Hi Stefano,
On 17/07/2018 21:05, Stefano Stabellini wrote:
On Mon, 9 Jul 2018, Julien Grall wrote:
Hi,
On 07/07/18 00:11, Stefano Stabellini wrote:
Introduce an is_console option to allow certain classes of domUs to use
the Xen console. Specifically, it will be used to give console access to
all domUs started from Xen from information on device tree.
Signed-off-by: Stefano Stabellini <stefa...@xilinx.com>
CC: andrew.coop...@citrix.com
CC: george.dun...@eu.citrix.com
CC: ian.jack...@eu.citrix.com
CC: jbeul...@suse.com
CC: konrad.w...@oracle.com
CC: t...@xen.org
CC: wei.l...@citrix.com
CC: dgde...@tycho.nsa.gov
---
Changes in v2:
- introduce is_console
- remove #ifdefs
---
xen/include/xen/sched.h | 2 ++
xen/include/xsm/dummy.h | 2 ++
xen/xsm/flask/hooks.c | 5 ++++-
3 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 99d2af2..d66cec0 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -379,6 +379,8 @@ struct domain
bool auto_node_affinity;
/* Is this guest fully privileged (aka dom0)? */
bool is_privileged;
+ /* Can this guest access the Xen console? */
+ bool is_console;
/* Is this a xenstore domain (not dom0)? */
bool is_xenstore;
/* Domain's VCPUs are pinned 1:1 to physical CPUs? */
diff --git a/xen/include/xsm/dummy.h b/xen/include/xsm/dummy.h
index ff6b2db..3888817 100644
--- a/xen/include/xsm/dummy.h
+++ b/xen/include/xsm/dummy.h
@@ -230,6 +230,8 @@ static XSM_INLINE int
xsm_memory_stat_reservation(XSM_DEFAULT_ARG struct domain
static XSM_INLINE int xsm_console_io(XSM_DEFAULT_ARG struct domain *d, int
cmd)
{
XSM_ASSERT_ACTION(XSM_OTHER);
+ if ( d->is_console )
+ return xsm_default_action(XSM_HOOK, d, NULL);
I will let Daniel commenting on this change. However ...
#ifdef CONFIG_VERBOSE_DEBUG
if ( cmd == CONSOLEIO_write )
return xsm_default_action(XSM_HOOK, d, NULL);
diff --git a/xen/xsm/flask/hooks.c b/xen/xsm/flask/hooks.c
index 78bc326..2551e4e 100644
--- a/xen/xsm/flask/hooks.c
+++ b/xen/xsm/flask/hooks.c
@@ -443,7 +443,10 @@ static int flask_console_io(struct domain *d, int cmd)
return avc_unknown_permission("console_io", cmd);
}
- return domain_has_xen(d, perm);
+ if ( !d->is_console )
+ return domain_has_xen(d, perm);
+ else
+ return 0;
... I don't think this change is correct. When a policy is used, the user is
free to define what is the behavior. With your solution, you impose the
console access even if the user didn't to not give the permission.
I was hoping Daniel would advise on the best way to do things here.
I thought that the idea was that granting a domain "is_console" is
equivalent to granting a domain XEN__READCONSOLE and XEN__WRITECONSOLE
permissions. Thus, if is_console is set, we return 0 from
flask_console_io because the permissions check succeeds.
Well, yes and no. That's equivalent when you use the dummy policy. When
you have a flask policy you want to give the control to the user.
If you look at the code there are no such as d->is_privilege in that
function. This means that the user define the policy for the hardware
domain. Why would be d->is_console different here?
Given that I have accumulated many changes to this patch series, I'll
send out a new version now without making changes to this patch for now.
I haven't finished to review the series yet and would appreciate some
more time before resending it.
Cheers,
--
Julien Grall
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