From d3ee7c71beacb018d91538b3d57e9ae92fd85d3e Mon Sep 17 00:00:00 2001
From: Denis Kenzior <denkenz@gmail.com>
Date: Fri, 19 Aug 2016 15:04:06 -0500
Subject: [PATCH] wscutil: Add M4 parser

---
 src/wscutil.c | 28 ++++++++++++++++++++++++++++
 src/wscutil.h | 12 ++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/src/wscutil.c b/src/wscutil.c
index f1b165e3..4df190ee 100644
--- a/src/wscutil.c
+++ b/src/wscutil.c
@@ -1106,6 +1106,34 @@ int wsc_parse_m3(const uint8_t *pdu, uint32_t len, struct wsc_m3 *out)
 	return 0;
 }
 
+int wsc_parse_m4(const uint8_t *pdu, uint32_t len, struct wsc_m4 *out,
+						struct iovec *out_encrypted)
+{
+	int r;
+	struct wsc_wfa_ext_iter iter;
+	uint8_t version;
+	enum wsc_message_type msg_type;
+
+	memset(out, 0, sizeof(struct wsc_m4));
+
+	r = wsc_parse_attrs(pdu, len, &out->version2, &iter, out->authenticator,
+		REQUIRED(VERSION, &version),
+		REQUIRED(MESSAGE_TYPE, &msg_type),
+		REQUIRED(ENROLLEE_NONCE, &out->enrollee_nonce),
+		REQUIRED(R_HASH1, &out->r_hash1),
+		REQUIRED(R_HASH2, &out->r_hash2),
+		REQUIRED(ENCRYPTED_SETTINGS, out_encrypted),
+		WSC_ATTR_INVALID);
+
+	if (r < 0)
+		return r;
+
+	if (msg_type != WSC_MESSAGE_TYPE_M4)
+		return -EBADMSG;
+
+	return 0;
+}
+
 struct wsc_attr_builder {
 	size_t capacity;
 	uint8_t *buf;
diff --git a/src/wscutil.h b/src/wscutil.h
index 0b0abead..47d03e80 100644
--- a/src/wscutil.h
+++ b/src/wscutil.h
@@ -20,6 +20,8 @@
  *
  */
 
+struct iovec;
+
 /* Wi-Fi Simple Configuration Technical Specification v2.0.5, Section 12 */
 enum wsc_attr {
 	WSC_ATTR_8021X_ENABLED					= 0x1062,
@@ -437,6 +439,14 @@ struct wsc_m3 {
 	uint8_t authenticator[8];
 };
 
+struct wsc_m4 {
+	bool version2;
+	uint8_t enrollee_nonce[16];
+	uint8_t r_hash1[32];
+	uint8_t r_hash2[32];
+	uint8_t authenticator[8];
+};
+
 int wsc_parse_beacon(const unsigned char *pdu, unsigned int len,
 				struct wsc_beacon *out);
 int wsc_parse_probe_response(const unsigned char *pdu, unsigned int len,
@@ -447,6 +457,8 @@ int wsc_parse_probe_request(const unsigned char *pdu, unsigned int len,
 int wsc_parse_m1(const uint8_t *pdu, uint32_t len, struct wsc_m1 *out);
 int wsc_parse_m2(const uint8_t *pdu, uint32_t len, struct wsc_m2 *out);
 int wsc_parse_m3(const uint8_t *pdu, uint32_t len, struct wsc_m3 *out);
+int wsc_parse_m4(const uint8_t *pdu, uint32_t len, struct wsc_m4 *out,
+						struct iovec *out_encrypted);
 
 uint8_t *wsc_build_probe_request(const struct wsc_probe_request *probe_request,
 				size_t *out_len);