1505d05c7Sgtb /* 2*159d09a2SMark Phalan * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 3505d05c7Sgtb * Use is subject to license terms. 4505d05c7Sgtb */ 5505d05c7Sgtb 67c478bd9Sstevel@tonic-gate /* 77c478bd9Sstevel@tonic-gate * lib/krb5/krb/gen_seqnum.c 87c478bd9Sstevel@tonic-gate * 97c478bd9Sstevel@tonic-gate * Copyright 1991 by the Massachusetts Institute of Technology. 107c478bd9Sstevel@tonic-gate * All Rights Reserved. 117c478bd9Sstevel@tonic-gate * 127c478bd9Sstevel@tonic-gate * Export of this software from the United States of America may 137c478bd9Sstevel@tonic-gate * require a specific license from the United States Government. 147c478bd9Sstevel@tonic-gate * It is the responsibility of any person or organization contemplating 157c478bd9Sstevel@tonic-gate * export to obtain such a license before exporting. 167c478bd9Sstevel@tonic-gate * 177c478bd9Sstevel@tonic-gate * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and 187c478bd9Sstevel@tonic-gate * distribute this software and its documentation for any purpose and 197c478bd9Sstevel@tonic-gate * without fee is hereby granted, provided that the above copyright 207c478bd9Sstevel@tonic-gate * notice appear in all copies and that both that copyright notice and 217c478bd9Sstevel@tonic-gate * this permission notice appear in supporting documentation, and that 227c478bd9Sstevel@tonic-gate * the name of M.I.T. not be used in advertising or publicity pertaining 237c478bd9Sstevel@tonic-gate * to distribution of the software without specific, written prior 247c478bd9Sstevel@tonic-gate * permission. Furthermore if you modify this software you must label 257c478bd9Sstevel@tonic-gate * your software as modified software and not distribute it in such a 267c478bd9Sstevel@tonic-gate * fashion that it might be confused with the original M.I.T. software. 277c478bd9Sstevel@tonic-gate * M.I.T. makes no representations about the suitability of 287c478bd9Sstevel@tonic-gate * this software for any purpose. It is provided "as is" without express 297c478bd9Sstevel@tonic-gate * or implied warranty. 307c478bd9Sstevel@tonic-gate * 317c478bd9Sstevel@tonic-gate * 327c478bd9Sstevel@tonic-gate * Routine to automatically generate a starting sequence number. 337c478bd9Sstevel@tonic-gate * We do this by getting a random key and encrypting something with it, 347c478bd9Sstevel@tonic-gate * then taking the output and slicing it up. 357c478bd9Sstevel@tonic-gate */ 367c478bd9Sstevel@tonic-gate 37*159d09a2SMark Phalan #include "k5-int.h" 387c478bd9Sstevel@tonic-gate 397c478bd9Sstevel@tonic-gate #ifndef MIN 407c478bd9Sstevel@tonic-gate #define MIN(a,b) ((a) < (b) ? (a) : (b)) 417c478bd9Sstevel@tonic-gate #endif 427c478bd9Sstevel@tonic-gate 437c478bd9Sstevel@tonic-gate krb5_error_code 44505d05c7Sgtb krb5_generate_seq_number(krb5_context context, const krb5_keyblock *key, krb5_ui_4 *seqno) 457c478bd9Sstevel@tonic-gate { 467c478bd9Sstevel@tonic-gate krb5_data seed; 477c478bd9Sstevel@tonic-gate krb5_error_code retval; 48505d05c7Sgtb #if 0 49505d05c7Sgtb /* 50505d05c7Sgtb * Solaris Kerberos: Don't bother with this PRNG stuff, 51505d05c7Sgtb * we have /dev/random and PKCS#11 to handle Random Numbers. 52505d05c7Sgtb */ 53505d05c7Sgtb 547c478bd9Sstevel@tonic-gate 557c478bd9Sstevel@tonic-gate seed.length = key->length; 56*159d09a2SMark Phalan seed.data = key->contents; 57505d05c7Sgtb if ((retval = krb5_c_random_add_entropy(context, KRB5_C_RANDSOURCE_TRUSTEDPARTY, &seed))) 587c478bd9Sstevel@tonic-gate return(retval); 59505d05c7Sgtb #endif /* 0 */ 607c478bd9Sstevel@tonic-gate 617c478bd9Sstevel@tonic-gate seed.length = sizeof(*seqno); 627c478bd9Sstevel@tonic-gate seed.data = (char *) seqno; 63505d05c7Sgtb retval = krb5_c_random_make_octets(context, &seed); 64505d05c7Sgtb if (retval) 65505d05c7Sgtb return retval; 66505d05c7Sgtb /* 67505d05c7Sgtb * Work around implementation incompatibilities by not generating 68505d05c7Sgtb * initial sequence numbers greater than 2^30. Previous MIT 69505d05c7Sgtb * implementations use signed sequence numbers, so initial 70505d05c7Sgtb * sequence numbers 2^31 to 2^32-1 inclusive will be rejected. 71505d05c7Sgtb * Letting the maximum initial sequence number be 2^30-1 allows 72505d05c7Sgtb * for about 2^30 messages to be sent before wrapping into 73505d05c7Sgtb * "negative" numbers. 74505d05c7Sgtb */ 75505d05c7Sgtb *seqno &= 0x3fffffff; 76505d05c7Sgtb if (*seqno == 0) 77505d05c7Sgtb *seqno = 1; 78505d05c7Sgtb return 0; 797c478bd9Sstevel@tonic-gate } 80