1 /* 2 * ---------------------------------------------------------------------------- 3 * "THE BEER-WARE LICENSE" (Revision 42): 4 * <phk@FreeBSD.org> wrote this file. As long as you retain this notice you 5 * can do whatever you want with this stuff. If we meet some day, and you think 6 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp 7 * ---------------------------------------------------------------------------- 8 */ 9 10 #include <sys/cdefs.h> 11 __FBSDID("$FreeBSD$"); 12 13 #include <unistd.h> 14 #include <stdio.h> 15 #include <string.h> 16 #include <md5.h> 17 #include <err.h> 18 #include "crypt.h" 19 20 /* 21 * UNIX password 22 */ 23 24 char * 25 crypt_md5(const char *pw, const char *salt) 26 { 27 MD5_CTX ctx,ctx1; 28 unsigned long l; 29 int sl, pl; 30 u_int i; 31 u_char final[MD5_SIZE]; 32 static const char *sp, *ep; 33 static char passwd[120], *p; 34 static const char *magic = "$1$"; /* 35 * This string is magic for 36 * this algorithm. Having 37 * it this way, we can get 38 * better later on. 39 */ 40 41 /* Refine the Salt first */ 42 sp = salt; 43 44 /* If it starts with the magic string, then skip that */ 45 if(!strncmp(sp, magic, strlen(magic))) 46 sp += strlen(magic); 47 48 /* It stops at the first '$', max 8 chars */ 49 for(ep = sp; *ep && *ep != '$' && ep < (sp + 8); ep++) 50 continue; 51 52 /* get the length of the true salt */ 53 sl = ep - sp; 54 55 MD5Init(&ctx); 56 57 /* The password first, since that is what is most unknown */ 58 MD5Update(&ctx, (const u_char *)pw, strlen(pw)); 59 60 /* Then our magic string */ 61 MD5Update(&ctx, (const u_char *)magic, strlen(magic)); 62 63 /* Then the raw salt */ 64 MD5Update(&ctx, (const u_char *)sp, (u_int)sl); 65 66 /* Then just as many characters of the MD5(pw,salt,pw) */ 67 MD5Init(&ctx1); 68 MD5Update(&ctx1, (const u_char *)pw, strlen(pw)); 69 MD5Update(&ctx1, (const u_char *)sp, (u_int)sl); 70 MD5Update(&ctx1, (const u_char *)pw, strlen(pw)); 71 MD5Final(final, &ctx1); 72 for(pl = (int)strlen(pw); pl > 0; pl -= MD5_SIZE) 73 MD5Update(&ctx, (const u_char *)final, 74 (u_int)(pl > MD5_SIZE ? MD5_SIZE : pl)); 75 76 /* Don't leave anything around in vm they could use. */ 77 memset(final, 0, sizeof(final)); 78 79 /* Then something really weird... */ 80 for (i = strlen(pw); i; i >>= 1) 81 if(i & 1) 82 MD5Update(&ctx, (const u_char *)final, 1); 83 else 84 MD5Update(&ctx, (const u_char *)pw, 1); 85 86 /* Now make the output string */ 87 strcpy(passwd, magic); 88 strncat(passwd, sp, (u_int)sl); 89 strcat(passwd, "$"); 90 91 MD5Final(final, &ctx); 92 93 /* 94 * and now, just to make sure things don't run too fast 95 * On a 60 Mhz Pentium this takes 34 msec, so you would 96 * need 30 seconds to build a 1000 entry dictionary... 97 */ 98 for(i = 0; i < 1000; i++) { 99 MD5Init(&ctx1); 100 if(i & 1) 101 MD5Update(&ctx1, (const u_char *)pw, strlen(pw)); 102 else 103 MD5Update(&ctx1, (const u_char *)final, MD5_SIZE); 104 105 if(i % 3) 106 MD5Update(&ctx1, (const u_char *)sp, (u_int)sl); 107 108 if(i % 7) 109 MD5Update(&ctx1, (const u_char *)pw, strlen(pw)); 110 111 if(i & 1) 112 MD5Update(&ctx1, (const u_char *)final, MD5_SIZE); 113 else 114 MD5Update(&ctx1, (const u_char *)pw, strlen(pw)); 115 MD5Final(final, &ctx1); 116 } 117 118 p = passwd + strlen(passwd); 119 120 l = (final[ 0]<<16) | (final[ 6]<<8) | final[12]; 121 _crypt_to64(p, l, 4); p += 4; 122 l = (final[ 1]<<16) | (final[ 7]<<8) | final[13]; 123 _crypt_to64(p, l, 4); p += 4; 124 l = (final[ 2]<<16) | (final[ 8]<<8) | final[14]; 125 _crypt_to64(p, l, 4); p += 4; 126 l = (final[ 3]<<16) | (final[ 9]<<8) | final[15]; 127 _crypt_to64(p, l, 4); p += 4; 128 l = (final[ 4]<<16) | (final[10]<<8) | final[ 5]; 129 _crypt_to64(p, l, 4); p += 4; 130 l = final[11] ; 131 _crypt_to64(p, l, 2); p += 2; 132 *p = '\0'; 133 134 /* Don't leave anything around in vm they could use. */ 135 memset(final, 0, sizeof(final)); 136 137 return passwd; 138 } 139 140