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EAP-SIM/AKA crypto helper supports key derivation for fast reauthentication

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This commit is contained in:
Martin Willi
2009-11-12 10:34:00 +01:00
parent e1a8729de0
commit 454b59c5fd
5 changed files with 119 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/charon/plugins/eap_aka/eap_aka_peer.c
+4 -2
View File
@@ -82,7 +82,7 @@ static status_t process_challenge(private_eap_aka_peer_t *this,
enumerator_t *enumerator;
simaka_attribute_t type;
sim_card_t *card;
chunk_t data, rand = chunk_empty, autn = chunk_empty;
chunk_t data, rand = chunk_empty, autn = chunk_empty, mk;
u_char res[AKA_RES_LEN], ck[AKA_CK_LEN], ik[AKA_IK_LEN], auts[AKA_AUTS_LEN];
status_t status = NOT_FOUND;
@@ -155,7 +155,9 @@ static status_t process_challenge(private_eap_aka_peer_t *this,
data = chunk_cata("cc", chunk_create(ik, AKA_IK_LEN),
chunk_create(ck, AKA_CK_LEN));
free(this->msk.ptr);
this->msk = this->crypto->derive_keys_full(this->crypto, this->peer, data);
this->msk = this->crypto->derive_keys_full(this->crypto, this->peer,
data, &mk);
free(mk.ptr);
/* verify EAP message MAC AT_MAC */
if (!in->verify(in, chunk_empty))
src/charon/plugins/eap_aka/eap_aka_server.c
+4 -2
View File
@@ -98,7 +98,7 @@ static status_t initiate(private_eap_aka_server_t *this, eap_payload_t **out)
sim_provider_t *provider;
char rand[AKA_RAND_LEN], xres[AKA_RES_LEN];
char ck[AKA_CK_LEN], ik[AKA_IK_LEN], autn[AKA_AUTN_LEN];
chunk_t data;
chunk_t data, mk;
bool found = FALSE;
enumerator = charon->sim->create_provider_enumerator(charon->sim);
@@ -122,7 +122,9 @@ static status_t initiate(private_eap_aka_server_t *this, eap_payload_t **out)
data = chunk_cata("cc", chunk_create(ik, AKA_IK_LEN),
chunk_create(ck, AKA_CK_LEN));
free(this->msk.ptr);
this->msk = this->crypto->derive_keys_full(this->crypto, this->peer, data);
this->msk = this->crypto->derive_keys_full(this->crypto, this->peer,
data, &mk);
free(mk.ptr);
this->rand = chunk_clone(chunk_create(rand, AKA_RAND_LEN));
this->xres = chunk_clone(chunk_create(xres, AKA_RES_LEN));
src/libsimaka/simaka_crypto.c
+78 -19
View File
@@ -97,41 +97,97 @@ static rng_t* get_rng(private_simaka_crypto_t *this)
* Implementation of simaka_crypto_t.derive_keys_full
*/
static chunk_t derive_keys_full(private_simaka_crypto_t *this,
identification_t *id, chunk_t data)
identification_t *id, chunk_t data, chunk_t *mk)
{
char mk[HASH_SIZE_SHA1], k_encr[KENCR_LEN], k_auth[KAUTH_LEN];
chunk_t str, msk;
chunk_t str, msk, k_encr, k_auth;
int i;
/* For SIM: MK = SHA1(Identity|n*Kc|NONCE_MT|Version List|Selected Version)
* For AKA: MK = SHA1(Identity|IK|CK) */
this->hasher->get_hash(this->hasher, id->get_encoding(id), NULL);
this->hasher->get_hash(this->hasher, data, mk);
DBG3(DBG_IKE, "MK %b", mk, HASH_SIZE_SHA1);
this->hasher->allocate_hash(this->hasher, data, mk);
DBG3(DBG_IKE, "MK %B", mk);
/* K_encr | K_auth | MSK | EMSK = prf() | prf() | prf() | prf() */
this->prf->set_key(this->prf, chunk_create(mk, HASH_SIZE_SHA1));
this->prf->set_key(this->prf, *mk);
str = chunk_alloca(this->prf->get_block_size(this->prf) * 3);
for (i = 0; i < 3; i++)
{
this->prf->get_bytes(this->prf, chunk_empty, str.ptr + str.len / 3 * i);
}
memcpy(k_encr, str.ptr, KENCR_LEN);
str = chunk_skip(str, KENCR_LEN);
memcpy(k_auth, str.ptr, KAUTH_LEN);
str = chunk_skip(str, KAUTH_LEN);
k_encr = chunk_create(str.ptr, KENCR_LEN);
k_auth = chunk_create(str.ptr + KENCR_LEN, KAUTH_LEN);
msk = chunk_create(str.ptr + KENCR_LEN + KAUTH_LEN, MSK_LEN);
DBG3(DBG_IKE, "K_encr %B\nK_auth %B\nMSK %B", &k_encr, &k_auth, &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));
msk = chunk_clone(chunk_create(str.ptr, MSK_LEN));
DBG3(DBG_IKE, "K_encr %b\nK_auth %b\nMSK %B",
k_encr, KENCR_LEN, k_auth, KAUTH_LEN, &msk);
this->signer->set_key(this->signer, k_auth);
this->crypter->set_key(this->crypter, k_encr);
this->derived = TRUE;
return msk;
return chunk_clone(msk);
}
/**
* Implementation of simaka_crypto_t.derive_keys_reauth
*/
static void derive_keys_reauth(private_simaka_crypto_t *this, chunk_t mk)
{
chunk_t str, k_encr, k_auth;
int i;
/* K_encr | K_auth = prf() | prf() */
this->prf->set_key(this->prf, mk);
str = chunk_alloca(this->prf->get_block_size(this->prf) * 2);
for (i = 0; i < 2; i++)
{
this->prf->get_bytes(this->prf, chunk_empty, str.ptr + str.len / 2 * i);
}
k_encr = chunk_create(str.ptr, KENCR_LEN);
k_auth = chunk_create(str.ptr + KENCR_LEN, KAUTH_LEN);
DBG3(DBG_IKE, "K_encr %B\nK_auth %B", &k_encr, &k_auth);
this->signer->set_key(this->signer, k_auth);
this->crypter->set_key(this->crypter, k_encr);
this->derived = TRUE;
}
/**
* Implementation of simaka_crypto_t.derive_keys_reauth_msk
*/
static chunk_t derive_keys_reauth_msk(private_simaka_crypto_t *this,
identification_t *id, chunk_t counter,
chunk_t nonce_s, chunk_t mk)
{
char xkey[HASH_SIZE_SHA1];
chunk_t str, msk;
int i;
this->hasher->get_hash(this->hasher, id->get_encoding(id), NULL);
this->hasher->get_hash(this->hasher, counter, NULL);
this->hasher->get_hash(this->hasher, nonce_s, NULL);
this->hasher->get_hash(this->hasher, mk, xkey);
/* MSK | EMSK = prf() | prf() | prf() | prf() */
this->prf->set_key(this->prf, chunk_create(xkey, sizeof(xkey)));
str = chunk_alloca(this->prf->get_block_size(this->prf) * 2);
for (i = 0; i < 2; i++)
{
this->prf->get_bytes(this->prf, chunk_empty, str.ptr + str.len / 2 * i);
}
msk = chunk_create(str.ptr, MSK_LEN);
DBG3(DBG_IKE, "MSK %B", &msk);
return chunk_clone(msk);
}
/**
* Implementation of simaka_crypto_t.clear_keys
*/
static void clear_keys(private_simaka_crypto_t *this)
{
this->derived = FALSE;
}
/**
@@ -157,7 +213,10 @@ simaka_crypto_t *simaka_crypto_create()
this->public.get_signer = (signer_t*(*)(simaka_crypto_t*))get_signer;
this->public.get_crypter = (crypter_t*(*)(simaka_crypto_t*))get_crypter;
this->public.get_rng = (rng_t*(*)(simaka_crypto_t*))get_rng;
this->public.derive_keys_full = (chunk_t(*)(simaka_crypto_t*, identification_t *id, chunk_t data))derive_keys_full;
this->public.derive_keys_full = (chunk_t(*)(simaka_crypto_t*, identification_t *id, chunk_t data, chunk_t *mk))derive_keys_full;
this->public.derive_keys_reauth = (void(*)(simaka_crypto_t*, chunk_t mk))derive_keys_reauth;
this->public.derive_keys_reauth_msk = (chunk_t(*)(simaka_crypto_t*, identification_t *id, chunk_t counter, chunk_t nonce_s, chunk_t mk))derive_keys_reauth_msk;
this->public.clear_keys = (void(*)(simaka_crypto_t*))clear_keys;
this->public.destroy = (void(*)(simaka_crypto_t*))destroy;
this->derived = FALSE;
src/libsimaka/simaka_crypto.h
+29 -1
View File
@@ -61,10 +61,38 @@ struct simaka_crypto_t {
*
* @param id peer identity
* @param data method specific data
* @param mk chunk receiving allocated master key MK
* @return allocated MSK value
*/
chunk_t (*derive_keys_full)(simaka_crypto_t *this, identification_t *id,
chunk_t data);
chunk_t data, chunk_t *mk);
/**
* Derive k_encr/k_auth keys from MK using fast reauthentication.
*
* This methods derives the k_encr/k_auth keys and loads them into the
* internal crypter/signer instances.
*
* @param mk master key
*/
void (*derive_keys_reauth)(simaka_crypto_t *this, chunk_t mk);
/**
* Derive MSK using fast reauthentication.
*
* @param id fast reauthentication identity
* @param counter fast reauthentication counter value, network order
* @param nonce_s server generated NONCE_S value
* @param mk master key of last full authentication
*/
chunk_t (*derive_keys_reauth_msk)(simaka_crypto_t *this,
identification_t *id, chunk_t counter,
chunk_t nonce_s, chunk_t mk);
/**
* Clear keys (partially) derived.
*/
void (*clear_keys)(simaka_crypto_t *this);
/**
* Destroy a simaka_crypto_t.
src/libsimaka/simaka_message.c
+4 -3
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@@ -469,6 +469,7 @@ static bool decrypt(private_simaka_message_t *this)
{
bool success;
crypter_t *crypter;
chunk_t plain;
crypter = this->crypto->get_crypter(this->crypto);
if (!crypter || !this->iv.len || !this->encr.len || this->encrypted)
@@ -482,12 +483,12 @@ static bool decrypt(private_simaka_message_t *this)
return FALSE;
}
/* decrypt inline */
crypter->decrypt(crypter, this->encr, this->iv, NULL);
crypter->decrypt(crypter, this->encr, this->iv, &plain);
this->encrypted = TRUE;
success = parse_attributes(this, this->encr);
success = parse_attributes(this, plain);
this->encrypted = FALSE;
free(plain.ptr);
return success;
}