#define _MSB(x) (((x)[0] & 0x80)?1:0)
-static inline void aes_cmac_128_left_shift_1(const uint8_t in[AES_BLOCK_SIZE],
- uint8_t out[AES_BLOCK_SIZE])
-{
- uint8_t overflow = 0;
- int8_t i;
-
- for (i = AES_BLOCK_SIZE - 1; i >= 0; i--) {
- out[i] = in[i] << 1;
-
- out[i] |= overflow;
-
- overflow = _MSB(&in[i]);
- }
-}
-
-static inline void aes_cmac_128_xor(const uint8_t in1[AES_BLOCK_SIZE],
- const uint8_t in2[AES_BLOCK_SIZE],
- uint8_t out[AES_BLOCK_SIZE])
-{
- uint8_t i;
-
- for (i = 0; i < AES_BLOCK_SIZE; i++) {
- out[i] = in1[i] ^ in2[i];
- }
-}
-
void aes_cmac_128_init(struct aes_cmac_128_context *ctx,
const uint8_t K[AES_BLOCK_SIZE])
{
- uint8_t L[AES_BLOCK_SIZE];
-
ZERO_STRUCTP(ctx);
AES_set_encrypt_key(K, 128, &ctx->aes_key);
/* step 1 - generate subkeys k1 and k2 */
- AES_encrypt(const_Zero, L, &ctx->aes_key);
+ AES_encrypt(const_Zero, ctx->L, &ctx->aes_key);
- if (_MSB(L) == 0) {
- aes_cmac_128_left_shift_1(L, ctx->K1);
+ if (_MSB(ctx->L) == 0) {
+ aes_block_lshift(ctx->L, ctx->K1);
} else {
- uint8_t tmp_block[AES_BLOCK_SIZE];
-
- aes_cmac_128_left_shift_1(L, tmp_block);
- aes_cmac_128_xor(tmp_block, const_Rb, ctx->K1);
- ZERO_STRUCT(tmp_block);
+ aes_block_lshift(ctx->L, ctx->tmp);
+ aes_block_xor(ctx->tmp, const_Rb, ctx->K1);
}
if (_MSB(ctx->K1) == 0) {
- aes_cmac_128_left_shift_1(ctx->K1, ctx->K2);
+ aes_block_lshift(ctx->K1, ctx->K2);
} else {
- uint8_t tmp_block[AES_BLOCK_SIZE];
-
- aes_cmac_128_left_shift_1(ctx->K1, tmp_block);
- aes_cmac_128_xor(tmp_block, const_Rb, ctx->K2);
- ZERO_STRUCT(tmp_block);
+ aes_block_lshift(ctx->K1, ctx->tmp);
+ aes_block_xor(ctx->tmp, const_Rb, ctx->K2);
}
-
- ZERO_STRUCT(L);
}
void aes_cmac_128_update(struct aes_cmac_128_context *ctx,
- const uint8_t *_msg, size_t _msg_len)
+ const uint8_t *msg, size_t msg_len)
{
- uint8_t tmp_block[AES_BLOCK_SIZE];
- uint8_t Y[AES_BLOCK_SIZE];
- const uint8_t *msg = _msg;
- size_t msg_len = _msg_len;
-
- /*
- * copy the remembered last block
- */
- ZERO_STRUCT(tmp_block);
- if (ctx->last_len) {
- memcpy(tmp_block, ctx->last, ctx->last_len);
- }
-
/*
* check if we expand the block
*/
if (ctx->last_len < AES_BLOCK_SIZE) {
size_t len = MIN(AES_BLOCK_SIZE - ctx->last_len, msg_len);
- memcpy(&tmp_block[ctx->last_len], msg, len);
- memcpy(ctx->last, tmp_block, AES_BLOCK_SIZE);
+ memcpy(&ctx->last[ctx->last_len], msg, len);
msg += len;
msg_len -= len;
ctx->last_len += len;
if (msg_len == 0) {
/* if it is still the last block, we are done */
- ZERO_STRUCT(tmp_block);
return;
}
- /*
- * It is not the last block anymore
- */
- ZERO_STRUCT(ctx->last);
- ctx->last_len = 0;
-
/*
* now checksum everything but the last block
*/
- aes_cmac_128_xor(ctx->X, tmp_block, Y);
- AES_encrypt(Y, ctx->X, &ctx->aes_key);
+ aes_block_xor(ctx->X, ctx->last, ctx->Y);
+ AES_encrypt(ctx->Y, ctx->X, &ctx->aes_key);
while (msg_len > AES_BLOCK_SIZE) {
- memcpy(tmp_block, msg, AES_BLOCK_SIZE);
+ aes_block_xor(ctx->X, msg, ctx->Y);
+ AES_encrypt(ctx->Y, ctx->X, &ctx->aes_key);
msg += AES_BLOCK_SIZE;
msg_len -= AES_BLOCK_SIZE;
-
- aes_cmac_128_xor(ctx->X, tmp_block, Y);
- AES_encrypt(Y, ctx->X, &ctx->aes_key);
}
/*
* copy the last block, it will be processed in
* aes_cmac_128_final().
*/
+ ZERO_STRUCT(ctx->last);
memcpy(ctx->last, msg, msg_len);
ctx->last_len = msg_len;
-
- ZERO_STRUCT(tmp_block);
- ZERO_STRUCT(Y);
}
void aes_cmac_128_final(struct aes_cmac_128_context *ctx,
uint8_t T[AES_BLOCK_SIZE])
{
- uint8_t tmp_block[AES_BLOCK_SIZE];
- uint8_t Y[AES_BLOCK_SIZE];
-
if (ctx->last_len < AES_BLOCK_SIZE) {
ctx->last[ctx->last_len] = 0x80;
- aes_cmac_128_xor(ctx->last, ctx->K2, tmp_block);
+ aes_block_xor(ctx->last, ctx->K2, ctx->tmp);
} else {
- aes_cmac_128_xor(ctx->last, ctx->K1, tmp_block);
+ aes_block_xor(ctx->last, ctx->K1, ctx->tmp);
}
- aes_cmac_128_xor(tmp_block, ctx->X, Y);
- AES_encrypt(Y, T, &ctx->aes_key);
+ aes_block_xor(ctx->tmp, ctx->X, ctx->Y);
+ AES_encrypt(ctx->Y, T, &ctx->aes_key);
- ZERO_STRUCT(tmp_block);
- ZERO_STRUCT(Y);
ZERO_STRUCTP(ctx);
}