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Sourcecode: postgresql-8.4 version File versions

crypt-md5.c

/*
 * ----------------------------------------------------------------------------
 * "THE BEER-WARE LICENSE" (Revision 42):
 * <phk@login.dknet.dk> wrote this file.  As long as you retain this notice you
 * can do whatever you want with this stuff. If we meet some day, and you think
 * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
 * ----------------------------------------------------------------------------
 *
 * $FreeBSD$
 *
 * $PostgreSQL$
 */

#include "postgres.h"

#include "px.h"
#include "px-crypt.h"

#define MD5_SIZE 16

static const char _crypt_a64[] =
"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

static void
_crypt_to64(char *s, unsigned long v, int n)
{
      while (--n >= 0)
      {
            *s++ = _crypt_a64[v & 0x3f];
            v >>= 6;
      }
}

/*
 * UNIX password
 */

char *
px_crypt_md5(const char *pw, const char *salt, char *passwd, unsigned dstlen)
{
      static char *magic = "$1$"; /* This string is magic for this algorithm.
                                                 * Having it this way, we can get get better
                                                 * later on */
      static char *p;
      static const char *sp,
                     *ep;
      unsigned char final[MD5_SIZE];
      int               sl,
                        pl,
                        i;
      PX_MD    *ctx,
                     *ctx1;
      int               err;
      unsigned long l;

      if (!passwd || dstlen < 120)
            return NULL;

      /* Refine the Salt first */
      sp = salt;

      /* If it starts with the magic string, then skip that */
      if (!strncmp(sp, magic, strlen(magic)))
            sp += strlen(magic);

      /* It stops at the first '$', max 8 chars */
      for (ep = sp; *ep && *ep != '$' && ep < (sp + 8); ep++)
            continue;

      /* get the length of the true salt */
      sl = ep - sp;

      /* */
      err = px_find_digest("md5", &ctx);
      if (err)
            return NULL;
      err = px_find_digest("md5", &ctx1);

      /* The password first, since that is what is most unknown */
      px_md_update(ctx, (uint8 *) pw, strlen(pw));

      /* Then our magic string */
      px_md_update(ctx, (uint8 *) magic, strlen(magic));

      /* Then the raw salt */
      px_md_update(ctx, (uint8 *) sp, sl);

      /* Then just as many characters of the MD5(pw,salt,pw) */
      px_md_update(ctx1, (uint8 *) pw, strlen(pw));
      px_md_update(ctx1, (uint8 *) sp, sl);
      px_md_update(ctx1, (uint8 *) pw, strlen(pw));
      px_md_finish(ctx1, final);
      for (pl = strlen(pw); pl > 0; pl -= MD5_SIZE)
            px_md_update(ctx, final, pl > MD5_SIZE ? MD5_SIZE : pl);

      /* Don't leave anything around in vm they could use. */
      memset(final, 0, sizeof final);

      /* Then something really weird... */
      for (i = strlen(pw); i; i >>= 1)
            if (i & 1)
                  px_md_update(ctx, final, 1);
            else
                  px_md_update(ctx, (uint8 *) pw, 1);

      /* Now make the output string */
      strcpy(passwd, magic);
      strncat(passwd, sp, sl);
      strcat(passwd, "$");

      px_md_finish(ctx, final);

      /*
       * and now, just to make sure things don't run too fast On a 60 Mhz
       * Pentium this takes 34 msec, so you would need 30 seconds to build a
       * 1000 entry dictionary...
       */
      for (i = 0; i < 1000; i++)
      {
            px_md_reset(ctx1);
            if (i & 1)
                  px_md_update(ctx1, (uint8 *) pw, strlen(pw));
            else
                  px_md_update(ctx1, final, MD5_SIZE);

            if (i % 3)
                  px_md_update(ctx1, (uint8 *) sp, sl);

            if (i % 7)
                  px_md_update(ctx1, (uint8 *) pw, strlen(pw));

            if (i & 1)
                  px_md_update(ctx1, final, MD5_SIZE);
            else
                  px_md_update(ctx1, (uint8 *) pw, strlen(pw));
            px_md_finish(ctx1, final);
      }

      p = passwd + strlen(passwd);

      l = (final[0] << 16) | (final[6] << 8) | final[12];
      _crypt_to64(p, l, 4);
      p += 4;
      l = (final[1] << 16) | (final[7] << 8) | final[13];
      _crypt_to64(p, l, 4);
      p += 4;
      l = (final[2] << 16) | (final[8] << 8) | final[14];
      _crypt_to64(p, l, 4);
      p += 4;
      l = (final[3] << 16) | (final[9] << 8) | final[15];
      _crypt_to64(p, l, 4);
      p += 4;
      l = (final[4] << 16) | (final[10] << 8) | final[5];
      _crypt_to64(p, l, 4);
      p += 4;
      l = final[11];
      _crypt_to64(p, l, 2);
      p += 2;
      *p = '\0';

      /* Don't leave anything around in vm they could use. */
      memset(final, 0, sizeof final);

      px_md_free(ctx1);
      px_md_free(ctx);

      return passwd;
}

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