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Minsoo Choo aff90c322e Fix spelling
2024-06-16 23:30:48 -04:00

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C

/*
* 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 set_tgs_creds(krb5_context, krb5_ccache,
krb5_const_principal,
krb5_const_principal, krb5_creds *);
static krb5_error_code get_cred(krb5_context, krb5_ccache, krb5_creds *,
krb5_flags, const char *, krb5_creds **);
static krb5_error_code get_addresses(krb5_context, krb5_ccache, krb5_creds *,
const char *, krb5_addresses *);
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.
*
* If the server's realm is configured for delegation of destination
* TGTs, forward a TGT for the server realm, rather than the client
* realm. This works better with destinations on the far side of a
* firewall. We also forward the destination TGT when the client
* TGT is not available (we may have just the destination TGT).
*
* @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_const_principal client,
krb5_const_principal server,
krb5_ccache ccache,
int forwardable,
krb5_data *out_data)
{
krb5_flags flags = 0;
krb5_creds creds;
krb5_error_code ret;
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;
}
/*
* Fill-in the request creds, the server principal will be the TGS
* of either the client's or the server's realm.
*/
ret = set_tgs_creds(context, ccache, client, server, &creds);
if (ret)
return ret;
ret = krb5_get_forwarded_creds (context,
auth_context,
ccache,
flags,
hostname,
&creds,
out_data);
krb5_free_cred_contents(context, &creds);
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
* addresses, 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 *creds;
/* Obtain the requested TGT */
ret = get_cred(context, ccache, in_creds, flags, hostname, &creds);
if (ret)
return ret;
/* Forward obtained creds */
ret = _krb5_mk_1cred(context, auth_context, creds, out_data, NULL);
krb5_free_creds(context, creds);
return ret;
}
/*
* Get a TGT for forwarding to hostname. If the client TGT is
* addressless, the forwarded ticket will also be addressless.
*
* If the TGT has any addresses, hostname will be used to determine
* the address to forward the ticket to. Thus, since this might use DNS,
* it's insecure and also may not capture all the addresses of the host.
* In general addressless tickets are more robust, be it at a small
* security penalty.
*
* @param context A kerberos 5 context.
* @param ccache The credential cache to use
* @param creds Creds with client and server principals
* @param flags The flags to control the resulting ticket flags
* @param hostname The hostname of server
* @param out_creds The resulting credential
*
* @return Return an error code or 0.
*/
static krb5_error_code
get_cred(krb5_context context,
krb5_ccache ccache,
krb5_creds *creds,
krb5_flags flags,
const char *hostname,
krb5_creds **out_creds)
{
krb5_error_code ret;
krb5_kdc_flags kdc_flags;
krb5_addresses addrs;
addrs.len = 0;
addrs.val = NULL;
ret = get_addresses(context, ccache, creds, hostname, &addrs);
if (ret)
return ret;
kdc_flags.b = int2KDCOptions(flags);
ret = krb5_get_kdc_cred(context, ccache, kdc_flags, &addrs, NULL,
creds, out_creds);
krb5_free_addresses(context, &addrs);
return ret;
}
static krb5_error_code
set_tgs_creds(krb5_context context,
krb5_ccache ccache,
krb5_const_principal client,
krb5_const_principal server,
krb5_creds *creds)
{
krb5_error_code ret;
krb5_const_realm client_realm;
krb5_const_realm server_realm;
krb5_boolean fwd_dest_tgt;
krb5_creds *client_tgt;
client_realm = krb5_principal_get_realm(context, client);
server_realm = krb5_principal_get_realm(context, server);
memset (creds, 0, sizeof(*creds));
ret = krb5_copy_principal(context, client, &creds->client);
if (ret)
return ret;
ret = krb5_make_principal(context, &creds->server, client_realm,
KRB5_TGS_NAME, client_realm, NULL);
if (ret) {
krb5_free_principal(context, creds->client);
return ret;
}
/*
* Optionally delegate a TGT for the server's realm, rather than
* the client's. Do this also when we don't have a client realm TGT.
*
* XXX: Note, when we have a start-realm, and delegate-destination-tgt
* is not set, we must use the start-realm.
*/
krb5_appdefault_boolean(context, NULL, server_realm,
"delegate-destination-tgt", FALSE, &fwd_dest_tgt);
if (!fwd_dest_tgt) {
ret = krb5_get_credentials(context, KRB5_GC_CACHED, ccache, creds,
&client_tgt);
if (ret == 0) {
krb5_free_creds(context, client_tgt);
return ret;
}
}
/*
* Client TGT inapplicable or unavailable
*/
krb5_free_principal(context, creds->server);
creds->server = 0;
return krb5_make_principal(context, &creds->server, server_realm,
KRB5_TGS_NAME, server_realm, NULL);
}
/*
* Obtain address list for hostname if server realm policy is not addressless.
*/
static krb5_error_code
get_addresses(krb5_context context,
krb5_ccache ccache,
krb5_creds *creds,
const char *hostname,
krb5_addresses *addrs)
{
krb5_error_code ret;
krb5_creds *ticket;
krb5_const_realm realm;
krb5_boolean noaddr;
struct addrinfo *ai, hints;
int eai;
if (hostname == 0)
return 0;
ret = krb5_get_credentials(context, 0, ccache, creds, &ticket);
if (ret == 0) {
noaddr = (ticket->addresses.len == 0) ? TRUE : FALSE;
krb5_free_creds(context, ticket);
} else {
realm = krb5_principal_get_realm(context, creds->server);
krb5_appdefault_boolean(context, NULL, realm, "no-addresses",
KRB5_ADDRESSLESS_DEFAULT, &noaddr);
}
if (noaddr)
return 0;
/* Need addresses, get the address of the remote host. */
memset(&hints, 0, sizeof(hints));
if (krb5_config_get_bool(context, NULL, "libdefaults", "block_dns",
NULL)) {
hints.ai_flags &= ~AI_CANONNAME;
hints.ai_flags |= AI_NUMERICHOST|AI_NUMERICSERV;
}
eai = getaddrinfo(hostname, NULL, &hints, &ai);
if (eai) {
ret = krb5_eai_to_heim_errno(eai, errno);
krb5_set_error_message(context, ret,
N_("resolving host %s failed: %s",
"hostname, error"),
hostname, gai_strerror(eai));
return ret;
}
ret = add_addrs(context, addrs, ai);
freeaddrinfo(ai);
return ret;
}