crypto/openssh-4/md5crypt.c

   1 /*
   2  * ----------------------------------------------------------------------------
   3  * "THE BEER-WARE LICENSE" (Revision 42):
   4  * <phk@login.dknet.dk> wrote this file.  As long as you retain this
   5  * notice you can do whatever you want with this stuff. If we meet some
   6  * day, and you think this stuff is worth it, you can buy me a beer in
   7  * return.   Poul-Henning Kamp
   8  * ----------------------------------------------------------------------------
   9  */
  10
  11 #include "includes.h"
  12
  13 #if defined(HAVE_MD5_PASSWORDS) && !defined(HAVE_MD5_CRYPT)
  14 #include <openssl/md5.h>
  15
  16 RCSID("$Id: md5crypt.c,v 1.9 2003/11/21 12:56:47 djm Exp $");
  17
  18 /* 0 ... 63 => ascii - 64 */
  19 static unsigned char itoa64[] =
  20     "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  21
  22 static char *magic = "$1$";
  23
  24 static char *
  25 to64(unsigned long v, int n)
  26 {
  27         static char buf[5];
  28         char *s = buf;
  29
  30         if (n > 4)
  31                 return (NULL);
  32
  33         memset(buf, '\0', sizeof(buf));
  34         while (--n >= 0) {
  35                 *s++ = itoa64[v&0x3f];
  36                 v >>= 6;
  37         }
  38
  39         return (buf);
  40 }
  41
  42 int
  43 is_md5_salt(const char *salt)
  44 {
  45         return (strncmp(salt, magic, strlen(magic)) == 0);
  46 }
  47
  48 char *
  49 md5_crypt(const char *pw, const char *salt)
  50 {
  51         static char passwd[120], salt_copy[9], *p;
  52         static const char *sp, *ep;
  53         unsigned char final[16];
  54         int sl, pl, i, j;
  55         MD5_CTX ctx, ctx1;
  56         unsigned long l;
  57
  58         /* Refine the Salt first */
  59         sp = salt;
  60
  61         /* If it starts with the magic string, then skip that */
  62         if(strncmp(sp, magic, strlen(magic)) == 0)
  63                 sp += strlen(magic);
  64
  65         /* It stops at the first '$', max 8 chars */
  66         for (ep = sp; *ep != '$'; ep++) {
  67                 if (*ep == '\0' || ep >= (sp + 8))
  68                         return (NULL);
  69         }
  70
  71         /* get the length of the true salt */
  72         sl = ep - sp;
  73
  74         /* Stash the salt */
  75         memcpy(salt_copy, sp, sl);
  76         salt_copy[sl] = '\0';
  77
  78         MD5_Init(&ctx);
  79
  80         /* The password first, since that is what is most unknown */
  81         MD5_Update(&ctx, pw, strlen(pw));
  82
  83         /* Then our magic string */
  84         MD5_Update(&ctx, magic, strlen(magic));
  85
  86         /* Then the raw salt */
  87         MD5_Update(&ctx, sp, sl);
  88
  89         /* Then just as many characters of the MD5(pw, salt, pw) */
  90         MD5_Init(&ctx1);
  91         MD5_Update(&ctx1, pw, strlen(pw));
  92         MD5_Update(&ctx1, sp, sl);
  93         MD5_Update(&ctx1, pw, strlen(pw));
  94         MD5_Final(final, &ctx1);
  95
  96         for(pl = strlen(pw); pl > 0; pl -= 16)
  97                 MD5_Update(&ctx, final, pl > 16 ? 16 : pl);
  98
  99         /* Don't leave anything around in vm they could use. */
 100         memset(final, '\0', sizeof final);
 101
 102         /* Then something really weird... */
 103         for (j = 0, i = strlen(pw); i != 0; i >>= 1)
 104                 if (i & 1)
 105                         MD5_Update(&ctx, final + j, 1);
 106                 else
 107                         MD5_Update(&ctx, pw + j, 1);
 108
 109         /* Now make the output string */
 110         snprintf(passwd, sizeof(passwd), "%s%s$", magic, salt_copy);
 111
 112         MD5_Final(final, &ctx);
 113
 114         /*
 115          * and now, just to make sure things don't run too fast
 116          * On a 60 Mhz Pentium this takes 34 msec, so you would
 117          * need 30 seconds to build a 1000 entry dictionary...
 118          */
 119         for(i = 0; i < 1000; i++) {
 120                 MD5_Init(&ctx1);
 121                 if (i & 1)
 122                         MD5_Update(&ctx1, pw, strlen(pw));
 123                 else
 124                         MD5_Update(&ctx1, final, 16);
 125
 126                 if (i % 3)
 127                         MD5_Update(&ctx1, sp, sl);
 128
 129                 if (i % 7)
 130                         MD5_Update(&ctx1, pw, strlen(pw));
 131
 132                 if (i & 1)
 133                         MD5_Update(&ctx1, final, 16);
 134                 else
 135                         MD5_Update(&ctx1, pw, strlen(pw));
 136
 137                 MD5_Final(final, &ctx1);
 138         }
 139
 140         p = passwd + strlen(passwd);
 141
 142         l = (final[ 0]<<16) | (final[ 6]<<8) | final[12];
 143         strlcat(passwd, to64(l, 4), sizeof(passwd));
 144         l = (final[ 1]<<16) | (final[ 7]<<8) | final[13];
 145         strlcat(passwd, to64(l, 4), sizeof(passwd));
 146         l = (final[ 2]<<16) | (final[ 8]<<8) | final[14];
 147         strlcat(passwd, to64(l, 4), sizeof(passwd));
 148         l = (final[ 3]<<16) | (final[ 9]<<8) | final[15];
 149         strlcat(passwd, to64(l, 4), sizeof(passwd));
 150         l = (final[ 4]<<16) | (final[10]<<8) | final[ 5];
 151         strlcat(passwd, to64(l, 4), sizeof(passwd));
 152         l =                    final[11]                ;
 153         strlcat(passwd, to64(l, 2), sizeof(passwd));
 154
 155         /* Don't leave anything around in vm they could use. */
 156         memset(final, 0, sizeof(final));
 157         memset(salt_copy, 0, sizeof(salt_copy));
 158         memset(&ctx, 0, sizeof(ctx));
 159         memset(&ctx1, 0, sizeof(ctx1));
 160         (void)to64(0, 4);
 161
 162         return (passwd);
 163 }
 164
 165 #endif /* defined(HAVE_MD5_PASSWORDS) && !defined(HAVE_MD5_CRYPT) */