Initial experimental CMAC implementation.

1 files changed, 232 insertions, 0 deletions

diff --git a/crypto/cmac/cmac.c b/crypto/cmac/cmac.c
new file mode 100644
index 0000000000..5ec88b3ad7
--- /dev/null
+++ b/crypto/cmac/cmac.c
@@ -0,0 +1,232 @@
+/* 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>
+
+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)
+	{
+	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_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];
+	/* All zeros means restart */
+	if (!key && !cipher && !impl && keylen == 0)
+		{
+		/* Not initialised */
+		if (ctx->last_block == -1)
+			return 0;
+		if (!EVP_EncryptInit_ex(&ctx->cctx, NULL, NULL, NULL, zero_iv))
+			return 0;
+		return 0;
+		}
+	/* 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;
+		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))
+			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;
+
+	}
+
+size_t CMAC_Final(CMAC_CTX *ctx, unsigned char *out)
+	{
+	int i, bl, lb;
+	if (ctx->nlast_block == -1)
+		return 0;
+	bl = EVP_CIPHER_CTX_block_size(&ctx->cctx);
+	lb = ctx->nlast_block;
+	/* Is last block complete? */
+	if (lb == bl)
+		{
+		for (i = 0; i < bl; 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++)
+			ctx->last_block[i] ^= ctx->k2[i];
+		}
+	if (!EVP_Cipher(&ctx->cctx, out, ctx->last_block, bl))
+		return 0;
+	return bl;
+	}