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md5crypt.c revision 1.10 
      1 /*	$NetBSD: md5crypt.c,v 1.10 2011/11/29 13:18:52 drochner 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 1.10 2011/11/29 13:18:52 drochner 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 
     36 #include "crypt.h"
     37 
     38 #define MD5_MAGIC	"$1$"
     39 #define MD5_MAGIC_LEN	3
     40 
     41 #ifdef libcrypto
     42 #define	INIT(x)			MD5_Init((x))
     43 #define	UPDATE(x, b, l)		MD5_Update((x), (b), (l))
     44 #define	FINAL(v, x)		MD5_Final((v), (x))
     45 #else
     46 #define	INIT(x)			MD5Init((x))
     47 #define	UPDATE(x, b, l)		MD5Update((x), (b), (l))
     48 #define	FINAL(v, x)		MD5Final((v), (x))
     49 #endif
     50 
     51 
     52 /*
     53  * MD5 password encryption.
     54  */
     55 char *
     56 __md5crypt(const char *pw, const char *salt)
     57 {
     58 	static char passwd[120], *p;
     59 	const char *sp, *ep;
     60 	unsigned char final[16];
     61 	unsigned int i, sl, pwl;
     62 	MD5_CTX	ctx, ctx1;
     63 	u_int32_t l;
     64 	int pl;
     65 
     66 	pwl = strlen(pw);
     67 
     68 	/* Refine the salt first */
     69 	sp = salt;
     70 
     71 	/* If it starts with the magic string, then skip that */
     72 	if (strncmp(sp, MD5_MAGIC, MD5_MAGIC_LEN) == 0)
     73 		sp += MD5_MAGIC_LEN;
     74 
     75 	/* It stops at the first '$', max 8 chars */
     76 	for (ep = sp; *ep != '\0' && *ep != '$' && ep < (sp + 8); ep++)
     77 		continue;
     78 
     79 	/* get the length of the true salt */
     80 	sl = ep - sp;
     81 
     82 	INIT(&ctx);
     83 
     84 	/* The password first, since that is what is most unknown */
     85 	UPDATE(&ctx, (const unsigned char *)pw, pwl);
     86 
     87 	/* Then our magic string */
     88 	UPDATE(&ctx, (const unsigned char *)MD5_MAGIC, MD5_MAGIC_LEN);
     89 
     90 	/* Then the raw salt */
     91 	UPDATE(&ctx, (const unsigned char *)sp, sl);
     92 
     93 	/* Then just as many characters of the MD5(pw,salt,pw) */
     94 	INIT(&ctx1);
     95 	UPDATE(&ctx1, (const unsigned char *)pw, pwl);
     96 	UPDATE(&ctx1, (const unsigned char *)sp, sl);
     97 	UPDATE(&ctx1, (const unsigned char *)pw, pwl);
     98 	FINAL(final, &ctx1);
     99 
    100 	for (pl = pwl; pl > 0; pl -= 16)
    101 		UPDATE(&ctx, final, (unsigned int)(pl > 16 ? 16 : pl));
    102 
    103 	/* Don't leave anything around in vm they could use. */
    104 	memset(final, 0, sizeof(final));
    105 
    106 	/* Then something really weird... */
    107 	for (i = pwl; i != 0; i >>= 1)
    108 		if ((i & 1) != 0)
    109 		    UPDATE(&ctx, final, 1);
    110 		else
    111 		    UPDATE(&ctx, (const unsigned char *)pw, 1);
    112 
    113 	/* Now make the output string */
    114 	memcpy(passwd, MD5_MAGIC, MD5_MAGIC_LEN);
    115 	strlcpy(passwd + MD5_MAGIC_LEN, sp, sl + 1);
    116 	strlcat(passwd, "$", sizeof(passwd));
    117 
    118 	FINAL(final, &ctx);
    119 
    120 	/* Don't leave anything around in vm they could use. */
    121 	memset(&ctx, 0, sizeof(ctx));
    122 
    123 	/*
    124 	 * And now, just to make sure things don't run too fast. On a 60 MHz
    125 	 * Pentium this takes 34 msec, so you would need 30 seconds to build
    126 	 * a 1000 entry dictionary...
    127 	 */
    128 	for (i = 0; i < 1000; i++) {
    129 		INIT(&ctx1);
    130 
    131 		if ((i & 1) != 0)
    132 			UPDATE(&ctx1, (const unsigned char *)pw, pwl);
    133 		else
    134 			UPDATE(&ctx1, final, 16);
    135 
    136 		if ((i % 3) != 0)
    137 			UPDATE(&ctx1, (const unsigned char *)sp, sl);
    138 
    139 		if ((i % 7) != 0)
    140 			UPDATE(&ctx1, (const unsigned char *)pw, pwl);
    141 
    142 		if ((i & 1) != 0)
    143 			UPDATE(&ctx1, final, 16);
    144 		else
    145 			UPDATE(&ctx1, (const unsigned char *)pw, pwl);
    146 
    147 		FINAL(final, &ctx1);
    148 	}
    149 
    150 	/* Don't leave anything around in vm they could use. */
    151 	memset(&ctx1, 0, sizeof(ctx1));
    152 
    153 	p = passwd + sl + MD5_MAGIC_LEN + 1;
    154 
    155 	l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; __crypt_to64(p,l,4); p += 4;
    156 	l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; __crypt_to64(p,l,4); p += 4;
    157 	l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; __crypt_to64(p,l,4); p += 4;
    158 	l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; __crypt_to64(p,l,4); p += 4;
    159 	l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; __crypt_to64(p,l,4); p += 4;
    160 	l =		       final[11]		; __crypt_to64(p,l,2); p += 2;
    161 	*p = '\0';
    162 
    163 	/* Don't leave anything around in vm they could use. */
    164 	memset(final, 0, sizeof(final));
    165 	return (passwd);
    166 }
    167