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md5crypt.c revision 1.8 
      1 /*	$NetBSD: md5crypt.c,v 1.8 2004/07/02 00:05:23 sjg Exp $	*/
      2 
      3 /*
      4  * ----------------------------------------------------------------------------
      5  * "THE BEER-WARE LICENSE" (Revision 42):
      6  * <phk (at) login.dknet.dk> wrote this file.  As long as you retain this notice you
      7  * can do whatever you want with this stuff. If we meet some day, and you think
      8  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
      9  * ----------------------------------------------------------------------------
     10  *
     11  * from FreeBSD: crypt.c,v 1.5 1996/10/14 08:34:02 phk Exp
     12  * via OpenBSD: md5crypt.c,v 1.9 1997/07/23 20:58:27 kstailey Exp
     13  *
     14  */
     15 
     16 #include <sys/cdefs.h>
     17 #if !defined(lint)
     18 __RCSID("$NetBSD: md5crypt.c,v 1.8 2004/07/02 00:05:23 sjg Exp $");
     19 #endif /* not lint */
     20 
     21 /*
     22  * NOTE: We are also built for inclusion in libcrypto; when built for that
     23  * environment, use the libcrypto versions of the MD5 routines, so save
     24  * having to pull two versions into the same program.
     25  */
     26 
     27 #include <unistd.h>
     28 #include <stdio.h>
     29 #include <string.h>
     30 #ifdef libcrypto
     31 #include <openssl/md5.h>
     32 #else
     33 #include <md5.h>
     34 #endif
     35 #include <string.h>
     36 
     37 #include "crypt.h"
     38 
     39 #define MD5_MAGIC	"$1$"
     40 #define MD5_MAGIC_LEN	3
     41 
     42 #ifdef libcrypto
     43 #define	INIT(x)			MD5_Init((x))
     44 #define	UPDATE(x, b, l)		MD5_Update((x), (b), (l))
     45 #define	FINAL(v, x)		MD5_Final((v), (x))
     46 #else
     47 #define	INIT(x)			MD5Init((x))
     48 #define	UPDATE(x, b, l)		MD5Update((x), (b), (l))
     49 #define	FINAL(v, x)		MD5Final((v), (x))
     50 #endif
     51 
     52 
     53 /*
     54  * MD5 password encryption.
     55  */
     56 char *
     57 __md5crypt(const char *pw, const char *salt)
     58 {
     59 	static char passwd[120], *p;
     60 	const char *sp, *ep;
     61 	unsigned char final[16];
     62 	unsigned int i, sl, pwl;
     63 	MD5_CTX	ctx, ctx1;
     64 	u_int32_t l;
     65 	int pl;
     66 
     67 	pwl = strlen(pw);
     68 
     69 	/* Refine the salt first */
     70 	sp = salt;
     71 
     72 	/* If it starts with the magic string, then skip that */
     73 	if (strncmp(sp, MD5_MAGIC, MD5_MAGIC_LEN) == 0)
     74 		sp += MD5_MAGIC_LEN;
     75 
     76 	/* It stops at the first '$', max 8 chars */
     77 	for (ep = sp; *ep != '\0' && *ep != '$' && ep < (sp + 8); ep++)
     78 		continue;
     79 
     80 	/* get the length of the true salt */
     81 	sl = ep - sp;
     82 
     83 	INIT(&ctx);
     84 
     85 	/* The password first, since that is what is most unknown */
     86 	UPDATE(&ctx, (const unsigned char *)pw, pwl);
     87 
     88 	/* Then our magic string */
     89 	UPDATE(&ctx, (const unsigned char *)MD5_MAGIC, MD5_MAGIC_LEN);
     90 
     91 	/* Then the raw salt */
     92 	UPDATE(&ctx, (const unsigned char *)sp, sl);
     93 
     94 	/* Then just as many characters of the MD5(pw,salt,pw) */
     95 	INIT(&ctx1);
     96 	UPDATE(&ctx1, (const unsigned char *)pw, pwl);
     97 	UPDATE(&ctx1, (const unsigned char *)sp, sl);
     98 	UPDATE(&ctx1, (const unsigned char *)pw, pwl);
     99 	FINAL(final, &ctx1);
    100 
    101 	for (pl = pwl; pl > 0; pl -= 16)
    102 		UPDATE(&ctx, final, (unsigned int)(pl > 16 ? 16 : pl));
    103 
    104 	/* Don't leave anything around in vm they could use. */
    105 	memset(final, 0, sizeof(final));
    106 
    107 	/* Then something really weird... */
    108 	for (i = pwl; i != 0; i >>= 1)
    109 		if ((i & 1) != 0)
    110 		    UPDATE(&ctx, final, 1);
    111 		else
    112 		    UPDATE(&ctx, (const unsigned char *)pw, 1);
    113 
    114 	/* Now make the output string */
    115 	memcpy(passwd, MD5_MAGIC, MD5_MAGIC_LEN);
    116 	strlcpy(passwd + MD5_MAGIC_LEN, sp, sl + 1);
    117 	strlcat(passwd, "$", sizeof(passwd));
    118 
    119 	FINAL(final, &ctx);
    120 
    121 	/*
    122 	 * And now, just to make sure things don't run too fast. On a 60 MHz
    123 	 * Pentium this takes 34 msec, so you would need 30 seconds to build
    124 	 * a 1000 entry dictionary...
    125 	 */
    126 	for (i = 0; i < 1000; i++) {
    127 		INIT(&ctx1);
    128 
    129 		if ((i & 1) != 0)
    130 			UPDATE(&ctx1, (const unsigned char *)pw, pwl);
    131 		else
    132 			UPDATE(&ctx1, final, 16);
    133 
    134 		if ((i % 3) != 0)
    135 			UPDATE(&ctx1, (const unsigned char *)sp, sl);
    136 
    137 		if ((i % 7) != 0)
    138 			UPDATE(&ctx1, (const unsigned char *)pw, pwl);
    139 
    140 		if ((i & 1) != 0)
    141 			UPDATE(&ctx1, final, 16);
    142 		else
    143 			UPDATE(&ctx1, (const unsigned char *)pw, pwl);
    144 
    145 		FINAL(final, &ctx1);
    146 	}
    147 
    148 	p = passwd + sl + MD5_MAGIC_LEN + 1;
    149 
    150 	l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; __crypt_to64(p,l,4); p += 4;
    151 	l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; __crypt_to64(p,l,4); p += 4;
    152 	l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; __crypt_to64(p,l,4); p += 4;
    153 	l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; __crypt_to64(p,l,4); p += 4;
    154 	l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; __crypt_to64(p,l,4); p += 4;
    155 	l =		       final[11]		; __crypt_to64(p,l,2); p += 2;
    156 	*p = '\0';
    157 
    158 	/* Don't leave anything around in vm they could use. */
    159 	memset(final, 0, sizeof(final));
    160 	return (passwd);
    161 }
    162