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/* Copyright 2015 The ChromiumOS Authors
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "internal.h"
#include "dcrypto_regs.h"
/**
* Define KEYMGR AES access structure.
*/
static volatile struct keymgr_aes *reg_aes = (void *)(GC_KEYMGR_BASE_ADDR);
static void set_control_register(enum cipher_mode mode, uint32_t key_size,
enum encrypt_mode encrypt)
{
/* Make sure we don't use key coming from keyladder. */
reg_aes->use_hidden_key = GC_KEYMGR_AES_USE_HIDDEN_KEY_ENABLE_DEFAULT;
/* Bring AES engine FIFO into known state. */
reg_aes->ctrl = GC_KEYMGR_AES_CTRL_RESET_MASK;
reg_aes->ctrl =
(CTRL_NO_SOFT_RESET << GC_KEYMGR_AES_CTRL_RESET_LSB) |
(key_size << GC_KEYMGR_AES_CTRL_KEYSIZE_LSB) |
(mode << GC_KEYMGR_AES_CTRL_CIPHER_MODE_LSB) |
(encrypt << GC_KEYMGR_AES_CTRL_ENC_MODE_LSB) |
(CTRL_CTR_BIG_ENDIAN << GC_KEYMGR_AES_CTRL_CTR_ENDIAN_LSB) |
(CTRL_ENABLE << GC_KEYMGR_AES_CTRL_ENABLE_LSB);
/* Turn off random nops (which are enabled by default). */
reg_aes->rand_stall = 0;
/* Configure random nop percentage at 25%, turn on random nops. */
reg_aes->rand_stall = (1 << GC_KEYMGR_AES_RAND_STALL_CTL_FREQ_LSB) |
GC_KEYMGR_AES_RAND_STALL_CTL_STALL_EN_MASK;
}
static int wait_read_data(volatile uint32_t *addr)
{
int empty;
int count = 20; /* Wait these many ~cycles. */
do {
empty = REG32(addr);
count--;
} while (count && empty);
return empty ? 0 : 1;
}
enum dcrypto_result dcrypto_aes_init(const uint8_t *key, size_t key_len,
const uint8_t *iv, enum cipher_mode c_mode,
enum encrypt_mode e_mode)
{
size_t i;
const struct access_helper *p;
uint32_t key_mode;
switch (key_len) {
case 128:
key_mode = 0;
break;
case 192:
key_mode = 1;
break;
case 256:
key_mode = 2;
break;
default:
/* Invalid key length specified. */
return DCRYPTO_FAIL;
}
switch (c_mode) {
case CIPHER_MODE_ECB:
case CIPHER_MODE_CTR:
case CIPHER_MODE_CBC:
set_control_register(c_mode, key_mode, e_mode);
break;
default:
/* Invalid mode specified. */
return DCRYPTO_FAIL;
}
/* Initialize hardware with AES key */
p = (struct access_helper *) key;
for (i = 0; i < (key_len >> 5); i++)
reg_aes->key[i] = p[i].udata;
/* Trigger key expansion. */
reg_aes->key_start = 1;
/* Wait for key expansion. */
if (!wait_read_data(®_aes->key_start)) {
/* Should not happen. */
return DCRYPTO_FAIL;
}
/* Initialize IV for modes that require it. */
if (iv)
DCRYPTO_aes_write_iv(iv);
return DCRYPTO_OK;
}
enum dcrypto_result DCRYPTO_aes_init(const uint8_t *key, size_t key_len,
const uint8_t *iv, enum cipher_mode c_mode,
enum encrypt_mode e_mode)
{
if (!fips_crypto_allowed())
return DCRYPTO_FAIL;
return dcrypto_aes_init(key, key_len, iv, c_mode, e_mode);
}
enum dcrypto_result DCRYPTO_aes_block(const uint8_t *in, uint8_t *out)
{
uint32_t buf[4];
const uint32_t *inw;
uint32_t *outw, *outw2;
if (is_not_aligned(in)) {
memcpy(buf, in, sizeof(buf));
inw = buf;
} else
inw = (const uint32_t *)in;
if (is_not_aligned(out))
outw = buf;
else
outw = (uint32_t *)out;
outw2 = outw;
dcrypto_aes_process(&outw, &inw, 16);
if (out != (uint8_t *)outw2)
memcpy(out, outw2, sizeof(buf));
return DCRYPTO_OK;
}
void DCRYPTO_aes_write_iv(const uint8_t *iv)
{
int i;
uint32_t buf[4];
const uint32_t *ivw;
if (is_not_aligned(iv)) {
memcpy(buf, iv, sizeof(buf));
ivw = buf;
} else
ivw = (uint32_t *)iv;
for (i = 0; i < 4; i++)
reg_aes->counter[i] = ivw[i];
}
void DCRYPTO_aes_read_iv(uint8_t *iv)
{
int i;
uint32_t buf[4];
uint32_t *ivw;
if (is_not_aligned(iv))
ivw = buf;
else
ivw = (uint32_t *)iv;
for (i = 0; i < 4; i++)
ivw[i] = reg_aes->counter[i];
if (iv != (uint8_t *)ivw)
memcpy(iv, ivw, sizeof(buf));
}
enum dcrypto_result DCRYPTO_aes_ctr(uint8_t *out, const uint8_t *key,
uint32_t key_bits, const uint8_t *iv,
const uint8_t *in, size_t in_len)
{
/* Initialize AES hardware. */
if (DCRYPTO_aes_init(key, key_bits, iv, CIPHER_MODE_CTR,
ENCRYPT_MODE) != DCRYPTO_OK)
return DCRYPTO_FAIL;
while (in_len > 0) {
uint32_t tmpin[4];
uint32_t tmpout[4];
const uint8_t *inp;
uint8_t *outp;
const size_t count = MIN(in_len, 16U);
if (count < 16) {
memcpy(tmpin, in, count);
inp = (uint8_t *)tmpin;
outp = (uint8_t *)tmpout;
} else {
inp = in;
outp = out;
}
if (DCRYPTO_aes_block(inp, outp) != DCRYPTO_OK)
return DCRYPTO_FAIL;
if (outp != out)
memcpy(out, outp, count);
in += count;
out += count;
in_len -= count;
}
return DCRYPTO_OK;
}
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