QueryInterface should call AddRef before returning pointer
Moderate severity
GitHub Reviewed
Published
Jun 16, 2022
to the GitHub Advisory Database
•
Updated Jun 13, 2023
Description
Published to the GitHub Advisory Database
Jun 16, 2022
Reviewed
Jun 16, 2022
Last updated
Jun 13, 2023
Affected version of this crate, which is a required dependency in com-impl,
provides a faulty implementation of the
IUnknown::QueryInterface
method.QueryInterface
implementation must callIUnknown::AddRef
before returning the pointer,as describe in this documentation:
https://docs.microsoft.com/en-us/windows/win32/api/unknwn/nf-unknwn-iunknown-queryinterface(refiid_void)
As it is not incrementing the refcount as expected, the following calls to
IUnknown::Release
methodwill cause WMI to drop reference to the interface, and can lead to invalid reference.
This is documented in https://docs.microsoft.com/en-us/windows/win32/learnwin32/managing-the-lifetime-of-an-object#reference-counting
There is no simple workaround, as you can't know how many time QueryInterface will be called.
The only way to quick fix this is to use the macro expanded version of the code and modify
the QueryInterface method to add the AddRef call yourself.
The issue was corrected in commit
9803f31fbd1717d482d848f041044d061fca6da7
.References