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