[Xen-devel] [PATCH 1/5] xen/domain: Introduce a new check_domain_config() helper

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Call it from the head of domain_create() (before doing any memory
allocations), which will apply the checks to dom0 as well as domU's.

For now, just subsume the XEN_DOMCTL_CDF_* check from XEN_DOMCTL_createdomain.
This means that the corner case of the toolstack providing bad configuration
will burn a domid, but production setups shouldn't ever get into this
situation.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>
CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
CC: Julien Grall <julien.grall@xxxxxxx>
---
 xen/common/domain.c | 15 +++++++++++++++
 xen/common/domctl.c |  9 ---------
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/xen/common/domain.c b/xen/common/domain.c
index 65151e2..3f09a57 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -288,6 +288,18 @@ static void _domain_destroy(struct domain *d)
     free_domain_struct(d);
 }
 
+static int check_domain_config(struct xen_domctl_createdomain *config)
+{
+    if ( config->flags & ~(XEN_DOMCTL_CDF_hvm_guest |
+                           XEN_DOMCTL_CDF_hap |
+                           XEN_DOMCTL_CDF_s3_integrity |
+                           XEN_DOMCTL_CDF_oos_off |
+                           XEN_DOMCTL_CDF_xs_domain) )
+        return -EINVAL;
+
+    return 0;
+}
+
 struct domain *domain_create(domid_t domid,
                              struct xen_domctl_createdomain *config,
                              bool is_priv)
@@ -297,6 +309,9 @@ struct domain *domain_create(domid_t domid,
            INIT_evtchn = 1u<<3, INIT_gnttab = 1u<<4, INIT_arch = 1u<<5 };
     int err, init_status = 0;
 
+    if ( config && (err = check_domain_config(config)) )
+        return ERR_PTR(err);
+
     if ( (d = alloc_domain_struct()) == NULL )
         return ERR_PTR(-ENOMEM);
 
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index b294881..d08b627 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -498,15 +498,6 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) 
u_domctl)
         domid_t        dom;
         static domid_t rover = 0;
 
-        ret = -EINVAL;
-        if ( (op->u.createdomain.flags &
-             ~(XEN_DOMCTL_CDF_hvm_guest
-               | XEN_DOMCTL_CDF_hap
-               | XEN_DOMCTL_CDF_s3_integrity
-               | XEN_DOMCTL_CDF_oos_off
-               | XEN_DOMCTL_CDF_xs_domain)) )
-            break;
-
         dom = op->domain;
         if ( (dom > 0) && (dom < DOMID_FIRST_RESERVED) )
         {
-- 
2.1.4


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