[PATCH] kernel32: CreateDirectory shouldn't return ERROR_ACCESS_DENIED for the root of the drive.

[Dmitry Timoshkov]

Alexandre Julliard <julliard at winehq.org> wrote:

> >> >> >> >> >> > According to the testbot results CreateDirectory("C:\\", NULL) fails
> >> >> >> >> >> > with ERROR_ACCESS_DENIED for not administrators. However with UAC enabled
> >> >> >> >> >> > and not and administrator account I get ERROR_ALREADY_EXISTS in that case
> >> >> >> >> >> > with Windows 7 64-bit running on real hardware. Moreover, Wine doesn't
> >> >> >> >> >> > really perform any access checks in that case and blindly assumes that
> >> >> >> >> >> > returning STATUS_ACCESS_DENIED is correct behaviour for the drive's root:
> >> >> >> >> >> > dlls/ntdll/directory.c,lookup_unix_name().
> >> >> >> >> >> >
> >> >> >> >> >> > This patch fixes an application that can't find its data files because
> >> >> >> >> >> > after it receives ERROR_ACCESS_DENIED it stops further directory traversing.
> >> >> >> >> >> 
> >> >> >> >> >> What app is that? Does it fail on Windows when not administrator?
> >> >> >> >> >
> >> >> >> >> > The application doesn't fail on Windows, and as I mentioned above under
> >> >> >> >> > a not administrator account and UAC enabled I don't get ERROR_ACCESS_DENIED
> >> >> >> >> > error with the tests included in the patch.
> >> >> >> >> 
> >> >> >> >> Your tests get ERROR_ACCESS_DENIED on every single testbot vm except
> >> >> >> >> w8adm, so that's not very convincing... Is the app going to fail on all
> >> >> >> >> these vms?
> >> >> >> >
> >> >> >> > I'd guess if the CreateDirectory("C:\") returns ERROR_ACCESS_DENIED
> >> >> >> > then the app would fail. It's not clear how the VMs are configured
> >> >> >> > and why I don't get ERROR_ACCESS_DENIED on real hardware under a not
> >> >> >> > admin account, but it should be pretty obvious that since Wine doesn't
> >> >> >> > perform any real administrator access checks, and if it would the checks
> >> >> >> > should be done on the server side, ntdll checks shouldn't return access
> >> >> >> > denied error.
> >> >> >> 
> >> >> >> It's also pretty obvious that this check was added for a reason, so it
> >> >> >> would need a more convincing argument to remove it.
> >> >> >
> >> >> > Do you recall the reason why that check was added? I can't find any
> >> >> > specific test case for this behaviour either.
> >> >> 
> >> >> As far as I can tell, you added it ;-)
> >> >> 
> >> >> https://source.winehq.org/git/wine.git/commit/d75aed2c92435e8ae4d5c260e31e815ee77db34b
> >> >
> >> > This doesn't look right, especially without any reasonable explanation.
> >> > Considering that now we have an application that depends on this, can
> >> > that change be reverted?
> >> 
> >> I'd like to see some more convincing test cases.
> >
> > Sure, I can add more tests. Do you have a suggestion what kind of checks
> > they should perform? I tried to find an existing test that somehow elevates
> > privileges and then executes CreateDirecory tests, but couldn't find such
> > a test.
> 
> It's possible that elevating privileges would avoid the access denied
> error, but that doesn't explain why the app would work on Windows,
> unless it also elevates privileges itself. Does it?

According to the log the doesn't elevate the privileges.

> And FWIW I'm getting access denied on Vista even running as
> administrator. If the behavior changed in recent Windows that would also
> need specific tests.

I just tested it under XP in a VM and I also get the access denied errors
for both an ordinal user and an administrator. So it looks like the behaviour
has changed (unless running in a VirtualBox changes the behaviour of a file
system).

-- 
Dmitry.