[PATCH v2 1/2] peap: Extend EAP Extensions to handle multiple TLVs

[Tim Kourt <tim.a.kourt@linux.intel.com>]

[-- Attachment #1: Type: text/plain, Size: 5143 bytes --]

The handler for EAP Extensions has been modified to support multiple
TLV types instead of the single Result TLV. This will allow to handle
the other TLVs such as Crypto-Binding TLV.
---
 src/eap-peap.c | 125 ++++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 88 insertions(+), 37 deletions(-)

diff --git a/src/eap-peap.c b/src/eap-peap.c
index ed18c667..8059e60b 100644
--- a/src/eap-peap.c
+++ b/src/eap-peap.c
@@ -111,6 +111,7 @@ static void eap_peap_phase2_complete(enum eap_result result, void *user_data)
  */
 #define EAP_EXTENSIONS_HEADER_LEN 5
 #define EAP_EXTENSIONS_TLV_HEADER_LEN 4
+#define EAP_EXTENSIONS_TLV_M_BIT_MASK 0x8000
 
 enum eap_extensions_tlv_type {
 	/* Reserved = 0x0000, */
@@ -127,39 +128,24 @@ enum eap_extensions_result {
 static int eap_extensions_handle_result_tlv(struct eap_state *eap,
 						const uint8_t *data,
 						size_t data_len,
-						uint8_t *response)
+						uint8_t *response,
+						uint8_t *result)
 {
+	static const uint8_t result_tlv_len = 2;
 	struct peap_state *peap_state;
-	uint16_t type;
-	uint16_t len;
-	uint16_t result;
 
-	if (data_len < EAP_EXTENSIONS_TLV_HEADER_LEN + 2)
-		return -ENOENT;
-
-	type = l_get_be16(data);
-
-	if (type != EAP_EXTENSIONS_TLV_TYPE_RESULT)
-		return -ENOENT;
-
-	data += 2;
-
-	len = l_get_be16(data);
-
-	if (len != 2)
-		return -ENOENT;
-
-	data += 2;
+	if (data_len != result_tlv_len)
+		return -EBADMSG;
 
-	result = l_get_be16(data);
+	*result = l_get_be16(data);
 
-	l_debug("result: %d", result);
+	l_debug("result: %d", *result);
 
-	switch (result) {
+	switch (*result) {
 	case EAP_EXTENSIONS_RESULT_SUCCCESS:
 		peap_state = eap_tls_common_get_variant_data(eap);
 
-		result = eap_method_is_success(peap_state->phase2) ?
+		*result = eap_method_is_success(peap_state->phase2) ?
 					EAP_EXTENSIONS_RESULT_SUCCCESS :
 					EAP_EXTENSIONS_RESULT_FAILURE;
 		/* fall through */
@@ -169,13 +155,68 @@ static int eap_extensions_handle_result_tlv(struct eap_state *eap,
 		return -ENOENT;
 	}
 
-	l_put_be16(EAP_EXTENSIONS_TLV_TYPE_RESULT,
-					&response[EAP_EXTENSIONS_HEADER_LEN]);
-	l_put_be16(2, &response[EAP_EXTENSIONS_HEADER_LEN + 2]);
-	l_put_be16(result, &response[EAP_EXTENSIONS_HEADER_LEN +
-						EAP_EXTENSIONS_TLV_HEADER_LEN]);
+	/* Build response Result TLV */
+
+	l_put_be16(EAP_EXTENSIONS_TLV_TYPE_RESULT, response);
+	response += 2;
+
+	l_put_be16(result_tlv_len, response);
+	response += 2;
+
+	l_put_be16(*result, response);
+
+	return EAP_EXTENSIONS_TLV_HEADER_LEN + result_tlv_len;
+}
+
+static int eap_extensions_process_tlvs(struct eap_state *eap,
+						const uint8_t *data,
+						size_t data_len,
+						uint8_t *response,
+						uint8_t *result)
+{
+	int response_len = 0;
+	uint16_t tlv_type;
+	uint16_t tlv_value_len;
+
+	while (data_len >= EAP_EXTENSIONS_TLV_HEADER_LEN) {
+		int response_tlv_len = 0;
+
+		tlv_type = l_get_be16(data);
+		data += 2;
+
+		tlv_value_len = l_get_be16(data);
+		data += 2;
+
+		data_len -= EAP_EXTENSIONS_TLV_HEADER_LEN;
+
+		if (data_len < tlv_value_len)
+			return -EBADMSG;
+
+		switch (tlv_type) {
+		case EAP_EXTENSIONS_TLV_TYPE_RESULT:
+			response_tlv_len = eap_extensions_handle_result_tlv(eap,
+						data, tlv_value_len, response,
+						result);
+
+			break;
+		default:
+			if (tlv_type & EAP_EXTENSIONS_TLV_M_BIT_MASK)
+				return -ENOENT;
+
+			break;
+		}
+
+		if (response_tlv_len < 0)
+			return response_tlv_len;
+
+		response += response_tlv_len;
+		response_len += response_tlv_len;
+
+		data += tlv_value_len;
+		data_len -= tlv_value_len;
+	}
 
-	return result;
+	return response_len;
 }
 
 static void eap_extensions_handle_request(struct eap_state *eap,
@@ -184,24 +225,34 @@ static void eap_extensions_handle_request(struct eap_state *eap,
 							size_t len)
 {
 	struct peap_state *peap_state;
-	uint8_t response[EAP_EXTENSIONS_HEADER_LEN +
-					EAP_EXTENSIONS_TLV_HEADER_LEN + 2];
-	int r = eap_extensions_handle_result_tlv(eap, pkt, len, response);
+	uint8_t result = EAP_EXTENSIONS_RESULT_FAILURE;
+	/*
+	 * The buffer size is chosen to satisfy the needs of the two supported
+	 * TLVs.
+	 */
+	uint8_t response[256];
+	int response_len;
 
-	if (r < 0)
+	response_len = eap_extensions_process_tlvs(eap, pkt, len,
+					&response[EAP_EXTENSIONS_HEADER_LEN],
+					&result);
+
+	if (response_len < 0)
 		return;
 
+	response_len += EAP_EXTENSIONS_HEADER_LEN;
+
 	response[0] = EAP_CODE_RESPONSE;
 	response[1] = id;
-	l_put_be16(sizeof(response), &response[2]);
+	l_put_be16(response_len, &response[2]);
 	response[4] = EAP_TYPE_EXTENSIONS;
 
-	eap_peap_phase2_send_response(response, sizeof(response), eap);
+	eap_peap_phase2_send_response(response, response_len, eap);
 
 	eap_discard_success_and_failure(eap, false);
 	eap_tls_common_set_completed(eap);
 
-	if (r != EAP_EXTENSIONS_RESULT_SUCCCESS) {
+	if (result != EAP_EXTENSIONS_RESULT_SUCCCESS) {
 		eap_tls_common_set_phase2_failed(eap);
 
 		eap_tls_common_tunnel_close(eap);
-- 
2.13.6