, 0x92, 0xcd, 0xca, 0x07, |
| 0x5d, 0x07, 0x82, 0xe7, 0x2d, 0xac, 0x31, 0x14, 0x79, 0x1f}; |
| |
| // Public key y-coordinate (Q.y) |
| static const uint8_t kPublicKeyQy[32] = { |
| 0x27, 0x9c, 0xe4, 0x23, 0x24, 0x10, 0xa2, 0xfa, 0xbd, 0x53, 0x73, |
| 0xf1, 0xa5, 0x08, 0xf0, 0x40, 0x9e, 0xc0, 0x55, 0x21, 0xa4, 0xf0, |
| 0x54, 0x59, 0x00, 0x3e, 0x5f, 0x15, 0x3c, 0xc6, 0x4b, 0x87}; |
| |
| // Private key (d) |
| static const uint8_t kPrivateKeyD[32] = { |
| 0xcd, 0xb4, 0x57, 0xaf, 0x1c, 0x9f, 0x4c, 0x74, 0x02, 0x0c, 0x7e, |
| 0x8b, 0xe9, 0x93, 0x3e, 0x28, 0x0c, 0xf0, 0x18, 0x0d, 0xf4, 0x6c, |
| 0x0b, 0xda, 0x7a, 0xbb, 0xe6, 0x8f, 0xb7, 0xa0, 0x45, 0x55}; |
| |
| // Initialize |
| uint64_t t_start_init = profile_start(); |
| CHECK_DIF_OK( |
| dif_otbn_init(mmio_region_from_addr(TOP_EARLGREY_OTBN_BASE_ADDR), &otbn)); |
| otbn_init_irq(); |
| otbn_testutils_load_app(&otbn, kOtbnAppP256Ecdsa); |
| profile_end(t_start_init, "Initialization"); |
| |
| // Sign |
| uint8_t signature_r[32] = {0}; |
| uint8_t signature_s[32] = {0}; |
| |
| LOG_INFO("Signing"); |
| uint64_t t_start_sign = profile_start(); |
| p256_ecdsa_sign(&otbn, kIn, kPrivateKeyD, signature_r, signature_s); |
| profile_end(t_start_sign, "Sign"); |
| |
| // Securely wipe OTBN data memory and reload app |
| LOG_INFO("Wiping OTBN DMEM and reloading app"); |
| otbn_wipe_dmem(&otbn); |
| otbn_testutils_load_app(&otbn, kOtbnAppP256Ecdsa); |
| |
| // Verify |
| uint8_t signature_x_r[32] = {0}; |
| |
| LOG_INFO("Verifying"); |
| uint64_t t_start_verify = profile_start(); |
| p256_ecdsa_verify(&otbn, kIn, signature_r, signature_s, kPublicKeyQx, |
| kPublicKeyQy, signature_x_r); |
| |
| // Include the r =? x_r comparison in the profiling as this is something |
| // either OTBN or the host CPU needs to do as part of the signature |
| // verification. |
| check_data("signature_x_r", signature_r, signature_x_r, 32); |
| profile_end(t_start_verify, "Verify"); |
| |
| // Securely wipe OTBN data memory |
| LOG_INFO("Wiping OTBN DMEM"); |
| otbn_wipe_dmem(&otbn); |
| } |
| |
| bool test_main(void) { |
| entropy_testutils_auto_mode_init(); |
| |
| test_ecdsa_p256_roundtrip(); |
| |
| return true; |
| } |