diff options
Diffstat (limited to 'lib/nettle/backport/cmac.c')
| -rw-r--r-- | lib/nettle/backport/cmac.c | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/lib/nettle/backport/cmac.c b/lib/nettle/backport/cmac.c new file mode 100644 index 0000000000..481e5c080d --- /dev/null +++ b/lib/nettle/backport/cmac.c @@ -0,0 +1,213 @@ +/* backport of cmac*.c for CMAC + + AES-CMAC-128 (rfc 4493) + Copyright (C) Stefan Metzmacher 2012 + Copyright (C) Jeremy Allison 2012 + Copyright (C) Michael Adam 2012 + Copyright (C) 2017, Red Hat Inc. + + This file is part of GNU Nettle. + + GNU Nettle is free software: you can redistribute it and/or + modify it under the terms of either: + + * the GNU Lesser General Public License as published by the Free + Software Foundation; either version 3 of the License, or (at your + option) any later version. + + or + + * 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. + + or both in parallel, as here. + + GNU Nettle 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 copies of the GNU General Public License and + the GNU Lesser General Public License along with this program. If + not, see http://www.gnu.org/licenses/. +*/ + +/* ############################################# + * THIS IS A BACKPORT FROM NETTLE, DO NOT MODIFY + * ############################################# + */ + +#ifndef HAVE_NETTLE_CMAC128_UPDATE + +#include <nettle/aes.h> +#include "cmac.h" +#include <assert.h> +#include <stdlib.h> +#include <string.h> + +#include <nettle/memxor.h> +#include <nettle/macros.h> + +/* shift one and XOR with 0x87. */ +static void +block_mulx(union nettle_block16 *dst, + const union nettle_block16 *src) +{ + uint64_t b1 = READ_UINT64(src->b); + uint64_t b2 = READ_UINT64(src->b+8); + + b1 = (b1 << 1) | (b2 >> 63); + b2 <<= 1; + + if (src->b[0] & 0x80) + b2 ^= 0x87; + + WRITE_UINT64(dst->b, b1); + WRITE_UINT64(dst->b+8, b2); +} + +void +cmac128_set_key(struct cmac128_ctx *ctx, const void *cipher, + nettle_cipher_func *encrypt) +{ + static const uint8_t const_zero[] = { + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 + }; + union nettle_block16 *L = &ctx->block; + memset(ctx, 0, sizeof(*ctx)); + + /* step 1 - generate subkeys k1 and k2 */ + encrypt(cipher, 16, L->b, const_zero); + + block_mulx(&ctx->K1, L); + block_mulx(&ctx->K2, &ctx->K1); +} + +#define MIN(x,y) ((x)<(y)?(x):(y)) + +void +cmac128_update(struct cmac128_ctx *ctx, const void *cipher, + nettle_cipher_func *encrypt, + size_t msg_len, const uint8_t *msg) +{ + union nettle_block16 Y; + /* + * check if we expand the block + */ + if (ctx->index < 16) + { + size_t len = MIN(16 - ctx->index, msg_len); + memcpy(&ctx->block.b[ctx->index], msg, len); + msg += len; + msg_len -= len; + ctx->index += len; + } + + if (msg_len == 0) { + /* if it is still the last block, we are done */ + return; + } + + /* + * now checksum everything but the last block + */ + memxor3(Y.b, ctx->X.b, ctx->block.b, 16); + encrypt(cipher, 16, ctx->X.b, Y.b); + + while (msg_len > 16) + { + memxor3(Y.b, ctx->X.b, msg, 16); + encrypt(cipher, 16, ctx->X.b, Y.b); + msg += 16; + msg_len -= 16; + } + + /* + * copy the last block, it will be processed in + * cmac128_digest(). + */ + memcpy(ctx->block.b, msg, msg_len); + ctx->index = msg_len; +} + +void +cmac128_digest(struct cmac128_ctx *ctx, const void *cipher, + nettle_cipher_func *encrypt, + unsigned length, + uint8_t *dst) +{ + union nettle_block16 Y; + + memset(ctx->block.b+ctx->index, 0, sizeof(ctx->block.b)-ctx->index); + + /* re-use ctx->block for memxor output */ + if (ctx->index < 16) + { + ctx->block.b[ctx->index] = 0x80; + memxor(ctx->block.b, ctx->K2.b, 16); + } + else + { + memxor(ctx->block.b, ctx->K1.b, 16); + } + + memxor3(Y.b, ctx->block.b, ctx->X.b, 16); + + assert(length <= 16); + if (length == 16) + { + encrypt(cipher, 16, dst, Y.b); + } + else + { + encrypt(cipher, 16, ctx->block.b, Y.b); + memcpy(dst, ctx->block.b, length); + } + + /* reset state for re-use */ + memset(&ctx->X, 0, sizeof(ctx->X)); + ctx->index = 0; +} + +void +cmac_aes128_set_key(struct cmac_aes128_ctx *ctx, const uint8_t *key) +{ + CMAC128_SET_KEY(ctx, aes128_set_encrypt_key, aes128_encrypt, key); +} + +void +cmac_aes128_update (struct cmac_aes128_ctx *ctx, + size_t length, const uint8_t *data) +{ + CMAC128_UPDATE (ctx, aes128_encrypt, length, data); +} + +void +cmac_aes128_digest(struct cmac_aes128_ctx *ctx, + size_t length, uint8_t *digest) +{ + CMAC128_DIGEST(ctx, aes128_encrypt, length, digest); +} + +void +cmac_aes256_set_key(struct cmac_aes256_ctx *ctx, const uint8_t *key) +{ + CMAC128_SET_KEY(ctx, aes256_set_encrypt_key, aes256_encrypt, key); +} + +void +cmac_aes256_update (struct cmac_aes256_ctx *ctx, + size_t length, const uint8_t *data) +{ + CMAC128_UPDATE (ctx, aes256_encrypt, length, data); +} + +void +cmac_aes256_digest(struct cmac_aes256_ctx *ctx, + size_t length, uint8_t *digest) +{ + CMAC128_DIGEST(ctx, aes256_encrypt, length, digest); +} +#endif /* HAVE_NETTLE_CMAC128_UPDATE */ |