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Use the EAP-SIM/AKA crypto helper in EAP-SIM

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This commit is contained in:
Martin Willi
2009-11-12 10:33:59 +01:00
parent 55916dcc9e
commit e9c03f5243
4 changed files with 81 additions and 213 deletions
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src/charon/plugins/eap_sim/eap_sim_server.c
+27 -99
View File
@@ -18,12 +18,11 @@
#include <daemon.h>
#include <simaka_message.h>
#include <simaka_crypto.h>
/* number of triplets for one authentication */
#define TRIPLET_COUNT 3
/** length of the AT_NONCE_MT/AT_NONCE_S nonce value */
#define NONCE_LEN 16
/** length of the AT_MAC value */
#define MAC_LEN 16
/** length of the AT_RAND value */
@@ -32,14 +31,6 @@
#define KC_LEN 8
/** length of SRES */
#define SRES_LEN 4
/** length of the k_encr key */
#define KENCR_LEN 16
/** length of the k_auth key */
#define KAUTH_LEN 16
/** length of the MSK */
#define MSK_LEN 64
/** length of the EMSK */
#define EMSK_LEN 64
typedef struct private_eap_sim_server_t private_eap_sim_server_t;
@@ -59,29 +50,9 @@ struct private_eap_sim_server_t {
identification_t *peer;
/**
* Random number generator for nonce, IVs
* EAP-SIM/AKA crypto helper
*/
rng_t *rng;
/**
* hashing function
*/
hasher_t *hasher;
/**
* prf
*/
prf_t *prf;
/**
* MAC function
*/
signer_t *signer;
/**
* encryption function
*/
crypter_t *crypter;
simaka_crypto_t *crypto;
/**
* unique EAP identifier
@@ -99,6 +70,9 @@ struct private_eap_sim_server_t {
chunk_t msk;
};
/* version of SIM protocol we speak */
static chunk_t version = chunk_from_chars(0x00,0x01);
/**
* Fetch a triplet from a provider
*/
@@ -125,44 +99,6 @@ static bool get_provider_triplet(private_eap_sim_server_t *this,
return FALSE;
}
/**
* Derive EAP keys from kc when using full authentication
*/
static void derive_keys_full(private_eap_sim_server_t *this,
chunk_t kcs, chunk_t nonce)
{
char mk[HASH_SIZE_SHA1], k_encr[KENCR_LEN], k_auth[KAUTH_LEN];
chunk_t tmp;
int i;
/* MK = SHA1(Identity|n*Kc|NONCE_MT|Version List|Selected Version) */
tmp = chunk_cata("ccccc", this->peer->get_encoding(this->peer),
kcs, nonce, version, version);
this->hasher->get_hash(this->hasher, tmp, mk);
DBG3(DBG_IKE, "MK = SHA1(%B\n) = %b", &tmp, mk, HASH_SIZE_SHA1);
/* K_encr | K_auth | MSK | EMSK = prf() | prf() | prf() | prf()
* We currently don't need EMSK, so three prf() are sufficient */
this->prf->set_key(this->prf, chunk_create(mk, HASH_SIZE_SHA1));
tmp = chunk_alloca(this->prf->get_block_size(this->prf) * 3);
for (i = 0; i < 3; i++)
{
this->prf->get_bytes(this->prf, chunk_empty, tmp.ptr + tmp.len / 3 * i);
}
memcpy(k_encr, tmp.ptr, KENCR_LEN);
tmp = chunk_skip(tmp, KENCR_LEN);
memcpy(k_auth, tmp.ptr, KAUTH_LEN);
tmp = chunk_skip(tmp, KAUTH_LEN);
free(this->msk.ptr);
this->msk = chunk_alloc(MSK_LEN);
memcpy(this->msk.ptr, tmp.ptr, MSK_LEN);
DBG3(DBG_IKE, "K_encr %b\nK_auth %b\nMSK %B",
k_encr, KENCR_LEN, k_auth, KAUTH_LEN, &this->msk);
this->signer->set_key(this->signer, chunk_create(k_auth, KAUTH_LEN));
this->crypter->set_key(this->crypter, chunk_create(k_encr, KENCR_LEN));
}
/**
* process an EAP-SIM/Response/Start message
*/
@@ -226,13 +162,15 @@ static status_t process_start(private_eap_sim_server_t *this,
free(this->sreses.ptr);
this->sreses = chunk_clone(sreses);
derive_keys_full(this, kcs, nonce);
data = chunk_cata("cccc", kcs, nonce, version, version);
free(this->msk.ptr);
this->msk = this->crypto->derive_keys_full(this->crypto, this->peer, data);
/* build response with AT_MAC, built over "EAP packet | NONCE_MT" */
message = simaka_message_create(TRUE, this->identifier++,
EAP_SIM, SIM_CHALLENGE);
message->add_attribute(message, AT_RAND, rands);
*out = message->generate(message, NULL, NULL, this->signer, nonce);
*out = message->generate(message, this->crypto, nonce);
message->destroy(message);
return NEED_MORE;
}
@@ -256,7 +194,7 @@ static status_t process_challenge(private_eap_sim_server_t *this,
enumerator->destroy(enumerator);
/* verify AT_MAC attribute, signature is over "EAP packet | n*SRES" */
if (!in->verify(in, this->signer, this->sreses))
if (!in->verify(in, this->crypto, this->sreses))
{
DBG1(DBG_IKE, "AT_MAC verification failed");
return FAILED;
@@ -305,7 +243,7 @@ static status_t process(private_eap_sim_server_t *this,
{
return FAILED;
}
if (!message->parse(message, this->crypter))
if (!message->parse(message, this->crypto))
{
message->destroy(message);
return FAILED;
@@ -341,7 +279,7 @@ static status_t initiate(private_eap_sim_server_t *this, eap_payload_t **out)
message = simaka_message_create(TRUE, this->identifier++,
EAP_SIM, SIM_START);
message->add_attribute(message, AT_VERSION_LIST, version);
*out = message->generate(message, NULL, NULL, NULL, chunk_empty);
*out = message->generate(message, this->crypto, chunk_empty);
message->destroy(message);
return NEED_MORE;
}
@@ -381,12 +319,8 @@ static bool is_mutual(private_eap_sim_server_t *this)
*/
static void destroy(private_eap_sim_server_t *this)
{
this->crypto->destroy(this->crypto);
this->peer->destroy(this->peer);
DESTROY_IF(this->rng);
DESTROY_IF(this->hasher);
DESTROY_IF(this->prf);
DESTROY_IF(this->signer);
DESTROY_IF(this->crypter);
free(this->sreses.ptr);
free(this->msk.ptr);
free(this);
@@ -400,6 +334,19 @@ eap_sim_server_t *eap_sim_server_create(identification_t *server,
{
private_eap_sim_server_t *this = malloc_thing(private_eap_sim_server_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->peer = peer->clone(peer);
this->sreses = chunk_empty;
this->msk = chunk_empty;
@@ -408,25 +355,6 @@ eap_sim_server_t *eap_sim_server_create(identification_t *server,
this->identifier = random();
} while (!this->identifier);
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->rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
this->hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA1);
this->prf = lib->crypto->create_prf(lib->crypto, PRF_FIPS_SHA1_160);
this->signer = lib->crypto->create_signer(lib->crypto, AUTH_HMAC_SHA1_128);
this->crypter = lib->crypto->create_crypter(lib->crypto, ENCR_AES_CBC, 16);
if (!this->rng || !this->hasher || !this->prf ||
!this->signer || !this->crypter)
{
DBG1(DBG_IKE, "unable to use EAP-SIM, missing algorithms");
destroy(this);
return NULL;
}
return &this->public;
}