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/*
* lib/krb5/krb/gen_seqnum.c
*
* Copyright 1991 by the Massachusetts Institute of Technology.
* All Rights Reserved.
*
* Export of this software from the United States of America may
* require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
*
* Routine to automatically generate a starting sequence number.
* We do this by getting a random key and encrypting something with it,
* then taking the output and slicing it up.
*/
#include "k5-int.h"
#ifndef MIN
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#endif
krb5_error_code INTERFACE
krb5_generate_seq_number(context, key, seqno)
krb5_context context;
const krb5_keyblock *key;
krb5_int32 *seqno;
{
krb5_pointer random_state;
krb5_encrypt_block eblock;
krb5_keyblock *subkey = 0;
krb5_error_code retval;
struct tval {
krb5_int32 seconds;
krb5_int32 microseconds;
} timenow;
krb5_octet *intmp = 0, *outtmp = 0;
int esize;
if (!valid_keytype(key->keytype))
return KRB5_PROG_KEYTYPE_NOSUPP;
krb5_use_keytype(context, &eblock, key->keytype);
if (retval = krb5_init_random_key(context, &eblock, key, &random_state))
return(retval);
if (retval = krb5_random_key(context, &eblock, random_state, &subkey)) {
(void) krb5_finish_random_key(context, &eblock, &random_state);
return retval;
}
/* ignore the error if any, since we've already gotten the key out */
if (retval = krb5_finish_random_key(context, &eblock, &random_state)) {
krb5_free_keyblock(context, subkey);
return retval;
}
esize = krb5_encrypt_size(sizeof(timenow), eblock.crypto_entry);
intmp = (krb5_octet *)malloc(esize);
if (!intmp) {
retval = ENOMEM;
goto cleanup;
}
outtmp = (krb5_octet *)malloc(esize);
if (!outtmp) {
retval = ENOMEM;
goto cleanup;
}
if (retval = krb5_process_key(context, &eblock, subkey)) {
goto cleanup;
}
if (retval = krb5_us_timeofday(context, &timenow.seconds,
&timenow.microseconds)) {
goto cleanup;
}
memcpy((char *)intmp, (char *)&timenow, sizeof(timenow));
retval = krb5_encrypt(context, (krb5_pointer)intmp, (krb5_pointer)outtmp,
sizeof(timenow), &eblock, 0);
(void) krb5_finish_key(context, &eblock);
if (retval)
goto cleanup;
memcpy((char *) seqno, (char *)outtmp, sizeof(krb5_int32));
cleanup:
if (subkey)
krb5_free_keyblock(context, subkey);
if (intmp)
krb5_xfree(intmp);
if (outtmp)
krb5_xfree(outtmp);
return retval;
}
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