From: Volodymyr Babchuk <volodymyr_babchuk@epam.com>
Date: Tue, 8 Apr 2025 07:36:38 +0000 (+0200)
Subject: xen: vm_event: do not do vm_event_op for an invalid domain
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=6a884750f3b86a45ee5ffbd825c346fcbce86080;p=people%2Fandrewcoop%2Fxen.git

xen: vm_event: do not do vm_event_op for an invalid domain

A privileged domain can issue XEN_DOMCTL_vm_event_op with
op->domain == DOMID_INVALID. In this case vm_event_domctl()
function will get NULL as the first parameter and this will
cause hypervisor panic, as it tries to derefer this pointer.

Fix the issue by checking if valid domain is passed in.

Fixes: 48b84249459f ("xen/vm-event: Drop unused u_domctl parameter from vm_event_domctl()")
Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>
Acked-by: Tamas K Lengyel <tamas@tklengyel.com>
---

diff --git a/xen/common/vm_event.c b/xen/common/vm_event.c
index fbf1aa0848..1666ff615f 100644
--- a/xen/common/vm_event.c
+++ b/xen/common/vm_event.c
@@ -600,6 +600,10 @@ int vm_event_domctl(struct domain *d, struct xen_domctl_vm_event_op *vec)
         return 0;
     }
 
+    /* All other subops need to target a real domain. */
+    if ( unlikely(d == NULL) )
+        return -ESRCH;
+
     rc = xsm_vm_event_control(XSM_PRIV, d, vec->mode, vec->op);
     if ( rc )
         return rc;