Option to log bad pointers

Author: tomsons26

dllmain.cpp

@@ -2,11 +2,31 @@
 #include <idp.hpp>
 #include <loader.hpp>
 #include <kernwin.hpp>
+#include <help.h>
 #include <name.hpp>
 #include "cvinfo.h"
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
 
+#define CHECK_SYMBOL_PTR
+
+#ifdef CHECK_SYMBOL_PTR
+bool is_bad_ptr(void * p)
+{
+	MEMORY_BASIC_INFORMATION mbi = {0};
+	if (::VirtualQuery(p, &mbi, sizeof(mbi))) {
+		DWORD mask = (PAGE_READONLY | PAGE_READWRITE | PAGE_WRITECOPY | PAGE_EXECUTE_READ | PAGE_EXECUTE_READWRITE | PAGE_EXECUTE_WRITECOPY);
+		bool b = !(mbi.Protect & mask);
+		// check if the page is not a guard page
+		if (mbi.Protect & (PAGE_GUARD | PAGE_NOACCESS)) {
+			b = true;
+		}
+		return b;
+	}
+	return true;
+}
+#endif
+
 unsigned long crc_table[256] = {
 	0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
 	0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
@@ -971,6 +991,12 @@ void export_unlinked_module(qstring name, qvector<unlink_entry>& vector)
 							{
 								insn_size = 4;
 								unsigned int* data = (unsigned int*)(CodeSymbols[j].Data + pos);
+								#ifdef CHECK_SYMBOL_PTR
+								if (is_bad_ptr(data)) {
+									msg("unlinker --- 1 Invalid Address pos %x\n", (int)pos);
+									continue;
+								}
+								#endif
 								if (IsSymbol(*data))
 								{
 									Symbol& fsym = FindSymbol(*data);
@@ -989,6 +1015,12 @@ void export_unlinked_module(qstring name, qvector<unlink_entry>& vector)
 						for (ea_t k = CodeSymbols[j].Address; k < CodeSymbols[j].Address + CodeSymbols[j].Size; k += 4)
 						{
 							unsigned int* data = (unsigned int*)(CodeSymbols[j].Data + k);
+							#ifdef CHECK_SYMBOL_PTR
+							if (is_bad_ptr(data)) {
+								msg("unlinker --- 2 Invalid  k %x\n", (int)k);
+								continue;
+							}
+							#endif
 							if (IsSymbol(*data))
 							{
 								Symbol& fsym = FindSymbol(*data);
@@ -1016,6 +1048,12 @@ void export_unlinked_module(qstring name, qvector<unlink_entry>& vector)
 				for (ssize_t k = 0; k < RDataSymbols[j].Size; k += 4)
 				{
 					unsigned int* data = (unsigned int*)(RDataSymbols[j].Data + k);
+					#ifdef CHECK_SYMBOL_PTR
+					if (is_bad_ptr(data)) {
+						msg("unlinker --- 3 Invalid Address k %x\n", (int)k);
+						continue;
+					}
+					#endif
 					if (IsSymbol(*data))
 					{
 						Symbol& fsym = FindSymbol(*data);
@@ -1036,6 +1074,12 @@ void export_unlinked_module(qstring name, qvector<unlink_entry>& vector)
 				for (ssize_t k = 0; k < DataSymbols[j].Size; k += 4)
 				{
 					unsigned int* data = (unsigned int*)(DataSymbols[j].Data + k);
+					#ifdef CHECK_SYMBOL_PTR
+					if (is_bad_ptr(data)) {
+						msg("unlinker --- 4 Invalid Address k %x\n", (int)k);
+						continue;
+					}
+					#endif
 					if (IsSymbol(*data))
 					{
 						Symbol& fsym = FindSymbol(*data);