From c991fc0c40816b677785d5bf1fe4dc18aec5583c Mon Sep 17 00:00:00 2001
From: Torusrxxx <torusrxxx@users.noreply.github.com>
Date: Sat, 29 Apr 2017 14:24:35 +0000
Subject: [PATCH] Warn the user about mismatch of database and executable
 (#1570)

---
 src/dbg/database.cpp | 36 ++++++++++++++++++++++++++++++++++++
 src/dbg/database.h   |  1 +
 src/dbg/debugger.cpp |  8 ++++++--
 src/dbg/module.cpp   | 15 +++++++++++++++
 src/dbg/module.h     |  1 +
 5 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/src/dbg/database.cpp b/src/dbg/database.cpp
index 858d3600..f475be74 100644
--- a/src/dbg/database.cpp
+++ b/src/dbg/database.cpp
@@ -31,6 +31,11 @@
 */
 char dbbasepath[deflen];
 
+/**
+\brief The hash of the debuggee stored in the database
+*/
+duint dbhash = 0;
+
 /**
 \brief Path of the current program database. UTF-8 encoding.
 */
@@ -66,6 +71,11 @@ void DbSave(DbLoadSaveType saveType, const char* dbfile, bool disablecompression
         TraceRecord.saveToDb(root);
         BpCacheSave(root);
         WatchCacheSave(root);
+        if(dbhash != 0)
+        {
+            json_object_set_new(root, "hashAlgorithm", json_string("murmurhash"));
+            json_object_set_new(root, "hash", json_hex(dbhash));
+        }
 
         //save notes
         char* text = nullptr;
@@ -215,6 +225,11 @@ void DbLoad(DbLoadSaveType loadType, const char* dbfile)
 
     if(loadType == DbLoadSaveType::DebugData || loadType == DbLoadSaveType::All)
     {
+        if(strcmp(json_string_value(json_object_get(root, "hashAlgorithm")), "murmurhash") == 0) //Checking checksum of the debuggee.
+            dbhash = json_hex_value(json_object_get(root, "hash"));
+        else
+            dbhash = 0;
+
         // Finally load all structures
         CommentCacheLoad(root);
         LabelCacheLoad(root);
@@ -287,7 +302,10 @@ void DbClear(bool terminating)
     GuiSetDebuggeeNotes("");
 
     if(terminating)
+    {
         PatchClear();
+        dbhash = 0;
+    }
 }
 
 void DbSetPath(const char* Directory, const char* ModulePath)
@@ -371,3 +389,21 @@ void DbSetPath(const char* Directory, const char* ModulePath)
         dprintf(QT_TRANSLATE_NOOP("DBG", "Database file: %s\n"), dbpath);
     }
 }
+
+/**
+\brief Warn the user if the hash in the database and the executable mismatch.
+*/
+bool DbCheckHash(duint currentHash)
+{
+    if(dbhash != 0 && currentHash != 0 && dbhash != currentHash)
+    {
+        dputs(QT_TRANSLATE_NOOP("DBG", "WARNING: The database has a checksum that is different from the module you are debugging. It is possible that your debuggee has been modified since last session. The content of this database may be incorrect."));
+        dbhash = currentHash;
+        return false;
+    }
+    else
+    {
+        dbhash = currentHash;
+        return true;
+    }
+}
\ No newline at end of file
diff --git a/src/dbg/database.h b/src/dbg/database.h
index 8394585c..7a4c3b60 100644
--- a/src/dbg/database.h
+++ b/src/dbg/database.h
@@ -15,5 +15,6 @@ void DbLoad(DbLoadSaveType loadType, const char* dbfile = nullptr);
 void DbClose();
 void DbClear(bool terminating = false);
 void DbSetPath(const char* Directory, const char* ModulePath);
+bool DbCheckHash(duint currentHash);
 
 #endif // _DATABASE_H
\ No newline at end of file
diff --git a/src/dbg/debugger.cpp b/src/dbg/debugger.cpp
index aff2f0f1..279dbf20 100644
--- a/src/dbg/debugger.cpp
+++ b/src/dbg/debugger.cpp
@@ -31,7 +31,9 @@
 #include "cmd-watch-control.h"
 #include "filemap.h"
 #include "jit.h"
-
+/**
+\brief Conditional tracing structures
+*/
 struct TraceCondition
 {
     ExpressionParser condition;
@@ -217,7 +219,7 @@ private:
     BufferedWriter* logWriter = nullptr;
     bool writeUtf16 = false;
 };
-
+// Debugging variables
 static PROCESS_INFORMATION g_pi = {0, 0, 0, 0};
 static char szBaseFileName[MAX_PATH] = "";
 static TraceState traceState;
@@ -1463,6 +1465,7 @@ static void cbCreateProcess(CREATE_PROCESS_DEBUG_INFO* CreateProcessInfo)
     if(!bFileIsDll && !bIsAttached) //Set entry breakpoint
     {
         pDebuggedBase = pCreateProcessBase; //debugged base = executable
+        DbCheckHash(ModContentHashFromAddr(pDebuggedBase)); //Check hash mismatch
         char command[deflen] = "";
 
         if(settingboolget("Events", "TlsCallbacks"))
@@ -1762,6 +1765,7 @@ static void cbLoadDll(LOAD_DLL_DEBUG_INFO* LoadDll)
     {
         bIsDebuggingThis = true;
         pDebuggedBase = (duint)base;
+        DbCheckHash(ModContentHashFromAddr(pDebuggedBase)); //Check hash mismatch
         if(settingboolget("Events", "EntryBreakpoint"))
         {
             bAlreadySetEntry = true;
diff --git a/src/dbg/module.cpp b/src/dbg/module.cpp
index ea524d6d..abc9a8f8 100644
--- a/src/dbg/module.cpp
+++ b/src/dbg/module.cpp
@@ -285,6 +285,21 @@ duint ModHashFromAddr(duint Address)
     return module->hash + (Address - module->base);
 }
 
+duint ModContentHashFromAddr(duint Address)
+{
+    SHARED_ACQUIRE(LockModules);
+
+    auto module = ModInfoFromAddr(Address);
+
+    if(!module)
+        return 0;
+
+    if(module->fileMapVA != 0 && module->loadedSize > 0)
+        return murmurhash((void*)module->fileMapVA, module->loadedSize);
+    else
+        return 0;
+}
+
 duint ModHashFromName(const char* Module)
 {
     // return MODINFO.hash (based on the name)
diff --git a/src/dbg/module.h b/src/dbg/module.h
index 3a80bc29..d15918ef 100644
--- a/src/dbg/module.h
+++ b/src/dbg/module.h
@@ -47,6 +47,7 @@ bool ModNameFromAddr(duint Address, char* Name, bool Extension);
 duint ModBaseFromAddr(duint Address);
 duint ModHashFromAddr(duint Address);
 duint ModHashFromName(const char* Module);
+duint ModContentHashFromAddr(duint Address);
 duint ModBaseFromName(const char* Module);
 duint ModSizeFromAddr(duint Address);
 std::string ModNameFromHash(duint Hash);