contrib/pgcrypto/crypt-md5.c

   1 /*
   2  * ----------------------------------------------------------------------------
   3  * "THE BEER-WARE LICENSE" (Revision 42):
   4  * <phk@login.dknet.dk> wrote this file.  As long as you retain this notice you
   5  * can do whatever you want with this stuff. If we meet some day, and you think
   6  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
   7  * ----------------------------------------------------------------------------
   8  *
   9  * $FreeBSD$
  10  *
  11  * $PostgreSQL$
  12  */
  13
  14 #include "postgres.h"
  15
  16 #include "px.h"
  17 #include "px-crypt.h"
  18
  19 #define MD5_SIZE 16
  20
  21 static const char _crypt_a64[] =
  22 "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  23
  24 static void
  25 _crypt_to64(char *s, unsigned long v, int n)
  26 {
  27         while (--n >= 0)
  28         {
  29                 *s++ = _crypt_a64[v & 0x3f];
  30                 v >>= 6;
  31         }
  32 }
  33
  34 /*
  35  * UNIX password
  36  */
  37
  38 char *
  39 px_crypt_md5(const char *pw, const char *salt, char *passwd, unsigned dstlen)
  40 {
  41         static char *magic = "$1$"; /* This string is magic for this algorithm.
  42                                                                  * Having it this way, we can get get better
  43                                                                  * later on */
  44         static char *p;
  45         static const char *sp,
  46                            *ep;
  47         unsigned char final[MD5_SIZE];
  48         int                     sl,
  49                                 pl,
  50                                 i;
  51         PX_MD      *ctx,
  52                            *ctx1;
  53         int                     err;
  54         unsigned long l;
  55
  56         if (!passwd || dstlen < 120)
  57                 return NULL;
  58
  59         /* Refine the Salt first */
  60         sp = salt;
  61
  62         /* If it starts with the magic string, then skip that */
  63         if (!strncmp(sp, magic, strlen(magic)))
  64                 sp += strlen(magic);
  65
  66         /* It stops at the first '$', max 8 chars */
  67         for (ep = sp; *ep && *ep != '$' && ep < (sp + 8); ep++)
  68                 continue;
  69
  70         /* get the length of the true salt */
  71         sl = ep - sp;
  72
  73         /* */
  74         err = px_find_digest("md5", &ctx);
  75         if (err)
  76                 return NULL;
  77         err = px_find_digest("md5", &ctx1);
  78
  79         /* The password first, since that is what is most unknown */
  80         px_md_update(ctx, (uint8 *) pw, strlen(pw));
  81
  82         /* Then our magic string */
  83         px_md_update(ctx, (uint8 *) magic, strlen(magic));
  84
  85         /* Then the raw salt */
  86         px_md_update(ctx, (uint8 *) sp, sl);
  87
  88         /* Then just as many characters of the MD5(pw,salt,pw) */
  89         px_md_update(ctx1, (uint8 *) pw, strlen(pw));
  90         px_md_update(ctx1, (uint8 *) sp, sl);
  91         px_md_update(ctx1, (uint8 *) pw, strlen(pw));
  92         px_md_finish(ctx1, final);
  93         for (pl = strlen(pw); pl > 0; pl -= MD5_SIZE)
  94                 px_md_update(ctx, final, pl > MD5_SIZE ? MD5_SIZE : pl);
  95
  96         /* Don't leave anything around in vm they could use. */
  97         memset(final, 0, sizeof final);
  98
  99         /* Then something really weird... */
 100         for (i = strlen(pw); i; i >>= 1)
 101                 if (i & 1)
 102                         px_md_update(ctx, final, 1);
 103                 else
 104                         px_md_update(ctx, (uint8 *) pw, 1);
 105
 106         /* Now make the output string */
 107         strcpy(passwd, magic);
 108         strncat(passwd, sp, sl);
 109         strcat(passwd, "$");
 110
 111         px_md_finish(ctx, final);
 112
 113         /*
 114          * and now, just to make sure things don't run too fast On a 60 Mhz
 115          * Pentium this takes 34 msec, so you would need 30 seconds to build a
 116          * 1000 entry dictionary...
 117          */
 118         for (i = 0; i < 1000; i++)
 119         {
 120                 px_md_reset(ctx1);
 121                 if (i & 1)
 122                         px_md_update(ctx1, (uint8 *) pw, strlen(pw));
 123                 else
 124                         px_md_update(ctx1, final, MD5_SIZE);
 125
 126                 if (i % 3)
 127                         px_md_update(ctx1, (uint8 *) sp, sl);
 128
 129                 if (i % 7)
 130                         px_md_update(ctx1, (uint8 *) pw, strlen(pw));
 131
 132                 if (i & 1)
 133                         px_md_update(ctx1, final, MD5_SIZE);
 134                 else
 135                         px_md_update(ctx1, (uint8 *) pw, strlen(pw));
 136                 px_md_finish(ctx1, final);
 137         }
 138
 139         p = passwd + strlen(passwd);
 140
 141         l = (final[0] << 16) | (final[6] << 8) | final[12];
 142         _crypt_to64(p, l, 4);
 143         p += 4;
 144         l = (final[1] << 16) | (final[7] << 8) | final[13];
 145         _crypt_to64(p, l, 4);
 146         p += 4;
 147         l = (final[2] << 16) | (final[8] << 8) | final[14];
 148         _crypt_to64(p, l, 4);
 149         p += 4;
 150         l = (final[3] << 16) | (final[9] << 8) | final[15];
 151         _crypt_to64(p, l, 4);
 152         p += 4;
 153         l = (final[4] << 16) | (final[10] << 8) | final[5];
 154         _crypt_to64(p, l, 4);
 155         p += 4;
 156         l = final[11];
 157         _crypt_to64(p, l, 2);
 158         p += 2;
 159         *p = '\0';
 160
 161         /* Don't leave anything around in vm they could use. */
 162         memset(final, 0, sizeof final);
 163
 164         px_md_free(ctx1);
 165         px_md_free(ctx);
 166
 167         return passwd;
 168 }