bug#11436: Please disable test cp/parent-perm-race on hurd-i386

[Eric Blake]

On 05/08/2012 12:38 PM, Samuel Thibault wrote:
> Hello,
> 
> (From http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=670478 )
> 
> cp/parent-perm-race tries to copy a fifo with the --copy-contents
> option.  The problem is that cp still uses O_NOFOLLOW in that case,
> strace shows:
> 
> open("mode/fifo", O_RDONLY|O_NOFOLLOW)
> 
> O_NOFOLLOW is actually normally meant for security, to avoid attacks
> through symlink redirection.  In that case, the Hurd thus disables
> translators too, to avoid any rogue translator that would achieve the
> same kind attack as symlink redirection.  But then --copy-contents can
> not work, since the fifo thus can not work (it's a translator that
> implements it).  I don't think either the Hurd or coreutils will want to
> change their behavior, so could the test be disabled on GNU/Hurd?

I can't help but think that Hurd is broken for disabling fifos, since
POSIX is quite clear that O_NOFOLLOW has no effect on any file type
except symlinks.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/open.html
O_NOFOLLOW
    If path names a symbolic link, fail and set errno to [ELOOP].

I wouldn't object to yet another O_* flag that can be used to disable
translators, but don't see how breaking POSIX semantics of a FIFO just
because O_NOFOLLOW was used is warranted.

-- 
Eric Blake   address@hidden    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

signature.asc
Description: OpenPGP digital signature