/* crypto/hmac/hmac.c */

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)

 * All rights reserved.

 *

 * This package is an SSL implementation written

 * by Eric Young (eay@cryptsoft.com).

 * The implementation was written so as to conform with Netscapes SSL.

 *

 * This library is free for commercial and non-commercial use as long as

 * the following conditions are aheared to.  The following conditions

 * apply to all code found in this distribution, be it the RC4, RSA,

 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation

 * included with this distribution is covered by the same copyright terms

 * except that the holder is Tim Hudson (tjh@cryptsoft.com).

 *

 * Copyright remains Eric Young's, and as such any Copyright notices in

 * the code are not to be removed.

 * If this package is used in a product, Eric Young should be given attribution

 * as the author of the parts of the library used.

 * This can be in the form of a textual message at program startup or

 * in documentation (online or textual) provided with the package.

 *

 * 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 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 acknowledgement:

 *    "This product includes cryptographic software written by

 *     Eric Young (eay@cryptsoft.com)"

 *    The word 'cryptographic' can be left out if the rouines from the library

 *    being used are not cryptographic related :-).

 * 4. If you include any Windows specific code (or a derivative thereof) from

 *    the apps directory (application code) you must include an acknowledgement:

 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"

 *

 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND

 * ANY EXPRESS 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 AUTHOR OR 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.

 *

 * The licence and distribution terms for any publically available version or

 * derivative of this code cannot be changed.  i.e. this code cannot simply be

 * copied and put under another distribution licence

 * [including the GNU Public Licence.]

 */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "cryptlib.h"

#include <openssl/hmac.h>

#ifdef OPENSSL_FIPS

# include <openssl/fips.h>

#endif

int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, int len,

                 const EVP_MD *md, ENGINE *impl)

{

    int i, j, reset = 0;

    unsigned char pad[HMAC_MAX_MD_CBLOCK];

#ifdef OPENSSL_FIPS

    /* If FIPS mode switch to approved implementation if possible */

    if (FIPS_mode()) {

        const EVP_MD *fipsmd;

        if (md) {

            fipsmd = FIPS_get_digestbynid(EVP_MD_type(md));

            if (fipsmd)

                md = fipsmd;

        }

    }

    if (FIPS_mode()) {

        /* If we have an ENGINE need to allow non FIPS */

        if ((impl || ctx->i_ctx.engine)

            && !(ctx->i_ctx.flags & EVP_CIPH_FLAG_NON_FIPS_ALLOW)) {

            EVPerr(EVP_F_HMAC_INIT_EX, EVP_R_DISABLED_FOR_FIPS);

            return 0;

        }

        /*

         * Other algorithm blocking will be done in FIPS_cmac_init, via

         * FIPS_hmac_init_ex().

         */

        if (!impl && !ctx->i_ctx.engine)

            return FIPS_hmac_init_ex(ctx, key, len, md, NULL);

    }

#endif

    /* If we are changing MD then we must have a key */

    if (md != NULL && md != ctx->md && (key == NULL || len < 0))

        return 0;

    if (md != NULL) {

        reset = 1;

        ctx->md = md;

    } else if (ctx->md) {

        md = ctx->md;

    } else {

        return 0;

    }

    if (key != NULL) {

        reset = 1;

        j = EVP_MD_block_size(md);

        OPENSSL_assert(j <= (int)sizeof(ctx->key));

        if (j < len) {

            if (!EVP_DigestInit_ex(&ctx->md_ctx, md, impl))

                goto err;

            if (!EVP_DigestUpdate(&ctx->md_ctx, key, len))

                goto err;

            if (!EVP_DigestFinal_ex(&(ctx->md_ctx), ctx->key,

                                    &ctx->key_length))

                goto err;

        } else {

            if (len < 0 || len > (int)sizeof(ctx->key))

                return 0;

            memcpy(ctx->key, key, len);

            ctx->key_length = len;

        }

        if (ctx->key_length != HMAC_MAX_MD_CBLOCK)

            memset(&ctx->key[ctx->key_length], 0,

                   HMAC_MAX_MD_CBLOCK - ctx->key_length);

    }

    if (reset) {

        for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++)

            pad[i] = 0x36 ^ ctx->key[i];

        if (!EVP_DigestInit_ex(&ctx->i_ctx, md, impl))

            goto err;

        if (!EVP_DigestUpdate(&ctx->i_ctx, pad, EVP_MD_block_size(md)))

            goto err;

        for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++)

            pad[i] = 0x5c ^ ctx->key[i];

        if (!EVP_DigestInit_ex(&ctx->o_ctx, md, impl))

            goto err;

        if (!EVP_DigestUpdate(&ctx->o_ctx, pad, EVP_MD_block_size(md)))

            goto err;

    }

    if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx))

        goto err;

    return 1;

 err:

    return 0;

}

int HMAC_Init(HMAC_CTX *ctx, const void *key, int len, const EVP_MD *md)

{

    if (key && md)

        HMAC_CTX_init(ctx);

    return HMAC_Init_ex(ctx, key, len, md, NULL);

}

int HMAC_Update(HMAC_CTX *ctx, const unsigned char *data, size_t len)

{

#ifdef OPENSSL_FIPS

    if (FIPS_mode() && !ctx->i_ctx.engine)

        return FIPS_hmac_update(ctx, data, len);

#endif

    if (!ctx->md)

        return 0;

    return EVP_DigestUpdate(&ctx->md_ctx, data, len);

}

int HMAC_Final(HMAC_CTX *ctx, unsigned char *md, unsigned int *len)

{

    unsigned int i;

    unsigned char buf[EVP_MAX_MD_SIZE];

#ifdef OPENSSL_FIPS

    if (FIPS_mode() && !ctx->i_ctx.engine)

        return FIPS_hmac_final(ctx, md, len);

#endif

    if (!ctx->md)

        goto err;

    if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i))

        goto err;

    if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx))

        goto err;

    if (!EVP_DigestUpdate(&ctx->md_ctx, buf, i))

        goto err;

    if (!EVP_DigestFinal_ex(&ctx->md_ctx, md, len))

        goto err;

    return 1;

 err:

    return 0;

}

void HMAC_CTX_init(HMAC_CTX *ctx)

{

    EVP_MD_CTX_init(&ctx->i_ctx);

    EVP_MD_CTX_init(&ctx->o_ctx);

    EVP_MD_CTX_init(&ctx->md_ctx);

    ctx->md = NULL;

}

int HMAC_CTX_copy(HMAC_CTX *dctx, HMAC_CTX *sctx)

{

    if (!EVP_MD_CTX_copy(&dctx->i_ctx, &sctx->i_ctx))

        goto err;

    if (!EVP_MD_CTX_copy(&dctx->o_ctx, &sctx->o_ctx))

        goto err;

    if (!EVP_MD_CTX_copy(&dctx->md_ctx, &sctx->md_ctx))

        goto err;

    memcpy(dctx->key, sctx->key, HMAC_MAX_MD_CBLOCK);

    dctx->key_length = sctx->key_length;

    dctx->md = sctx->md;

    return 1;

 err:

    return 0;

}

void HMAC_CTX_cleanup(HMAC_CTX *ctx)

{

#ifdef OPENSSL_FIPS

    if (FIPS_mode() && !ctx->i_ctx.engine) {

        FIPS_hmac_ctx_cleanup(ctx);

        return;

    }

#endif

    EVP_MD_CTX_cleanup(&ctx->i_ctx);

    EVP_MD_CTX_cleanup(&ctx->o_ctx);

    EVP_MD_CTX_cleanup(&ctx->md_ctx);

    OPENSSL_cleanse(ctx, sizeof *ctx);

}

unsigned char *HMAC(const EVP_MD *evp_md, const void *key, int key_len,

                    const unsigned char *d, size_t n, unsigned char *md,

                    unsigned int *md_len)

{

    HMAC_CTX c;

    static unsigned char m[EVP_MAX_MD_SIZE];

    if (md == NULL)

        md = m;

    HMAC_CTX_init(&c);

    if (!HMAC_Init(&c, key, key_len, evp_md))

        goto err;

    if (!HMAC_Update(&c, d, n))

        goto err;

    if (!HMAC_Final(&c, md, md_len))

        goto err;

    HMAC_CTX_cleanup(&c);

    return md;

 err:

    HMAC_CTX_cleanup(&c);

    return NULL;

}

void HMAC_CTX_set_flags(HMAC_CTX *ctx, unsigned long flags)

{

    EVP_MD_CTX_set_flags(&ctx->i_ctx, flags);

    EVP_MD_CTX_set_flags(&ctx->o_ctx, flags);

    EVP_MD_CTX_set_flags(&ctx->md_ctx, flags);

}