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Moving charon to libcharon.

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This commit is contained in:
Tobias Brunner
2010-03-19 13:34:52 +01:00
parent 7c11d10eb8
commit 08c5572602
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src/libcharon/plugins/eap_sim/eap_sim_peer.c
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/*
* Copyright (C) 2007-2009 Martin Willi
* Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
#include "eap_sim_peer.h"
#include <daemon.h>
#include <simaka_message.h>
/* number of tries we do authenticate */
#define MAX_TRIES 3
/* number of triplets for one authentication */
#define TRIPLET_COUNT 3
/** length of the AT_NONCE_MT nonce value */
#define NONCE_LEN 16
typedef struct private_eap_sim_peer_t private_eap_sim_peer_t;
/**
* Private data of an eap_sim_peer_t object.
*/
struct private_eap_sim_peer_t {
/**
* Public authenticator_t interface.
*/
eap_sim_peer_t public;
/**
* permanent ID of peer
*/
identification_t *permanent;
/**
* Pseudonym identity the peer uses
*/
identification_t *pseudonym;
/**
* Reauthentication identity the peer uses
*/
identification_t *reauth;
/**
* EAP-SIM crypto helper
*/
simaka_crypto_t *crypto;
/**
* how many times we try to authenticate
*/
int tries;
/**
* version list received from server
*/
chunk_t version_list;
/**
* Nonce value used in AT_NONCE_MT/AT_NONCE_S
*/
chunk_t nonce;
/**
* MSK, used for EAP-SIM based IKEv2 authentication
*/
chunk_t msk;
/**
* Master key, if reauthentication is used
*/
char mk[HASH_SIZE_SHA1];
/**
* Counter value if reauthentication is used
*/
u_int16_t counter;
};
/* version of SIM protocol we speak */
static chunk_t version = chunk_from_chars(0x00,0x01);
/**
* Create a SIM_CLIENT_ERROR
*/
static eap_payload_t* create_client_error(private_eap_sim_peer_t *this,
u_int8_t identifier, simaka_client_error_t code)
{
simaka_message_t *message;
eap_payload_t *out;
u_int16_t encoded;
DBG1(DBG_IKE, "sending client error '%N'", simaka_client_error_names, code);
message = simaka_message_create(FALSE, identifier, EAP_SIM,
SIM_CLIENT_ERROR, this->crypto);
encoded = htons(code);
message->add_attribute(message, AT_CLIENT_ERROR_CODE,
chunk_create((char*)&encoded, sizeof(encoded)));
out = message->generate(message, chunk_empty);
message->destroy(message);
return out;
}
/**
* process an EAP-SIM/Request/Start message
*/
static status_t process_start(private_eap_sim_peer_t *this,
simaka_message_t *in, eap_payload_t **out)
{
simaka_message_t *message;
enumerator_t *enumerator;
simaka_attribute_t type;
chunk_t data, id = chunk_empty;
rng_t *rng;
bool supported = FALSE;
simaka_attribute_t id_req = 0;
/* reset previously uses reauthentication/pseudonym data */
this->crypto->clear_keys(this->crypto);
DESTROY_IF(this->pseudonym);
this->pseudonym = NULL;
DESTROY_IF(this->reauth);
this->reauth = NULL;
enumerator = in->create_attribute_enumerator(in);
while (enumerator->enumerate(enumerator, &type, &data))
{
switch (type)
{
case AT_VERSION_LIST:
{
free(this->version_list.ptr);
this->version_list = chunk_clone(data);
while (data.len >= version.len)
{
if (memeq(data.ptr, version.ptr, version.len))
{
supported = TRUE;
break;
}
}
break;
}
case AT_ANY_ID_REQ:
case AT_FULLAUTH_ID_REQ:
case AT_PERMANENT_ID_REQ:
id_req = type;
break;
default:
if (!simaka_attribute_skippable(type))
{
*out = create_client_error(this, in->get_identifier(in),
SIM_UNABLE_TO_PROCESS);
enumerator->destroy(enumerator);
return NEED_MORE;
}
break;
}
}
enumerator->destroy(enumerator);
if (!supported)
{
DBG1(DBG_IKE, "server does not support EAP-SIM version number 1");
*out = create_client_error(this, in->get_identifier(in),
SIM_UNSUPPORTED_VERSION);
return NEED_MORE;
}
switch (id_req)
{
case AT_ANY_ID_REQ:
this->reauth = charon->sim->card_get_reauth(charon->sim,
this->permanent, this->mk, &this->counter);
if (this->reauth)
{
id = this->reauth->get_encoding(this->reauth);
break;
}
/* FALL */
case AT_FULLAUTH_ID_REQ:
this->pseudonym = charon->sim->card_get_pseudonym(charon->sim,
this->permanent);
if (this->pseudonym)
{
id = this->pseudonym->get_encoding(this->pseudonym);
break;
}
/* FALL */
case AT_PERMANENT_ID_REQ:
id = this->permanent->get_encoding(this->permanent);
break;
default:
break;
}
/* generate AT_NONCE_MT value */
rng = this->crypto->get_rng(this->crypto);
free(this->nonce.ptr);
rng->allocate_bytes(rng, NONCE_LEN, &this->nonce);
message = simaka_message_create(FALSE, in->get_identifier(in), EAP_SIM,
SIM_START, this->crypto);
if (!this->reauth)
{
message->add_attribute(message, AT_SELECTED_VERSION, version);
message->add_attribute(message, AT_NONCE_MT, this->nonce);
}
if (id.len)
{
message->add_attribute(message, AT_IDENTITY, id);
}
*out = message->generate(message, chunk_empty);
message->destroy(message);
return NEED_MORE;
}
/**
* process an EAP-SIM/Request/Challenge message
*/
static status_t process_challenge(private_eap_sim_peer_t *this,
simaka_message_t *in, eap_payload_t **out)
{
simaka_message_t *message;
enumerator_t *enumerator;
simaka_attribute_t type;
chunk_t data, rands = chunk_empty, kcs, kc, sreses, sres, mk;
identification_t *id;
if (this->tries-- <= 0)
{
/* give up without notification. This hack is required as some buggy
* server implementations won't respect our client-error. */
return FAILED;
}
enumerator = in->create_attribute_enumerator(in);
while (enumerator->enumerate(enumerator, &type, &data))
{
switch (type)
{
case AT_RAND:
rands = data;
break;
default:
if (!simaka_attribute_skippable(type))
{
*out = create_client_error(this, in->get_identifier(in),
SIM_UNABLE_TO_PROCESS);
enumerator->destroy(enumerator);
return NEED_MORE;
}
break;
}
}
enumerator->destroy(enumerator);
/* excepting two or three RAND, each 16 bytes. We require two valid
* and different RANDs */
if ((rands.len != 2 * SIM_RAND_LEN && rands.len != 3 * SIM_RAND_LEN) ||
memeq(rands.ptr, rands.ptr + SIM_RAND_LEN, SIM_RAND_LEN))
{
DBG1(DBG_IKE, "no valid AT_RAND received");
*out = create_client_error(this, in->get_identifier(in),
SIM_INSUFFICIENT_CHALLENGES);
return NEED_MORE;
}
/* get two or three KCs/SRESes from SIM using RANDs */
kcs = kc = chunk_alloca(rands.len / 2);
sreses = sres = chunk_alloca(rands.len / 4);
while (rands.len >= SIM_RAND_LEN)
{
if (!charon->sim->card_get_triplet(charon->sim, this->permanent,
rands.ptr, sres.ptr, kc.ptr))
{
DBG1(DBG_IKE, "unable to get EAP-SIM triplet");
*out = create_client_error(this, in->get_identifier(in),
SIM_UNABLE_TO_PROCESS);
return NEED_MORE;
}
DBG3(DBG_IKE, "got triplet for RAND %b\n Kc %b\n SRES %b",
rands.ptr, SIM_RAND_LEN, sres.ptr, SIM_SRES_LEN, kc.ptr, SIM_KC_LEN);
kc = chunk_skip(kc, SIM_KC_LEN);
sres = chunk_skip(sres, SIM_SRES_LEN);
rands = chunk_skip(rands, SIM_RAND_LEN);
}
id = this->permanent;
if (this->pseudonym)
{
id = this->pseudonym;
}
data = chunk_cata("cccc", kcs, this->nonce, this->version_list, version);
free(this->msk.ptr);
this->msk = this->crypto->derive_keys_full(this->crypto, id, data, &mk);
memcpy(this->mk, mk.ptr, mk.len);
free(mk.ptr);
/* Verify AT_MAC attribute, signature is over "EAP packet | NONCE_MT", and
* parse() again after key derivation, reading encrypted attributes */
if (!in->verify(in, this->nonce) || !in->parse(in))
{
*out = create_client_error(this, in->get_identifier(in),
SIM_UNABLE_TO_PROCESS);
return NEED_MORE;
}
enumerator = in->create_attribute_enumerator(in);
while (enumerator->enumerate(enumerator, &type, &data))
{
switch (type)
{
case AT_NEXT_REAUTH_ID:
this->counter = 0;
id = identification_create_from_data(data);
charon->sim->card_set_reauth(charon->sim, this->permanent, id,
this->mk, this->counter);
id->destroy(id);
break;
case AT_NEXT_PSEUDONYM:
id = identification_create_from_data(data);
charon->sim->card_set_pseudonym(charon->sim, this->permanent, id);
id->destroy(id);
break;
default:
break;
}
}
enumerator->destroy(enumerator);
/* build response with AT_MAC, built over "EAP packet | n*SRES" */
message = simaka_message_create(FALSE, in->get_identifier(in), EAP_SIM,
SIM_CHALLENGE, this->crypto);
*out = message->generate(message, sreses);
message->destroy(message);
return NEED_MORE;
}
/**
* Check if a received counter value is acceptable
*/
static bool counter_too_small(private_eap_sim_peer_t *this, chunk_t chunk)
{
u_int16_t counter;
memcpy(&counter, chunk.ptr, sizeof(counter));
counter = htons(counter);
return counter < this->counter;
}
/**
* process an EAP-SIM/Request/Re-Authentication message
*/
static status_t process_reauthentication(private_eap_sim_peer_t *this,
simaka_message_t *in, eap_payload_t **out)
{
simaka_message_t *message;
enumerator_t *enumerator;
simaka_attribute_t type;
chunk_t data, counter = chunk_empty, nonce = chunk_empty, id = chunk_empty;
if (!this->reauth)
{
DBG1(DBG_IKE, "received %N, but not expected",
simaka_subtype_names, SIM_REAUTHENTICATION);
*out = create_client_error(this, in->get_identifier(in),
SIM_UNABLE_TO_PROCESS);
return NEED_MORE;
}
this->crypto->derive_keys_reauth(this->crypto,
chunk_create(this->mk, HASH_SIZE_SHA1));
/* verify MAC and parse again with decryption key */
if (!in->verify(in, chunk_empty) || !in->parse(in))
{
*out = create_client_error(this, in->get_identifier(in),
SIM_UNABLE_TO_PROCESS);
return NEED_MORE;
}
enumerator = in->create_attribute_enumerator(in);
while (enumerator->enumerate(enumerator, &type, &data))
{
switch (type)
{
case AT_COUNTER:
counter = data;
break;
case AT_NONCE_S:
nonce = data;
break;
case AT_NEXT_REAUTH_ID:
id = data;
break;
default:
if (!simaka_attribute_skippable(type))
{
*out = create_client_error(this, in->get_identifier(in),
SIM_UNABLE_TO_PROCESS);
enumerator->destroy(enumerator);
return NEED_MORE;
}
break;
}
}
enumerator->destroy(enumerator);
if (!nonce.len || !counter.len)
{
DBG1(DBG_IKE, "EAP-SIM/Request/Re-Authentication message incomplete");
*out = create_client_error(this, in->get_identifier(in),
SIM_UNABLE_TO_PROCESS);
return NEED_MORE;
}
message = simaka_message_create(FALSE, in->get_identifier(in), EAP_SIM,
SIM_REAUTHENTICATION, this->crypto);
if (counter_too_small(this, counter))
{
DBG1(DBG_IKE, "reauthentication counter too small");
message->add_attribute(message, AT_COUNTER_TOO_SMALL, chunk_empty);
}
else
{
free(this->msk.ptr);
this->msk = this->crypto->derive_keys_reauth_msk(this->crypto,
this->reauth, counter, nonce,
chunk_create(this->mk, HASH_SIZE_SHA1));
if (id.len)
{
identification_t *reauth;
reauth = identification_create_from_data(data);
charon->sim->card_set_reauth(charon->sim, this->permanent, reauth,
this->mk, this->counter);
reauth->destroy(reauth);
}
}
message->add_attribute(message, AT_COUNTER, counter);
*out = message->generate(message, nonce);
message->destroy(message);
return NEED_MORE;
}
/**
* process an EAP-SIM/Request/Notification message
*/
static status_t process_notification(private_eap_sim_peer_t *this,
simaka_message_t *in, eap_payload_t **out)
{
simaka_message_t *message;
enumerator_t *enumerator;
simaka_attribute_t type;
chunk_t data;
bool success = TRUE;
enumerator = in->create_attribute_enumerator(in);
while (enumerator->enumerate(enumerator, &type, &data))
{
if (type == AT_NOTIFICATION)
{
u_int16_t code;
memcpy(&code, data.ptr, sizeof(code));
code = ntohs(code);
/* test success bit */
if (!(data.ptr[0] & 0x80))
{
success = FALSE;
DBG1(DBG_IKE, "received EAP-SIM notification error '%N'",
simaka_notification_names, code);
}
else
{
DBG1(DBG_IKE, "received EAP-SIM notification '%N'",
simaka_notification_names, code);
}
}
else if (!simaka_attribute_skippable(type))
{
success = FALSE;
break;
}
}
enumerator->destroy(enumerator);
if (success)
{ /* empty notification reply */
message = simaka_message_create(FALSE, in->get_identifier(in), EAP_SIM,
SIM_NOTIFICATION, this->crypto);
*out = message->generate(message, chunk_empty);
message->destroy(message);
}
else
{
*out = create_client_error(this, in->get_identifier(in),
SIM_UNABLE_TO_PROCESS);
}
return NEED_MORE;
}
/**
* Implementation of eap_method_t.process
*/
static status_t process(private_eap_sim_peer_t *this,
eap_payload_t *in, eap_payload_t **out)
{
simaka_message_t *message;
status_t status;
message = simaka_message_create_from_payload(in, this->crypto);
if (!message)
{
*out = create_client_error(this, in->get_identifier(in),
SIM_UNABLE_TO_PROCESS);
return NEED_MORE;
}
if (!message->parse(message))
{
message->destroy(message);
*out = create_client_error(this, in->get_identifier(in),
SIM_UNABLE_TO_PROCESS);
return NEED_MORE;
}
switch (message->get_subtype(message))
{
case SIM_START:
status = process_start(this, message, out);
break;
case SIM_CHALLENGE:
status = process_challenge(this, message, out);
break;
case SIM_REAUTHENTICATION:
status = process_reauthentication(this, message, out);
break;
case SIM_NOTIFICATION:
status = process_notification(this, message, out);
break;
default:
DBG1(DBG_IKE, "unable to process EAP-SIM subtype %N",
simaka_subtype_names, message->get_subtype(message));
*out = create_client_error(this, in->get_identifier(in),
SIM_UNABLE_TO_PROCESS);
status = NEED_MORE;
break;
}
message->destroy(message);
return status;
}
/**
* Implementation of eap_method_t.initiate
*/
static status_t initiate(private_eap_sim_peer_t *this, eap_payload_t **out)
{
/* peer never initiates */
return FAILED;
}
/**
* Implementation of eap_method_t.get_type.
*/
static eap_type_t get_type(private_eap_sim_peer_t *this, u_int32_t *vendor)
{
*vendor = 0;
return EAP_SIM;
}
/**
* Implementation of eap_method_t.get_msk.
*/
static status_t get_msk(private_eap_sim_peer_t *this, chunk_t *msk)
{
if (this->msk.ptr)
{
*msk = this->msk;
return SUCCESS;
}
return FAILED;
}
/**
* Implementation of eap_method_t.is_mutual.
*/
static bool is_mutual(private_eap_sim_peer_t *this)
{
return TRUE;
}
/**
* Implementation of eap_method_t.destroy.
*/
static void destroy(private_eap_sim_peer_t *this)
{
this->permanent->destroy(this->permanent);
DESTROY_IF(this->pseudonym);
DESTROY_IF(this->reauth);
this->crypto->destroy(this->crypto);
free(this->version_list.ptr);
free(this->nonce.ptr);
free(this->msk.ptr);
free(this);
}
/*
* Described in header.
*/
eap_sim_peer_t *eap_sim_peer_create(identification_t *server,
identification_t *peer)
{
private_eap_sim_peer_t *this = malloc_thing(private_eap_sim_peer_t);
this->public.interface.initiate = (status_t(*)(eap_method_t*,eap_payload_t**))initiate;
this->public.interface.process = (status_t(*)(eap_method_t*,eap_payload_t*,eap_payload_t**))process;
this->public.interface.get_type = (eap_type_t(*)(eap_method_t*,u_int32_t*))get_type;
this->public.interface.is_mutual = (bool(*)(eap_method_t*))is_mutual;
this->public.interface.get_msk = (status_t(*)(eap_method_t*,chunk_t*))get_msk;
this->public.interface.destroy = (void(*)(eap_method_t*))destroy;
this->crypto = simaka_crypto_create();
if (!this->crypto)
{
free(this);
return NULL;
}
this->permanent = peer->clone(peer);
this->pseudonym = NULL;
this->reauth = NULL;
this->tries = MAX_TRIES;
this->version_list = chunk_empty;
this->nonce = chunk_empty;
this->msk = chunk_empty;
return &this->public;
}