[arch-general] Opening symlinks in tmpfs as root fails!

[Mohammad_AlSaleh]

On Tue, Dec 30, 2014 at 01:42:03PM +0100, Christian Hesse wrote:
> Mohammad_AlSaleh <ce.mohammad.alsaleh at gmail.com> on Tue, 2014/12/30 14:36:
> > Hello.
> > 
> > I just came across some weird behavior.
> > 
> > A small testcase:
> > 
> > cd /tmp # should be tmpfs
> > touch tfile
> > ln -s tfile tlink
> > cat tlink
> > 
> > When cat executes, it returns with success(0). But, if cat is executed
> > as root, it fails with a permission denied error.
> > 
> > What's really happening is, the open() syscall fails with EACCESS when
> > the file is a symlink in a tmpfs-mounted dir. But only fails when run
> > as root!
> > 
> > I'm assuming this is a bug. Can anyone confirm it?
> 
> This is expected as /tmp has the sticky bit set.
> 
> https://wiki.ubuntu.com/Security/Features#Symlink_restrictions

Aha.

Thanks for the info.

> -- 
> main(a){char*c=/*    Schoene Gruesse                         */"B?IJj;MEH"
> "CX:;",b;for(a/*    Chris           get my mail address:    */=0;b=c[a++];)
> putchar(b-1/(/*               gcc -o sig sig.c && ./sig    */b/42*2-3)*42);}