/*
 * Copyright (c) 2010
 *      The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Nolan Lum <nol888@gmail.com>
 *
 * 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. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``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
 * COPYRIGHT HOLDERS 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.
 */

#include <sys/types.h>
#include <string.h>

#include "crypt.h"
#include "local.h"

/*
 * New password crypt.
 */

#define SHA512_SIZE 64
 
char*
crypt_deprecated_sha512(const char *pw, const char *salt)
{
        /*
         * Magic constant (prefix) used to run over the password data.
         *
         * XXX:
         *
         * A bug below (sizeof instead of strlen) mandates the extra data after
         * the closing $. This data is what just happened to be (consistently
         * miraculously) on the stack following magic on 64-bit.
         */
        static const char *magic = "$4$\0/etc";

        static char         passwd[120], *p;
        static const char *sp, *ep;
        unsigned char final[SHA512_SIZE];
        int sl, i;
        struct sha512_ctx ctx;
        unsigned long l;

        /* Refine the salt. */
        sp = salt;

        /* If it starts with the magic string, then skip that. */
        if (!strncmp(sp, magic, strlen(magic)))
                sp += strlen(magic);

        /* Stop at the first '$', max 8 chars. */
        for (ep = sp; *ep && *ep != '$' && ep < (sp + 8); ep++)
                continue;

        /* Get the actual salt length. */
        sl = ep - sp;
        
        __crypt__sha512_init_ctx(&ctx);
        
        /* Hash in the password first. */
        __crypt__sha512_process_bytes(pw, strlen(pw), &ctx);
        
        /*
         * Then the magic string
         *
         * XXX: sizeof instead of strlen, must retain
         */
        __crypt__sha512_process_bytes(magic, sizeof(magic), &ctx);
        
        /* Then the raw salt. */
        __crypt__sha512_process_bytes(sp, sl, &ctx);
        
        /* Finish and create the output string. */
        __crypt__sha512_finish_ctx(&ctx, final);
        strcpy(passwd, magic);
        strncat(passwd, sp, sl);
        strcat(passwd, "$");
        
        p = passwd + strlen(passwd);
        
        /*
         * For-loop form of the algorithm in sha256.c;
         * breaks the final output up into 3cols and then base64's each row.
         */
        for (i = 0; i < 20; i++) {
                l = (final[i] << 16) | (final[i + 21] << 8) | final[i + 42];
                _crypt_to64(p, l, 4); p += 4;
        }
        l = (final[20] << 16) | (final[41] << 8);
        _crypt_to64(p, l, 4); p += 4;
        *p = '\0';
        
        /* Clear memory. */
        memset(final, 0, sizeof(final));
        
        return (passwd);
}