EAP-EKE: Do not pass full request to eap_eke_build_fail()

This function is only using the Identifier field from the EAP request
header, so there is no need to pass it a pointer to the full message.
This makes it a bit easier to analyze the area that gets access to
unverified message payload.

Signed-off-by: Jouni Malinen <j@w1.fi>

src/eap_peer/eap_eke.c

@@ -195,15 +195,14 @@ static int eap_eke_supp_mac(u8 mac)
 
 static struct wpabuf * eap_eke_build_fail(struct eap_eke_data *data,
 					  struct eap_method_ret *ret,
-					  const struct wpabuf *reqData,
-					  u32 failure_code)
+					  u8 id, u32 failure_code)
 {
 	struct wpabuf *resp;
 
 	wpa_printf(MSG_DEBUG, "EAP-EKE: Sending EAP-EKE-Failure/Response - code=0x%x",
 		   failure_code);
 
-	resp = eap_eke_build_msg(data, eap_get_id(reqData), 4, EAP_EKE_FAILURE);
+	resp = eap_eke_build_msg(data, id, 4, EAP_EKE_FAILURE);
 	if (resp)
 		wpabuf_put_be32(resp, failure_code);
 
@@ -230,9 +229,10 @@ static struct wpabuf * eap_eke_process_id(struct eap_eke_data *data,
 	const u8 *pos, *end;
 	const u8 *prop = NULL;
 	u8 idtype;
+	u8 id = eap_get_id(reqData);
 
 	if (data->state != IDENTITY) {
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PROTO_ERROR);
 	}
 
@@ -240,7 +240,7 @@ static struct wpabuf * eap_eke_process_id(struct eap_eke_data *data,
 
 	if (payload_len < 2 + 4) {
 		wpa_printf(MSG_DEBUG, "EAP-EKE: Too short ID/Request Data");
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PROTO_ERROR);
 	}
 
@@ -253,7 +253,7 @@ static struct wpabuf * eap_eke_process_id(struct eap_eke_data *data,
 	if (pos + num_prop * 4 > end) {
 		wpa_printf(MSG_DEBUG, "EAP-EKE: Too short ID/Request Data (num_prop=%u)",
 			   num_prop);
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PROTO_ERROR);
 	}
 
@@ -293,7 +293,7 @@ static struct wpabuf * eap_eke_process_id(struct eap_eke_data *data,
 
 	if (prop == NULL) {
 		wpa_printf(MSG_DEBUG, "EAP-EKE: No acceptable proposal found");
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_NO_PROPOSAL_CHOSEN);
 	}
 
@@ -301,7 +301,7 @@ static struct wpabuf * eap_eke_process_id(struct eap_eke_data *data,
 
 	if (pos == end) {
 		wpa_printf(MSG_DEBUG, "EAP-EKE: Too short ID/Request Data to include IDType/Identity");
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PROTO_ERROR);
 	}
 
@@ -312,7 +312,7 @@ static struct wpabuf * eap_eke_process_id(struct eap_eke_data *data,
 	os_free(data->serverid);
 	data->serverid = os_malloc(end - pos);
 	if (data->serverid == NULL) {
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 	os_memcpy(data->serverid, pos, end - pos);
@@ -320,11 +320,11 @@ static struct wpabuf * eap_eke_process_id(struct eap_eke_data *data,
 
 	wpa_printf(MSG_DEBUG, "EAP-EKE: Sending EAP-EKE-ID/Response");
 
-	resp = eap_eke_build_msg(data, eap_get_id(reqData),
+	resp = eap_eke_build_msg(data, id,
 				 2 + 4 + 1 + data->peerid_len,
 				 EAP_EKE_ID);
 	if (resp == NULL) {
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 
@@ -339,7 +339,7 @@ static struct wpabuf * eap_eke_process_id(struct eap_eke_data *data,
 	data->msgs = wpabuf_alloc(wpabuf_len(reqData) + wpabuf_len(resp));
 	if (data->msgs == NULL) {
 		wpabuf_free(resp);
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 	wpabuf_put_buf(data->msgs, reqData);
@@ -366,10 +366,11 @@ static struct wpabuf * eap_eke_process_commit(struct eap_sm *sm,
 	u8 pub[EAP_EKE_MAX_DH_LEN];
 	const u8 *password;
 	size_t password_len;
+	u8 id = eap_get_id(reqData);
 
 	if (data->state != COMMIT) {
 		wpa_printf(MSG_DEBUG, "EAP-EKE: EAP-EKE-Commit/Request received in unexpected state (%d)", data->state);
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PROTO_ERROR);
 	}
 
@@ -378,7 +379,7 @@ static struct wpabuf * eap_eke_process_commit(struct eap_sm *sm,
 	password = eap_get_config_password(sm, &password_len);
 	if (password == NULL) {
 		wpa_printf(MSG_INFO, "EAP-EKE: No password configured!");
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PASSWD_NOT_FOUND);
 	}
 
@@ -387,7 +388,7 @@ static struct wpabuf * eap_eke_process_commit(struct eap_sm *sm,
 
 	if (pos + data->sess.dhcomp_len > end) {
 		wpa_printf(MSG_DEBUG, "EAP-EKE: Too short EAP-EKE-Commit");
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PROTO_ERROR);
 	}
 
@@ -405,7 +406,7 @@ static struct wpabuf * eap_eke_process_commit(struct eap_sm *sm,
 			       data->serverid, data->serverid_len,
 			       data->peerid, data->peerid_len, key) < 0) {
 		wpa_printf(MSG_INFO, "EAP-EKE: Failed to derive key");
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 
@@ -416,7 +417,7 @@ static struct wpabuf * eap_eke_process_commit(struct eap_sm *sm,
 	if (eap_eke_dh_init(data->sess.dhgroup, data->dh_priv, pub) < 0) {
 		wpa_printf(MSG_INFO, "EAP-EKE: Failed to initialize DH");
 		os_memset(key, 0, sizeof(key));
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 
@@ -424,7 +425,7 @@ static struct wpabuf * eap_eke_process_commit(struct eap_sm *sm,
 	{
 		wpa_printf(MSG_INFO, "EAP-EKE: Failed to derive shared secret");
 		os_memset(key, 0, sizeof(key));
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 
@@ -433,18 +434,18 @@ static struct wpabuf * eap_eke_process_commit(struct eap_sm *sm,
 				 data->peerid, data->peerid_len) < 0) {
 		wpa_printf(MSG_INFO, "EAP-EKE: Failed to derive Ke/Ki");
 		os_memset(key, 0, sizeof(key));
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 
 	wpa_printf(MSG_DEBUG, "EAP-EKE: Sending EAP-EKE-Commit/Response");
 
-	resp = eap_eke_build_msg(data, eap_get_id(reqData),
+	resp = eap_eke_build_msg(data, id,
 				 data->sess.dhcomp_len + data->sess.pnonce_len,
 				 EAP_EKE_COMMIT);
 	if (resp == NULL) {
 		os_memset(key, 0, sizeof(key));
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 
@@ -453,7 +454,7 @@ static struct wpabuf * eap_eke_process_commit(struct eap_sm *sm,
 	if (eap_eke_dhcomp(&data->sess, key, pub, rpos) < 0) {
 		wpa_printf(MSG_INFO, "EAP-EKE: Failed to build DHComponent_P");
 		os_memset(key, 0, sizeof(key));
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 	os_memset(key, 0, sizeof(key));
@@ -463,7 +464,7 @@ static struct wpabuf * eap_eke_process_commit(struct eap_sm *sm,
 
 	if (random_get_bytes(data->nonce_p, data->sess.nonce_len)) {
 		wpabuf_free(resp);
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 	wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Nonce_P",
@@ -472,7 +473,7 @@ static struct wpabuf * eap_eke_process_commit(struct eap_sm *sm,
 	if (eap_eke_prot(&data->sess, data->nonce_p, data->sess.nonce_len,
 			 wpabuf_put(resp, 0), &prot_len) < 0) {
 		wpabuf_free(resp);
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 	wpa_hexdump(MSG_DEBUG, "EAP-EKE: PNonce_P",
@@ -484,7 +485,7 @@ static struct wpabuf * eap_eke_process_commit(struct eap_sm *sm,
 	if (wpabuf_resize(&data->msgs, wpabuf_len(reqData) + wpabuf_len(resp))
 	    < 0) {
 		wpabuf_free(resp);
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 	wpabuf_put_buf(data->msgs, reqData);
@@ -509,11 +510,12 @@ static struct wpabuf * eap_eke_process_confirm(struct eap_eke_data *data,
 	u8 auth_s[EAP_EKE_MAX_HASH_LEN];
 	size_t decrypt_len;
 	u8 *auth;
+	u8 id = eap_get_id(reqData);
 
 	if (data->state != CONFIRM) {
 		wpa_printf(MSG_DEBUG, "EAP-EKE: EAP-EKE-Confirm/Request received in unexpected state (%d)",
 			   data->state);
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PROTO_ERROR);
 	}
 
@@ -524,7 +526,7 @@ static struct wpabuf * eap_eke_process_confirm(struct eap_eke_data *data,
 
 	if (pos + data->sess.pnonce_ps_len + data->sess.prf_len > end) {
 		wpa_printf(MSG_DEBUG, "EAP-EKE: Too short EAP-EKE-Confirm");
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PROTO_ERROR);
 	}
 
@@ -532,19 +534,19 @@ static struct wpabuf * eap_eke_process_confirm(struct eap_eke_data *data,
 	if (eap_eke_decrypt_prot(&data->sess, pos, data->sess.pnonce_ps_len,
 				 nonces, &decrypt_len) < 0) {
 		wpa_printf(MSG_INFO, "EAP-EKE: Failed to decrypt PNonce_PS");
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_AUTHENTICATION_FAIL);
 	}
 	if (decrypt_len != (size_t) 2 * data->sess.nonce_len) {
 		wpa_printf(MSG_INFO, "EAP-EKE: PNonce_PS protected data length does not match length of Nonce_P and Nonce_S");
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_AUTHENTICATION_FAIL);
 	}
 	wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Received Nonce_P | Nonce_S",
 			nonces, 2 * data->sess.nonce_len);
 	if (os_memcmp(data->nonce_p, nonces, data->sess.nonce_len) != 0) {
 		wpa_printf(MSG_INFO, "EAP-EKE: Received Nonce_P does not match transmitted Nonce_P");
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_AUTHENTICATION_FAIL);
 	}
 
@@ -556,30 +558,30 @@ static struct wpabuf * eap_eke_process_confirm(struct eap_eke_data *data,
 	if (eap_eke_derive_ka(&data->sess, data->serverid, data->serverid_len,
 			      data->peerid, data->peerid_len,
 			      data->nonce_p, data->nonce_s) < 0) {
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 
 	if (eap_eke_auth(&data->sess, "EAP-EKE server", data->msgs, auth_s) < 0)
 	{
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 	wpa_hexdump(MSG_DEBUG, "EAP-EKE: Auth_S", auth_s, data->sess.prf_len);
 	if (os_memcmp_const(auth_s, pos + data->sess.pnonce_ps_len,
 			    data->sess.prf_len) != 0) {
 		wpa_printf(MSG_INFO, "EAP-EKE: Auth_S does not match");
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_AUTHENTICATION_FAIL);
 	}
 
 	wpa_printf(MSG_DEBUG, "EAP-EKE: Sending EAP-EKE-Confirm/Response");
 
-	resp = eap_eke_build_msg(data, eap_get_id(reqData),
+	resp = eap_eke_build_msg(data, id,
 				 data->sess.pnonce_len + data->sess.prf_len,
 				 EAP_EKE_CONFIRM);
 	if (resp == NULL) {
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 
@@ -587,7 +589,7 @@ static struct wpabuf * eap_eke_process_confirm(struct eap_eke_data *data,
 	if (eap_eke_prot(&data->sess, data->nonce_s, data->sess.nonce_len,
 			 wpabuf_put(resp, 0), &prot_len) < 0) {
 		wpabuf_free(resp);
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 	wpabuf_put(resp, prot_len);
@@ -595,7 +597,7 @@ static struct wpabuf * eap_eke_process_confirm(struct eap_eke_data *data,
 	auth = wpabuf_put(resp, data->sess.prf_len);
 	if (eap_eke_auth(&data->sess, "EAP-EKE peer", data->msgs, auth) < 0) {
 		wpabuf_free(resp);
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 	wpa_hexdump(MSG_DEBUG, "EAP-EKE: Auth_P", auth, data->sess.prf_len);
@@ -606,7 +608,7 @@ static struct wpabuf * eap_eke_process_confirm(struct eap_eke_data *data,
 			       data->msk, data->emsk) < 0) {
 		wpa_printf(MSG_INFO, "EAP-EKE: Failed to derive MSK/EMSK");
 		wpabuf_free(resp);
-		return eap_eke_build_fail(data, ret, reqData,
+		return eap_eke_build_fail(data, ret, id,
 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
 	}
 
@@ -638,7 +640,8 @@ static struct wpabuf * eap_eke_process_failure(struct eap_eke_data *data,
 		wpa_printf(MSG_INFO, "EAP-EKE: Failure-Code 0x%x", code);
 	}
 
-	return eap_eke_build_fail(data, ret, reqData, EAP_EKE_FAIL_NO_ERROR);
+	return eap_eke_build_fail(data, ret, eap_get_id(reqData),
+				  EAP_EKE_FAIL_NO_ERROR);
 }