From 951852bab1d1127f9a8d7adfcaa37e9be1d06362 Mon Sep 17 00:00:00 2001
From: cw2k <3834079+cw2k@users.noreply.github.com>
Date: Tue, 3 Nov 2020 21:52:22 +0100
Subject: [PATCH] ConvertVAtoFileOffsetEx() now supports VA values

* ConvertVAtoFileOffsetEx(): implemented a handler for the bool AddressIsRVA.
  Before AddressToConvert was always assumed to be a RVA
  what lead to problems if a VA was passed in AddressToConvert [what was shown by AddressIsRVA=true]

  Combined with previous bug that returns INVALID_VALUE in case of an error it crashed the gleebug clientapp since they interpreted  INVALID_VALUE  as a file offset

* ConvertFileOffsetToVA: fix for return value.
  In case an error occurs it now returns 0.  Before it returned INVALID_VALUE.

* Start commenting function purpose and it's parameters
---
 TitanEngineEmulator/Emulator.h | 54 ++++++++++++++++++++++++++++++----
 1 file changed, 48 insertions(+), 6 deletions(-)

diff --git a/TitanEngineEmulator/Emulator.h b/TitanEngineEmulator/Emulator.h
index 9ed8ac9..8df767c 100644
--- a/TitanEngineEmulator/Emulator.h
+++ b/TitanEngineEmulator/Emulator.h
@@ -571,29 +571,71 @@ public:
     ULONG_PTR ConvertFileOffsetToVA(ULONG_PTR FileMapVA, ULONG_PTR AddressToConvert, bool ReturnType)
     {
         auto found = mappedFiles.find(FileMapVA);
+
         if(found == mappedFiles.end())
             __debugbreak(); //return 0;
+
         if(!found->second.pe->IsValidPe())
             __debugbreak(); //return 0;
-        return found->second.pe->ConvertOffsetToRva(uint32(AddressToConvert));
+
+        auto offset =   found->second.pe->ConvertOffsetToRva( uint32( AddressToConvert ) );
+
+        if (offset == INVALID_VALUE)
+            return 0;
     }
 
-    ULONG_PTR ConvertVAtoFileOffset(ULONG_PTR FileMapVA, ULONG_PTR AddressToConvert, bool ReturnType)
+    ////
+    ///
+    // ConvertVAtoFileOffset    -   converts virtual addresses to its physical counterpart.
+    //
+    // Returns: converted physical address
+    //          or NULL if conversion has failed.
+    //
+    ULONG_PTR ConvertVAtoFileOffset(
+        ULONG_PTR FileMapVA,        // [in] Pointer to the mapped file content. It's either StaticFileLoad function or Windows API for file mapping.
+        ULONG_PTR AddressToConvert, // [in] Virtual address to convert to a physical address.
+        bool ReturnType             // [in] Add the FileMapVA return value?
+    )
     {
-        return ConvertVAtoFileOffsetEx(FileMapVA, 0, 0, AddressToConvert, false, ReturnType);
+        return ConvertVAtoFileOffsetEx(
+                    FileMapVA ,0 ,0 , 
+                    AddressToConvert, false, ReturnType );
     }
 
-    ULONG_PTR ConvertVAtoFileOffsetEx(ULONG_PTR FileMapVA, DWORD FileSize, ULONG_PTR ImageBase, ULONG_PTR AddressToConvert, bool AddressIsRVA, bool ReturnType)
+    ////
+    ///
+    // ConvertVAtoFileOffsetEx  -   converts virtual addresses to its physical counterpart.
+    //                              checks if PE file is valid and if memory is accessible
+    // Returns: converted physical address
+    //          or NULL if conversion has failed.
+    //
+    ULONG_PTR ConvertVAtoFileOffsetEx(
+        ULONG_PTR FileMapVA,        // [in] Pointer to the mapped file content. It's either StaticFileLoad function or Windows API for file mapping.
+        DWORD FileSize,             // [in] Size of the mapped file.
+        ULONG_PTR ImageBase,        // [in] ImageBase of the mapped file
+        ULONG_PTR AddressToConvert, // [in] Virtual address to convert to a physical address.
+        bool AddressIsRVA,          // [in] true => AddressToConvert is relative virtual address
+        bool ReturnType             // [in] Add the FileMapVA return value?
+    )
     {
         auto found = mappedFiles.find(FileMapVA);
         if(found == mappedFiles.end())
             __debugbreak(); //return 0;
+
         if(!found->second.pe->IsValidPe())
             __debugbreak(); //return 0;
-        auto offset = found->second.pe->ConvertRvaToOffset(uint32(AddressToConvert));
+
+        // Convert to RVA if needed
+        auto RVA_ToConvert = AddressIsRVA ?
+                        AddressToConvert :
+                        AddressToConvert - ImageBase;
+
+        auto offset =   found->second.pe->ConvertRvaToOffset(
+                            uint32( RVA_ToConvert )
+                        );
+
         if (offset == INVALID_VALUE)
             return 0;
-        return ReturnType ? FileMapVA + offset : offset;
     }
 
     template<typename T>