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

[Christian Hesse]

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
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