234 lines
6.8 KiB
C
234 lines
6.8 KiB
C
/*
|
|
* Copyright 2010-2020 The OpenSSL Project Authors. All Rights Reserved.
|
|
*
|
|
* Licensed under the OpenSSL license (the "License"). You may not use
|
|
* this file except in compliance with the License. You can obtain a copy
|
|
* in the file LICENSE in the source distribution or at
|
|
* https://www.openssl.org/source/license.html
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include "internal/cryptlib.h"
|
|
#include <openssl/cmac.h>
|
|
#include <openssl/err.h>
|
|
|
|
struct CMAC_CTX_st {
|
|
/* Cipher context to use */
|
|
EVP_CIPHER_CTX *cctx;
|
|
/* Keys k1 and k2 */
|
|
unsigned char k1[EVP_MAX_BLOCK_LENGTH];
|
|
unsigned char k2[EVP_MAX_BLOCK_LENGTH];
|
|
/* Temporary block */
|
|
unsigned char tbl[EVP_MAX_BLOCK_LENGTH];
|
|
/* Last (possibly partial) block */
|
|
unsigned char last_block[EVP_MAX_BLOCK_LENGTH];
|
|
/* Number of bytes in last block: -1 means context not initialised */
|
|
int nlast_block;
|
|
};
|
|
|
|
/* Make temporary keys K1 and K2 */
|
|
|
|
static void make_kn(unsigned char *k1, const unsigned char *l, int bl)
|
|
{
|
|
int i;
|
|
unsigned char c = l[0], carry = c >> 7, cnext;
|
|
|
|
/* Shift block to left, including carry */
|
|
for (i = 0; i < bl - 1; i++, c = cnext)
|
|
k1[i] = (c << 1) | ((cnext = l[i + 1]) >> 7);
|
|
|
|
/* If MSB set fixup with R */
|
|
k1[i] = (c << 1) ^ ((0 - carry) & (bl == 16 ? 0x87 : 0x1b));
|
|
}
|
|
|
|
CMAC_CTX *CMAC_CTX_new(void)
|
|
{
|
|
CMAC_CTX *ctx;
|
|
|
|
if ((ctx = OPENSSL_malloc(sizeof(*ctx))) == NULL) {
|
|
CRYPTOerr(CRYPTO_F_CMAC_CTX_NEW, ERR_R_MALLOC_FAILURE);
|
|
return NULL;
|
|
}
|
|
ctx->cctx = EVP_CIPHER_CTX_new();
|
|
if (ctx->cctx == NULL) {
|
|
OPENSSL_free(ctx);
|
|
return NULL;
|
|
}
|
|
ctx->nlast_block = -1;
|
|
return ctx;
|
|
}
|
|
|
|
void CMAC_CTX_cleanup(CMAC_CTX *ctx)
|
|
{
|
|
EVP_CIPHER_CTX_reset(ctx->cctx);
|
|
OPENSSL_cleanse(ctx->tbl, EVP_MAX_BLOCK_LENGTH);
|
|
OPENSSL_cleanse(ctx->k1, EVP_MAX_BLOCK_LENGTH);
|
|
OPENSSL_cleanse(ctx->k2, EVP_MAX_BLOCK_LENGTH);
|
|
OPENSSL_cleanse(ctx->last_block, EVP_MAX_BLOCK_LENGTH);
|
|
ctx->nlast_block = -1;
|
|
}
|
|
|
|
EVP_CIPHER_CTX *CMAC_CTX_get0_cipher_ctx(CMAC_CTX *ctx)
|
|
{
|
|
return ctx->cctx;
|
|
}
|
|
|
|
void CMAC_CTX_free(CMAC_CTX *ctx)
|
|
{
|
|
if (!ctx)
|
|
return;
|
|
CMAC_CTX_cleanup(ctx);
|
|
EVP_CIPHER_CTX_free(ctx->cctx);
|
|
OPENSSL_free(ctx);
|
|
}
|
|
|
|
int CMAC_CTX_copy(CMAC_CTX *out, const CMAC_CTX *in)
|
|
{
|
|
int bl;
|
|
if (in->nlast_block == -1)
|
|
return 0;
|
|
if (!EVP_CIPHER_CTX_copy(out->cctx, in->cctx))
|
|
return 0;
|
|
bl = EVP_CIPHER_CTX_block_size(in->cctx);
|
|
memcpy(out->k1, in->k1, bl);
|
|
memcpy(out->k2, in->k2, bl);
|
|
memcpy(out->tbl, in->tbl, bl);
|
|
memcpy(out->last_block, in->last_block, bl);
|
|
out->nlast_block = in->nlast_block;
|
|
return 1;
|
|
}
|
|
|
|
int CMAC_Init(CMAC_CTX *ctx, const void *key, size_t keylen,
|
|
const EVP_CIPHER *cipher, ENGINE *impl)
|
|
{
|
|
static const unsigned char zero_iv[EVP_MAX_BLOCK_LENGTH] = { 0 };
|
|
/* All zeros means restart */
|
|
if (!key && !cipher && !impl && keylen == 0) {
|
|
/* Not initialised */
|
|
if (ctx->nlast_block == -1)
|
|
return 0;
|
|
if (!EVP_EncryptInit_ex(ctx->cctx, NULL, NULL, NULL, zero_iv))
|
|
return 0;
|
|
memset(ctx->tbl, 0, EVP_CIPHER_CTX_block_size(ctx->cctx));
|
|
ctx->nlast_block = 0;
|
|
return 1;
|
|
}
|
|
/* Initialise context */
|
|
if (cipher != NULL) {
|
|
/* Ensure we can't use this ctx until we also have a key */
|
|
ctx->nlast_block = -1;
|
|
if (!EVP_EncryptInit_ex(ctx->cctx, cipher, impl, NULL, NULL))
|
|
return 0;
|
|
}
|
|
/* Non-NULL key means initialisation complete */
|
|
if (key != NULL) {
|
|
int bl;
|
|
|
|
/* If anything fails then ensure we can't use this ctx */
|
|
ctx->nlast_block = -1;
|
|
if (!EVP_CIPHER_CTX_cipher(ctx->cctx))
|
|
return 0;
|
|
if (!EVP_CIPHER_CTX_set_key_length(ctx->cctx, keylen))
|
|
return 0;
|
|
if (!EVP_EncryptInit_ex(ctx->cctx, NULL, NULL, key, zero_iv))
|
|
return 0;
|
|
bl = EVP_CIPHER_CTX_block_size(ctx->cctx);
|
|
if (EVP_Cipher(ctx->cctx, ctx->tbl, zero_iv, bl) <= 0)
|
|
return 0;
|
|
make_kn(ctx->k1, ctx->tbl, bl);
|
|
make_kn(ctx->k2, ctx->k1, bl);
|
|
OPENSSL_cleanse(ctx->tbl, bl);
|
|
/* Reset context again ready for first data block */
|
|
if (!EVP_EncryptInit_ex(ctx->cctx, NULL, NULL, NULL, zero_iv))
|
|
return 0;
|
|
/* Zero tbl so resume works */
|
|
memset(ctx->tbl, 0, bl);
|
|
ctx->nlast_block = 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
int CMAC_Update(CMAC_CTX *ctx, const void *in, size_t dlen)
|
|
{
|
|
const unsigned char *data = in;
|
|
size_t bl;
|
|
if (ctx->nlast_block == -1)
|
|
return 0;
|
|
if (dlen == 0)
|
|
return 1;
|
|
bl = EVP_CIPHER_CTX_block_size(ctx->cctx);
|
|
/* Copy into partial block if we need to */
|
|
if (ctx->nlast_block > 0) {
|
|
size_t nleft;
|
|
nleft = bl - ctx->nlast_block;
|
|
if (dlen < nleft)
|
|
nleft = dlen;
|
|
memcpy(ctx->last_block + ctx->nlast_block, data, nleft);
|
|
dlen -= nleft;
|
|
ctx->nlast_block += nleft;
|
|
/* If no more to process return */
|
|
if (dlen == 0)
|
|
return 1;
|
|
data += nleft;
|
|
/* Else not final block so encrypt it */
|
|
if (EVP_Cipher(ctx->cctx, ctx->tbl, ctx->last_block, bl) <= 0)
|
|
return 0;
|
|
}
|
|
/* Encrypt all but one of the complete blocks left */
|
|
while (dlen > bl) {
|
|
if (EVP_Cipher(ctx->cctx, ctx->tbl, data, bl) <= 0)
|
|
return 0;
|
|
dlen -= bl;
|
|
data += bl;
|
|
}
|
|
/* Copy any data left to last block buffer */
|
|
memcpy(ctx->last_block, data, dlen);
|
|
ctx->nlast_block = dlen;
|
|
return 1;
|
|
|
|
}
|
|
|
|
int CMAC_Final(CMAC_CTX *ctx, unsigned char *out, size_t *poutlen)
|
|
{
|
|
int i, bl, lb;
|
|
if (ctx->nlast_block == -1)
|
|
return 0;
|
|
bl = EVP_CIPHER_CTX_block_size(ctx->cctx);
|
|
*poutlen = (size_t)bl;
|
|
if (!out)
|
|
return 1;
|
|
lb = ctx->nlast_block;
|
|
/* Is last block complete? */
|
|
if (lb == bl) {
|
|
for (i = 0; i < bl; i++)
|
|
out[i] = ctx->last_block[i] ^ ctx->k1[i];
|
|
} else {
|
|
ctx->last_block[lb] = 0x80;
|
|
if (bl - lb > 1)
|
|
memset(ctx->last_block + lb + 1, 0, bl - lb - 1);
|
|
for (i = 0; i < bl; i++)
|
|
out[i] = ctx->last_block[i] ^ ctx->k2[i];
|
|
}
|
|
if (!EVP_Cipher(ctx->cctx, out, out, bl)) {
|
|
OPENSSL_cleanse(out, bl);
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
int CMAC_resume(CMAC_CTX *ctx)
|
|
{
|
|
if (ctx->nlast_block == -1)
|
|
return 0;
|
|
/*
|
|
* The buffer "tbl" contains the last fully encrypted block which is the
|
|
* last IV (or all zeroes if no last encrypted block). The last block has
|
|
* not been modified since CMAC_final(). So reinitialising using the last
|
|
* decrypted block will allow CMAC to continue after calling
|
|
* CMAC_Final().
|
|
*/
|
|
return EVP_EncryptInit_ex(ctx->cctx, NULL, NULL, NULL, ctx->tbl);
|
|
}
|