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implemented MS_MPPE encryption

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This commit is contained in:
Andreas Steffen
2012-03-13 23:26:15 +01:00
parent 5fdb849293
commit 6fd612913e
4 changed files with 148 additions and 35 deletions
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src/libcharon/plugins/tnc_pdp/tnc_pdp.c
+93 -14
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@@ -20,9 +20,11 @@
#include <unistd.h>
#include <radius_message.h>
#include <radius_mppe.h>
#include <daemon.h>
#include <debug.h>
#include <pen/pen.h>
#include <threading/thread.h>
#include <processing/jobs/callback_job.h>
#include <sa/authenticators/eap/eap_method.h>
@@ -84,6 +86,11 @@ struct private_tnc_pdp_t {
*/
signer_t *signer;
/**
* Random number generator for MS-MPPE salt values
*/
rng_t *rng;
/**
* List of registered TNC-PDP connections
*/
@@ -176,16 +183,73 @@ static void send_message(private_tnc_pdp_t *this, radius_message_t *message,
}
}
/**
* Encrypt a MS-MPPE-Send/Recv-Key
*/
static chunk_t encrypt_mppe_key(private_tnc_pdp_t *this, u_int8_t type,
chunk_t key, radius_message_t *request)
{
chunk_t a, r, seed, data;
u_char b[HASH_SIZE_MD5], *c;
mppe_key_t *mppe_key;
/**
* From RFC2548 (encryption):
* b(1) = MD5(S + R + A) c(1) = p(1) xor b(1) C = c(1)
* b(2) = MD5(S + c(1)) c(2) = p(2) xor b(2) C = C + c(2)
* . . .
* b(i) = MD5(S + c(i-1)) c(i) = p(i) xor b(i) C = C + c(i)
*/
data = chunk_alloc(sizeof(mppe_key_t) +
HASH_SIZE_MD5 * (1 + key.len / HASH_SIZE_MD5));
memset(data.ptr, 0x00, data.len);
mppe_key = (mppe_key_t*)data.ptr;
mppe_key->id = htonl(PEN_MICROSOFT);
mppe_key->type = type;
mppe_key->length = data.len - sizeof(mppe_key->id);
mppe_key->key[0] = key.len;
memcpy(&mppe_key->key[1], key.ptr, key.len);
/* generate a 16 bit random salt value */
a = chunk_create((u_char*)&(mppe_key->salt), sizeof(mppe_key->salt));
this->rng->get_bytes(this->rng, a.len, a.ptr);
/* the MSB of the salt MUST be set to 1 */
*a.ptr |= 0x80;
r = chunk_create(request->get_authenticator(request), HASH_SIZE_MD5);
seed = chunk_cata("cc", r, a);
c = mppe_key->key;
while (c < data.ptr + data.len)
{
/* b(i) = MD5(S + c(i-1)) */
this->hasher->get_hash(this->hasher, this->secret, NULL);
this->hasher->get_hash(this->hasher, seed, b);
/* c(i) = b(i) xor p(1) */
memxor(c, b, HASH_SIZE_MD5);
/* prepare next round */
seed = chunk_create(c, HASH_SIZE_MD5);
c += HASH_SIZE_MD5;
}
return data;
}
/**
* Send a RADIUS response for a request
*/
static void send_response(private_tnc_pdp_t *this,
radius_message_t *request, radius_message_code_t code,
eap_payload_t *eap, identification_t *group,
host_t *client)
static void send_response(private_tnc_pdp_t *this, radius_message_t *request,
radius_message_code_t code, eap_payload_t *eap,
identification_t *group, chunk_t msk, host_t *client)
{
radius_message_t *response;
chunk_t data;
chunk_t data, recv, send;
u_int32_t tunnel_type;
response = radius_message_create(code);
@@ -211,6 +275,18 @@ static void send_response(private_tnc_pdp_t *this,
response->add(response, RAT_TUNNEL_TYPE, data);
response->add(response, RAT_FILTER_ID, group->get_encoding(group));
}
if (msk.len)
{
recv = chunk_create(msk.ptr, msk.len / 2);
data = encrypt_mppe_key(this, MS_MPPE_RECV_KEY, recv, request);
response->add(response, RAT_VENDOR_SPECIFIC, data);
chunk_free(&data);
send = chunk_create(msk.ptr + recv.len, msk.len - recv.len);
data = encrypt_mppe_key(this, MS_MPPE_SEND_KEY, send, request);
response->add(response, RAT_VENDOR_SPECIFIC, data);
chunk_free(&data);
}
response->set_identifier(response, request->get_identifier(request));
response->sign(response, request->get_authenticator(request),
this->secret, this->hasher, this->signer, NULL, TRUE);
@@ -232,7 +308,7 @@ static void process_eap(private_tnc_pdp_t *this, radius_message_t *request,
eap_method_t *method;
eap_type_t eap_type;
u_int32_t eap_vendor;
chunk_t data, message = chunk_empty;
chunk_t data, message = chunk_empty, msk = chunk_empty;
chunk_t user_name = chunk_empty, nas_id = chunk_empty;
identification_t *group = NULL;
radius_message_code_t code = RMC_ACCESS_CHALLENGE;
@@ -315,7 +391,7 @@ static void process_eap(private_tnc_pdp_t *this, radius_message_t *request,
break;
case SUCCESS:
code = RMC_ACCESS_ACCEPT;
method->get_msk(method, &msk);
auth = ike_sa->get_auth_cfg(ike_sa, FALSE);
e = auth->create_enumerator(auth);
while (e->enumerate(e, &type, &data))
@@ -342,7 +418,7 @@ static void process_eap(private_tnc_pdp_t *this, radius_message_t *request,
charon->bus->set_sa(charon->bus, NULL);
}
send_response(this, request, code, out, group, source);
send_response(this, request, code, out, group, msk, source);
out->destroy(out);
if (code == RMC_ACCESS_ACCEPT || code == RMC_ACCESS_REJECT)
@@ -475,6 +551,7 @@ METHOD(tnc_pdp_t, destroy, void,
DESTROY_IF(this->server);
DESTROY_IF(this->signer);
DESTROY_IF(this->hasher);
DESTROY_IF(this->rng);
DESTROY_IF(this->connections);
free(this);
}
@@ -495,12 +572,19 @@ tnc_pdp_t *tnc_pdp_create(u_int16_t port)
.ipv6 = open_socket(this, AF_INET6, port),
.hasher = lib->crypto->create_hasher(lib->crypto, HASH_MD5),
.signer = lib->crypto->create_signer(lib->crypto, AUTH_HMAC_MD5_128),
.rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK),
.connections = tnc_pdp_connections_create(),
);
if (!this->hasher || !this->signer || !this->rng)
{
DBG1(DBG_CFG, "RADIUS initialization failed, HMAC/MD5/RNG required");
destroy(this);
return NULL;
}
if (!this->ipv4 && !this->ipv6)
{
DBG1(DBG_NET, "couldd not create any RADIUS sockets");
DBG1(DBG_NET, "could not create any RADIUS sockets");
destroy(this);
return NULL;
}
@@ -512,11 +596,6 @@ tnc_pdp_t *tnc_pdp_create(u_int16_t port)
{
DBG1(DBG_NET, "could not open IPv6 RADIUS socket, IPv6 disabled");
}
if (!this->hasher || !this->signer)
{
destroy(this);
return NULL;
}
server = lib->settings->get_str(lib->settings,
"charon.plugins.tnc-pdp.server", NULL);