1 /* $NetBSD: md5crypt.c,v 1.14 2013/08/28 17:47:07 riastradh Exp $ */ 2 3 /* 4 * ---------------------------------------------------------------------------- 5 * "THE BEER-WARE LICENSE" (Revision 42): 6 * <phk@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 1.14 2013/08/28 17:47:07 riastradh Exp $"); 19 #endif /* not lint */ 20 21 #include <unistd.h> 22 #include <stdio.h> 23 #include <string.h> 24 #include <md5.h> 25 26 #include "crypt.h" 27 28 #define MD5_MAGIC "$1$" 29 #define MD5_MAGIC_LEN 3 30 31 #define INIT(x) MD5Init((x)) 32 #define UPDATE(x, b, l) MD5Update((x), (b), (l)) 33 #define FINAL(v, x) MD5Final((v), (x)) 34 35 36 /* 37 * MD5 password encryption. 38 */ 39 char * 40 __md5crypt(const char *pw, const char *salt) 41 { 42 static char passwd[120], *p; 43 const char *sp, *ep; 44 unsigned char final[16]; 45 unsigned int i, sl, pwl; 46 MD5_CTX ctx, ctx1; 47 u_int32_t l; 48 int pl; 49 50 pwl = strlen(pw); 51 52 /* Refine the salt first */ 53 sp = salt; 54 55 /* If it starts with the magic string, then skip that */ 56 if (strncmp(sp, MD5_MAGIC, MD5_MAGIC_LEN) == 0) 57 sp += MD5_MAGIC_LEN; 58 59 /* It stops at the first '$', max 8 chars */ 60 for (ep = sp; *ep != '\0' && *ep != '$' && ep < (sp + 8); ep++) 61 continue; 62 63 /* get the length of the true salt */ 64 sl = ep - sp; 65 66 INIT(&ctx); 67 68 /* The password first, since that is what is most unknown */ 69 UPDATE(&ctx, (const unsigned char *)pw, pwl); 70 71 /* Then our magic string */ 72 UPDATE(&ctx, (const unsigned char *)MD5_MAGIC, MD5_MAGIC_LEN); 73 74 /* Then the raw salt */ 75 UPDATE(&ctx, (const unsigned char *)sp, sl); 76 77 /* Then just as many characters of the MD5(pw,salt,pw) */ 78 INIT(&ctx1); 79 UPDATE(&ctx1, (const unsigned char *)pw, pwl); 80 UPDATE(&ctx1, (const unsigned char *)sp, sl); 81 UPDATE(&ctx1, (const unsigned char *)pw, pwl); 82 FINAL(final, &ctx1); 83 84 for (pl = pwl; pl > 0; pl -= 16) 85 UPDATE(&ctx, final, (unsigned int)(pl > 16 ? 16 : pl)); 86 87 /* Don't leave anything around in vm they could use. */ 88 memset(final, 0, sizeof(final)); 89 90 /* Then something really weird... */ 91 for (i = pwl; i != 0; i >>= 1) 92 if ((i & 1) != 0) 93 UPDATE(&ctx, final, 1); 94 else 95 UPDATE(&ctx, (const unsigned char *)pw, 1); 96 97 /* Now make the output string */ 98 memcpy(passwd, MD5_MAGIC, MD5_MAGIC_LEN); 99 strlcpy(passwd + MD5_MAGIC_LEN, sp, sl + 1); 100 strlcat(passwd, "$", sizeof(passwd)); 101 102 FINAL(final, &ctx); 103 104 /* memset(&ctx, 0, sizeof(ctx)); done by MD5Final() */ 105 106 /* 107 * And now, just to make sure things don't run too fast. On a 60 MHz 108 * Pentium this takes 34 msec, so you would need 30 seconds to build 109 * a 1000 entry dictionary... 110 */ 111 for (i = 0; i < 1000; i++) { 112 INIT(&ctx1); 113 114 if ((i & 1) != 0) 115 UPDATE(&ctx1, (const unsigned char *)pw, pwl); 116 else 117 UPDATE(&ctx1, final, 16); 118 119 if ((i % 3) != 0) 120 UPDATE(&ctx1, (const unsigned char *)sp, sl); 121 122 if ((i % 7) != 0) 123 UPDATE(&ctx1, (const unsigned char *)pw, pwl); 124 125 if ((i & 1) != 0) 126 UPDATE(&ctx1, final, 16); 127 else 128 UPDATE(&ctx1, (const unsigned char *)pw, pwl); 129 130 FINAL(final, &ctx1); 131 } 132 133 /* memset(&ctx1, 0, sizeof(ctx1)); done by MD5Final() */ 134 135 p = passwd + sl + MD5_MAGIC_LEN + 1; 136 137 l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; __crypt_to64(p,l,4); p += 4; 138 l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; __crypt_to64(p,l,4); p += 4; 139 l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; __crypt_to64(p,l,4); p += 4; 140 l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; __crypt_to64(p,l,4); p += 4; 141 l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; __crypt_to64(p,l,4); p += 4; 142 l = final[11] ; __crypt_to64(p,l,2); p += 2; 143 *p = '\0'; 144 145 /* Don't leave anything around in vm they could use. */ 146 explicit_memset(final, 0, sizeof(final)); 147 return (passwd); 148 } 149