Fix the potential illegal EBC opcode issue.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@7500 6f19259b-4bc3-4df7-8a09-765794883524

2 files changed, 16 insertions, 22 deletions

diff --git a/MdeModulePkg/Universal/EbcDxe/EbcExecute.c b/MdeModulePkg/Universal/EbcDxe/EbcExecute.c
index 788f505617..0a15fc938a 100644
--- a/MdeModulePkg/Universal/EbcDxe/EbcExecute.c
+++ b/MdeModulePkg/Universal/EbcDxe/EbcExecute.c
@@ -1330,7 +1330,13 @@ CONST VM_TABLE_ENTRY           mVmOpcodeTable[] = {
   { ExecutePOPn },              // opcode 0x36

   { ExecuteMOVI },              // opcode 0x37 - mov immediate data

   { ExecuteMOVIn },             // opcode 0x38 - mov immediate natural

-  { ExecuteMOVREL }             // opcode 0x39 - move data relative to PC

+  { ExecuteMOVREL },            // opcode 0x39 - move data relative to PC

+  { NULL },                     // opcode 0x3a

+  { NULL },                     // opcode 0x3b 

+  { NULL },                     // opcode 0x3c 

+  { NULL },                     // opcode 0x3d 

+  { NULL },                     // opcode 0x3e 

+  { NULL }                      // opcode 0x3f 

 };

 

 //

@@ -1370,11 +1376,6 @@ EbcExecuteInstructions (
   UINTN       InstructionsLeft;

   UINTN       SavedInstructionCount;

 

-  if ((*VmPtr->Ip & 0x3F) >= sizeof(mVmOpcodeTable)/sizeof(mVmOpcodeTable[0])) {

-    EbcDebugSignalException (EXCEPT_EBC_INVALID_OPCODE, EXCEPTION_FLAG_FATAL, VmPtr);

-    return EFI_UNSUPPORTED;

-  }

-

   Status = EFI_SUCCESS;

 

   if (*InstructionCount == 0) {

@@ -1392,12 +1393,12 @@ EbcExecuteInstructions (
   // call it if it's not null.

   //

   while (InstructionsLeft != 0) {

-    ExecFunc = (UINTN) mVmOpcodeTable[(*VmPtr->Ip & 0x3F)].ExecuteFunction;

+    ExecFunc = (UINTN) mVmOpcodeTable[(*VmPtr->Ip & OPCODE_M_OPCODE)].ExecuteFunction;

     if (ExecFunc == (UINTN) NULL) {

       EbcDebugSignalException (EXCEPT_EBC_INVALID_OPCODE, EXCEPTION_FLAG_FATAL, VmPtr);

       return EFI_UNSUPPORTED;

     } else {

-      mVmOpcodeTable[(*VmPtr->Ip & 0x3F)].ExecuteFunction (VmPtr);

+      mVmOpcodeTable[(*VmPtr->Ip & OPCODE_M_OPCODE)].ExecuteFunction (VmPtr);

       *InstructionCount = *InstructionCount + 1;

     }

 

@@ -1483,14 +1484,6 @@ EbcExecute (
     DEBUG_CODE_END ();

 

     //

-    // Verify the opcode is in range. Otherwise generate an exception.

-    //

-    if ((*VmPtr->Ip & OPCODE_M_OPCODE) >= (sizeof (mVmOpcodeTable) / sizeof (mVmOpcodeTable[0]))) {

-      EbcDebugSignalException (EXCEPT_EBC_INVALID_OPCODE, EXCEPTION_FLAG_FATAL, VmPtr);

-      Status = EFI_UNSUPPORTED;

-      goto Done;

-    }

-    //

     // Use the opcode bits to index into the opcode dispatch table. If the

     // function pointer is null then generate an exception.

     //

@@ -4139,6 +4132,7 @@ ExecuteDataManip (
   UINT8   Size;

   UINT64  Op1;

   UINT64  Op2;

+  INTN    DataManipDispatchTableIndex;

 

   //

   // Get opcode and operands

@@ -4220,9 +4214,9 @@ ExecuteDataManip (
   //

   // Dispatch to the computation function

   //

-  if (((Opcode & OPCODE_M_OPCODE) - OPCODE_NOT) >=

-        (sizeof (mDataManipDispatchTable) / sizeof (mDataManipDispatchTable[0]))

-        ) {

+  DataManipDispatchTableIndex = (Opcode & OPCODE_M_OPCODE) - OPCODE_NOT;

+  if ((DataManipDispatchTableIndex < 0) ||

+      (DataManipDispatchTableIndex >= sizeof (mDataManipDispatchTable) / sizeof (mDataManipDispatchTable[0]))) {

     EbcDebugSignalException (

       EXCEPT_EBC_INVALID_OPCODE,

       EXCEPTION_FLAG_ERROR,

@@ -4234,7 +4228,7 @@ ExecuteDataManip (
     VmPtr->Ip += Size;

     return EFI_UNSUPPORTED;

   } else {

-    Op2 = mDataManipDispatchTable[(Opcode & OPCODE_M_OPCODE) - OPCODE_NOT](VmPtr, Op1, Op2);

+    Op2 = mDataManipDispatchTable[DataManipDispatchTableIndex](VmPtr, Op1, Op2);

   }

   //

   // Write back the result.

diff --git a/MdeModulePkg/Universal/EbcDxe/EbcInt.h b/MdeModulePkg/Universal/EbcDxe/EbcInt.h
index 8512d6743d..1bc40e6dee 100644
--- a/MdeModulePkg/Universal/EbcDxe/EbcInt.h
+++ b/MdeModulePkg/Universal/EbcDxe/EbcInt.h
@@ -106,7 +106,7 @@ EbcCreateThunks (
 

 /**

   Add a thunk to our list of thunks for a given image handle.

-  Also flush the instruction cache since we have written thunk code

+  Also flush the instruction cache since we've written thunk code

   to memory that will be executed eventually.

 

   @param  ImageHandle            The image handle to which the thunk is tied.

@@ -249,7 +249,7 @@ EbcLLGetReturnValue (
   );

 

 /**

-  Returns the stack index and buffer associated with the Handle parameter.

+  Returns the stack index and buffer assosicated with the Handle parameter.

 

   @param  Handle                The EFI handle as the index to the EBC stack.

   @param  StackBuffer           A pointer to hold the returned stack buffer.