Quoting Serge E. Hallyn (serue@xxxxxxxxxx):
> Quoting Stephen Smalley (sds@xxxxxxxxxxxxxx):
> > On Fri, 2009-06-19 at 20:32 -0500, Serge E. Hallyn wrote:
> > > diff --git a/ipc/checkpoint_msg.c b/ipc/checkpoint_msg.c
> > > index 51385b0..ca55339 100644
> > > --- a/ipc/checkpoint_msg.c
> > > +++ b/ipc/checkpoint_msg.c
> > <snip>
> > > @@ -175,11 +183,26 @@ static int load_ipc_msg_hdr(struct ckpt_ctx *ctx,
> > > struct msg_queue *msq)
> > > {
> > > int ret = 0;
> > > + int secid = 0;
> > >
> > > ret = restore_load_ipc_perms(&h->perms, &msq->q_perm);
> > > if (ret < 0)
> > > return ret;
> > >
> > > + if (h->perms.secref) {
> > > + struct sec_store *s;
> > > + s = ckpt_obj_fetch(ctx, h->perms.secref, CKPT_OBJ_SECURITY);
> > > + if (IS_ERR(s))
> > > + return PTR_ERR(s);
> > > + secid = s->secid;
> > > + }
> > > + ret = security_msg_queue_alloc(msq);
> > > + if (ret)
> > > + return ret;
> > > + ret = security_msg_queue_restore(msq, secid);
> > > + if (ret < 0)
> > > + return ret;
> >
> > I don't think you want to call security_msg_queue_alloc() here, as that
> > both allocates the security struct and performs the create check. So I
> > would just call the _restore() function, and let it internally call
> > ipc_alloc_security() to allocate the struct but then apply its own
> > distinct restore check. Likewise for the rest of them.
>
> Ok, will change that.
Hmm, but that means that if there is some new LSM which allocates memory
in security_msg_queue_alloc(), but which does not define
security_msg_queue_restore() (for some stupid reason), it'll end up
causing a bug.
It's something we can certainly catch through code review, but do we
want to set such a scenario up at all?
Speaking just for SELinux, the security_msg_queue_alloc() hook would
return -EPERM only if the task calling sys_restart() wasn't allowed
to create a msg queue with its own type, right? Is that something
which is often disallowed?
I suppose we could have the default (cap_msg_queue_restore) call
security_ops->msg_queue_alloc() - feels frail, but maybe it's ok...
thanks,
-serge
--
This message was distributed to subscribers of the selinux mailing list.
If you no longer wish to subscribe, send mail to majordomo@xxxxxxxxxxxxx with
the words "unsubscribe selinux" without quotes as the message.
