core/platform/novena - Platform-specific files for the Novena PVT1

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Diffstat (limited to 'i2c/iseconfig/novena_i2c.xise')

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/* * aes_keywrap.c * ------------- * Implementation of RFC 5649 over Cryptech AES core. * * Authors: Rob Austein * Copyright (c) 2015, 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. */ /* * Note that there are two different block sizes involved here: the * key wrap algorithm deals entirely with 64-bit blocks, while AES * itself deals with 128-bit blocks. In practice, this is not as * confusing as it sounds, because we combine two 64-bit blocks to * create one 128-bit block just prior to performing an AES operation, * then split the result back to 64-bit blocks immediately afterwards. */ #include <stdio.h> #include <stdlib.h> #include <stdint.h> #include <string.h> #include <assert.h> #include "cryptech.h" /* * How long the ciphertext will be for a given plaintext length. */ size_t hal_aes_keywrap_ciphertext_length(const size_t plaintext_length) { return (plaintext_length + 15) & ~7; } /* * Check the KEK, then load it into the AES core. * Note that our AES core only supports 128 and 256 bit keys. */ typedef enum { KEK_encrypting, KEK_decrypting } kek_action_t; static hal_error_t load_kek(const uint8_t *K, const size_t K_len, const kek_action_t action) { uint8_t config[4]; hal_error_t err; if (K == NULL) return HAL_ERROR_BAD_ARGUMENTS; memset(config, 0, sizeof(config)); switch (K_len) { case bitsToBytes(128): config[3] &= ~AES_CONFIG_KEYLEN; break; case bitsToBytes(256): config[3] |= AES_CONFIG_KEYLEN; break; case bitsToBytes(192): return HAL_ERROR_UNSUPPORTED_KEY; default: return HAL_ERROR_BAD_ARGUMENTS; } switch (action) { case KEK_encrypting: config[3] |= AES_CONFIG_ENCDEC; break; case KEK_decrypting: config[3] &= ~AES_CONFIG_ENCDEC; break; default: return HAL_ERROR_BAD_ARGUMENTS; } /* * Load the KEK and tell the core to expand it. */ if ((err = hal_io_write(AES_ADDR_KEY0, K, K_len)) != HAL_OK || (err = hal_io_write(AES_ADDR_CONFIG, config, sizeof(config))) != HAL_OK || (err = hal_io_init(AES_ADDR_CTRL)) != HAL_OK) return err; return HAL_OK; } /* * Process one block. Since AES Key Wrap always deals with 64-bit * half blocks and since the bus is going to break this up into 32-bit * words no matter what we do, we can eliminate a few gratuitous * memcpy() operations by receiving our arguments as two half blocks. * * Since the length of these half blocks is constant, there's no real * point in passing the length as an argument, we'd just be checking a * constant against a constant and a smart compiler will optimize * the whole check out. * * Just be VERY careful if you change anything here. */ static hal_error_t do_block(uint8_t *b1, uint8_t *b2) { hal_error_t err; assert(b1 != NULL && b2 != NULL); if ((err = hal_io_write(AES_ADDR_BLOCK0, b1, 8)) != HAL_OK || (err = hal_io_write(AES_ADDR_BLOCK2, b2, 8)) != HAL_OK || (err = hal_io_next(AES_ADDR_CTRL)) != HAL_OK || (err = hal_io_wait_ready(AES_ADDR_STATUS)) != HAL_OK || (err = hal_io_read(AES_ADDR_RESULT0, b1, 8)) != HAL_OK || (err = hal_io_read(AES_ADDR_RESULT2, b2, 8)) != HAL_OK) return err; return HAL_OK; } /* * Wrap plaintext Q using KEK K, placing result in C. * * Q and C can overlap. For encrypt-in-place, use Q = C + 8 (that is, * leave 8 empty bytes before the plaintext). * * Use hal_aes_keywrap_ciphertext_length() to calculate the correct * buffer size. */ hal_error_t hal_aes_keywrap(const uint8_t *K, const size_t K_len, const uint8_t * const Q, const size_t m, uint8_t *C, size_t *C_len) { const size_t calculated_C_len = hal_aes_keywrap_ciphertext_length(m); hal_error_t err; uint32_t n; long i, j; assert(calculated_C_len % 8 == 0); if (Q == NULL || C == NULL || C_len == NULL || *C_len < calculated_C_len) return HAL_ERROR_BAD_ARGUMENTS; if ((err = load_kek(K, K_len, KEK_encrypting)) != HAL_OK) return err; *C_len = calculated_C_len; if (C + 8 != Q) memmove(C + 8, Q, m); if (m % 8 != 0) memset(C + 8 + m, 0, 8 - (m % 8)); C[0] = 0xA6; C[1] = 0x59; C[2] = 0x59; C[3] = 0xA6; C[4] = (m >> 24) & 0xFF; C[5] = (m >> 16) & 0xFF; C[6] = (m >> 8) & 0xFF; C[7] = (m >> 0) & 0xFF; n = calculated_C_len/8 - 1; if (n == 1) { if ((err = do_block(C, C + 8)) != HAL_OK) return err; } else { for (j = 0; j <= 5; j++) { for (i = 1; i <= n; i++) { uint32_t t = n * j + i; if ((err = do_block(C, C + i * 8)) != HAL_OK) return err; C[7] ^= t & 0xFF; t >>= 8; C[6] ^= t & 0xFF; t >>= 8; C[5] ^= t & 0xFF; t >>= 8; C[4] ^= t & 0xFF; } } } return HAL_OK; } /* * Unwrap ciphertext C using KEK K, placing result in Q. * * Q should be the same size as C. Q and C can overlap. */ hal_error_t hal_aes_keyunwrap(const uint8_t *K, const size_t K_len, const uint8_t * const C, const size_t C_len, uint8_t *Q, size_t *Q_len) { hal_error_t err; uint32_t n; long i, j; size_t m; if (C == NULL || Q == NULL || C_len % 8 != 0 || C_len < 16 || Q_len == NULL || *Q_len < C_len) return HAL_ERROR_BAD_ARGUMENTS; if ((err = load_kek(K, K_len, KEK_decrypting)) != HAL_OK) return err; n = (C_len / 8) - 1; if (Q != C) memmove(Q, C, C_len); if (n == 1) { if ((err = do_block(Q, Q + 8)) != HAL_OK) return err; } else { for (j = 5; j >= 0; j--) { for (i = n; i >= 1; i--) { uint32_t t = n * j + i; Q[7] ^= t & 0xFF; t >>= 8; Q[6] ^= t & 0xFF; t >>= 8; Q[5] ^= t & 0xFF; t >>= 8; Q[4] ^= t & 0xFF; if ((err = do_block(Q, Q + i * 8)) != HAL_OK) return err; } } } if (Q[0] != 0xA6 || Q[1] != 0x59 || Q[2] != 0x59 || Q[3] != 0xA6) return HAL_ERROR_KEYWRAP_BAD_MAGIC; m = (((((Q[4] << 8) + Q[5]) << 8) + Q[6]) << 8) + Q[7]; if (m <= 8 * (n - 1) || m > 8 * n) return HAL_ERROR_KEYWRAP_BAD_LENGTH; if (m % 8 != 0) for (i = m + 8; i < 8 * (n + 1); i++) if (Q[i] != 0x00) return HAL_ERROR_KEYWRAP_BAD_PADDING; *Q_len = m; memmove(Q, Q + 8, m); return HAL_OK; } /* * "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: */


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