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freebsd-dev/crypto/heimdal/lib/krb5/rd_req.c
Stanislav Sedov ae77177087 - Update FreeBSD Heimdal distribution to version 1.5.1. This also brings 
several new kerberos related libraries and applications to FreeBSD:
  o kgetcred(1) allows one to manually get a ticket for a particular service.
  o kf(1) securily forwards ticket to another host through an authenticated
    and encrypted stream.
  o kcc(1) is an umbrella program around klist(1), kswitch(1), kgetcred(1)
    and other user kerberos operations. klist and kswitch are just symlinks
    to kcc(1) now.
  o kswitch(1) allows you to easily switch between kerberos credentials if
    you're running KCM.
  o hxtool(1) is a certificate management tool to use with PKINIT.
  o string2key(1) maps a password into key.
  o kdigest(8) is a userland tool to access the KDC's digest interface.
  o kimpersonate(8) creates a "fake" ticket for a service.

  We also now install manpages for some lirbaries that were not installed
  before, libheimntlm and libhx509.

- The new HEIMDAL version no longer supports Kerberos 4.  All users are
  recommended to switch to Kerberos 5.

- Weak ciphers are now disabled by default.  To enable DES support (used
  by telnet(8)), use "allow_weak_crypto" option in krb5.conf.

- libtelnet, pam_ksu and pam_krb5 are now compiled with error on warnings
  disabled due to the function they use (krb5_get_err_text(3)) being
  deprecated.  I plan to work on this next.

- Heimdal's KDC now require sqlite to operate.  We use the bundled version
  and install it as libheimsqlite.  If some other FreeBSD components will
  require it in the future we can rename it to libbsdsqlite and use for these
  components as well.

- This is not a latest Heimdal version, the new one was released while I was
  working on the update.  I will update it to 1.5.2 soon, as it fixes some
  important bugs and security issues.
2012-03-22 08:48:42 +00:00

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/*
* Copyright (c) 1997 - 2007 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* 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. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``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 THE INSTITUTE OR CONTRIBUTORS 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.
*/
#include "krb5_locl.h"
static krb5_error_code
decrypt_tkt_enc_part (krb5_context context,
krb5_keyblock *key,
EncryptedData *enc_part,
EncTicketPart *decr_part)
{
krb5_error_code ret;
krb5_data plain;
size_t len;
krb5_crypto crypto;
ret = krb5_crypto_init(context, key, 0, &crypto);
if (ret)
return ret;
ret = krb5_decrypt_EncryptedData (context,
crypto,
KRB5_KU_TICKET,
enc_part,
&plain);
krb5_crypto_destroy(context, crypto);
if (ret)
return ret;
ret = decode_EncTicketPart(plain.data, plain.length, decr_part, &len);
if (ret)
krb5_set_error_message(context, ret,
N_("Failed to decode encrypted "
"ticket part", ""));
krb5_data_free (&plain);
return ret;
}
static krb5_error_code
decrypt_authenticator (krb5_context context,
EncryptionKey *key,
EncryptedData *enc_part,
Authenticator *authenticator,
krb5_key_usage usage)
{
krb5_error_code ret;
krb5_data plain;
size_t len;
krb5_crypto crypto;
ret = krb5_crypto_init(context, key, 0, &crypto);
if (ret)
return ret;
ret = krb5_decrypt_EncryptedData (context,
crypto,
usage /* KRB5_KU_AP_REQ_AUTH */,
enc_part,
&plain);
/* for backwards compatibility, also try the old usage */
if (ret && usage == KRB5_KU_TGS_REQ_AUTH)
ret = krb5_decrypt_EncryptedData (context,
crypto,
KRB5_KU_AP_REQ_AUTH,
enc_part,
&plain);
krb5_crypto_destroy(context, crypto);
if (ret)
return ret;
ret = decode_Authenticator(plain.data, plain.length,
authenticator, &len);
krb5_data_free (&plain);
return ret;
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_decode_ap_req(krb5_context context,
const krb5_data *inbuf,
krb5_ap_req *ap_req)
{
krb5_error_code ret;
size_t len;
ret = decode_AP_REQ(inbuf->data, inbuf->length, ap_req, &len);
if (ret)
return ret;
if (ap_req->pvno != 5){
free_AP_REQ(ap_req);
krb5_clear_error_message (context);
return KRB5KRB_AP_ERR_BADVERSION;
}
if (ap_req->msg_type != krb_ap_req){
free_AP_REQ(ap_req);
krb5_clear_error_message (context);
return KRB5KRB_AP_ERR_MSG_TYPE;
}
if (ap_req->ticket.tkt_vno != 5){
free_AP_REQ(ap_req);
krb5_clear_error_message (context);
return KRB5KRB_AP_ERR_BADVERSION;
}
return 0;
}
static krb5_error_code
check_transited(krb5_context context, Ticket *ticket, EncTicketPart *enc)
{
char **realms;
unsigned int num_realms, n;
krb5_error_code ret;
/*
* Windows 2000 and 2003 uses this inside their TGT so it's normaly
* not seen by others, however, samba4 joined with a Windows AD as
* a Domain Controller gets exposed to this.
*/
if(enc->transited.tr_type == 0 && enc->transited.contents.length == 0)
return 0;
if(enc->transited.tr_type != DOMAIN_X500_COMPRESS)
return KRB5KDC_ERR_TRTYPE_NOSUPP;
if(enc->transited.contents.length == 0)
return 0;
ret = krb5_domain_x500_decode(context, enc->transited.contents,
&realms, &num_realms,
enc->crealm,
ticket->realm);
if(ret)
return ret;
ret = krb5_check_transited(context, enc->crealm,
ticket->realm,
realms, num_realms, NULL);
for (n = 0; n < num_realms; n++)
free(realms[n]);
free(realms);
return ret;
}
static krb5_error_code
find_etypelist(krb5_context context,
krb5_auth_context auth_context,
EtypeList *etypes)
{
krb5_error_code ret;
krb5_authdata *ad;
krb5_authdata adIfRelevant;
unsigned i;
memset(&adIfRelevant, 0, sizeof(adIfRelevant));
etypes->len = 0;
etypes->val = NULL;
ad = auth_context->authenticator->authorization_data;
if (ad == NULL)
return 0;
for (i = 0; i < ad->len; i++) {
if (ad->val[i].ad_type == KRB5_AUTHDATA_IF_RELEVANT) {
ret = decode_AD_IF_RELEVANT(ad->val[i].ad_data.data,
ad->val[i].ad_data.length,
&adIfRelevant,
NULL);
if (ret)
return ret;
if (adIfRelevant.len == 1 &&
adIfRelevant.val[0].ad_type ==
KRB5_AUTHDATA_GSS_API_ETYPE_NEGOTIATION) {
break;
}
free_AD_IF_RELEVANT(&adIfRelevant);
adIfRelevant.len = 0;
}
}
if (adIfRelevant.len == 0)
return 0;
ret = decode_EtypeList(adIfRelevant.val[0].ad_data.data,
adIfRelevant.val[0].ad_data.length,
etypes,
NULL);
if (ret)
krb5_clear_error_message(context);
free_AD_IF_RELEVANT(&adIfRelevant);
return ret;
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_decrypt_ticket(krb5_context context,
Ticket *ticket,
krb5_keyblock *key,
EncTicketPart *out,
krb5_flags flags)
{
EncTicketPart t;
krb5_error_code ret;
ret = decrypt_tkt_enc_part (context, key, &ticket->enc_part, &t);
if (ret)
return ret;
{
krb5_timestamp now;
time_t start = t.authtime;
krb5_timeofday (context, &now);
if(t.starttime)
start = *t.starttime;
if(start - now > context->max_skew
|| (t.flags.invalid
&& !(flags & KRB5_VERIFY_AP_REQ_IGNORE_INVALID))) {
free_EncTicketPart(&t);
krb5_clear_error_message (context);
return KRB5KRB_AP_ERR_TKT_NYV;
}
if(now - t.endtime > context->max_skew) {
free_EncTicketPart(&t);
krb5_clear_error_message (context);
return KRB5KRB_AP_ERR_TKT_EXPIRED;
}
if(!t.flags.transited_policy_checked) {
ret = check_transited(context, ticket, &t);
if(ret) {
free_EncTicketPart(&t);
return ret;
}
}
}
if(out)
*out = t;
else
free_EncTicketPart(&t);
return 0;
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_verify_authenticator_checksum(krb5_context context,
krb5_auth_context ac,
void *data,
size_t len)
{
krb5_error_code ret;
krb5_keyblock *key;
krb5_authenticator authenticator;
krb5_crypto crypto;
ret = krb5_auth_con_getauthenticator (context,
ac,
&authenticator);
if(ret)
return ret;
if(authenticator->cksum == NULL) {
krb5_free_authenticator(context, &authenticator);
return -17;
}
ret = krb5_auth_con_getkey(context, ac, &key);
if(ret) {
krb5_free_authenticator(context, &authenticator);
return ret;
}
ret = krb5_crypto_init(context, key, 0, &crypto);
if(ret)
goto out;
ret = krb5_verify_checksum (context,
crypto,
KRB5_KU_AP_REQ_AUTH_CKSUM,
data,
len,
authenticator->cksum);
krb5_crypto_destroy(context, crypto);
out:
krb5_free_authenticator(context, &authenticator);
krb5_free_keyblock(context, key);
return ret;
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_verify_ap_req(krb5_context context,
krb5_auth_context *auth_context,
krb5_ap_req *ap_req,
krb5_const_principal server,
krb5_keyblock *keyblock,
krb5_flags flags,
krb5_flags *ap_req_options,
krb5_ticket **ticket)
{
return krb5_verify_ap_req2 (context,
auth_context,
ap_req,
server,
keyblock,
flags,
ap_req_options,
ticket,
KRB5_KU_AP_REQ_AUTH);
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_verify_ap_req2(krb5_context context,
krb5_auth_context *auth_context,
krb5_ap_req *ap_req,
krb5_const_principal server,
krb5_keyblock *keyblock,
krb5_flags flags,
krb5_flags *ap_req_options,
krb5_ticket **ticket,
krb5_key_usage usage)
{
krb5_ticket *t;
krb5_auth_context ac;
krb5_error_code ret;
EtypeList etypes;
if (ticket)
*ticket = NULL;
if (auth_context && *auth_context) {
ac = *auth_context;
} else {
ret = krb5_auth_con_init (context, &ac);
if (ret)
return ret;
}
t = calloc(1, sizeof(*t));
if (t == NULL) {
ret = ENOMEM;
krb5_clear_error_message (context);
goto out;
}
if (ap_req->ap_options.use_session_key && ac->keyblock){
ret = krb5_decrypt_ticket(context, &ap_req->ticket,
ac->keyblock,
&t->ticket,
flags);
krb5_free_keyblock(context, ac->keyblock);
ac->keyblock = NULL;
}else
ret = krb5_decrypt_ticket(context, &ap_req->ticket,
keyblock,
&t->ticket,
flags);
if(ret)
goto out;
ret = _krb5_principalname2krb5_principal(context,
&t->server,
ap_req->ticket.sname,
ap_req->ticket.realm);
if (ret) goto out;
ret = _krb5_principalname2krb5_principal(context,
&t->client,
t->ticket.cname,
t->ticket.crealm);
if (ret) goto out;
ret = decrypt_authenticator (context,
&t->ticket.key,
&ap_req->authenticator,
ac->authenticator,
usage);
if (ret)
goto out;
{
krb5_principal p1, p2;
krb5_boolean res;
_krb5_principalname2krb5_principal(context,
&p1,
ac->authenticator->cname,
ac->authenticator->crealm);
_krb5_principalname2krb5_principal(context,
&p2,
t->ticket.cname,
t->ticket.crealm);
res = krb5_principal_compare (context, p1, p2);
krb5_free_principal (context, p1);
krb5_free_principal (context, p2);
if (!res) {
ret = KRB5KRB_AP_ERR_BADMATCH;
krb5_clear_error_message (context);
goto out;
}
}
/* check addresses */
if (t->ticket.caddr
&& ac->remote_address
&& !krb5_address_search (context,
ac->remote_address,
t->ticket.caddr)) {
ret = KRB5KRB_AP_ERR_BADADDR;
krb5_clear_error_message (context);
goto out;
}
/* check timestamp in authenticator */
{
krb5_timestamp now;
krb5_timeofday (context, &now);
if (abs(ac->authenticator->ctime - now) > context->max_skew) {
ret = KRB5KRB_AP_ERR_SKEW;
krb5_clear_error_message (context);
goto out;
}
}
if (ac->authenticator->seq_number)
krb5_auth_con_setremoteseqnumber(context, ac,
*ac->authenticator->seq_number);
/* XXX - Xor sequence numbers */
if (ac->authenticator->subkey) {
ret = krb5_auth_con_setremotesubkey(context, ac,
ac->authenticator->subkey);
if (ret)
goto out;
}
ret = find_etypelist(context, ac, &etypes);
if (ret)
goto out;
ac->keytype = ETYPE_NULL;
if (etypes.val) {
size_t i;
for (i = 0; i < etypes.len; i++) {
if (krb5_enctype_valid(context, etypes.val[i]) == 0) {
ac->keytype = etypes.val[i];
break;
}
}
}
/* save key */
ret = krb5_copy_keyblock(context, &t->ticket.key, &ac->keyblock);
if (ret) goto out;
if (ap_req_options) {
*ap_req_options = 0;
if (ac->keytype != ETYPE_NULL)
*ap_req_options |= AP_OPTS_USE_SUBKEY;
if (ap_req->ap_options.use_session_key)
*ap_req_options |= AP_OPTS_USE_SESSION_KEY;
if (ap_req->ap_options.mutual_required)
*ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
}
if(ticket)
*ticket = t;
else
krb5_free_ticket (context, t);
if (auth_context) {
if (*auth_context == NULL)
*auth_context = ac;
} else
krb5_auth_con_free (context, ac);
free_EtypeList(&etypes);
return 0;
out:
if (t)
krb5_free_ticket (context, t);
if (auth_context == NULL || *auth_context == NULL)
krb5_auth_con_free (context, ac);
return ret;
}
/*
*
*/
struct krb5_rd_req_in_ctx_data {
krb5_keytab keytab;
krb5_keyblock *keyblock;
krb5_boolean check_pac;
};
struct krb5_rd_req_out_ctx_data {
krb5_keyblock *keyblock;
krb5_flags ap_req_options;
krb5_ticket *ticket;
krb5_principal server;
};
/**
* Allocate a krb5_rd_req_in_ctx as an input parameter to
* krb5_rd_req_ctx(). The caller should free the context with
* krb5_rd_req_in_ctx_free() when done with the context.
*
* @param context Keberos 5 context.
* @param ctx in ctx to krb5_rd_req_ctx().
*
* @return Kerberos 5 error code, see krb5_get_error_message().
*
* @ingroup krb5_auth
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_in_ctx_alloc(krb5_context context, krb5_rd_req_in_ctx *ctx)
{
*ctx = calloc(1, sizeof(**ctx));
if (*ctx == NULL) {
krb5_set_error_message(context, ENOMEM,
N_("malloc: out of memory", ""));
return ENOMEM;
}
(*ctx)->check_pac = (context->flags & KRB5_CTX_F_CHECK_PAC) ? 1 : 0;
return 0;
}
/**
* Set the keytab that krb5_rd_req_ctx() will use.
*
* @param context Keberos 5 context.
* @param in in ctx to krb5_rd_req_ctx().
* @param keytab keytab that krb5_rd_req_ctx() will use, only copy the
* pointer, so the caller must free they keytab after
* krb5_rd_req_in_ctx_free() is called.
*
* @return Kerberos 5 error code, see krb5_get_error_message().
*
* @ingroup krb5_auth
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_in_set_keytab(krb5_context context,
krb5_rd_req_in_ctx in,
krb5_keytab keytab)
{
in->keytab = keytab;
return 0;
}
/**
* Set if krb5_rq_red() is going to check the Windows PAC or not
*
* @param context Keberos 5 context.
* @param in krb5_rd_req_in_ctx to check the option on.
* @param flag flag to select if to check the pac (TRUE) or not (FALSE).
*
* @return Kerberos 5 error code, see krb5_get_error_message().
*
* @ingroup krb5_auth
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_in_set_pac_check(krb5_context context,
krb5_rd_req_in_ctx in,
krb5_boolean flag)
{
in->check_pac = flag;
return 0;
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_in_set_keyblock(krb5_context context,
krb5_rd_req_in_ctx in,
krb5_keyblock *keyblock)
{
in->keyblock = keyblock; /* XXX should make copy */
return 0;
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_out_get_ap_req_options(krb5_context context,
krb5_rd_req_out_ctx out,
krb5_flags *ap_req_options)
{
*ap_req_options = out->ap_req_options;
return 0;
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_out_get_ticket(krb5_context context,
krb5_rd_req_out_ctx out,
krb5_ticket **ticket)
{
return krb5_copy_ticket(context, out->ticket, ticket);
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_out_get_keyblock(krb5_context context,
krb5_rd_req_out_ctx out,
krb5_keyblock **keyblock)
{
return krb5_copy_keyblock(context, out->keyblock, keyblock);
}
/**
* Get the principal that was used in the request from the
* client. Might not match whats in the ticket if krb5_rd_req_ctx()
* searched in the keytab for a matching key.
*
* @param context a Kerberos 5 context.
* @param out a krb5_rd_req_out_ctx from krb5_rd_req_ctx().
* @param principal return principal, free with krb5_free_principal().
*
* @ingroup krb5_auth
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_out_get_server(krb5_context context,
krb5_rd_req_out_ctx out,
krb5_principal *principal)
{
return krb5_copy_principal(context, out->server, principal);
}
KRB5_LIB_FUNCTION void KRB5_LIB_CALL
krb5_rd_req_in_ctx_free(krb5_context context, krb5_rd_req_in_ctx ctx)
{
free(ctx);
}
/**
* Free the krb5_rd_req_out_ctx.
*
* @param context Keberos 5 context.
* @param ctx krb5_rd_req_out_ctx context to free.
*
* @ingroup krb5_auth
*/
KRB5_LIB_FUNCTION void KRB5_LIB_CALL
krb5_rd_req_out_ctx_free(krb5_context context, krb5_rd_req_out_ctx ctx)
{
if (ctx->ticket)
krb5_free_ticket(context, ctx->ticket);
if (ctx->keyblock)
krb5_free_keyblock(context, ctx->keyblock);
if (ctx->server)
krb5_free_principal(context, ctx->server);
free(ctx);
}
/*
*
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req(krb5_context context,
krb5_auth_context *auth_context,
const krb5_data *inbuf,
krb5_const_principal server,
krb5_keytab keytab,
krb5_flags *ap_req_options,
krb5_ticket **ticket)
{
krb5_error_code ret;
krb5_rd_req_in_ctx in;
krb5_rd_req_out_ctx out;
ret = krb5_rd_req_in_ctx_alloc(context, &in);
if (ret)
return ret;
ret = krb5_rd_req_in_set_keytab(context, in, keytab);
if (ret) {
krb5_rd_req_in_ctx_free(context, in);
return ret;
}
ret = krb5_rd_req_ctx(context, auth_context, inbuf, server, in, &out);
krb5_rd_req_in_ctx_free(context, in);
if (ret)
return ret;
if (ap_req_options)
*ap_req_options = out->ap_req_options;
if (ticket) {
ret = krb5_copy_ticket(context, out->ticket, ticket);
if (ret)
goto out;
}
out:
krb5_rd_req_out_ctx_free(context, out);
return ret;
}
/*
*
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_with_keyblock(krb5_context context,
krb5_auth_context *auth_context,
const krb5_data *inbuf,
krb5_const_principal server,
krb5_keyblock *keyblock,
krb5_flags *ap_req_options,
krb5_ticket **ticket)
{
krb5_error_code ret;
krb5_rd_req_in_ctx in;
krb5_rd_req_out_ctx out;
ret = krb5_rd_req_in_ctx_alloc(context, &in);
if (ret)
return ret;
ret = krb5_rd_req_in_set_keyblock(context, in, keyblock);
if (ret) {
krb5_rd_req_in_ctx_free(context, in);
return ret;
}
ret = krb5_rd_req_ctx(context, auth_context, inbuf, server, in, &out);
krb5_rd_req_in_ctx_free(context, in);
if (ret)
return ret;
if (ap_req_options)
*ap_req_options = out->ap_req_options;
if (ticket) {
ret = krb5_copy_ticket(context, out->ticket, ticket);
if (ret)
goto out;
}
out:
krb5_rd_req_out_ctx_free(context, out);
return ret;
}
/*
*
*/
static krb5_error_code
get_key_from_keytab(krb5_context context,
krb5_ap_req *ap_req,
krb5_const_principal server,
krb5_keytab keytab,
krb5_keyblock **out_key)
{
krb5_keytab_entry entry;
krb5_error_code ret;
int kvno;
krb5_keytab real_keytab;
if(keytab == NULL)
krb5_kt_default(context, &real_keytab);
else
real_keytab = keytab;
if (ap_req->ticket.enc_part.kvno)
kvno = *ap_req->ticket.enc_part.kvno;
else
kvno = 0;
ret = krb5_kt_get_entry (context,
real_keytab,
server,
kvno,
ap_req->ticket.enc_part.etype,
&entry);
if(ret)
goto out;
ret = krb5_copy_keyblock(context, &entry.keyblock, out_key);
krb5_kt_free_entry (context, &entry);
out:
if(keytab == NULL)
krb5_kt_close(context, real_keytab);
return ret;
}
/**
* The core server function that verify application authentication
* requests from clients.
*
* @param context Keberos 5 context.
* @param auth_context the authentication context, can be NULL, then
* default values for the authentication context will used.
* @param inbuf the (AP-REQ) authentication buffer
*
* @param server the server with authenticate as, if NULL the function
* will try to find any available credential in the keytab
* that will verify the reply. The function will prefer the
* server the server client specified in the AP-REQ, but if
* there is no mach, it will try all keytab entries for a
* match. This have serious performance issues for larger keytabs.
*
* @param inctx control the behavior of the function, if NULL, the
* default behavior is used.
* @param outctx the return outctx, free with krb5_rd_req_out_ctx_free().
* @return Kerberos 5 error code, see krb5_get_error_message().
*
* @ingroup krb5_auth
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_rd_req_ctx(krb5_context context,
krb5_auth_context *auth_context,
const krb5_data *inbuf,
krb5_const_principal server,
krb5_rd_req_in_ctx inctx,
krb5_rd_req_out_ctx *outctx)
{
krb5_error_code ret;
krb5_ap_req ap_req;
krb5_rd_req_out_ctx o = NULL;
krb5_keytab id = NULL, keytab = NULL;
krb5_principal service = NULL;
*outctx = NULL;
o = calloc(1, sizeof(*o));
if (o == NULL) {
krb5_set_error_message(context, ENOMEM,
N_("malloc: out of memory", ""));
return ENOMEM;
}
if (*auth_context == NULL) {
ret = krb5_auth_con_init(context, auth_context);
if (ret)
goto out;
}
ret = krb5_decode_ap_req(context, inbuf, &ap_req);
if(ret)
goto out;
/* Save that principal that was in the request */
ret = _krb5_principalname2krb5_principal(context,
&o->server,
ap_req.ticket.sname,
ap_req.ticket.realm);
if (ret)
goto out;
if (ap_req.ap_options.use_session_key &&
(*auth_context)->keyblock == NULL) {
ret = KRB5KRB_AP_ERR_NOKEY;
krb5_set_error_message(context, ret,
N_("krb5_rd_req: user to user auth "
"without session key given", ""));
goto out;
}
if (inctx && inctx->keytab)
id = inctx->keytab;
if((*auth_context)->keyblock){
ret = krb5_copy_keyblock(context,
(*auth_context)->keyblock,
&o->keyblock);
if (ret)
goto out;
} else if(inctx && inctx->keyblock){
ret = krb5_copy_keyblock(context,
inctx->keyblock,
&o->keyblock);
if (ret)
goto out;
} else {
if(id == NULL) {
krb5_kt_default(context, &keytab);
id = keytab;
}
if (id == NULL)
goto out;
if (server == NULL) {
ret = _krb5_principalname2krb5_principal(context,
&service,
ap_req.ticket.sname,
ap_req.ticket.realm);
if (ret)
goto out;
server = service;
}
ret = get_key_from_keytab(context,
&ap_req,
server,
id,
&o->keyblock);
if (ret) {
/* If caller specified a server, fail. */
if (service == NULL && (context->flags & KRB5_CTX_F_RD_REQ_IGNORE) == 0)
goto out;
/* Otherwise, fall back to iterating over the keytab. This
* have serious performace issues for larger keytab.
*/
o->keyblock = NULL;
}
}
if (o->keyblock) {
/*
* We got an exact keymatch, use that.
*/
ret = krb5_verify_ap_req2(context,
auth_context,
&ap_req,
server,
o->keyblock,
0,
&o->ap_req_options,
&o->ticket,
KRB5_KU_AP_REQ_AUTH);
if (ret)
goto out;
} else {
/*
* Interate over keytab to find a key that can decrypt the request.
*/
krb5_keytab_entry entry;
krb5_kt_cursor cursor;
int done = 0, kvno = 0;
memset(&cursor, 0, sizeof(cursor));
if (ap_req.ticket.enc_part.kvno)
kvno = *ap_req.ticket.enc_part.kvno;
ret = krb5_kt_start_seq_get(context, id, &cursor);
if (ret)
goto out;
done = 0;
while (!done) {
krb5_principal p;
ret = krb5_kt_next_entry(context, id, &entry, &cursor);
if (ret) {
_krb5_kt_principal_not_found(context, ret, id, o->server,
ap_req.ticket.enc_part.etype,
kvno);
goto out;
}
if (entry.keyblock.keytype != ap_req.ticket.enc_part.etype) {
krb5_kt_free_entry (context, &entry);
continue;
}
ret = krb5_verify_ap_req2(context,
auth_context,
&ap_req,
server,
&entry.keyblock,
0,
&o->ap_req_options,
&o->ticket,
KRB5_KU_AP_REQ_AUTH);
if (ret) {
krb5_kt_free_entry (context, &entry);
continue;
}
/*
* Found a match, save the keyblock for PAC processing,
* and update the service principal in the ticket to match
* whatever is in the keytab.
*/
ret = krb5_copy_keyblock(context,
&entry.keyblock,
&o->keyblock);
if (ret) {
krb5_kt_free_entry (context, &entry);
goto out;
}
ret = krb5_copy_principal(context, entry.principal, &p);
if (ret) {
krb5_kt_free_entry (context, &entry);
goto out;
}
krb5_free_principal(context, o->ticket->server);
o->ticket->server = p;
krb5_kt_free_entry (context, &entry);
done = 1;
}
krb5_kt_end_seq_get (context, id, &cursor);
}
/* If there is a PAC, verify its server signature */
if (inctx == NULL || inctx->check_pac) {
krb5_pac pac;
krb5_data data;
ret = krb5_ticket_get_authorization_data_type(context,
o->ticket,
KRB5_AUTHDATA_WIN2K_PAC,
&data);
if (ret == 0) {
ret = krb5_pac_parse(context, data.data, data.length, &pac);
krb5_data_free(&data);
if (ret)
goto out;
ret = krb5_pac_verify(context,
pac,
o->ticket->ticket.authtime,
o->ticket->client,
o->keyblock,
NULL);
krb5_pac_free(context, pac);
if (ret)
goto out;
} else
ret = 0;
}
out:
if (ret || outctx == NULL) {
krb5_rd_req_out_ctx_free(context, o);
} else
*outctx = o;
free_AP_REQ(&ap_req);
if (service)
krb5_free_principal(context, service);
if (keytab)
krb5_kt_close(context, keytab);
return ret;
}
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