IRP_MJ_QUERY_SECURITY (FS and filter drivers)
When Sent
The I/O Manager sends the IRP_MJ_QUERY_SECURITY request. It can be sent, for example, when a user-mode application has called a Win32 function such as GetSecurityInfo.
Operation: File System Drivers
The file system driver should extract and decode the file object to determine whether it represents a user file or directory open. If it does, the driver should process the query and complete the IRP. Otherwise, the driver should complete the IRP as appropriate without processing the query.
Operation: Legacy File System Filter Drivers
The filter driver should pass this IRP down to the next-lower driver on the stack.
Parameters
A file system or filter driver calls IoGetCurrentIrpStackLocation for the given IRP to get a pointer to its own stack location in the IRP. In the following parameters, Irp points to the IRP and IrpSp points to the IO_STACK_LOCATION. The driver can use the information that is set in the following members of the IRP and the IRP stack location to process a query security request:
DeviceObject is a pointer to the target device object.
Irp->IoStatus points to an IO_STATUS_BLOCK structure that receives the final completion status and information about the requested operation.
Irp->UserBuffer points to a caller-supplied output buffer that receives a copy of the security descriptor of the specified object. The calling process must have the right to view the specified aspects of the object's security status. The SECURITY_DESCRIPTOR structure is returned in self-relative format.
IrpSp->FileObject points to the file object that is associated with DeviceObject.
On Windows XP and later, the file object can represent a named data stream. For more information about named data streams, see FILE_STREAM_INFORMATION.
The IrpSp->FileObject parameter contains a pointer to the RelatedFileObject field, which is also a FILE_OBJECT structure. The RelatedFileObject field of the FILE_OBJECT structure isn't valid during the processing of IRP_MJ_QUERY_SECURITY and shouldn't be used.
IrpSp->MajorFunction is set to IRP_MJ_QUERY_SECURITY.
IrpSp->Parameters.QuerySecurity.Length is the size, in bytes, of the buffer pointed to by the Irp->UserBuffer parameter.
IrpSp->Parameters.QuerySecurity.SecurityInformation points to the SECURITY_INFORMATION structure for the operation. This value can be a valid combination of the following bits.
SecurityInformation Value Meaning OWNER_SECURITY_INFORMATION Indicates that the owner identifier of the object is being queried. Requires READ_CONTROL access. GROUP_SECURITY_INFORMATION Indicates that the primary group identifier of the object is being queried. Requires READ_CONTROL access. DACL_SECURITY_INFORMATION Indicates that the discretionary access control list (DACL) of the object is being queried. Requires READ_CONTROL access. SACL_SECURITY_INFORMATION Indicates that the system ACL (SACL) of the object is being queried. Requires ACCESS_SYSTEM_SECURITY access.
See also
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