fix: hook failed in wayland

不在拷贝全部虚表，只覆盖当前虚表函数入口，不考虑各种trunk和offset Log: 修复在wayland下hook失败
kegechen · Mar 27, 2023 · 623ce74 · 623ce74
1 parent 9d425d3
commit 623ce74
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Showing 2 changed files with 3 additions and 24 deletions.
diff --git a/src/vtablehook.cpp b/src/vtablehook.cpp
@@ -299,8 +299,7 @@ quintptr VtableHook::originalFun(const void *obj, quintptr functionOffset)
         qCWarning(vtableHook) << "Not override the object virtual table: " << obj;
         return 0;
     }
-    if (!isFinalClass((quintptr *)*_obj))
-        _obj = adjustThis((quintptr *)*_obj);
+
     Q_CHECK_PTR(_obj);
     int vtable_size = getVtableSize(_obj);
     // 获取obj对象原本虚表的入口
@@ -314,17 +313,6 @@ quintptr VtableHook::originalFun(const void *obj, quintptr functionOffset)
     return *(vfptr_t2 + functionOffset / sizeof(quintptr));
 }
 
-bool VtableHook::isFinalClass(quintptr *obj) {
-    return *(obj - 2) == 0 ? true : false;
-}
-
-quintptr **VtableHook::adjustThis(quintptr *obj) {
-    qint64 offset = *(quintptr *)(obj - 2);
-    if (offset > 0)  // invalid offset
-        return nullptr;
-    return (quintptr **)(obj + offset);
-}
-
 #if defined(Q_OS_LINUX)
 static int readProtFromPsm(quintptr adr, size_t length)
 {

diff --git a/src/vtablehook.h b/src/vtablehook.h
@@ -182,14 +182,7 @@ class VtableHook
 
         if (fun1_offset < 0 || fun1_offset > UINT_LEAST16_MAX)
             return false;
-        if (!isFinalClass(vfptr_t1)) {
-            vfptr_t1 = (quintptr *)adjustThis(vfptr_t1);
-            if (!vfptr_t1) {
-                qCWarning(vtableHook) << "The type of target object isn't the last item of inheritance chain and can't adjust pointer "
-                          "'This' to correct address, abort. " << vfptr_t1;
-                return false;
-            }
-        }
+
         quintptr *vfun = vfptr_t1 + fun1_offset / sizeof(quintptr);
 
         if (forceWrite)
@@ -247,7 +240,7 @@ class VtableHook
      * \note 因为如果分开写为&B::foo1和&C::foo2的话，指针转换内部会记录多张虚表，重载多份析构函数，可能导致最开始的部分无法正常析构！
      */
     template<typename Fun1, typename Fun2>
-    static bool overrideVfptrFun(const typename QtPrivate::FunctionPointer<Fun1>::Object *t1, Fun1 fun1, Fun2 fun2)
+    static bool overrideVfptrFun(const typename QtPrivate::FunctionPointer<Fun1>::Object *t1, Fun1 fun1, Fun2 fun2) //THIS
     {
         typedef QtPrivate::FunctionPointer<Fun1> FunInfo1;
         // 检查析构函数是否为虚
@@ -336,8 +329,6 @@ class VtableHook
     static bool copyVtable(quintptr **obj);
     static bool clearGhostVtable(const void *obj);
     static void clearAllGhostVtable();
-    static bool isFinalClass(quintptr *obj);
-    static quintptr **adjustThis(quintptr *obj);
 
     template <typename T>
     static T adjustToTop(T obj)  // vtableTop: vtable start address, Usually refers to offset_to_top