eap_peap.c

IEEE 802.11a/b/g 服务器端AP

	if (!data->phase2_method->isSuccess(sm, data->phase2_priv)) {
		wpa_printf(MSG_DEBUG, "EAP-PEAP: Phase2 method failed");
		eap_peap_req_failure(sm, data);
		next_type = EAP_TYPE_NONE;
		eap_peap_phase2_init(sm, data, next_type);
		return;
	}

	os_free(data->phase2_key);
	if (data->phase2_method->getKey) {
		data->phase2_key = data->phase2_method->getKey(
			sm, data->phase2_priv, &data->phase2_key_len);
		if (data->phase2_key == NULL) {
			wpa_printf(MSG_DEBUG, "EAP-PEAP: Phase2 getKey "
				   "failed");
			eap_peap_req_failure(sm, data);
			eap_peap_phase2_init(sm, data, EAP_TYPE_NONE);
			return;
		}

		if (data->phase2_key_len == 32 &&
		    data->phase2_method->vendor == EAP_VENDOR_IETF &&
		    data->phase2_method->method == EAP_TYPE_MSCHAPV2) {
			/*
			 * Microsoft uses reverse order for MS-MPPE keys in
			 * EAP-PEAP when compared to EAP-FAST derivation of
			 * ISK. Swap the keys here to get the correct ISK for
			 * EAP-PEAPv0 cryptobinding.
			 */
			u8 tmp[16];
			os_memcpy(tmp, data->phase2_key, 16);
			os_memcpy(data->phase2_key, data->phase2_key + 16, 16);
			os_memcpy(data->phase2_key + 16, tmp, 16);
		}
	}

	switch (data->state) {
	case PHASE1_ID2:
	case PHASE2_ID:
	case PHASE2_SOH:
		if (eap_user_get(sm, sm->identity, sm->identity_len, 1) != 0) {
			wpa_hexdump_ascii(MSG_DEBUG, "EAP_PEAP: Phase2 "
					  "Identity not found in the user "
					  "database",
					  sm->identity, sm->identity_len);
			eap_peap_req_failure(sm, data);
			next_type = EAP_TYPE_NONE;
			break;
		}

#ifdef EAP_TNC
		if (data->state != PHASE2_SOH && sm->tnc &&
		    data->peap_version == 0) {
			eap_peap_state(data, PHASE2_SOH);
			wpa_printf(MSG_DEBUG, "EAP-PEAP: Try to initialize "
				   "TNC (NAP SOH)");
			next_type = EAP_TYPE_NONE;
			break;
		}
#endif /* EAP_TNC */

		eap_peap_state(data, PHASE2_METHOD);
		next_type = sm->user->methods[0].method;
		sm->user_eap_method_index = 1;
		wpa_printf(MSG_DEBUG, "EAP-PEAP: try EAP type %d", next_type);
		break;
	case PHASE2_METHOD:
		eap_peap_req_success(sm, data);
		next_type = EAP_TYPE_NONE;
		break;
	case FAILURE:
		break;
	default:
		wpa_printf(MSG_DEBUG, "EAP-PEAP: %s - unexpected state %d",
			   __func__, data->state);
		break;
	}

	eap_peap_phase2_init(sm, data, next_type);
}


static void eap_peap_process_phase2(struct eap_sm *sm,
				    struct eap_peap_data *data,
				    const struct wpabuf *respData,
				    struct wpabuf *in_buf)
{
	struct wpabuf *in_decrypted;
	int len_decrypted;
	const struct eap_hdr *hdr;
	size_t buf_len, len;
	u8 *in_data;
	size_t in_len;

	in_data = wpabuf_mhead(in_buf);
	in_len = wpabuf_len(in_buf);

	wpa_printf(MSG_DEBUG, "EAP-PEAP: received %lu bytes encrypted data for"
		   " Phase 2", (unsigned long) in_len);

	if (data->pending_phase2_resp) {
		wpa_printf(MSG_DEBUG, "EAP-PEAP: Pending Phase 2 response - "
			   "skip decryption and use old data");
		eap_peap_process_phase2_response(sm, data,
						 data->pending_phase2_resp);
		wpabuf_free(data->pending_phase2_resp);
		data->pending_phase2_resp = NULL;
		return;
	}

	buf_len = in_len;
	/*
	 * Even though we try to disable TLS compression, it is possible that
	 * this cannot be done with all TLS libraries. Add extra buffer space
	 * to handle the possibility of the decrypted data being longer than
	 * input data.
	 */
	buf_len += 500;
	buf_len *= 3;
	in_decrypted = wpabuf_alloc(buf_len);
	if (in_decrypted == NULL) {
		wpa_printf(MSG_WARNING, "EAP-PEAP: failed to allocate memory "
			   "for decryption");
		return;
	}

	len_decrypted = tls_connection_decrypt(sm->ssl_ctx, data->ssl.conn,
					       in_data, in_len,
					       wpabuf_mhead(in_decrypted),
					       buf_len);
	if (len_decrypted < 0) {
		wpa_printf(MSG_INFO, "EAP-PEAP: Failed to decrypt Phase 2 "
			   "data");
		wpabuf_free(in_decrypted);
		eap_peap_state(data, FAILURE);
		return;
	}
	wpabuf_put(in_decrypted, len_decrypted);

	wpa_hexdump_buf_key(MSG_DEBUG, "EAP-PEAP: Decrypted Phase 2 EAP",
			    in_decrypted);

	hdr = wpabuf_head(in_decrypted);

	if (data->peap_version == 0 && data->state != PHASE2_TLV) {
		const struct eap_hdr *resp;
		struct eap_hdr *nhdr;
		struct wpabuf *nbuf =
			wpabuf_alloc(sizeof(struct eap_hdr) +
				     wpabuf_len(in_decrypted));
		if (nbuf == NULL) {
			wpabuf_free(in_decrypted);
			return;
		}

		resp = wpabuf_head(respData);
		nhdr = wpabuf_put(nbuf, sizeof(*nhdr));
		nhdr->code = resp->code;
		nhdr->identifier = resp->identifier;
		nhdr->length = host_to_be16(sizeof(struct eap_hdr) +
					    wpabuf_len(in_decrypted));
		wpabuf_put_buf(nbuf, in_decrypted);
		wpabuf_free(in_decrypted);

		in_decrypted = nbuf;
	} else if (data->peap_version >= 2) {
		struct eap_tlv_hdr *tlv;
		struct wpabuf *nmsg;

		if (wpabuf_len(in_decrypted) < sizeof(*tlv) + sizeof(*hdr)) {
			wpa_printf(MSG_INFO, "EAP-PEAPv2: Too short Phase 2 "
				   "EAP TLV");
			wpabuf_free(in_decrypted);
			return;
		}
		tlv = wpabuf_mhead(in_decrypted);
		if ((be_to_host16(tlv->tlv_type) & EAP_TLV_TYPE_MASK) !=
		    EAP_TLV_EAP_PAYLOAD_TLV) {
			wpa_printf(MSG_INFO, "EAP-PEAPv2: Not an EAP TLV");
			wpabuf_free(in_decrypted);
			return;
		}
		if (sizeof(*tlv) + be_to_host16(tlv->length) >
		    wpabuf_len(in_decrypted)) {
			wpa_printf(MSG_INFO, "EAP-PEAPv2: Invalid EAP TLV "
				   "length");
			wpabuf_free(in_decrypted);
			return;
		}
		hdr = (struct eap_hdr *) (tlv + 1);
		if (be_to_host16(hdr->length) > be_to_host16(tlv->length)) {
			wpa_printf(MSG_INFO, "EAP-PEAPv2: No room for full "
				   "EAP packet in EAP TLV");
			wpabuf_free(in_decrypted);
			return;
		}

		nmsg = wpabuf_alloc(be_to_host16(hdr->length));
		if (nmsg == NULL) {
			wpabuf_free(in_decrypted);
			return;
		}

		wpabuf_put_data(nmsg, hdr, be_to_host16(hdr->length));
		wpabuf_free(in_decrypted);
		in_decrypted = nmsg;
	}

	hdr = wpabuf_head(in_decrypted);
	if (wpabuf_len(in_decrypted) < (int) sizeof(*hdr)) {
		wpa_printf(MSG_INFO, "EAP-PEAP: Too short Phase 2 "
			   "EAP frame (len=%lu)",
			   (unsigned long) wpabuf_len(in_decrypted));
		wpabuf_free(in_decrypted);
		eap_peap_req_failure(sm, data);
		return;
	}
	len = be_to_host16(hdr->length);
	if (len > wpabuf_len(in_decrypted)) {
		wpa_printf(MSG_INFO, "EAP-PEAP: Length mismatch in "
			   "Phase 2 EAP frame (len=%lu hdr->length=%lu)",
			   (unsigned long) wpabuf_len(in_decrypted),
			   (unsigned long) len);
		wpabuf_free(in_decrypted);
		eap_peap_req_failure(sm, data);
		return;
	}
	wpa_printf(MSG_DEBUG, "EAP-PEAP: received Phase 2: code=%d "
		   "identifier=%d length=%lu", hdr->code, hdr->identifier,
		   (unsigned long) len);
	switch (hdr->code) {
	case EAP_CODE_RESPONSE:
		eap_peap_process_phase2_response(sm, data, in_decrypted);
		break;
	case EAP_CODE_SUCCESS:
		wpa_printf(MSG_DEBUG, "EAP-PEAP: Phase 2 Success");
		if (data->state == SUCCESS_REQ) {
			eap_peap_state(data, SUCCESS);
		}
		break;
	case EAP_CODE_FAILURE:
		wpa_printf(MSG_DEBUG, "EAP-PEAP: Phase 2 Failure");
		eap_peap_state(data, FAILURE);
		break;
	default:
		wpa_printf(MSG_INFO, "EAP-PEAP: Unexpected code=%d in "
			   "Phase 2 EAP header", hdr->code);
		break;
	}

	os_free(in_decrypted);
}


static int eap_peapv2_start_phase2(struct eap_sm *sm,
				   struct eap_peap_data *data)
{
	struct wpabuf *buf, *buf2;
	int res;

	wpa_printf(MSG_DEBUG, "EAP-PEAPv2: Phase1 done, include first Phase2 "
		   "payload in the same message");
	eap_peap_state(data, PHASE1_ID2);
	if (eap_peap_phase2_init(sm, data, EAP_TYPE_IDENTITY))
		return -1;

	/* TODO: which Id to use here? */
	buf = data->phase2_method->buildReq(sm, data->phase2_priv, 6);
	if (buf == NULL)
		return -1;

	buf2 = eap_peapv2_tlv_eap_payload(buf);
	if (buf2 == NULL)
		return -1;

	wpa_hexdump_buf(MSG_DEBUG, "EAP-PEAPv2: Identity Request", buf2);

	buf = wpabuf_alloc(data->ssl.tls_out_limit);
	if (buf == NULL) {
		wpabuf_free(buf2);
		return -1;
	}

	res = tls_connection_encrypt(sm->ssl_ctx, data->ssl.conn,
				     wpabuf_head(buf2), wpabuf_len(buf2),
				     wpabuf_put(buf, 0),
				     data->ssl.tls_out_limit);
	wpabuf_free(buf2);

	if (res < 0) {
		wpa_printf(MSG_INFO, "EAP-PEAPv2: Failed to encrypt Phase 2 "
			   "data");
		wpabuf_free(buf);
		return -1;
	}

	wpabuf_put(buf, res);
	wpa_hexdump_buf(MSG_DEBUG, "EAP-PEAPv2: Encrypted Identity Request",
			buf);

	/* Append TLS data into the pending buffer after the Server Finished */
	if (wpabuf_resize(&data->ssl.out_buf, wpabuf_len(buf)) < 0) {
		wpabuf_free(buf);
		return -1;
	}
	wpabuf_put_buf(data->ssl.out_buf, buf);
	wpabuf_free(buf);

	return 0;
}


static int eap_peap_process_version(struct eap_sm *sm, void *priv,
				    int peer_version)
{
	struct eap_peap_data *data = priv;

	data->recv_version = peer_version;
	if (data->force_version >= 0 && peer_version != data->force_version) {
		wpa_printf(MSG_INFO, "EAP-PEAP: peer did not select the forced"
			   " version (forced=%d peer=%d) - reject",
			   data->force_version, peer_version);
		return -1;
	}
	if (peer_version < data->peap_version) {
		wpa_printf(MSG_DEBUG, "EAP-PEAP: peer ver=%d, own ver=%d; "
			   "use version %d",
			   peer_version, data->peap_version, peer_version);
		data->peap_version = peer_version;
	}

	return 0;
}


static void eap_peap_process_msg(struct eap_sm *sm, void *priv,
				 const struct wpabuf *respData)
{
	struct eap_peap_data *data = priv;

	switch (data->state) {
	case PHASE1:
		if (eap_server_tls_phase1(sm, &data->ssl) < 0) {
			eap_peap_state(data, FAILURE);
			break;
		}

		if (data->peap_version >= 2 &&
		    tls_connection_established(sm->ssl_ctx, data->ssl.conn)) {
			if (eap_peapv2_start_phase2(sm, data)) {
				eap_peap_state(data, FAILURE);
				break;
			}
		}
		break;
	case PHASE2_START:
		eap_peap_state(data, PHASE2_ID);
		eap_peap_phase2_init(sm, data, EAP_TYPE_IDENTITY);
		break;
	case PHASE1_ID2:
	case PHASE2_ID:
	case PHASE2_METHOD:
	case PHASE2_SOH:
	case PHASE2_TLV:
		eap_peap_process_phase2(sm, data, respData, data->ssl.in_buf);
		break;
	case SUCCESS_REQ:
		eap_peap_state(data, SUCCESS);
		break;
	case FAILURE_REQ:
		eap_peap_state(data, FAILURE);
		break;
	default:
		wpa_printf(MSG_DEBUG, "EAP-PEAP: Unexpected state %d in %s",
			   data->state, __func__);
		break;
	}
}


static void eap_peap_process(struct eap_sm *sm, void *priv,
			     struct wpabuf *respData)
{
	struct eap_peap_data *data = priv;
	if (eap_server_tls_process(sm, &data->ssl, respData, data,
				   EAP_TYPE_PEAP, eap_peap_process_version,
				   eap_peap_process_msg) < 0)
		eap_peap_state(data, FAILURE);
}


static Boolean eap_peap_isDone(struct eap_sm *sm, void *priv)
{
	struct eap_peap_data *data = priv;
	return data->state == SUCCESS || data->state == FAILURE;
}


static u8 * eap_peap_getKey(struct eap_sm *sm, void *priv, size_t *len)
{
	struct eap_peap_data *data = priv;
	u8 *eapKeyData;

	if (data->state != SUCCESS)
		return NULL;

	if (data->crypto_binding_used) {
		u8 csk[128];
		/*
		 * Note: It looks like Microsoft implementation requires null
		 * termination for this label while the one used for deriving
		 * IPMK|CMK did not use null termination.
		 */
		peap_prfplus(data->peap_version, data->ipmk, 40,
			     "Session Key Generating Function",
			     (u8 *) "\00", 1, csk, sizeof(csk));
		wpa_hexdump_key(MSG_DEBUG, "EAP-PEAP: CSK", csk, sizeof(csk));
		eapKeyData = os_malloc(EAP_TLS_KEY_LEN);
		if (eapKeyData) {
			os_memcpy(eapKeyData, csk, EAP_TLS_KEY_LEN);
			*len = EAP_TLS_KEY_LEN;
			wpa_hexdump(MSG_DEBUG, "EAP-PEAP: Derived key",
				    eapKeyData, EAP_TLS_KEY_LEN);
		} else {
			wpa_printf(MSG_DEBUG, "EAP-PEAP: Failed to derive "
				   "key");
		}

		return eapKeyData;
	}

	/* TODO: PEAPv1 - different label in some cases */
	eapKeyData = eap_server_tls_derive_key(sm, &data->ssl,
					       "client EAP encryption",
					       EAP_TLS_KEY_LEN);
	if (eapKeyData) {
		*len = EAP_TLS_KEY_LEN;
		wpa_hexdump(MSG_DEBUG, "EAP-PEAP: Derived key",
			    eapKeyData, EAP_TLS_KEY_LEN);
	} else {
		wpa_printf(MSG_DEBUG, "EAP-PEAP: Failed to derive key");
	}

	return eapKeyData;
}


static Boolean eap_peap_isSuccess(struct eap_sm *sm, void *priv)
{
	struct eap_peap_data *data = priv;
	return data->state == SUCCESS;
}


int eap_server_peap_register(void)
{
	struct eap_method *eap;
	int ret;

	eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
				      EAP_VENDOR_IETF, EAP_TYPE_PEAP, "PEAP");
	if (eap == NULL)
		return -1;

	eap->init = eap_peap_init;
	eap->reset = eap_peap_reset;
	eap->buildReq = eap_peap_buildReq;
	eap->check = eap_peap_check;
	eap->process = eap_peap_process;
	eap->isDone = eap_peap_isDone;
	eap->getKey = eap_peap_getKey;
	eap->isSuccess = eap_peap_isSuccess;

	ret = eap_server_method_register(eap);
	if (ret)
		eap_server_method_free(eap);
	return ret;
}