From 84e544c2f6dbf14f76b930b2672c3cc2b77bfc3f Mon Sep 17 00:00:00 2001
From: Simon Rozman <simon@rozman.si>
Date: Fri, 12 Aug 2016 21:09:38 +0200
Subject: [PATCH] eap_attr::create_ms_mppe_key() method for MS-MPPE-Send-Key
 and MS-MPPE-Recv-Key generation added

---
 include/WinStd/EAP.h | 12 ++++++++++++
 src/EAP.cpp          | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/include/WinStd/EAP.h b/include/WinStd/EAP.h
index fc5c3d06..fe843089 100644
--- a/include/WinStd/EAP.h
+++ b/include/WinStd/EAP.h
@@ -151,6 +151,18 @@ namespace winstd
             }
             return *this;
         }
+
+        ///
+        /// Creates MS-MPPE-Send-Key or MS-MPPE-Recv-Key
+        ///
+        /// \sa [RADIUS Vendor-Specific](https://tools.ietf.org/html/rfc2865#section-5.26)
+        /// \sa [MS-MPPE-Send-Key](https://tools.ietf.org/html/rfc2548#section-2.4.2)
+        /// \sa [MS-MPPE-Recv-Key](https://tools.ietf.org/html/rfc2548#section-2.4.3)
+        ///
+        void create_ms_mppe_key(_In_ BYTE bVendorType, _In_count_(nKeySize) LPCBYTE pbKey, _In_ BYTE nKeySize);
+
+    public:
+        static const EAP_ATTRIBUTE blank;
     };
 
 
diff --git a/src/EAP.cpp b/src/EAP.cpp
index 3787a0af..6b84daab 100644
--- a/src/EAP.cpp
+++ b/src/EAP.cpp
@@ -32,6 +32,43 @@ winstd::eap_attr::~eap_attr()
 }
 
 
+void winstd::eap_attr::create_ms_mppe_key(_In_ BYTE bVendorType, _In_count_(nKeySize) LPCBYTE pbKey, _In_ BYTE nKeySize)
+{
+    BYTE nPaddingLength = (BYTE)((16 - (1 + nKeySize)) % 16);
+    DWORD dwLengthNew =
+        4              + // Vendor-Id
+        1              + // Vendor type
+        1              + // Vendor length
+        2              + // Salt
+        1              + // Key-Length
+        nKeySize       + // Key
+        nPaddingLength;  // Padding
+
+    LPBYTE p = new BYTE[dwLengthNew];
+    p[0] = 0x00;                                    // Vendor-Id (0x137 = 311 = Microsoft)
+    p[1] = 0x00;                                    // --|
+    p[2] = 0x01;                                    // --|
+    p[3] = 0x37;                                    // --^
+    p[4] = bVendorType;                             // Vendor type
+    p[5] = (BYTE)(dwLengthNew - 4);                 // Vendor length
+    p[6] = 0x00;                                    // Salt
+    p[7] = 0x00;                                    // --^
+    p[8] = nKeySize;                                // Key-Length
+    memcpy(p + 9, pbKey, nKeySize);                 // Key
+    memset(p + 9 + nKeySize, 0, nPaddingLength);    // Padding
+
+    if (pValue)
+        delete [] pValue;
+
+    eaType   = eatVendorSpecific;
+    dwLength = dwLengthNew;
+    pValue   = p;
+}
+
+
+const EAP_ATTRIBUTE winstd::eap_attr::blank = {};
+
+
 //////////////////////////////////////////////////////////////////////
 // winstd::eap_packet
 //////////////////////////////////////////////////////////////////////