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md5crypt.c revision 1.5 
      1 /*	$NetBSD: md5crypt.c,v 1.5 2003/04/17 00:29:43 thorpej 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 1.5 2003/04/17 00:29:43 thorpej 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 #define MD5_MAGIC	"$1$"
     38 #define MD5_MAGIC_LEN	3
     39 
     40 char	*__md5crypt(const char *pw, const char *salt);	/* XXX */
     41 
     42 static unsigned char itoa64[] =		/* 0 ... 63 => ascii - 64 */
     43 	"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
     44 
     45 #ifdef libcrypto
     46 #define	INIT(x)			MD5_Init((x))
     47 #define	UPDATE(x, b, l)		MD5_Update((x), (b), (l))
     48 #define	FINAL(v, x)		MD5_Final((v), (x))
     49 #else
     50 #define	INIT(x)			MD5Init((x))
     51 #define	UPDATE(x, b, l)		MD5Update((x), (b), (l))
     52 #define	FINAL(v, x)		MD5Final((v), (x))
     53 #endif
     54 
     55 static void
     56 to64(char *s, u_int32_t v, int n)
     57 {
     58 
     59 	while (--n >= 0) {
     60 		*s++ = itoa64[v & 0x3f];
     61 		v >>= 6;
     62 	}
     63 }
     64 
     65 /*
     66  * MD5 password encryption.
     67  */
     68 char *
     69 __md5crypt(const char *pw, const char *salt)
     70 {
     71 	static char passwd[120], *p;
     72 	const char *sp, *ep;
     73 	unsigned char final[16];
     74 	unsigned int i, sl, pwl;
     75 	MD5_CTX	ctx, ctx1;
     76 	u_int32_t l;
     77 	int pl;
     78 
     79 	pwl = strlen(pw);
     80 
     81 	/* Refine the salt first */
     82 	sp = salt;
     83 
     84 	/* If it starts with the magic string, then skip that */
     85 	if (strncmp(sp, MD5_MAGIC, MD5_MAGIC_LEN) == 0)
     86 		sp += MD5_MAGIC_LEN;
     87 
     88 	/* It stops at the first '$', max 8 chars */
     89 	for (ep = sp; *ep != '\0' && *ep != '$' && ep < (sp + 8); ep++)
     90 		continue;
     91 
     92 	/* get the length of the true salt */
     93 	sl = ep - sp;
     94 
     95 	INIT(&ctx);
     96 
     97 	/* The password first, since that is what is most unknown */
     98 	UPDATE(&ctx, (const unsigned char *)pw, pwl);
     99 
    100 	/* Then our magic string */
    101 	UPDATE(&ctx, (const unsigned char *)MD5_MAGIC, MD5_MAGIC_LEN);
    102 
    103 	/* Then the raw salt */
    104 	UPDATE(&ctx, (const unsigned char *)sp, sl);
    105 
    106 	/* Then just as many characters of the MD5(pw,salt,pw) */
    107 	INIT(&ctx1);
    108 	UPDATE(&ctx1, (const unsigned char *)pw, pwl);
    109 	UPDATE(&ctx1, (const unsigned char *)sp, sl);
    110 	UPDATE(&ctx1, (const unsigned char *)pw, pwl);
    111 	FINAL(final, &ctx1);
    112 
    113 	for (pl = pwl; pl > 0; pl -= 16)
    114 		UPDATE(&ctx, final, (unsigned int)(pl > 16 ? 16 : pl));
    115 
    116 	/* Don't leave anything around in vm they could use. */
    117 	memset(final, 0, sizeof(final));
    118 
    119 	/* Then something really weird... */
    120 	for (i = pwl; i != 0; i >>= 1)
    121 		if ((i & 1) != 0)
    122 		    UPDATE(&ctx, final, 1);
    123 		else
    124 		    UPDATE(&ctx, (const unsigned char *)pw, 1);
    125 
    126 	/* Now make the output string */
    127 	memcpy(passwd, MD5_MAGIC, MD5_MAGIC_LEN);
    128 	strlcpy(passwd + MD5_MAGIC_LEN, sp, sl + 1);
    129 	strcat(passwd, "$");
    130 
    131 	FINAL(final, &ctx);
    132 
    133 	/*
    134 	 * And now, just to make sure things don't run too fast. On a 60 MHz
    135 	 * Pentium this takes 34 msec, so you would need 30 seconds to build
    136 	 * a 1000 entry dictionary...
    137 	 */
    138 	for (i = 0; i < 1000; i++) {
    139 		INIT(&ctx1);
    140 
    141 		if ((i & 1) != 0)
    142 			UPDATE(&ctx1, (const unsigned char *)pw, pwl);
    143 		else
    144 			UPDATE(&ctx1, final, 16);
    145 
    146 		if ((i % 3) != 0)
    147 			UPDATE(&ctx1, (const unsigned char *)sp, sl);
    148 
    149 		if ((i % 7) != 0)
    150 			UPDATE(&ctx1, (const unsigned char *)pw, pwl);
    151 
    152 		if ((i & 1) != 0)
    153 			UPDATE(&ctx1, final, 16);
    154 		else
    155 			UPDATE(&ctx1, (const unsigned char *)pw, pwl);
    156 
    157 		FINAL(final, &ctx1);
    158 	}
    159 
    160 	p = passwd + sl + MD5_MAGIC_LEN + 1;
    161 
    162 	l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; to64(p,l,4); p += 4;
    163 	l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; to64(p,l,4); p += 4;
    164 	l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; to64(p,l,4); p += 4;
    165 	l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; to64(p,l,4); p += 4;
    166 	l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; to64(p,l,4); p += 4;
    167 	l =		       final[11]		; to64(p,l,2); p += 2;
    168 	*p = '\0';
    169 
    170 	/* Don't leave anything around in vm they could use. */
    171 	memset(final, 0, sizeof(final));
    172 	return (passwd);
    173 }
    174