On Sat, Dec 21, 2013 at 04:33:42PM +0100, Armin K. wrote:
> devpts should also be bind-mounted, as it will override default devpts
> flags and permissions which were mounted before.
> 
> In my case:
> 
> mount output before mounting devpts at $LFS/dev/pts
> 
> devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620)

Why add nosuid or noexec?

Only root can create files in the devpts filesystem anyway (the
directory post mount is 0755 root/root), so users can't add setuid or
executable files anyway.  And the filesystem contents can't be persisted
anyway (it's not like a CD or USB drive, which might have the "user"
option present, allowing users to attach arbitrary files to the system),
so that's not a vector for introducing setuid or executable files
either.

Seems like trying to restrict root isn't the best idea.  :-)

> I would certainly not want lfs to modify my host system.

That's one good reason that it's *not* a bind mount, IMO.

> In some cases,
> tty gid could be different

This is about the only potential issue.  However, the /etc/group file
that's about to be created in the book at this point does definitely
assign tty to gid 5, so inside the chroot, /dev/pts will definitely be
correct regardless of the host group assignment.

...And in fact, I think that's another reason to avoid a bind mount.  If
the host assigns tty to gid 4, then the bind mount will be broken inside
chroot, since glibc will require it to be 5 in there.

> Furthermore, I think that /run should also be mounted when building lfs,
> since that is meant to be a tmpfs too, but some packages might install
> files in there.

That I can see.  :-)

-- 
http://linuxfromscratch.org/mailman/listinfo/lfs-dev
FAQ: http://www.linuxfromscratch.org/faq/
Unsubscribe: See the above information page

Reply via email to