Re: cannot run setup64.exe without admin privileges (even if renamed foo.exe)

[Shaddy Baddah <lithium-cygwin@shaddybaddah.name>]

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Hi Corinna,

On 15/10/13 20:08, Corinna Vinschen wrote:
> [Redirected to cygwin-apps]
>
>
> On Sep 23 13:57, Buchbinder, Barry (NIH/NIAID) [E] wrote:
>> Larry Hall (Cygwin) sent the following at Sunday, September 22, 2013 9:42 PM
>>> No, "All Users" is also required to set up services (like sshd, crond,
>>> etc.) to work for all users (i.e. switch user context). This is the
>>> recommended way to install so that these subsequent facilities can be
>>> used with a minimum of fuss or trouble.
>>
>> Thank you for the explanation.
>>
>> Still, I'd like to urge the setup-meisters to keep those of us without
>> admin rights in mind.  If we have to compile setup ourselves, many of
>> us will be staying with 32 bit for a long time.
>
> I just had a weird idea how we *might* accomplish this for 32 and 64 bit
> in the same way.
>
> Assuming setup would get an "asInvoker" manifest, so it runs with the
> privileges of the current user.  First thing it would check its user
> token.  There are three cases:
>
> - When started by a non-admin user, the user token would contain no
>    trace of the administrators group in the user token group list.
>    In this case, setup would just run along as usual for the current user.
>
> - When started elevated (with "Run as administrator...", for instance),
>    the user token group list would contain the administrators group,
>    enabled.  So setup knows it has admin rights anyway and just runs along
>    as in the non-admin user case.  So, in fact, these two cases are just
>    one case.
>
> - Now, when started by an admin user, but not elevated, the group list
>    would contain the administrators group, too, but with the "Use for
>    deny only" flag set.  If setup recognizes this flag, rather than running
>    along, it calls ShellExecute on itself, with the "runas" flag set.
>    So it elevates a copy of itself and just exits.  The elevated copy
>    then runs as usual.
>
> The only downside with this concept, as far as I can see, is, somebody
> would have to implement it...
>
> Does that sound feasible?

I apologise... I've been sitting on an almost-there implementation of
this for almost two weeks, waiting for a moment to polish it properly
for patch submission.

I can't elaborate on the pros and cons of the patch at the moment, as
I am accessing my desktop remotely. But I will follow-up later tonight
with more details.

-- 
Regards,
Shaddy



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