Re: X authentication and su (Re: changing framebuffer device owner during login)
On Sun, 1 Jul 2001, Herbert Xu wrote:
> Matt Zimmerman <mdz@debian.org> wrote:
>
> > introduce a dependency on X by using the library routines. Does anyone know
> > how to gen xauth to cooperate, or am I stuck using a temporary file?
>
> Would /dev/stdout work?
It does not work: xauth tries to lock /dev/stdout and fails:
$ xauth -f /dev/stdout generate $DISPLAY . untrusted timeout 10
xauth: timeout in locking authority file /dev/stdout
The problem is xauth expects this file to be in the .Xauthority
format and thus I guess it tries to lock it, read it and rewrite it to
add the new cookie. Maybe the intention was that user X would directly
add the cookie to uer Y's .Xauthority file but of course it cannot work
because of the access right issues. Even if X were root it would no work
because roout would end up owning Y's file.
What's needed is for xauth to output the generated cookie in
extract/nextract or list mode. Then it makes sense to send it to stdout.
But how would you choose the output format, I'm not sure. Or maybe '-f'
should mean read from stdin and write to stdout. Then you would do:
$ xauth -f - generate $DISPLAY . untrusted timeout 10 | xauth -f - extract
Also the role of '-f' wrt. '~/.Xauthority' when generate is used
really needs clarification in the documentation.
--
Francois Gouget fgouget@free.fr http://fgouget.free.fr/
The software said it requires Win95 or better, so I installed Linux.
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