From 096165d1425ae299bfee8ce8b29a4738a0d5a6b8 Mon Sep 17 00:00:00 2001
From: Denis Kenzior <denkenz@gmail.com>
Date: Sat, 27 Dec 2014 22:37:39 -0600
Subject: [PATCH] eapol: Add eapol_calculate_mic

---
 Makefile.am |  1 +
 src/eapol.c | 32 ++++++++++++++++++++++++++++++++
 src/eapol.h |  3 +++
 3 files changed, 36 insertions(+)

diff --git a/Makefile.am b/Makefile.am
index 4e3cc51f..695b7cf9 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -67,6 +67,7 @@ monitor_iwmon_SOURCES = monitor/main.c linux/nl80211.h \
 					src/ie.h src/ie.c \
 					src/util.h src/util.c \
 					src/sha1.h src/sha1.c \
+					src/md5.h src/md5.c \
 					src/eapol.h src/eapol.c
 monitor_iwmon_LDADD = ell/libell-internal.la
 
diff --git a/src/eapol.c b/src/eapol.c
index 680a3878..52fb48cc 100644
--- a/src/eapol.c
+++ b/src/eapol.c
@@ -27,6 +27,8 @@
 #include <string.h>
 #include <ell/ell.h>
 
+#include "sha1.h"
+#include "md5.h"
 #include "eapol.h"
 
 #define VERIFY_IS_ZERO(field)					\
@@ -37,6 +39,36 @@
 				return false;			\
 	} while (false)						\
 
+/*
+ * MIC calculation depends on the selected hash function.  The has function
+ * is given in the EAPoL Key Descriptor Version field.
+ *
+ * The MIC length is always 16 bytes for currently known Key Descriptor
+ * Versions.
+ *
+ * The input struct eapol_key *frame should have a zero-d MIC field
+ */
+bool eapol_calculate_mic(const uint8_t *kck, const struct eapol_key *frame,
+				uint8_t *mic)
+{
+	size_t frame_len = sizeof(struct eapol_key);
+
+	frame_len += L_BE16_TO_CPU(frame->key_data_len);
+
+	switch (frame->key_descriptor_version) {
+	case EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_MD5_ARC4:
+		return hmac_md5(kck, 16, (uint8_t *) frame, frame_len,
+					mic, 16);
+	case EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_SHA1_AES:
+		return hmac_sha1(kck, 16, (uint8_t *) frame, frame_len,
+					mic, 16);
+	case EAPOL_KEY_DESCRIPTOR_VERSION_AES_128_CMAC_AES:
+		return false;
+	default:
+		return false;
+	}
+}
+
 bool eapol_verify(const uint8_t *data, size_t len)
 {
 	struct eapol_key *ek;
diff --git a/src/eapol.h b/src/eapol.h
index 7f5a2332..27e80e71 100644
--- a/src/eapol.h
+++ b/src/eapol.h
@@ -93,6 +93,9 @@ struct eapol_key {
 	uint8_t key_data[0];
 } __attribute__ ((packed));
 
+bool eapol_calculate_mic(const uint8_t *kck, const struct eapol_key *frame,
+				uint8_t *mic);
+
 bool eapol_verify(const uint8_t *data, size_t len);
 
 bool eapol_process_ptk_1_of_4(const uint8_t *data, size_t len,