/* * IRC - Internet Relay Chat, ircd/ircd_crypt_smd5.c * Copyright (C) 2002 hikari * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 1, or (at your option) * any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ /** * @file * @brief Routines for Salted MD5 passwords * @version $Id: ircd_crypt_smd5.c 1334 2005-03-20 16:06:30Z entrope $ * * ircd_crypt_smd5 is largely taken from md5_crypt.c from the Linux PAM * source code. it's been modified to fit in with ircu and some of the * unneeded code has been removed. the source file md5_crypt.c has the * following license, so if any of our opers or admins are in Denmark * they better go buy them a drink ;) -- hikari * * ---------------------------------------------------------------------------- * "THE BEER-WARE LICENSE" (Revision 42): * wrote this file. As long as you retain this notice you * can do whatever you want with this stuff. If we meet some day, and you think * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp * ---------------------------------------------------------------------------- * */ #include "config.h" #include "ircd_crypt.h" #include "ircd_crypt_smd5.h" #include "ircd_log.h" #include "ircd_md5.h" #include "s_debug.h" #include "ircd_alloc.h" /* #include -- Now using assert in ircd_log.h */ #include #include static unsigned char itoa64[] = /* 0 ... 63 => ascii - 64 */ "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; /** Converts a binary value into a BASE64 encoded string. * @param s Pointer to the output string * @param v The unsigned long we're working on * @param n The number of bytes we're working with * * This is used to produce the normal MD5 hash everyone is familiar with. * It takes the value v and converts n bytes of it it into an ASCII string in * 6-bit chunks, the resulting string is put at the address pointed to by s. * */ static void to64(char *s, unsigned long v, int n) { while (--n >= 0) { *s++ = itoa64[v & 0x3f]; v >>= 6; } } /** Produces a Salted MD5 crypt of a password using the supplied salt * @param key The password we're encrypting * @param salt The salt we're using to encrypt it * @return The Salted MD5 password of key and salt * * Erm does exactly what the brief comment says. If you think I'm writing a * description of how MD5 works, you have another think coming. Go and read * Applied Cryptography by Bruce Schneier. The only difference is we use a * salt at the beginning of the password to perturb it so that the same password * doesn't always produce the same hash. * */ const char* ircd_crypt_smd5(const char* key, const char* salt) { const char *magic = "$1$"; static char passwd[120]; char *p; const char *sp, *ep; unsigned char final[16]; int sl, pl, i, j; MD5_CTX ctx, ctx1; unsigned long l; assert(NULL != key); assert(NULL != salt); Debug((DEBUG_DEBUG, "ircd_crypt_smd5: key = %s", key)); Debug((DEBUG_DEBUG, "ircd_crypt_smd5: salt = %s", salt)); /* Refine the Salt first */ ep = sp = salt; for (ep = sp; *ep && *ep != '$' && ep < (sp + 8); ep++) continue; /* get the length of the true salt */ sl = ep - sp; MD5Init(&ctx); /* The password first, since that is what is most unknown */ MD5Update(&ctx,(unsigned const char *)key,strlen(key)); /* Then our magic string */ MD5Update(&ctx,(unsigned const char *)magic,strlen(magic)); /* Then the raw salt */ MD5Update(&ctx,(unsigned const char *)sp,sl); /* Then just as many characters of the MD5(key,salt,key) */ MD5Init(&ctx1); MD5Update(&ctx1,(unsigned const char *)key,strlen(key)); MD5Update(&ctx1,(unsigned const char *)sp,sl); MD5Update(&ctx1,(unsigned const char *)key,strlen(key)); MD5Final(final,&ctx1); for (pl = strlen(key); pl > 0; pl -= 16) MD5Update(&ctx,(unsigned const char *)final,pl>16 ? 16 : pl); /* Don't leave anything around in vm they could use. */ memset(final, 0, sizeof final); /* Then something really weird... */ for (j = 0, i = strlen(key); i; i >>= 1) if (i & 1) MD5Update(&ctx, (unsigned const char *)final+j, 1); else MD5Update(&ctx, (unsigned const char *)key+j, 1); /* Now make the output string. */ memset(passwd, 0, 120); strncpy(passwd, sp, sl); strcat(passwd, "$"); MD5Final(final,&ctx); /* * and now, just to make sure things don't run too fast * On a 60 Mhz Pentium this takes 34 msec, so you would * need 30 seconds to build a 1000 entry dictionary... */ for (i = 0; i < 1000; i++) { MD5Init(&ctx1); if (i & 1) MD5Update(&ctx1,(unsigned const char *)key,strlen(key)); else MD5Update(&ctx1,(unsigned const char *)final,16); if (i % 3) MD5Update(&ctx1,(unsigned const char *)sp,sl); if (i % 7) MD5Update(&ctx1,(unsigned const char *)key,strlen(key)); if (i & 1) MD5Update(&ctx1,(unsigned const char *)final,16); else MD5Update(&ctx1,(unsigned const char *)key,strlen(key)); MD5Final(final,&ctx1); } p = passwd + strlen(passwd); Debug((DEBUG_DEBUG, "passwd = %s", passwd)); /* Turn the encrypted binary data into a BASE64 encoded string we can read * and display -- hikari */ l = (final[0] << 16) | (final[6] << 8) | final[12]; to64(p, l, 4); p += 4; l = (final[1] << 16) | (final[7] << 8) | final[13]; to64(p, l, 4); p += 4; l = (final[2] << 16) | (final[8] << 8) | final[14]; to64(p, l, 4); p += 4; l = (final[3] << 16) | (final[9] << 8) | final[15]; to64(p, l, 4); p += 4; l = (final[4] << 16) | (final[10] << 8) | final[5]; to64(p, l, 4); p += 4; l = final[11]; to64(p, l, 2); p += 2; *p = '\0'; /* Don't leave anything around in vm they could use. */ memset(final, 0, sizeof final); return passwd; } /* end borrowed code */ /** Register ourself with the list of crypt mechanisms * Registers the SMD5 mechanism in the list of available crypt mechanisms. When * we're modular this will be the entry function for the module. * */ void ircd_register_crypt_smd5(void) { crypt_mech_t* crypt_mech; if ((crypt_mech = (crypt_mech_t*)MyMalloc(sizeof(crypt_mech_t))) == NULL) { Debug((DEBUG_MALLOC, "Could not allocate space for crypt_smd5")); return; } crypt_mech->mechname = "smd5"; crypt_mech->shortname = "crypt_smd5"; crypt_mech->description = "Salted MD5 password hash mechanism."; crypt_mech->crypt_function = &ircd_crypt_smd5; crypt_mech->crypt_token = "$SMD5$"; crypt_mech->crypt_token_size = 6 ; ircd_crypt_register_mech(crypt_mech); return; }