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/*
* $Source$
* $Author$
*
* Copyright 1990 by the Massachusetts Institute of Technology.
*
* For copying and distribution information, please see the file
* <krb5/copyright.h>.
*
* krb5_rd_req_decoded()
*/
#if !defined(lint) && !defined(SABER)
static char rd_req_dec_c[] =
"$Id$";
#endif /* !lint & !SABER */
#include <krb5/copyright.h>
#include <krb5/krb5.h>
#include <krb5/ext-proto.h>
#include <krb5/libos-proto.h>
#include <krb5/asn1.h>
/*
essentially the same as krb_rd_req, but uses a decoded AP_REQ as the input
rather than an encoded input.
*/
/*
Parses a KRB_AP_REQ message, returning its contents.
server specifies the expected server's name for the ticket.
sender_addr specifies the address(es) expected to be present in the
ticket.
rcache specifies a replay detection cache used to store authenticators and
server names
keyproc specifies a procedure to generate a decryption key for the
ticket. If keyproc is non-NULL, keyprocarg is passed to it, and the result
used as a decryption key. If keyproc is NULL, then fetchfrom is checked;
if it is non-NULL, it specifies a parameter name from which to retrieve the
decryption key. If fetchfrom is NULL, then the default key store is
consulted.
authdat->ticket and authdat->authenticator are set to allocated storage
structures; the caller should free them when finished.
returns system errors, encryption errors, replay errors
*/
static krb5_error_code decrypt_authenticator PROTOTYPE((const krb5_ap_req *,
krb5_authenticator **));
extern krb5_deltat krb5_clockskew;
#define in_clock_skew(date) (abs((date)-currenttime) < krb5_clockskew)
krb5_error_code
krb5_rd_req_decoded(req, server, sender_addr, fetchfrom, keyproc, keyprocarg,
rcache, tktauthent)
const krb5_ap_req *req;
const krb5_principal server;
const krb5_address *sender_addr;
const krb5_pointer fetchfrom;
krb5_error_code (*keyproc) PROTOTYPE((krb5_pointer,
krb5_principal,
krb5_kvno,
krb5_keyblock **));
const krb5_pointer keyprocarg;
krb5_rcache rcache;
krb5_tkt_authent *tktauthent;
{
krb5_error_code retval;
krb5_keyblock *tkt_key;
krb5_keyblock tkt_key_real;
krb5_timestamp currenttime;
if (!krb5_principal_compare(server, req->ticket->server))
return KRB5KRB_AP_WRONG_PRINC;
/* if (req->ap_options & AP_OPTS_USE_SESSION_KEY)
do we need special processing here ? */
/* fetch a server key */
if (keyproc) {
retval = (*keyproc)(keyprocarg, req->ticket->server,
req->ticket->skvno, &tkt_key);
} else {
krb5_keytab keytabid;
krb5_keytab_entry ktentry;
if (fetchfrom) {
/* use the named keytab */
retval = krb5_kt_resolve((char *)fetchfrom, &keytabid);
} else {
/* use default keytab */
retval = krb5_kt_default(&keytabid);
}
if (!retval) {
retval = krb5_kt_get_entry(keytabid, req->ticket->server,
req->ticket->skvno, &ktentry);
(void) krb5_kt_close(keytabid);
if (!retval) {
retval = krb5_copy_keyblock(&ktentry.key, &tkt_key_real);
tkt_key = &tkt_key_real;
(void) krb5_kt_free_entry(&ktentry);
}
}
}
if (retval)
return retval; /* some error in getting the key */
/* decrypt the ticket */
if (retval = krb5_decrypt_tkt_part(tkt_key, req->ticket))
return(retval);
#define clean_ticket() krb5_free_enc_tkt_part(req->ticket->enc_part2)
if (retval = decrypt_authenticator(req, &tktauthent->authenticator)) {
clean_ticket();
return retval;
}
#define clean_authenticator() {(void) krb5_free_authenticator(tktauthent->authenticator); tktauthent->authenticator = 0;}
if (!krb5_principal_compare(tktauthent->authenticator->client,
req->ticket->enc_part2->client)) {
clean_authenticator();
return KRB5KRB_AP_ERR_BADMATCH;
}
if (sender_addr && !krb5_address_search(sender_addr, req->ticket->enc_part2->caddrs)) {
clean_authenticator();
return KRB5KRB_AP_ERR_BADADDR;
}
if (retval = krb5_timeofday(¤ttime)) {
clean_authenticator();
return retval;
}
if (!in_clock_skew(tktauthent->authenticator->ctime)) {
clean_authenticator();
return KRB5KRB_AP_ERR_SKEW;
}
tktauthent->ticket = req->ticket; /* only temporarily...allocated
below */
if ((retval = krb5_rc_store(rcache, tktauthent))) {
tktauthent->ticket = 0;
clean_authenticator();
return retval;
}
tktauthent->ticket = 0;
if (req->ticket->enc_part2->times.starttime - currenttime > krb5_clockskew) {
clean_authenticator();
return KRB5KRB_AP_ERR_TKT_NYV; /* ticket not yet valid */
}
if (currenttime - req->ticket->enc_part2->times.endtime > krb5_clockskew) {
clean_authenticator();
return KRB5KRB_AP_ERR_TKT_EXPIRED; /* ticket expired */
}
if (req->ticket->enc_part2->flags & TKT_FLG_INVALID) {
clean_authenticator();
return KRB5KRB_AP_ERR_TKT_INVALID;
}
if (retval = krb5_copy_ticket(req->ticket, &tktauthent->ticket)) {
clean_authenticator();
} else
tktauthent->ap_options = req->ap_options;
return retval;
}
static krb5_error_code
decrypt_authenticator(request, authpp)
const krb5_ap_req *request;
krb5_authenticator **authpp;
{
krb5_authenticator *local_auth;
krb5_error_code retval;
krb5_encrypt_block eblock;
krb5_data scratch;
krb5_keyblock *sesskey;
sesskey = request->ticket->enc_part2->session;
if (!valid_keytype(sesskey->keytype))
return KRB5_PROG_KEYTYPE_NOSUPP;
/* put together an eblock for this encryption */
eblock.crypto_entry = krb5_keytype_array[sesskey->keytype]->system;
scratch.length = request->authenticator.length;
if (!(scratch.data = malloc(scratch.length)))
return(ENOMEM);
/* do any necessary key pre-processing */
if (retval = (*eblock.crypto_entry->process_key)(&eblock, sesskey)) {
free(scratch.data);
return(retval);
}
/* call the encryption routine */
if (retval =
(*eblock.crypto_entry->decrypt_func)((krb5_pointer) request->authenticator.data,
(krb5_pointer) scratch.data,
scratch.length, &eblock, 0)) {
(void) (*eblock.crypto_entry->finish_key)(&eblock);
free(scratch.data);
return retval;
}
#define clean_scratch() {bzero(scratch.data, scratch.length); free(scratch.data);}
if (retval = (*eblock.crypto_entry->finish_key)(&eblock)) {
clean_scratch();
return retval;
}
/* now decode the decrypted stuff */
if (!(retval = decode_krb5_authenticator(&scratch, &local_auth))) {
*authpp = local_auth;
}
clean_scratch();
return retval;
}
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