Re: unshare -m should not be a privileged option

[Mike Frysinger <vapier@gentoo.org>]

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On 16 Nov 2015 03:26, U.Mutlu wrote:
> I'm proposing that "unshare -m" should not be a privileged option,

what you're asking for is not coming from util-linux.  unshare is merely an
interface to the unshare() syscall.  if you dislike the security semantics
there, you can post to the namespace mailing list:
https://lists.linuxfoundation.org/mailman/listinfo/containers

> Therefore the -m option (and maybe even most of the other options) of unshare
> should be made to work for users, without needing root permission.

they do already -- with user namespaces.  if you give people the ability to
mount anything in the existing mount namespace, you open up attacks:
- create an ext2 fs as the user with some setuid programs
- create a new mount namespace
- mount that image
- instant root

> The other solution via user namespace is IMHO overkill and in my case 
> impractical and irritating because user gets a root-prompt (#)
> eventhough it is only inside the user namespace.

so remap it to your own user instead of to root

> As said in previous postings of mine: "chmod u+s unshare" does what I need,

i would like shell access to your systems please.  free root is fun.
-mike

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