lib/libcrypt/deprecated-crypt-sha512.c

   1 /*
   2  * Copyright (c) 2010
   3  *      The DragonFly Project.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to The DragonFly Project
   6  * by Nolan Lum <nol888@gmail.com>
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the
  17  *    distribution.
  18  * 3. Neither the name of The DragonFly Project nor the names of its
  19  *    contributors may be used to endorse or promote products derived
  20  *    from this software without specific, prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include <sys/types.h>
  37 #include <string.h>
  38
  39 #include "crypt.h"
  40 #include "local.h"
  41
  42 /*
  43  * New password crypt.
  44  */
  45
  46 #define SHA512_SIZE 64
  47
  48 char*
  49 crypt_deprecated_sha512(const char *pw, const char *salt)
  50 {
  51         /*
  52          * Magic constant (prefix) used to run over the password data.
  53          *
  54          * XXX:
  55          *
  56          * A bug below (sizeof instead of strlen) mandates the extra data after
  57          * the closing $. This data is what just happened to be (consistently
  58          * miraculously) on the stack following magic on 64-bit.
  59          */
  60         static const char *magic = "$4$\0/etc";
  61
  62         static char         passwd[120], *p;
  63         static const char *sp, *ep;
  64         unsigned char final[SHA512_SIZE];
  65         int sl, i;
  66         struct sha512_ctx ctx;
  67         unsigned long l;
  68
  69         /* Refine the salt. */
  70         sp = salt;
  71
  72         /* If it starts with the magic string, then skip that. */
  73         if (!strncmp(sp, magic, strlen(magic)))
  74                 sp += strlen(magic);
  75
  76         /* Stop at the first '$', max 8 chars. */
  77         for (ep = sp; *ep && *ep != '$' && ep < (sp + 8); ep++)
  78                 continue;
  79
  80         /* Get the actual salt length. */
  81         sl = ep - sp;
  82
  83         __crypt__sha512_init_ctx(&ctx);
  84
  85         /* Hash in the password first. */
  86         __crypt__sha512_process_bytes(pw, strlen(pw), &ctx);
  87
  88         /*
  89          * Then the magic string
  90          *
  91          * XXX: sizeof instead of strlen, must retain
  92          */
  93         __crypt__sha512_process_bytes(magic, sizeof(magic), &ctx);
  94
  95         /* Then the raw salt. */
  96         __crypt__sha512_process_bytes(sp, sl, &ctx);
  97
  98         /* Finish and create the output string. */
  99         __crypt__sha512_finish_ctx(&ctx, final);
 100         strcpy(passwd, magic);
 101         strncat(passwd, sp, sl);
 102         strcat(passwd, "$");
 103
 104         p = passwd + strlen(passwd);
 105
 106         /*
 107          * For-loop form of the algorithm in sha256.c;
 108          * breaks the final output up into 3cols and then base64's each row.
 109          */
 110         for (i = 0; i < 20; i++) {
 111                 l = (final[i] << 16) | (final[i + 21] << 8) | final[i + 42];
 112                 _crypt_to64(p, l, 4); p += 4;
 113         }
 114         l = (final[20] << 16) | (final[41] << 8);
 115         _crypt_to64(p, l, 4); p += 4;
 116         *p = '\0';
 117
 118         /* Clear memory. */
 119         memset(final, 0, sizeof(final));
 120
 121         return (passwd);
 122 }