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Diffstat (limited to 'arch/arm/cpu/tegra20-common/crypto.c')
| -rw-r--r-- | arch/arm/cpu/tegra20-common/crypto.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/arch/arm/cpu/tegra20-common/crypto.c b/arch/arm/cpu/tegra20-common/crypto.c new file mode 100644 index 000000000..5f0b240e2 --- /dev/null +++ b/arch/arm/cpu/tegra20-common/crypto.c @@ -0,0 +1,230 @@ +/* + * Copyright (c) 2011 The Chromium OS Authors. + * (C) Copyright 2010 - 2011 NVIDIA Corporation <www.nvidia.com> + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <common.h> +#include <asm/errno.h> +#include "crypto.h" +#include "aes.h" + +static u8 zero_key[16]; + +#define AES_CMAC_CONST_RB 0x87 /* from RFC 4493, Figure 2.2 */ + +enum security_op { + SECURITY_SIGN = 1 << 0, /* Sign the data */ + SECURITY_ENCRYPT = 1 << 1, /* Encrypt the data */ +}; + +static void debug_print_vector(char *name, u32 num_bytes, u8 *data) +{ + u32 i; + + debug("%s [%d] @0x%08x", name, num_bytes, (u32)data); + for (i = 0; i < num_bytes; i++) { + if (i % 16 == 0) + debug(" = "); + debug("%02x", data[i]); + if ((i+1) % 16 != 0) + debug(" "); + } + debug("\n"); +} + +/** + * Apply chain data to the destination using EOR + * + * Each array is of length AES_AES_KEY_LENGTH. + * + * \param cbc_chain_data Chain data + * \param src Source data + * \param dst Destination data, which is modified here + */ +static void apply_cbc_chain_data(u8 *cbc_chain_data, u8 *src, u8 *dst) +{ + int i; + + for (i = 0; i < 16; i++) + *dst++ = *src++ ^ *cbc_chain_data++; +} + +/** + * Encrypt some data with AES. + * + * \param key_schedule Expanded key to use + * \param src Source data to encrypt + * \param dst Destination buffer + * \param num_aes_blocks Number of AES blocks to encrypt + */ +static void encrypt_object(u8 *key_schedule, u8 *src, u8 *dst, + u32 num_aes_blocks) +{ + u8 tmp_data[AES_KEY_LENGTH]; + u8 *cbc_chain_data; + u32 i; + + cbc_chain_data = zero_key; /* Convenient array of 0's for IV */ + + for (i = 0; i < num_aes_blocks; i++) { + debug("encrypt_object: block %d of %d\n", i, num_aes_blocks); + debug_print_vector("AES Src", AES_KEY_LENGTH, src); + + /* Apply the chain data */ + apply_cbc_chain_data(cbc_chain_data, src, tmp_data); + debug_print_vector("AES Xor", AES_KEY_LENGTH, tmp_data); + + /* encrypt the AES block */ + aes_encrypt(tmp_data, key_schedule, dst); + debug_print_vector("AES Dst", AES_KEY_LENGTH, dst); + + /* Update pointers for next loop. */ + cbc_chain_data = dst; + src += AES_KEY_LENGTH; + dst += AES_KEY_LENGTH; + } +} + +/** + * Shift a vector left by one bit + * + * \param in Input vector + * \param out Output vector + * \param size Length of vector in bytes + */ +static void left_shift_vector(u8 *in, u8 *out, int size) +{ + int carry = 0; + int i; + + for (i = size - 1; i >= 0; i--) { + out[i] = (in[i] << 1) | carry; + carry = in[i] >> 7; /* get most significant bit */ + } +} + +/** + * Sign a block of data, putting the result into dst. + * + * \param key Input AES key, length AES_KEY_LENGTH + * \param key_schedule Expanded key to use + * \param src Source data of length 'num_aes_blocks' blocks + * \param dst Destination buffer, length AES_KEY_LENGTH + * \param num_aes_blocks Number of AES blocks to encrypt + */ +static void sign_object(u8 *key, u8 *key_schedule, u8 *src, u8 *dst, + u32 num_aes_blocks) +{ + u8 tmp_data[AES_KEY_LENGTH]; + u8 left[AES_KEY_LENGTH]; + u8 k1[AES_KEY_LENGTH]; + u8 *cbc_chain_data; + unsigned i; + + cbc_chain_data = zero_key; /* Convenient array of 0's for IV */ + + /* compute K1 constant needed by AES-CMAC calculation */ + for (i = 0; i < AES_KEY_LENGTH; i++) + tmp_data[i] = 0; + + encrypt_object(key_schedule, tmp_data, left, 1); + debug_print_vector("AES(key, nonce)", AES_KEY_LENGTH, left); + + left_shift_vector(left, k1, sizeof(left)); + debug_print_vector("L", AES_KEY_LENGTH, left); + + if ((left[0] >> 7) != 0) /* get MSB of L */ + k1[AES_KEY_LENGTH-1] ^= AES_CMAC_CONST_RB; + debug_print_vector("K1", AES_KEY_LENGTH, k1); + + /* compute the AES-CMAC value */ + for (i = 0; i < num_aes_blocks; i++) { + /* Apply the chain data */ + apply_cbc_chain_data(cbc_chain_data, src, tmp_data); + + /* for the final block, XOR K1 into the IV */ + if (i == num_aes_blocks - 1) + apply_cbc_chain_data(tmp_data, k1, tmp_data); + + /* encrypt the AES block */ + aes_encrypt(tmp_data, key_schedule, dst); + + debug("sign_obj: block %d of %d\n", i, num_aes_blocks); + debug_print_vector("AES-CMAC Src", AES_KEY_LENGTH, src); + debug_print_vector("AES-CMAC Xor", AES_KEY_LENGTH, tmp_data); + debug_print_vector("AES-CMAC Dst", AES_KEY_LENGTH, dst); + + /* Update pointers for next loop. */ + cbc_chain_data = dst; + src += AES_KEY_LENGTH; + } + + debug_print_vector("AES-CMAC Hash", AES_KEY_LENGTH, dst); +} + +/** + * Encrypt and sign a block of data (depending on security mode). + * + * \param key Input AES key, length AES_KEY_LENGTH + * \param oper Security operations mask to perform (enum security_op) + * \param src Source data + * \param length Size of source data + * \param sig_dst Destination address for signature, AES_KEY_LENGTH bytes + */ +static int encrypt_and_sign(u8 *key, enum security_op oper, u8 *src, + u32 length, u8 *sig_dst) +{ + u32 num_aes_blocks; + u8 key_schedule[AES_EXPAND_KEY_LENGTH]; + + debug("encrypt_and_sign: length = %d\n", length); + debug_print_vector("AES key", AES_KEY_LENGTH, key); + + /* + * The only need for a key is for signing/checksum purposes, so + * if not encrypting, expand a key of 0s. + */ + aes_expand_key(oper & SECURITY_ENCRYPT ? key : zero_key, key_schedule); + + num_aes_blocks = (length + AES_KEY_LENGTH - 1) / AES_KEY_LENGTH; + + if (oper & SECURITY_ENCRYPT) { + /* Perform this in place, resulting in src being encrypted. */ + debug("encrypt_and_sign: begin encryption\n"); + encrypt_object(key_schedule, src, src, num_aes_blocks); + debug("encrypt_and_sign: end encryption\n"); + } + + if (oper & SECURITY_SIGN) { + /* encrypt the data, overwriting the result in signature. */ + debug("encrypt_and_sign: begin signing\n"); + sign_object(key, key_schedule, src, sig_dst, num_aes_blocks); + debug("encrypt_and_sign: end signing\n"); + } + + return 0; +} + +int sign_data_block(u8 *source, unsigned length, u8 *signature) +{ + return encrypt_and_sign(zero_key, SECURITY_SIGN, source, + length, signature); +} |