"Illegal" use of RegNotifyChangeKeyValue on WINAPI_PARTITION_GAMES platforms

[redbaron]

Describe the bug

GAMECORE builds, a.k.a. GDK, a.k.a. WINAPI_PARTITION_GAMES don't normally have access to RegNotifyChangeKeyValue function:

• it is not defined in winreg.h for GAMES API family
• this symbol is not provided by GDK's xgameplatform.lib

Currently msquic cheats by:

• extern defining this function circumventing WINAPI_FAMILY_PARTITION guards in winreg.h
• linking to advapi32.lib even though this lib is in /NODEFAULTLIB list in GDK samples.

I believe GDK titles are not supposed to link to any regular windows libs, except those provided by GDK itself. As a result msquic essentially uses undocumented function in GAMECORE build. If correct, then this can likely affect game consoles certification of any product bundling msquic as a dependency.

Affected OS

• Windows
• Linux
• macOS
• Other (specify below)

Additional OS information

GDK builds

MsQuic version

main

Steps taken to reproduce bug

Expected behavior

Actual outcome

Additional details

No response

[nibanks]

I believe we already have consumers of this for xbox, and I've never heard anyone have any problems. I'll try to find someone internally to follow up and ask.

[nibanks]

That being said, I don't think it'd be a blocker to not support registry changes for xbox. I don't see it as a common scenario for some external entity to change the registry while a game is running, and then expect the game to dynamically respond. Thoughts?

[redbaron]

It is not just registry access, there are other functions pulled in with some dodgy defines:

advapi32:

platform.lib(storage_winuser.c.obj) : error LNK2019: unresolved external symbol __imp_RegNotifyChangeKeyValue referenced in function CxPlatStorageOpen

ntdll:

platform.lib(crypt_bcrypt.c.obj) : error LNK2019: unresolved external symbol RtlNtStatusToDosError referenced in function CxPlatKeyCreate
platform.lib(datapath_winuser.c.obj) : error LNK2001: unresolved external symbol RtlNtStatusToDosError

Following are defined for WINAPI_PARTITION_GAMES in Windows SDK headers, but symbol is found in secur32.lib only:

platform.lib(tls_schannel.c.obj) : error LNK2019: unresolved external symbol __imp_QuerySecurityContextToken referenced in function CxPlatTlsParamGet

None of these libraries/symbols are in GDK. I couldn't find any mentions whether linking these libs is allowed for Xbox builds, but at least advapi32 is "disabled" in GDK samples.

[nibanks]

Those other ones should be fine. I believe I had an internal email thread on them years ago and there were no issues with referencing them. But I don't remember the details.

[nibanks]

FYI, while looking, I found that this bug is essentially a duplicate of #3564.

[redbaron]

If it fails WACK I expect Xbox certification is even more strict or at least comparable in requirements to UWP.

[nibanks]

I pinged my internal thread asking for clarification.

[redbaron]

I found this official (?) answer in Xbox forums advising against advapi32: https://forums.xboxlive.com/questions/137981/advapi32libのリンクについて.html