lib/libcrypt/md5crypt.c

   1 /*      $NetBSD: md5crypt.c,v 1.9 2007/01/17 23:24:22 hubertf Exp $     */
   2
   3 /*
   4  * ----------------------------------------------------------------------------
   5  * "THE BEER-WARE LICENSE" (Revision 42):
   6  * <phk@login.dknet.dk> wrote this file.  As long as you retain this notice you
   7  * can do whatever you want with this stuff. If we meet some day, and you think
   8  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
   9  * ----------------------------------------------------------------------------
  10  *
  11  * from FreeBSD: crypt.c,v 1.5 1996/10/14 08:34:02 phk Exp
  12  * via OpenBSD: md5crypt.c,v 1.9 1997/07/23 20:58:27 kstailey Exp
  13  *
  14  */
  15
  16 #include <sys/cdefs.h>
  17 #if !defined(lint)
  18 __RCSID("$NetBSD: md5crypt.c,v 1.9 2007/01/17 23:24:22 hubertf Exp $");
  19 #endif /* not lint */
  20
  21 /*
  22  * NOTE: We are also built for inclusion in libcrypto; when built for that
  23  * environment, use the libcrypto versions of the MD5 routines, so save
  24  * having to pull two versions into the same program.
  25  */
  26
  27 #include <unistd.h>
  28 #include <stdio.h>
  29 #include <string.h>
  30 #ifdef libcrypto
  31 #include <openssl/md5.h>
  32 #else
  33 #include <md5.h>
  34 #endif
  35
  36 #include "crypt.h"
  37
  38 #define MD5_MAGIC       "$1$"
  39 #define MD5_MAGIC_LEN   3
  40
  41 #ifdef libcrypto
  42 #define INIT(x)                 MD5_Init((x))
  43 #define UPDATE(x, b, l)         MD5_Update((x), (b), (l))
  44 #define FINAL(v, x)             MD5_Final((v), (x))
  45 #else
  46 #define INIT(x)                 MD5Init((x))
  47 #define UPDATE(x, b, l)         MD5Update((x), (b), (l))
  48 #define FINAL(v, x)             MD5Final((v), (x))
  49 #endif
  50
  51
  52 /*
  53  * MD5 password encryption.
  54  */
  55 char *
  56 __md5crypt(const char *pw, const char *salt)
  57 {
  58         static char passwd[120], *p;
  59         const char *sp, *ep;
  60         unsigned char final[16];
  61         unsigned int i, sl, pwl;
  62         MD5_CTX ctx, ctx1;
  63         u_int32_t l;
  64         int pl;
  65
  66         pwl = strlen(pw);
  67
  68         /* Refine the salt first */
  69         sp = salt;
  70
  71         /* If it starts with the magic string, then skip that */
  72         if (strncmp(sp, MD5_MAGIC, MD5_MAGIC_LEN) == 0)
  73                 sp += MD5_MAGIC_LEN;
  74
  75         /* It stops at the first '$', max 8 chars */
  76         for (ep = sp; *ep != '\0' && *ep != '$' && ep < (sp + 8); ep++)
  77                 continue;
  78
  79         /* get the length of the true salt */
  80         sl = ep - sp;
  81
  82         INIT(&ctx);
  83
  84         /* The password first, since that is what is most unknown */
  85         UPDATE(&ctx, (const unsigned char *)pw, pwl);
  86
  87         /* Then our magic string */
  88         UPDATE(&ctx, (const unsigned char *)MD5_MAGIC, MD5_MAGIC_LEN);
  89
  90         /* Then the raw salt */
  91         UPDATE(&ctx, (const unsigned char *)sp, sl);
  92
  93         /* Then just as many characters of the MD5(pw,salt,pw) */
  94         INIT(&ctx1);
  95         UPDATE(&ctx1, (const unsigned char *)pw, pwl);
  96         UPDATE(&ctx1, (const unsigned char *)sp, sl);
  97         UPDATE(&ctx1, (const unsigned char *)pw, pwl);
  98         FINAL(final, &ctx1);
  99
 100         for (pl = pwl; pl > 0; pl -= 16)
 101                 UPDATE(&ctx, final, (unsigned int)(pl > 16 ? 16 : pl));
 102
 103         /* Don't leave anything around in vm they could use. */
 104         memset(final, 0, sizeof(final));
 105
 106         /* Then something really weird... */
 107         for (i = pwl; i != 0; i >>= 1)
 108                 if ((i & 1) != 0)
 109                     UPDATE(&ctx, final, 1);
 110                 else
 111                     UPDATE(&ctx, (const unsigned char *)pw, 1);
 112
 113         /* Now make the output string */
 114         memcpy(passwd, MD5_MAGIC, MD5_MAGIC_LEN);
 115         strlcpy(passwd + MD5_MAGIC_LEN, sp, sl + 1);
 116         strlcat(passwd, "$", sizeof(passwd));
 117
 118         FINAL(final, &ctx);
 119
 120         /*
 121          * And now, just to make sure things don't run too fast. On a 60 MHz
 122          * Pentium this takes 34 msec, so you would need 30 seconds to build
 123          * a 1000 entry dictionary...
 124          */
 125         for (i = 0; i < 1000; i++) {
 126                 INIT(&ctx1);
 127
 128                 if ((i & 1) != 0)
 129                         UPDATE(&ctx1, (const unsigned char *)pw, pwl);
 130                 else
 131                         UPDATE(&ctx1, final, 16);
 132
 133                 if ((i % 3) != 0)
 134                         UPDATE(&ctx1, (const unsigned char *)sp, sl);
 135
 136                 if ((i % 7) != 0)
 137                         UPDATE(&ctx1, (const unsigned char *)pw, pwl);
 138
 139                 if ((i & 1) != 0)
 140                         UPDATE(&ctx1, final, 16);
 141                 else
 142                         UPDATE(&ctx1, (const unsigned char *)pw, pwl);
 143
 144                 FINAL(final, &ctx1);
 145         }
 146
 147         p = passwd + sl + MD5_MAGIC_LEN + 1;
 148
 149         l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; __crypt_to64(p,l,4); p += 4;
 150         l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; __crypt_to64(p,l,4); p += 4;
 151         l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; __crypt_to64(p,l,4); p += 4;
 152         l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; __crypt_to64(p,l,4); p += 4;
 153         l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; __crypt_to64(p,l,4); p += 4;
 154         l =                    final[11]                ; __crypt_to64(p,l,2); p += 2;
 155         *p = '\0';
 156
 157         /* Don't leave anything around in vm they could use. */
 158         memset(final, 0, sizeof(final));
 159         return (passwd);
 160 }