domctl/XSM: drop scheduler_op hook

Integrate the checking with xsm_domctl(), now that it has the full op
struct passed. As a positive side effect, permissions are then checked at
the same early point with and without Flask.

This is part of XSA-492.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Daniel P. Smith <dpsmith@apertussolutions.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
(cherry picked from commit 3ba374d388)

xen/common/sched/core.c

@@ -2058,10 +2058,6 @@ long sched_adjust(struct domain *d, struct xen_domctl_scheduler_op *op)
 {
     long ret;
 
-    ret = xsm_domctl_scheduler_op(XSM_HOOK, d, op->cmd);
-    if ( ret )
-        return ret;
-
     if ( op->sched_id != dom_scheduler(d)->sched_id )
         return -EINVAL;
 

xen/include/xsm/dummy.h

@@ -141,13 +141,6 @@ static XSM_INLINE int cf_check xsm_getdomaininfo(
     return xsm_default_action(action, current->domain, d);
 }
 
-static XSM_INLINE int cf_check xsm_domctl_scheduler_op(
-    XSM_DEFAULT_ARG struct domain *d, int cmd)
-{
-    XSM_ASSERT_ACTION(XSM_HOOK);
-    return xsm_default_action(action, current->domain, d);
-}
-
 static XSM_INLINE int cf_check xsm_sysctl_scheduler_op(XSM_DEFAULT_ARG int cmd)
 {
     XSM_ASSERT_ACTION(XSM_HOOK);

xen/include/xsm/xsm.h

@@ -57,7 +57,6 @@ struct xsm_ops {
                                 struct xen_domctl_getdomaininfo *info);
     int (*domain_create)(struct domain *d, uint32_t ssidref);
     int (*getdomaininfo)(struct domain *d);
-    int (*domctl_scheduler_op)(struct domain *d, int op);
     int (*sysctl_scheduler_op)(int op);
     int (*set_target)(struct domain *d, struct domain *e);
     int (*domctl)(struct domain *d, struct xen_domctl *op);
@@ -229,12 +228,6 @@ static inline int xsm_getdomaininfo(xsm_default_t def, struct domain *d)
     return alternative_call(xsm_ops.getdomaininfo, d);
 }
 
-static inline int xsm_domctl_scheduler_op(
-    xsm_default_t def, struct domain *d, int cmd)
-{
-    return alternative_call(xsm_ops.domctl_scheduler_op, d, cmd);
-}
-
 static inline int xsm_sysctl_scheduler_op(xsm_default_t def, int cmd)
 {
     return alternative_call(xsm_ops.sysctl_scheduler_op, cmd);

xen/xsm/dummy.c

@@ -18,7 +18,6 @@ static const struct xsm_ops __initconst_cf_clobber dummy_ops = {
     .security_domaininfo           = xsm_security_domaininfo,
     .domain_create                 = xsm_domain_create,
     .getdomaininfo                 = xsm_getdomaininfo,
-    .domctl_scheduler_op           = xsm_domctl_scheduler_op,
     .sysctl_scheduler_op           = xsm_sysctl_scheduler_op,
     .set_target                    = xsm_set_target,
     .domctl                        = xsm_domctl,

xen/xsm/flask/hooks.c

@@ -607,7 +607,7 @@ static int cf_check flask_getdomaininfo(struct domain *d)
     return current_has_perm(d, SECCLASS_DOMAIN, DOMAIN__GETDOMAININFO);
 }
 
-static int cf_check flask_domctl_scheduler_op(struct domain *d, int op)
+static int flask_domctl_scheduler_op(struct domain *d, int op)
 {
     switch ( op )
     {
@@ -691,7 +691,6 @@ static int cf_check flask_domctl(struct domain *d, struct xen_domctl *op)
         return -EILSEQ;
 
     /* These have individual XSM hooks (common/domctl.c) */
-    case XEN_DOMCTL_scheduler_op:
     case XEN_DOMCTL_set_target:
 
 #ifdef CONFIG_X86
@@ -739,6 +738,9 @@ static int cf_check flask_domctl(struct domain *d, struct xen_domctl *op)
     case XEN_DOMCTL_setdomainhandle:
         return current_has_perm(d, SECCLASS_DOMAIN, DOMAIN__SETDOMAINHANDLE);
 
+    case XEN_DOMCTL_scheduler_op:
+        return flask_domctl_scheduler_op(d, op->u.scheduler_op.cmd);
+
     case XEN_DOMCTL_set_ext_vcpucontext:
     case XEN_DOMCTL_set_vcpu_msrs:
     case XEN_DOMCTL_setvcpucontext:
@@ -1849,7 +1851,6 @@ static const struct xsm_ops __initconst_cf_clobber flask_ops = {
     .security_domaininfo = flask_security_domaininfo,
     .domain_create = flask_domain_create,
     .getdomaininfo = flask_getdomaininfo,
-    .domctl_scheduler_op = flask_domctl_scheduler_op,
     .sysctl_scheduler_op = flask_sysctl_scheduler_op,
     .set_target = flask_set_target,
     .domctl = flask_domctl,