/* crypto/cmac/cmac.c */ /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL * project. */ /* ==================================================================== * Copyright (c) 2010 The OpenSSL Project. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. All advertising materials mentioning features or use of this * software must display the following acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" * * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to * endorse or promote products derived from this software without * prior written permission. For written permission, please contact * licensing@OpenSSL.org. * * 5. Products derived from this software may not be called "OpenSSL" * nor may "OpenSSL" appear in their names without prior written * permission of the OpenSSL Project. * * 6. Redistributions of any form whatsoever must retain the following * acknowledgment: * "This product includes software developed by the OpenSSL Project * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" * * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * ==================================================================== */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include "cryptlib.h" #include <openssl/cmac.h> #ifdef OPENSSL_FIPS #include <openssl/fips.h> #endif 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, unsigned char *l, int bl) { int i; /* Shift block to left, including carry */ for (i = 0; i < bl; i++) { k1[i] = l[i] << 1; if (i < bl - 1 && l[i + 1] & 0x80) k1[i] |= 1; } /* If MSB set fixup with R */ if (l[0] & 0x80) k1[bl - 1] ^= bl == 16 ? 0x87 : 0x1b; } CMAC_CTX *CMAC_CTX_new(void) { CMAC_CTX *ctx; ctx = OPENSSL_malloc(sizeof(CMAC_CTX)); if (!ctx) return NULL; EVP_CIPHER_CTX_init(&ctx->cctx); ctx->nlast_block = -1; return ctx; } void CMAC_CTX_cleanup(CMAC_CTX *ctx) { #ifdef OPENSSL_FIPS if (FIPS_mode() && !ctx->cctx.engine) { FIPS_cmac_ctx_cleanup(ctx); return; } #endif EVP_CIPHER_CTX_cleanup(&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) { CMAC_CTX_cleanup(ctx); 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 unsigned char zero_iv[EVP_MAX_BLOCK_LENGTH]; #ifdef OPENSSL_FIPS if (FIPS_mode()) { /* If we have an ENGINE need to allow non FIPS */ if ((impl || ctx->cctx.engine) && !(ctx->cctx.flags & EVP_CIPH_FLAG_NON_FIPS_ALLOW)) { EVPerr(EVP_F_CMAC_INIT, EVP_R_DISABLED_FOR_FIPS); return 0; } /* Other algorithm blocking will be done in FIPS_cmac_init, * via FIPS_cipherinit(). */ if (!impl && !ctx->cctx.engine) return FIPS_cmac_init(ctx, key, keylen, cipher, NULL); } #endif /* 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; } /* Initialiase context */ if (cipher && !EVP_EncryptInit_ex(&ctx->cctx, cipher, impl, NULL, NULL)) return 0; /* Non-NULL key means initialisation complete */ if (key) { int bl; 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)) 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; #ifdef OPENSSL_FIPS if (FIPS_mode() && !ctx->cctx.engine) return FIPS_cmac_update(ctx, in, dlen); #endif 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)) return 0; } /* Encrypt all but one of the complete blocks left */ while(dlen > bl) { if (!EVP_Cipher(&ctx->cctx, ctx->tbl, data, bl)) 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; #ifdef OPENSSL_FIPS if (FIPS_mode() && !ctx->cctx.engine) return FIPS_cmac_final(ctx, out, poutlen); #endif 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" containes 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 reinitliasing 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); }