CPUDisassembly : Removed some code that was repeated from DisassembleAt function

Added a warning when user tries to assemble an instruction thats points to Non-executable memory and DEP is enabled

src/bridge/bridgemain.cpp

@@ -1250,6 +1250,11 @@ BRIDGE_IMPEXP void GuiDumpAtN(duint va, int index)
     _gui_sendmessage(GUI_DUMP_AT_N, (void*)va, (void*)index);
 }
 
+BRIDGE_IMPEXP void GuiDisplayWarning(const char *title, const char *text)
+{
+    _gui_sendmessage(GUI_DISPLAY_WARNING, (void*)title, (void*)text);
+}
+
 BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
 {
     hInst = hinstDLL;

src/bridge/bridgemain.h

@@ -787,6 +787,7 @@ typedef enum
     GUI_SET_DEBUGGEE_NOTES,         // param1=const char* text,     param2=unused
     GUI_GET_DEBUGGEE_NOTES,         // param1=char** text,          param2=unused
     GUI_DUMP_AT_N,                  // param1=int index,            param2=duint va
+    GUI_DISPLAY_WARNING             // param1=const char *text,     param2=unused
 } GUIMSG;
 
 //GUI Typedefs
@@ -886,6 +887,7 @@ BRIDGE_IMPEXP void GuiGetGlobalNotes(char** text);
 BRIDGE_IMPEXP void GuiSetDebuggeeNotes(const char* text);
 BRIDGE_IMPEXP void GuiGetDebuggeeNotes(char** text);
 BRIDGE_IMPEXP void GuiDumpAtN(duint va, int index);
+BRIDGE_IMPEXP void GuiDisplayWarning(const char *title, const char *text);
 
 #ifdef __cplusplus
 }

src/dbg/_global.h

@@ -1,7 +1,7 @@
 #ifndef _GLOBAL_H
 #define _GLOBAL_H
 
-#define _WIN32_WINNT 0x0501
+#define _WIN32_WINNT 0x0601
 #define WINVER 0x0501
 #define _WIN32_IE 0x0500
 

src/dbg/assemble.cpp

@@ -9,6 +9,7 @@
 #include "XEDParse\XEDParse.h"
 #include "value.h"
 #include "disasm_helper.h"
+#include "debugger.h"
 
 static bool cbUnknown(const char* text, ULONGLONG* value)
 {
@@ -67,6 +68,10 @@ bool assembleat(duint addr, const char* instruction, int* size, char* error, boo
     if(size)
         *size = destSize;
 
+    // Check if the instruction doesn't set IP to non-executable memory
+    if (!isInstructionPointingToExMemory(addr, dest))
+        GuiDisplayWarning("Non-executable memory region", "Assembled instruction points to non-executable memory region !");
+
     bool ret = MemPatch(addr, dest, destSize);
 
     if (ret)
@@ -91,3 +96,81 @@ bool assembleat(duint addr, const char* instruction, int* size, char* error, boo
 
     return ret;
 }
+
+bool isInstructionPointingToExMemory(duint addr, const unsigned char* dest)
+{
+    MEMMAP wMemMapStruct;
+    DISASM_ARG arg;
+    DISASM_INSTR wDisasInstrStruct;
+    MEMORY_BASIC_INFORMATION *wMbiStruct = NULL;
+    duint instrArgCount;
+    dsint instrMemValues[3] = {0};
+    duint instrMemValuesIndex = 0;
+    dsint mbiBaseAddr, mbiEndAddr;
+
+    disasmget((unsigned char*)dest, 0, &wDisasInstrStruct);
+
+    instrArgCount = wDisasInstrStruct.argcount;
+    if (instrArgCount)
+    {
+        // Loop through all arguements
+        for (int i = 0; i < wDisasInstrStruct.argcount; i++)
+        {
+            arg = wDisasInstrStruct.arg[i];
+
+            // Check if any of the arguments is a memory
+            if (arg.type == arg_memory)
+            {
+                instrMemValues[instrMemValuesIndex] = addr + arg.memvalue; // add current instruction VA for rip-relative addressing
+                instrMemValuesIndex++;
+            }
+            else if (wDisasInstrStruct.type == instr_branch)
+            {
+                instrMemValues[instrMemValuesIndex] = addr + arg.value;
+                instrMemValuesIndex++;
+            }
+        }
+    }
+
+    // No memory pointer in the instruction, no need to go further
+    if (!instrMemValuesIndex)
+        return false;
+
+    // Get memory map to locate the sections to which the instr memory address belongs to
+    DbgMemMap(&wMemMapStruct);
+
+    // For each memPointerValue
+    for (auto & memValue : instrMemValues)
+    {
+        // Loop through the memMaps
+        for (int i = 0; i < wMemMapStruct.count; i++)
+        {
+            wMbiStruct  = &(wMemMapStruct.page)[i].mbi;
+            mbiBaseAddr = (dsint)wMbiStruct->BaseAddress;
+            mbiEndAddr  = (dsint)wMbiStruct->BaseAddress + (dsint)wMbiStruct->RegionSize;
+            if (memValue >= mbiBaseAddr && memValue < mbiEndAddr)
+            {
+                if (wMbiStruct->Protect == PAGE_EXECUTE ||
+                        wMbiStruct->Protect == PAGE_EXECUTE_READ ||
+                        wMbiStruct->Protect == PAGE_EXECUTE_READWRITE ||
+                        wMbiStruct->Protect == PAGE_EXECUTE_WRITECOPY)
+                {
+                    // Memory region is marked as executable
+#ifndef _WIN64
+                    DWORD lpFlagsDep;
+                    BOOL bPermanentDep;
+
+                    // DEP is disabled if lpFlagsDep == 0
+                    if (GetProcessDEPPolicy(fdProcessInfo->hProcess, &lpFlagsDep, &bPermanentDep) && lpFlagsDep != 0)
+                        return true;
+#else
+                    // DEP enabled on x64
+                    return true;
+#endif
+                }
+            }
+        }
+    }
+
+    return false;
+}

src/dbg/assemble.h

@@ -5,5 +5,6 @@
 
 bool assemble(duint addr, unsigned char* dest, int* size, const char* instruction, char* error);
 bool assembleat(duint addr, const char* instruction, int* size, char* error, bool fillnop);
+bool isInstructionPointingToExMemory(duint addr, const unsigned char* dest);
 
 #endif // _ASSEMBLE_H

src/gui/Src/Bridge/Bridge.cpp

@@ -528,6 +528,14 @@ void* Bridge::processMessage(GUIMSG type, void* param1, void* param2)
         emit dumpAtN((duint)param1, (int)param2);
     }
     break;
+
+    case GUI_DISPLAY_WARNING:
+    {
+        QString title = QString((const char*)param1);
+        QString text = QString((const char*)param2);
+        emit displayWarning(title, text);
+    }
+    break;
     }
     return nullptr;
 }

src/gui/Src/Bridge/Bridge.h

@@ -115,6 +115,7 @@ signals:
     void setDebuggeeNotes(const QString text);
     void getDebuggeeNotes(void* text);
     void dumpAtN(duint va, int index);
+    void displayWarning(QString title, QString text);
 
 private:
     QMutex* mBridgeMutex;

src/gui/Src/Gui/CPUDisassembly.cpp

@@ -24,6 +24,7 @@ CPUDisassembly::CPUDisassembly(CPUWidget* parent) : Disassembly(parent)
     connect(Bridge::getBridge(), SIGNAL(dbgStateChanged(DBGSTATE)), this, SLOT(debugStateChangedSlot(DBGSTATE)));
     connect(Bridge::getBridge(), SIGNAL(selectionDisasmGet(SELECTIONDATA*)), this, SLOT(selectionGetSlot(SELECTIONDATA*)));
     connect(Bridge::getBridge(), SIGNAL(selectionDisasmSet(const SELECTIONDATA*)), this, SLOT(selectionSetSlot(const SELECTIONDATA*)));
+    connect(Bridge::getBridge(), SIGNAL(displayWarning(QString, QString)), this, SLOT(displayWarningSlot(QString, QString)));
 
     Initialize();
 }
@@ -704,24 +705,7 @@ void CPUDisassembly::assembleSlot()
         duint wVA = rvaToVa(wRVA);
         QString addr_text = QString("%1").arg(wVA, sizeof(dsint) * 2, 16, QChar('0')).toUpper();
 
-        QByteArray wBuffer;
-
-        dsint wMaxByteCountToRead = 16 * 2;
-
-        //TODO: fix size problems
-        dsint size = getSize();
-        if(!size)
-            size = wRVA;
-
-        // Bounding
-        wMaxByteCountToRead = wMaxByteCountToRead > (size - wRVA) ? (size - wRVA) : wMaxByteCountToRead;
-
-        wBuffer.resize(wMaxByteCountToRead);
-
-        mMemPage->read(reinterpret_cast<byte_t*>(wBuffer.data()), wRVA, wMaxByteCountToRead);
-
-        QBeaEngine disasm(-1);
-        Instruction_t instr = disasm.DisassembleAt(reinterpret_cast<byte_t*>(wBuffer.data()), wMaxByteCountToRead, 0, 0, wVA);
+        Instruction_t instr = this->DisassembleAt(wRVA);
 
         QString actual_inst = instr.instStr;
 
@@ -1250,6 +1234,11 @@ void CPUDisassembly::decompileFunctionSlot()
     }
 }
 
+void CPUDisassembly::displayWarningSlot(QString title, QString text)
+{
+    QMessageBox::QMessageBox(QMessageBox::Information, title, text, QMessageBox::Ok).exec();
+}
+
 void CPUDisassembly::paintEvent(QPaintEvent* event)
 {
     // Hook/hack to update the sidebar at the same time as this widget.

src/gui/Src/Gui/CPUDisassembly.h

@@ -83,6 +83,7 @@ public slots:
     void openSourceSlot();
     void decompileSelectionSlot();
     void decompileFunctionSlot();
+    void displayWarningSlot(QString title, QString text);
 
 protected:
     void paintEvent(QPaintEvent* event);