[Devel] Re: [RFC][PATCH 0/2] user namespace [try #2]

[Herbert Poetzl]

On Tue, Sep 12, 2006 at 05:52:40PM +0400, Kirill Korotaev wrote:
> Herbert Poetzl wrote:
> > On Thu, Sep 07, 2006 at 08:09:38PM +0400, Kirill Korotaev wrote:

> >>>>imho this in acceptable for OpenVZ as makes VE files to be
> >>>>inaccessiable from host. At least this is how I understand your
> >>>>idea... Am I correct?

> >>>>>I assume the list of other things we'll need to consider includes
> >>>>>	signals between user namespaces
> >>>>>	keystore
> >>>>>	sys_setpriority and the like
> >>>>>I might argue that all of these should be sufficiently protected
> >>>>>by proper setup by userspace. Can you explain why that is not the
> >>>>>case?

> >>>>The same requirement (ability to send signals from host to VE)
> >>>>is also applicable to signals.

> >>>at some point, we tried to move all cross context signalling
> >>>(from the host to the guests) into a special context, but later
> >>>on we moved away from that, because it was much simpler and more
> >>>intuitive to handle the signalling with a separate syscall command

> >>I'm not sure what a separate context is for, but a separate syscall
> >>is definetely not a good idea.

> > care to explain _why_ you think so?
> cause duplicating syscalls with the same meaning but just working in a
> bit different situations doesn't look good.

hmm ... well, I guess the kernel doesn't look too good then :)

	.long sys_setuid16
	.long sys_getuid16
	.long sys_geteuid16
	.long sys_setreuid16	/* 70 */
	.long sys_setfsuid16
	.long sys_setresuid16
	.long sys_getresuid16	/* 165 */
	.long sys_getuid
	.long sys_geteuid
	.long sys_setreuid
	.long sys_setresuid
	.long sys_getresuid
	.long sys_setuid
	.long sys_setfsuid	/* 215 */

	.long sys_umount	/* recycled never used phys() */
	.long sys_oldumount

	.long sys_olduname
	.long sys_uname
	.long sys_newuname

	.long sys_old_getrlimit
	.long sys_getrlimit


best,
Herbert

> Kirill