crypto/openssh/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 <sys/types.h>
  15
  16 #include <string.h>
  17
  18 #include <openssl/md5.h>
  19
  20 /* 0 ... 63 => ascii - 64 */
  21 static unsigned char itoa64[] =
  22     "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  23
  24 static char *magic = "$1$";
  25
  26 static char *
  27 to64(unsigned long v, int n)
  28 {
  29         static char buf[5];
  30         char *s = buf;
  31
  32         if (n > 4)
  33                 return (NULL);
  34
  35         memset(buf, '\0', sizeof(buf));
  36         while (--n >= 0) {
  37                 *s++ = itoa64[v&0x3f];
  38                 v >>= 6;
  39         }
  40
  41         return (buf);
  42 }
  43
  44 int
  45 is_md5_salt(const char *salt)
  46 {
  47         return (strncmp(salt, magic, strlen(magic)) == 0);
  48 }
  49
  50 char *
  51 md5_crypt(const char *pw, const char *salt)
  52 {
  53         static char passwd[120], salt_copy[9], *p;
  54         static const char *sp, *ep;
  55         unsigned char final[16];
  56         int sl, pl, i, j;
  57         MD5_CTX ctx, ctx1;
  58         unsigned long l;
  59
  60         /* Refine the Salt first */
  61         sp = salt;
  62
  63         /* If it starts with the magic string, then skip that */
  64         if(strncmp(sp, magic, strlen(magic)) == 0)
  65                 sp += strlen(magic);
  66
  67         /* It stops at the first '$', max 8 chars */
  68         for (ep = sp; *ep != '$'; ep++) {
  69                 if (*ep == '\0' || ep >= (sp + 8))
  70                         return (NULL);
  71         }
  72
  73         /* get the length of the true salt */
  74         sl = ep - sp;
  75
  76         /* Stash the salt */
  77         memcpy(salt_copy, sp, sl);
  78         salt_copy[sl] = '\0';
  79
  80         MD5_Init(&ctx);
  81
  82         /* The password first, since that is what is most unknown */
  83         MD5_Update(&ctx, pw, strlen(pw));
  84
  85         /* Then our magic string */
  86         MD5_Update(&ctx, magic, strlen(magic));
  87
  88         /* Then the raw salt */
  89         MD5_Update(&ctx, sp, sl);
  90
  91         /* Then just as many characters of the MD5(pw, salt, pw) */
  92         MD5_Init(&ctx1);
  93         MD5_Update(&ctx1, pw, strlen(pw));
  94         MD5_Update(&ctx1, sp, sl);
  95         MD5_Update(&ctx1, pw, strlen(pw));
  96         MD5_Final(final, &ctx1);
  97
  98         for(pl = strlen(pw); pl > 0; pl -= 16)
  99                 MD5_Update(&ctx, final, pl > 16 ? 16 : pl);
 100
 101         /* Don't leave anything around in vm they could use. */
 102         memset(final, '\0', sizeof final);
 103
 104         /* Then something really weird... */
 105         for (j = 0, i = strlen(pw); i != 0; i >>= 1)
 106                 if (i & 1)
 107                         MD5_Update(&ctx, final + j, 1);
 108                 else
 109                         MD5_Update(&ctx, pw + j, 1);
 110
 111         /* Now make the output string */
 112         snprintf(passwd, sizeof(passwd), "%s%s$", magic, salt_copy);
 113
 114         MD5_Final(final, &ctx);
 115
 116         /*
 117          * and now, just to make sure things don't run too fast
 118          * On a 60 Mhz Pentium this takes 34 msec, so you would
 119          * need 30 seconds to build a 1000 entry dictionary...
 120          */
 121         for(i = 0; i < 1000; i++) {
 122                 MD5_Init(&ctx1);
 123                 if (i & 1)
 124                         MD5_Update(&ctx1, pw, strlen(pw));
 125                 else
 126                         MD5_Update(&ctx1, final, 16);
 127
 128                 if (i % 3)
 129                         MD5_Update(&ctx1, sp, sl);
 130
 131                 if (i % 7)
 132                         MD5_Update(&ctx1, pw, strlen(pw));
 133
 134                 if (i & 1)
 135                         MD5_Update(&ctx1, final, 16);
 136                 else
 137                         MD5_Update(&ctx1, pw, strlen(pw));
 138
 139                 MD5_Final(final, &ctx1);
 140         }
 141
 142         p = passwd + strlen(passwd);
 143
 144         l = (final[ 0]<<16) | (final[ 6]<<8) | final[12];
 145         strlcat(passwd, to64(l, 4), sizeof(passwd));
 146         l = (final[ 1]<<16) | (final[ 7]<<8) | final[13];
 147         strlcat(passwd, to64(l, 4), sizeof(passwd));
 148         l = (final[ 2]<<16) | (final[ 8]<<8) | final[14];
 149         strlcat(passwd, to64(l, 4), sizeof(passwd));
 150         l = (final[ 3]<<16) | (final[ 9]<<8) | final[15];
 151         strlcat(passwd, to64(l, 4), sizeof(passwd));
 152         l = (final[ 4]<<16) | (final[10]<<8) | final[ 5];
 153         strlcat(passwd, to64(l, 4), sizeof(passwd));
 154         l =                    final[11]                ;
 155         strlcat(passwd, to64(l, 2), sizeof(passwd));
 156
 157         /* Don't leave anything around in vm they could use. */
 158         memset(final, 0, sizeof(final));
 159         memset(salt_copy, 0, sizeof(salt_copy));
 160         memset(&ctx, 0, sizeof(ctx));
 161         memset(&ctx1, 0, sizeof(ctx1));
 162         (void)to64(0, 4);
 163
 164         return (passwd);
 165 }
 166
 167 #endif /* defined(HAVE_MD5_PASSWORDS) && !defined(HAVE_MD5_CRYPT) */