- 1 year ago
VirtualProtectEx, ERROR_INVALID_PARAMETER (error 87)
The error code ERROR_INVALID_PARAMETER
(error 87) typically indicates that one or more of the parameters passed to the VirtualProtectEx
function in Windows is incorrect or invalid. Here are a few possible reasons for this error and some troubleshooting steps you can take:
Check the Memory Region: Ensure that the memory region you are trying to protect with
VirtualProtectEx
is valid and accessible. Verify that you have the correct base address and the correct size for the memory region.Validate Protection Flags: Double-check the protection flags you are passing to
VirtualProtectEx
. Make sure you are using one of the valid protection flags defined in the Windows SDK documentation. Common protection flags includePAGE_EXECUTE
,PAGE_READWRITE
,PAGE_READONLY
, etc., depending on the desired access level for the memory region.Verify Access Rights: Ensure that the handle to the target process obtained with
OpenProcess
has the necessary access rights to modify the memory region. You may need to pass thePROCESS_VM_OPERATION
andPROCESS_VM_WRITE
access rights when opening the process handle.Check Buffer Alignment: Ensure that the buffer used to store the original protection value is properly aligned. The buffer should be aligned to the size of a
DWORD
(4 bytes) for 32-bit processes or to the size of aDWORDLONG
(8 bytes) for 64-bit processes.Verify Pointer Sizes: Make sure you are using the correct pointer sizes (
LPVOID
orPVOID
) based on whether you are compiling your code as 32-bit or 64-bit.Check Parameter Values: Validate all the other parameters you are passing to
VirtualProtectEx
. Ensure they are correct and in the expected format.
If you have checked all the above points and are still encountering the ERROR_INVALID_PARAMETER
(error 87) with VirtualProtectEx
, it would be helpful to see the specific code snippet you are using and any relevant details about the memory region you are attempting to protect. That way, I can assist you more effectively in identifying and resolving the issue.