/* * cryptech_novena_i2c_trng.c * ------------------------------ * * This is an early prototype Hardware Adaption Layer (HAL) for using * Cryptlib with the Cryptech project's FGPA cores over an I2C bus on * the Novena PVT1 development board using the "coretest" byte stream * protocol. This is compatible with the test/novena_trng FPGA build. * * The communication channel used here is not suitable for production * use, this is just a prototype. * * Authors: Joachim Strömbergson, Paul Selkirk, Rob Austein * Copyright (c) 2014, SUNET * * 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. * * 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 OWNER 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. * * The HAL framework is taken from the Cryptlib hw_dummy.c template, * and is Copyright 1998-2009 by Peter Gutmann. */ #include #include #include #include #include #include #include #include #if defined( INC_ALL ) #include "crypt.h" #include "context.h" #include "hardware.h" #else #include "crypt.h" #include "context/context.h" #include "device/hardware.h" #endif /* Compiler-specific includes */ /* * I2C_SLAVE comes from /usr/include/linux/i2c-dev.h, but if we * include that we won't be able to compile this except on Linux. It * won't *run* anywhere but on Linux, but it's useful to be able to do * compilation tests on other platforms, eg, with Clang, so for now we * take the small risk that this one magic constant might change. */ #define I2C_SLAVE 0x0703 #ifdef USE_HARDWARE /* * I2C-related parameters, copied from hash_tester.c */ /* I2C configuration */ #define I2C_DEV "/dev/i2c-2" #define I2C_ADDR 0x0f /* command codes */ #define SOC 0x55 #define EOC 0xaa #define READ_CMD 0x10 #define WRITE_CMD 0x11 #define RESET_CMD 0x01 /* response codes */ #define SOR 0xaa #define EOR 0x55 #define READ_OK 0x7f #define WRITE_OK 0x7e #define RESET_OK 0x7d #define UNKNOWN 0xfe #define ERROR 0xfd /* addresses and codes common to all cores */ #define ADDR_NAME0 0x00 #define ADDR_NAME1 0x01 #define ADDR_VERSION 0x02 #define ADDR_CTRL 0x08 #define CTRL_INIT_CMD 1 #define CTRL_NEXT_CMD 2 #define ADDR_STATUS 0x09 #define STATUS_READY_BIT 1 #define STATUS_VALID_BIT 2 /* * Address for reading 32 bits of entropy from the noise board. * TRNG_VALID is nonzero if valid random bits are available. */ #define TRNG_PREFIX 0x0b #define TRNG_DATA 0x20 #define TRNG_VALID 0x11 static int i2cfd = -1; static int debug = 0; /* * I2C low-level code */ static int i2c_open(void) { if (i2cfd >= 0) return 1; i2cfd = open(I2C_DEV, O_RDWR); if (i2cfd < 0) { perror("Unable to open " I2C_DEV); i2cfd = -1; return 0; } if (ioctl(i2cfd, I2C_SLAVE, I2C_ADDR) < 0) { perror("Unable to set i2c slave device"); return 0; } if (debug) fprintf(stderr, "[ Opened %s, fd %d ]\n", I2C_DEV, i2cfd); return 1; } static int i2c_write_bytes(const unsigned char *buf, const size_t len) { if (debug) { int i; fprintf(stderr, "write ["); for (i = 0; i < len; ++i) fprintf(stderr, " %02x", buf[i]); fprintf(stderr, " ]\n"); } if (!i2c_open()) return 0; if (write(i2cfd, buf, len) != len) { perror("i2c write failed"); return 0; } return 1; } static int i2c_read_byte(unsigned char *b) { /* * read() on the i2c device only returns one byte at a time, * and we need to parse the response one byte at a time anyway. */ if (!i2c_open()) return 0; if (read(i2cfd, b, 1) != 1) { perror("i2c read failed"); return 0; } return 1; } static int i2c_send_write_cmd(const unsigned char addr0, const unsigned char addr1, const unsigned char data[]) { unsigned char buf[9]; buf[0] = SOC; buf[1] = WRITE_CMD; buf[2] = addr0; buf[3] = addr1; buf[4] = data[0]; buf[5] = data[1]; buf[6] = data[2]; buf[7] = data[3]; buf[8] = EOC; return i2c_write_bytes(buf, sizeof(buf)); } static int i2c_send_read_cmd(const unsigned char addr0, const unsigned char addr1) { unsigned char buf[5]; buf[0] = SOC; buf[1] = READ_CMD; buf[2] = addr0; buf[3] = addr1; buf[4] = EOC; return i2c_write_bytes(buf, sizeof(buf)); } static int i2c_get_resp(unsigned char *buf, const size_t length) { int i, len = length; for (i = 0; i < len; ++i) { assert(len <= length); /* Paranoia */ if (!i2c_read_byte(&buf[i])) return 0; switch (i) { /* Special handling for certain positions in response */ case 0: if (buf[i] == SOR) /* Start of record (we hope) */ continue; fprintf(stderr, "Lost sync: expected 0x%02x (SOR), got 0x%02x\n", SOR, buf[0]); return 0; case 1: /* Response code */ switch (buf[i]) { case READ_OK: len = 9; continue; case WRITE_OK: len = 5; continue; case RESET_OK: len = 3; continue; case ERROR: case UNKNOWN: len = 4; continue; default: fprintf(stderr, "Lost sync: unknown response code 0x%02x\n", buf[i]); return 0; } } } if (debug) { fprintf(stderr, "read ["); for (i = 0; i < len; ++i) fprintf(stderr, " %02x", buf[i]); fprintf(stderr, " ]\n"); } return 1; } static int i2c_check_expected(const unsigned char buf[], const int i, const unsigned char expected) { if (buf[i] == expected) return 1; fprintf(stderr, "Response byte %d: expected 0x%02x, got 0x%02x\n", i, expected, buf[i]); return 0; } static int i2c_write(const unsigned char addr0, const unsigned char addr1, const unsigned char data[]) { unsigned char buf[5]; if (!i2c_send_write_cmd(addr0, addr1, data) || !i2c_get_resp(buf, sizeof(buf)) || !i2c_check_expected(buf, 0, SOR) || !i2c_check_expected(buf, 1, WRITE_OK) || !i2c_check_expected(buf, 2, addr0) || !i2c_check_expected(buf, 3, addr1) || !i2c_check_expected(buf, 4, EOR)) return 0; return 1; } static int i2c_read(const unsigned char addr0, const unsigned char addr1, unsigned char data[]) { unsigned char buf[9]; if (!i2c_send_read_cmd(addr0, addr1) || !i2c_get_resp(buf, sizeof(buf)) || !i2c_check_expected(buf, 0, SOR) || !i2c_check_expected(buf, 1, READ_OK) || !i2c_check_expected(buf, 2, addr0) || !i2c_check_expected(buf, 3, addr1) || !i2c_check_expected(buf, 8, EOR)) return 0; data[0] = buf[4]; data[1] = buf[5]; data[2] = buf[6]; data[3] = buf[7]; return 1; } static int i2c_ctrl(const unsigned char addr0, const unsigned char ctrl_cmd) { unsigned char data[4]; memset(data, 0, sizeof(data)); data[3] = ctrl_cmd; return i2c_write(addr0, ADDR_CTRL, data); } static int i2c_wait(const unsigned char addr0, const unsigned char status) { unsigned char buf[9]; do { if (!i2c_send_read_cmd(addr0, ADDR_STATUS)) return 0; if (!i2c_get_resp(buf, sizeof(buf))) return 0; if (buf[1] != READ_OK) return 0; } while ((buf[7] & status) != status); if (debug) fprintf(stderr, "[ Done waiting ]\n"); return 1; } static int i2c_wait_ready(const unsigned char addr0) { if (debug) fprintf(stderr, "[ Waiting for ready ]\n"); return i2c_wait(addr0, STATUS_READY_BIT); } static int i2c_wait_valid(const unsigned char addr0) { if (debug) fprintf(stderr, "[ Waiting for valid ]\n"); return i2c_wait(addr0, STATUS_VALID_BIT); } /**************************************************************************** * * * Random Numbers * * * ****************************************************************************/ /* * First attempt at reading random data from the Novena. * * In theory, we should wait for TRNG_VALID before reading random * data, but as long as this is running over I2C we're going to be so * slow that there's no point, and checking would just make us slower. */ #define WAIT_FOR_TRNG_VALID 0 static int readRandom(void *buffer, const int length) { unsigned char temp[4], *buf = buffer; int i, last; assert(isWritePtr(buffer, length)); REQUIRES_B(length >= 1 && length < MAX_INTLENGTH); for (i = 0; i < length; i += 4) { #if WAIT_FOR_TRNG_VALID if (!i2c_wait_valid(TRNG_PREFIX)) { fprintf(stderr, "[ i2c_wait_valid(TRNG_PREFIX) failed ]\n"); return 0; } do { if (!i2c_read(TRNG_PREFIX, TRNG_VALID, temp)) { fprintf(stderr, "[ i2c_read(TRNG_VALID) failed ]\n"); return 0; } } while (!temp[3]); if (!i2c_wait_valid(TRNG_PREFIX)) { fprintf(stderr, "[ i2c_wait_valid(TRNG_PREFIX) failed ]\n"); return 0; } #endif /* WAIT_FOR_TRNG_VALID */ last = (length - i) < 4; if (!i2c_read(TRNG_PREFIX, TRNG_DATA, (last ? temp : (buf + i)))) { fprintf(stderr, "[ i2c_read(TRNG_DATA) failed ]\n"); return 0; } if (last) { for (; i < length; i++) buf[i] = temp[i & i]; } } return 1; } /**************************************************************************** * * * Hardware External Interface * * * ****************************************************************************/ /* The capability information for this device */ static const CAPABILITY_INFO capabilities[] = { { CRYPT_ALGO_NONE }, { CRYPT_ALGO_NONE } }; /* Return the hardware capabilities list */ int hwGetCapabilities(const CAPABILITY_INFO **capabilityInfo, int *noCapabilities) { assert(isReadPtr(capabilityInfo, sizeof(CAPABILITY_INFO *))); assert(isWritePtr(noCapabilities, sizeof(int))); *capabilityInfo = capabilities; *noCapabilities = FAILSAFE_ARRAYSIZE(capabilities, CAPABILITY_INFO); return CRYPT_OK; } /* Get random data from the hardware. */ int hwGetRandom(void *buffer, const int length) { assert(isWritePtr(buffer, length)); REQUIRES(length >= 1 && length < MAX_INTLENGTH); if (readRandom(buffer, length)) return CRYPT_OK; else return CRYPT_ERROR_RANDOM; } /* * These "personality" methods are trivial stubs, as we do not yet * have any cores which do encyrption or signature. When we do, these * methods will need to be rewritten, and whoever does that rewriting * will definitely want to look at the detailed comments and template * code in device/hw_dummy.c. */ /* Look up an item held in the hardware */ int hwLookupItem(const void *keyID, const int keyIDlength, int *keyHandle) { assert(keyHandle != NULL); *keyHandle = CRYPT_ERROR; return CRYPT_ERROR_NOTFOUND; } /* Delete an item held in the hardware */ int hwDeleteItem(const int keyHandle) { return CRYPT_OK; } /* Initialise/zeroise the hardware */ int hwInitialise(void) { return CRYPT_OK; } #endif /* USE_HARDWARE */ /* * "Any programmer who fails to comply with the standard naming, formatting, * or commenting conventions should be shot. If it so happens that it is * inconvenient to shoot him, then he is to be politely requested to recode * his program in adherence to the above standard." * -- Michael Spier, Digital Equipment Corporation * * Local variables: * indent-tabs-mode: nil * End: */