/* $NetBSD: get_for_creds.c,v 1.2 2017/01/28 21:31:49 christos Exp $ */
/*
* Copyright (c) 1997 - 2004 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
add_addrs(krb5_context context,
krb5_addresses *addr,
struct addrinfo *ai)
{
krb5_error_code ret;
unsigned n, i;
void *tmp;
struct addrinfo *a;
n = 0;
for (a = ai; a != NULL; a = a->ai_next)
++n;
tmp = realloc(addr->val, (addr->len + n) * sizeof(*addr->val));
if (tmp == NULL && (addr->len + n) != 0) {
ret = krb5_enomem(context);
goto fail;
}
addr->val = tmp;
for (i = addr->len; i < (addr->len + n); ++i) {
addr->val[i].addr_type = 0;
krb5_data_zero(&addr->val[i].address);
}
i = addr->len;
for (a = ai; a != NULL; a = a->ai_next) {
krb5_address ad;
ret = krb5_sockaddr2address (context, a->ai_addr, &ad);
if (ret == 0) {
if (krb5_address_search(context, &ad, addr))
krb5_free_address(context, &ad);
else
addr->val[i++] = ad;
}
else if (ret == KRB5_PROG_ATYPE_NOSUPP)
krb5_clear_error_message (context);
else
goto fail;
addr->len = i;
}
return 0;
fail:
krb5_free_addresses (context, addr);
return ret;
}
/**
* Forward credentials for client to host hostname , making them
* forwardable if forwardable, and returning the blob of data to sent
* in out_data. If hostname == NULL, pick it from server.
*
* @param context A kerberos 5 context.
* @param auth_context the auth context with the key to encrypt the out_data.
* @param hostname the host to forward the tickets too.
* @param client the client to delegate from.
* @param server the server to delegate the credential too.
* @param ccache credential cache to use.
* @param forwardable make the forwarded ticket forwabledable.
* @param out_data the resulting credential.
*
* @return Return an error code or 0.
*
* @ingroup krb5_credential
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_fwd_tgt_creds (krb5_context context,
krb5_auth_context auth_context,
const char *hostname,
krb5_principal client,
krb5_principal server,
krb5_ccache ccache,
int forwardable,
krb5_data *out_data)
{
krb5_flags flags = 0;
krb5_creds creds;
krb5_error_code ret;
krb5_const_realm client_realm;
flags |= KDC_OPT_FORWARDED;
if (forwardable)
flags |= KDC_OPT_FORWARDABLE;
if (hostname == NULL &&
krb5_principal_get_type(context, server) == KRB5_NT_SRV_HST) {
const char *inst = krb5_principal_get_comp_string(context, server, 0);
const char *host = krb5_principal_get_comp_string(context, server, 1);
if (inst != NULL &&
strcmp(inst, "host") == 0 &&
host != NULL &&
krb5_principal_get_comp_string(context, server, 2) == NULL)
hostname = host;
}
client_realm = krb5_principal_get_realm(context, client);
memset (&creds, 0, sizeof(creds));
creds.client = client;
ret = krb5_make_principal(context,
&creds.server,
client_realm,
KRB5_TGS_NAME,
client_realm,
NULL);
if (ret)
return ret;
ret = krb5_get_forwarded_creds (context,
auth_context,
ccache,
flags,
hostname,
&creds,
out_data);
return ret;
}
/**
* Gets tickets forwarded to hostname. If the tickets that are
* forwarded are address-less, the forwarded tickets will also be
* address-less.
*
* If the ticket have any address, hostname will be used for figure
* out the address to forward the ticket too. This since this might
* use DNS, its insecure and also doesn't represent configured all
* addresses of the host. For example, the host might have two
* adresses, one IPv4 and one IPv6 address where the later is not
* published in DNS. This IPv6 address might be used communications
* and thus the resulting ticket useless.
*
* @param context A kerberos 5 context.
* @param auth_context the auth context with the key to encrypt the out_data.
* @param ccache credential cache to use
* @param flags the flags to control the resulting ticket flags
* @param hostname the host to forward the tickets too.
* @param in_creds the in client and server ticket names. The client
* and server components forwarded to the remote host.
* @param out_data the resulting credential.
*
* @return Return an error code or 0.
*
* @ingroup krb5_credential
*/
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_get_forwarded_creds (krb5_context context,
krb5_auth_context auth_context,
krb5_ccache ccache,
krb5_flags flags,
const char *hostname,
krb5_creds *in_creds,
krb5_data *out_data)
{
krb5_error_code ret;
krb5_creds *out_creds;
krb5_addresses addrs, *paddrs;
KRB_CRED cred;
KrbCredInfo *krb_cred_info;
EncKrbCredPart enc_krb_cred_part;
size_t len;
unsigned char *buf;
size_t buf_size;
krb5_kdc_flags kdc_flags;
krb5_crypto crypto;
struct addrinfo *ai;
krb5_creds *ticket;
paddrs = NULL;
addrs.len = 0;
addrs.val = NULL;
ret = krb5_get_credentials(context, 0, ccache, in_creds, &ticket);
if(ret == 0) {
if (ticket->addresses.len)
paddrs = &addrs;
krb5_free_creds (context, ticket);
} else {
krb5_boolean noaddr;
krb5_appdefault_boolean(context, NULL,
krb5_principal_get_realm(context,
in_creds->client),
"no-addresses", KRB5_ADDRESSLESS_DEFAULT,
&noaddr);
if (!noaddr)
paddrs = &addrs;
}
/*
* If tickets have addresses, get the address of the remote host.
*/
if (paddrs != NULL) {
ret = getaddrinfo (hostname, NULL, NULL, &ai);
if (ret) {
krb5_error_code ret2 = krb5_eai_to_heim_errno(ret, errno);
krb5_set_error_message(context, ret2,
N_("resolving host %s failed: %s",
"hostname, error"),
hostname, gai_strerror(ret));
return ret2;
}
ret = add_addrs (context, &addrs, ai);
freeaddrinfo (ai);
if (ret)
return ret;
}
kdc_flags.b = int2KDCOptions(flags);
ret = krb5_get_kdc_cred (context,
ccache,
kdc_flags,
paddrs,
NULL,
in_creds,
&out_creds);
krb5_free_addresses (context, &addrs);
if (ret)
return ret;
memset (&cred, 0, sizeof(cred));
cred.pvno = 5;
cred.msg_type = krb_cred;
ALLOC_SEQ(&cred.tickets, 1);
if (cred.tickets.val == NULL) {
ret = krb5_enomem(context);
goto out2;
}
ret = decode_Ticket(out_creds->ticket.data,
out_creds->ticket.length,
cred.tickets.val, &len);
if (ret)
goto out3;
memset (&enc_krb_cred_part, 0, sizeof(enc_krb_cred_part));
ALLOC_SEQ(&enc_krb_cred_part.ticket_info, 1);
if (enc_krb_cred_part.ticket_info.val == NULL) {
ret = krb5_enomem(context);
goto out4;
}
if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
krb5_timestamp sec;
int32_t usec;
krb5_us_timeofday (context, &sec, &usec);
ALLOC(enc_krb_cred_part.timestamp, 1);
if (enc_krb_cred_part.timestamp == NULL) {
ret = krb5_enomem(context);
goto out4;
}
*enc_krb_cred_part.timestamp = sec;
ALLOC(enc_krb_cred_part.usec, 1);
if (enc_krb_cred_part.usec == NULL) {
ret = krb5_enomem(context);
goto out4;
}
*enc_krb_cred_part.usec = usec;
} else {
enc_krb_cred_part.timestamp = NULL;
enc_krb_cred_part.usec = NULL;
}
if (auth_context->local_address && auth_context->local_port && paddrs) {
ret = krb5_make_addrport (context,
&enc_krb_cred_part.s_address,
auth_context->local_address,
auth_context->local_port);
if (ret)
goto out4;
}
if (auth_context->remote_address) {
if (auth_context->remote_port) {
krb5_boolean noaddr;
krb5_const_realm srealm;
srealm = krb5_principal_get_realm(context, out_creds->server);
/* Is this correct, and should we use the paddrs == NULL
trick here as well? Having an address-less ticket may
indicate that we don't know our own global address, but
it does not necessary mean that we don't know the
server's. */
krb5_appdefault_boolean(context, NULL, srealm, "no-addresses",
FALSE, &noaddr);
if (!noaddr) {
ret = krb5_make_addrport (context,
&enc_krb_cred_part.r_address,
auth_context->remote_address,
auth_context->remote_port);
if (ret)
goto out4;
}
} else {
ALLOC(enc_krb_cred_part.r_address, 1);
if (enc_krb_cred_part.r_address == NULL) {
ret = krb5_enomem(context);
goto out4;
}
ret = krb5_copy_address (context, auth_context->remote_address,
enc_krb_cred_part.r_address);
if (ret)
goto out4;
}
}
/* fill ticket_info.val[0] */
enc_krb_cred_part.ticket_info.len = 1;
krb_cred_info = enc_krb_cred_part.ticket_info.val;
copy_EncryptionKey (&out_creds->session, &krb_cred_info->key);
ALLOC(krb_cred_info->prealm, 1);
copy_Realm (&out_creds->client->realm, krb_cred_info->prealm);
ALLOC(krb_cred_info->pname, 1);
copy_PrincipalName(&out_creds->client->name, krb_cred_info->pname);
ALLOC(krb_cred_info->flags, 1);
*krb_cred_info->flags = out_creds->flags.b;
ALLOC(krb_cred_info->authtime, 1);
*krb_cred_info->authtime = out_creds->times.authtime;
ALLOC(krb_cred_info->starttime, 1);
*krb_cred_info->starttime = out_creds->times.starttime;
ALLOC(krb_cred_info->endtime, 1);
*krb_cred_info->endtime = out_creds->times.endtime;
ALLOC(krb_cred_info->renew_till, 1);
*krb_cred_info->renew_till = out_creds->times.renew_till;
ALLOC(krb_cred_info->srealm, 1);
copy_Realm (&out_creds->server->realm, krb_cred_info->srealm);
ALLOC(krb_cred_info->sname, 1);
copy_PrincipalName (&out_creds->server->name, krb_cred_info->sname);
ALLOC(krb_cred_info->caddr, 1);
copy_HostAddresses (&out_creds->addresses, krb_cred_info->caddr);
krb5_free_creds (context, out_creds);
/* encode EncKrbCredPart */
ASN1_MALLOC_ENCODE(EncKrbCredPart, buf, buf_size,
&enc_krb_cred_part, &len, ret);
free_EncKrbCredPart (&enc_krb_cred_part);
if (ret) {
free_KRB_CRED(&cred);
return ret;
}
if(buf_size != len)
krb5_abortx(context, "internal error in ASN.1 encoder");
/**
* Some older of the MIT gssapi library used clear-text tickets
* (warped inside AP-REQ encryption), use the krb5_auth_context
* flag KRB5_AUTH_CONTEXT_CLEAR_FORWARDED_CRED to support those
* tickets. The session key is used otherwise to encrypt the
* forwarded ticket.
*/
if (auth_context->flags & KRB5_AUTH_CONTEXT_CLEAR_FORWARDED_CRED) {
cred.enc_part.etype = KRB5_ENCTYPE_NULL;
cred.enc_part.kvno = NULL;
cred.enc_part.cipher.data = buf;
cred.enc_part.cipher.length = buf_size;
} else {
/*
* Here older versions then 0.7.2 of Heimdal used the local or
* remote subkey. That is wrong, the session key should be
* used. Heimdal 0.7.2 and newer have code to try both in the
* receiving end.
*/
ret = krb5_crypto_init(context, auth_context->keyblock, 0, &crypto);
if (ret) {
free(buf);
free_KRB_CRED(&cred);
return ret;
}
ret = krb5_encrypt_EncryptedData (context,
crypto,
KRB5_KU_KRB_CRED,
buf,
len,
0,
&cred.enc_part);
free(buf);
krb5_crypto_destroy(context, crypto);
if (ret) {
free_KRB_CRED(&cred);
return ret;
}
}
ASN1_MALLOC_ENCODE(KRB_CRED, buf, buf_size, &cred, &len, ret);
free_KRB_CRED (&cred);
if (ret)
return ret;
if(buf_size != len)
krb5_abortx(context, "internal error in ASN.1 encoder");
out_data->length = len;
out_data->data = buf;
return 0;
out4:
free_EncKrbCredPart(&enc_krb_cred_part);
out3:
free_KRB_CRED(&cred);
out2:
krb5_free_creds (context, out_creds);
return ret;
}