/* $OpenBSD: token.c,v 1.6 2001/08/18 18:31:21 deraadt Exp $ */ /*- * Copyright (c) 1995 Migration Associates Corp. All Rights Reserved * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by Berkeley Software Design, * Inc. * 4. The name of Berkeley Software Design, Inc. may not be used to endorse * or promote products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN, INC. ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN, INC. BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * BSDI $From: token.c,v 1.2 1996/08/28 22:07:55 prb Exp $ */ /* * DES functions for one-way encrypting Authentication Tokens. * All knowledge of DES is confined to this file. */ #include #include #include #include #include #include #include #include #include #include #include #include "token.h" #include "tokendb.h" /* * Define a union of various types of arguments to DES functions. * All native DES types are modulo 8 bytes in length. Cipher text * needs a trailing null byte. */ typedef union { des_cblock cb; char ct[9]; unsigned long ul[2]; } TOKEN_CBlock; /* * Static definition of random number challenge for token. * Challenge length is 8 bytes, left-justified with trailing null byte. */ static TOKEN_CBlock tokennumber; /* * Static function prototypes */ static void tokenseed(TOKEN_CBlock *); static void lcase(char *); static void h2d(char *); static void h2cb(char *, TOKEN_CBlock *); static void cb2h(TOKEN_CBlock, char *); /* * Generate random DES cipherblock seed. Feedback key into * new_random_key to strengthen. */ static void tokenseed(TOKEN_CBlock *cb) { cb->ul[0] = arc4random(); cb->ul[1] = arc4random(); } /* * Send a random challenge string to the token. The challenge * is always base 10 as there are no alpha keys on the keyboard. */ void tokenchallenge(char *user, char *challenge, int size, char *card_type) { TOKENDB_Rec tr; TOKEN_CBlock cb; des_key_schedule ks; int r, c; r = 1; /* no reduced input mode by default! */ if ((tt->modes & TOKEN_RIM) && tokendb_getrec(user, &tr) == 0 && (tr.mode & TOKEN_RIM)) { c = 0; while ((r = tokendb_lockrec(user, &tr, TOKEN_LOCKED)) == 1) { if (c++ >= 60) break; sleep(1); } tr.flags &= ~TOKEN_LOCKED; if (r == 0 && tr.rim[0]) { h2cb(tr.secret, &cb); des_fixup_key_parity(&cb.cb); des_key_sched(&cb.cb, ks); des_ecb_encrypt(&tr.rim, &cb.cb, ks, DES_ENCRYPT); memcpy(tr.rim, cb.cb, 8); for (r = 0; r < 8; ++r) { if ((tr.rim[r] &= 0xf) > 9) tr.rim[r] -= 10; tr.rim[r] |= 0x30; } r = 0; /* reset it back */ memcpy(tokennumber.ct, tr.rim, 8); tokennumber.ct[8] = 0; tokendb_putrec(user, &tr); } } if (r != 0 || tr.rim[0] == '\0') { memset(tokennumber.ct, 0, sizeof(tokennumber.ct)); snprintf(tokennumber.ct, sizeof(tokennumber.ct), "%8.8u", arc4random()); if (r == 0) { memcpy(tr.rim, tokennumber.ct, 8); tokendb_putrec(user, &tr); } } snprintf(challenge, size, "%s Challenge \"%s\"\r\n%s Response: ", card_type, tokennumber.ct, card_type); } /* * Verify response from user against token's predicted cipher * of the random number challenge. */ int tokenverify(char *username, char *challenge, char *response) { char *state; TOKENDB_Rec tokenrec; TOKEN_CBlock tmp; TOKEN_CBlock cmp_text; TOKEN_CBlock user_seed; TOKEN_CBlock cipher_text; des_key_schedule key_schedule; memset(cmp_text.ct, 0, sizeof(cmp_text.ct)); memset(user_seed.ct, 0, sizeof(user_seed.ct)); memset(cipher_text.ct, 0, sizeof(cipher_text.ct)); memset(tokennumber.ct, 0, sizeof(tokennumber.ct)); state = strtok(challenge, "\""); state = strtok(NULL, "\""); tmp.ul[0] = strtoul(state, NULL, 10); snprintf(tokennumber.ct, sizeof(tokennumber.ct), "%8.8lu",tmp.ul[0]); /* * Retrieve the db record for the user. Nuke it as soon as * we have translated out the user's shared secret just in * case we (somehow) get core dumped... */ if (tokendb_getrec(username, &tokenrec)) return (-1); h2cb(tokenrec.secret, &user_seed); memset((char*)&tokenrec.secret, 0, sizeof(tokenrec.secret)); if (!(tokenrec.flags & TOKEN_ENABLED)) return (-1); /* * Compute the anticipated response in hex. Nuke the user's * shared secret asap. */ des_fixup_key_parity(&user_seed.cb); des_key_sched(&user_seed.cb, key_schedule); memset(user_seed.ct, 0, sizeof(user_seed.ct)); des_ecb_encrypt(&tokennumber.cb, &cipher_text.cb, key_schedule, DES_ENCRYPT); memset(key_schedule, 0, sizeof(key_schedule)); /* * The token thinks it's descended from VAXen. Deal with i386 * endian-ness of binary cipher prior to generating ascii from first * 32 bits. */ HTONL(cipher_text.ul[0]); snprintf(cmp_text.ct, sizeof(cmp_text.ct), "%8.8lx", cipher_text.ul[0]); if (tokenrec.mode & TOKEN_PHONEMODE) { /* * If we are a CRYPTOCard, we need to see if we are in * "telephone number mode". If so, transmogrify the fourth * digit of the cipher. Lower case response just in case * it's * hex. Compare hex cipher with anticipated response * from token. */ lcase(response); if (response[3] == '-') cmp_text.ct[3] = '-'; } if ((tokenrec.mode & TOKEN_HEXMODE) && !strcmp(response, cmp_text.ct)) return (0); /* * No match against the computed hex cipher. The token could be * in decimal mode. Pervert the string to magic decimal equivalent. */ h2d(cmp_text.ct); if ((tokenrec.mode & TOKEN_DECMODE) && !strcmp(response, cmp_text.ct)) return (0); return (-1); } /* * Initialize a new user record in the token database. */ int tokenuserinit(int flags, char *username, unsigned char *usecret, unsigned mode) { TOKENDB_Rec tokenrec; TOKEN_CBlock secret; TOKEN_CBlock nulls; TOKEN_CBlock checksum; TOKEN_CBlock checktxt; des_key_schedule key_schedule; memset(&secret.ct, 0, sizeof(secret)); /* * If no user secret passed in, create one */ if ( (flags & TOKEN_GENSECRET) ) tokenseed(&secret); else memcpy(&secret, usecret, sizeof(des_cblock)); des_fixup_key_parity(&secret.cb); /* * Check if the db record already exists. If no * force-init flag and it exists, go away. Else, * create the user's db record and put to the db. */ if (!(flags & TOKEN_FORCEINIT) && tokendb_getrec(username, &tokenrec) == 0) return (1); memset(&tokenrec, 0, sizeof(tokenrec)); strlcpy(tokenrec.uname, username, sizeof(tokenrec.uname)); cb2h(secret, tokenrec.secret); tokenrec.mode = 0; tokenrec.flags = TOKEN_ENABLED | TOKEN_USEMODES; tokenrec.mode = mode; memset(tokenrec.reserved_char1, '0', sizeof(tokenrec.reserved_char1)); memset(tokenrec.reserved_char2, '0', sizeof(tokenrec.reserved_char2)); if (tokendb_putrec(username, &tokenrec)) return (-1); /* * Check if the shared secret was generated here. If so, we * need to inform the user about it in order that it can be * programmed into the token. See tokenverify() (above) for * discussion of cipher generation. */ if (!(flags & TOKEN_GENSECRET)) { memset(&secret.ct, 0, sizeof(secret)); return (0); } printf("Shared secret for %s\'s token: " "%03o %03o %03o %03o %03o %03o %03o %03o\n", username, secret.cb[0], secret.cb[1], secret.cb[2], secret.cb[3], secret.cb[4], secret.cb[5], secret.cb[6], secret.cb[7]); des_key_sched(&secret.cb, key_schedule); memset(&secret.ct, 0, sizeof(secret)); memset(&nulls, 0, sizeof(nulls)); des_ecb_encrypt(&nulls.cb, &checksum.cb, key_schedule, DES_ENCRYPT); memset(key_schedule, 0, sizeof(key_schedule)); HTONL(checksum.ul[0]); snprintf(checktxt.ct, sizeof(checktxt.ct), "%8.8lx", checksum.ul[0]); printf("Hex Checksum: \"%s\"", checktxt.ct); h2d(checktxt.ct); printf("\tDecimal Checksum: \"%s\"\n", checktxt.ct); return (0); } /* * Magically transform a hex character string into a decimal character * string as defined by the token card vendor. The string should have * been lowercased by now. */ static void h2d(char *cp) { int i; for (i=0; i= 'a' && *cp <= 'f') *cp = tt->map[*cp - 'a']; } } /* * Translate an hex 16 byte ascii representation of an unsigned * integer to a des_cblock. */ static void h2cb(char *hp, TOKEN_CBlock *cb) { char scratch[9]; strlcpy(scratch, hp, sizeof(scratch)); cb->ul[0] = strtoul(scratch, NULL, 16); strlcpy(scratch, hp + 8, sizeof(scratch)); cb->ul[1] = strtoul(scratch, NULL, 16); } /* * Translate a des_cblock to an 16 byte ascii hex representation. */ static void cb2h(TOKEN_CBlock cb, char* hp) { char scratch[17]; snprintf(scratch, 9, "%8.8lx", cb.ul[0]); snprintf(scratch+8, 9, "%8.8lx", cb.ul[1]); memcpy(hp, scratch, 16); } /* * Lowercase possible hex response */ static void lcase(char *cp) { while (*cp) { if (isupper(*cp)) *cp = tolower(*cp); cp++; } }