Fix GitHub_25027 in the interpreter by verifying stack depth at CEE_RET (#118976)

Author: kg

src/coreclr/interpreter/compiler.cpp

@@ -623,6 +623,19 @@ void InterpCompiler::CheckStackHelper(int n)
     }
 }
 
+void InterpCompiler::CheckStackExact(int n)
+{
+    int32_t currentSize = (int32_t)(m_pStackPointer - m_pStackBase);
+    if (currentSize < n)
+    {
+        BADCODE("Stack underflow");
+    }
+    else if (currentSize > n)
+    {
+        BADCODE("Stack contains extra data");
+    }
+}
+
 void InterpCompiler::PushTypeExplicit(StackType stackType, CORINFO_CLASS_HANDLE clsHnd, int size)
 {
     EnsureStack(1);
@@ -3921,11 +3934,12 @@ void InterpCompiler::GenerateCode(CORINFO_METHOD_INFO* methodInfo)
 
                 if (retType == InterpTypeVoid)
                 {
+                    CheckStackExact(0);
                     AddIns(INTOP_RET_VOID);
                 }
                 else if (retType == InterpTypeVT)
                 {
-                    CHECK_STACK(1);
+                    CheckStackExact(1);
                     AddIns(INTOP_RET_VT);
                     m_pStackPointer--;
                     int32_t retVar = m_pStackPointer[0].var;
@@ -3934,7 +3948,7 @@ void InterpCompiler::GenerateCode(CORINFO_METHOD_INFO* methodInfo)
                 }
                 else
                 {
-                    CHECK_STACK(1);
+                    CheckStackExact(1);
                     AddIns(INTOP_RET);
                     m_pStackPointer--;
                     m_pLastNewIns->SetSVar(m_pStackPointer[0].var);

src/coreclr/interpreter/compiler.h

@@ -690,6 +690,7 @@ class InterpCompiler
     int32_t m_stackCapacity;
 
     void CheckStackHelper(int n);
+    void CheckStackExact(int n);
     void EnsureStack(int additional);
     void PushTypeExplicit(StackType stackType, CORINFO_CLASS_HANDLE clsHnd, int size);
     void PushStackType(StackType stackType, CORINFO_CLASS_HANDLE clsHnd);