/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is the Netscape security libraries.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1994-2000
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
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#include "secport.h"
#include "hasht.h"
#include "blapit.h"
#include "alghmac.h"
#include "secerr.h"

#define HMAC_PAD_SIZE HASH_BLOCK_LENGTH_MAX

struct HMACContextStr {
    void *hash;
    const SECHashObject *hashobj;
    PRBool        wasAllocated;
    unsigned char ipad[HMAC_PAD_SIZE];
    unsigned char opad[HMAC_PAD_SIZE];
};

void
HMAC_Destroy(HMACContext *cx, PRBool freeit)
{
    if (cx == NULL)
	return;

    PORT_Assert(!freeit == !cx->wasAllocated);
    if (cx->hash != NULL) {
	cx->hashobj->destroy(cx->hash, PR_TRUE);
	PORT_Memset(cx, 0, sizeof *cx);
    }
    if (freeit)
	PORT_Free(cx);
}

SECStatus
HMAC_Init( HMACContext * cx, const SECHashObject *hash_obj, 
	   const unsigned char *secret, unsigned int secret_len, PRBool isFIPS)
{
    unsigned int i;
    unsigned char hashed_secret[HASH_LENGTH_MAX];

    /* required by FIPS 198 Section 3 */
    if (isFIPS && secret_len < hash_obj->length/2) {
	PORT_SetError(SEC_ERROR_INVALID_ARGS);
	return SECFailure;
    }
    if (cx == NULL) {
	PORT_SetError(SEC_ERROR_INVALID_ARGS);
	return SECFailure;
    }
    cx->wasAllocated = PR_FALSE;
    cx->hashobj = hash_obj;
    cx->hash = cx->hashobj->create();
    if (cx->hash == NULL)
	goto loser;

    if (secret_len > cx->hashobj->blocklength) {
	cx->hashobj->begin( cx->hash);
	cx->hashobj->update(cx->hash, secret, secret_len);
	PORT_Assert(cx->hashobj->length <= sizeof hashed_secret);
	cx->hashobj->end(   cx->hash, hashed_secret, &secret_len, 
	                 sizeof hashed_secret);
	if (secret_len != cx->hashobj->length) {
	    PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
	    goto loser;
	}
	secret = (const unsigned char *)&hashed_secret[0];
    }

    PORT_Memset(cx->ipad, 0x36, cx->hashobj->blocklength);
    PORT_Memset(cx->opad, 0x5c, cx->hashobj->blocklength);

    /* fold secret into padding */
    for (i = 0; i < secret_len; i++) {
	cx->ipad[i] ^= secret[i];
	cx->opad[i] ^= secret[i];
    }
    PORT_Memset(hashed_secret, 0, sizeof hashed_secret);
    return SECSuccess;

loser:
    PORT_Memset(hashed_secret, 0, sizeof hashed_secret);
    if (cx->hash != NULL)
	cx->hashobj->destroy(cx->hash, PR_TRUE);
    return SECFailure;
}

HMACContext *
HMAC_Create(const SECHashObject *hash_obj, const unsigned char *secret, 
            unsigned int secret_len, PRBool isFIPS)
{
    SECStatus rv;
    HMACContext * cx = PORT_ZNew(HMACContext);
    if (cx == NULL)
	return NULL;
    rv = HMAC_Init(cx, hash_obj, secret, secret_len, isFIPS);
    cx->wasAllocated = PR_TRUE;
    if (rv != SECSuccess) {
	PORT_Free(cx); /* contains no secret info */
	cx = NULL;
    }
    return cx;
}

void
HMAC_Begin(HMACContext *cx)
{
    /* start inner hash */
    cx->hashobj->begin(cx->hash);
    cx->hashobj->update(cx->hash, cx->ipad, cx->hashobj->blocklength);
}

void
HMAC_Update(HMACContext *cx, const unsigned char *data, unsigned int data_len)
{
    cx->hashobj->update(cx->hash, data, data_len);
}

SECStatus
HMAC_Finish(HMACContext *cx, unsigned char *result, unsigned int *result_len,
	    unsigned int max_result_len)
{
    if (max_result_len < cx->hashobj->length) {
	PORT_SetError(SEC_ERROR_INVALID_ARGS);
	return SECFailure;
    }

    cx->hashobj->end(cx->hash, result, result_len, max_result_len);
    if (*result_len != cx->hashobj->length)
	return SECFailure;

    cx->hashobj->begin(cx->hash);
    cx->hashobj->update(cx->hash, cx->opad, cx->hashobj->blocklength);
    cx->hashobj->update(cx->hash, result, *result_len);
    cx->hashobj->end(cx->hash, result, result_len, max_result_len);
    return SECSuccess;
}

HMACContext *
HMAC_Clone(HMACContext *cx)
{
    HMACContext *newcx;

    newcx = (HMACContext*)PORT_ZAlloc(sizeof(HMACContext));
    if (newcx == NULL)
	goto loser;

    newcx->wasAllocated = PR_TRUE;
    newcx->hashobj = cx->hashobj;
    newcx->hash = cx->hashobj->clone(cx->hash);
    if (newcx->hash == NULL)
	goto loser;
    PORT_Memcpy(newcx->ipad, cx->ipad, cx->hashobj->blocklength);
    PORT_Memcpy(newcx->opad, cx->opad, cx->hashobj->blocklength);
    return newcx;

loser:
    HMAC_Destroy(newcx, PR_TRUE);
    return NULL;
}