1 files changed, 62 insertions, 0 deletions
diff --git a/system/xen/xsa/xsa410-4.16-04.patch b/system/xen/xsa/xsa410-4.16-04.patch
new file mode 100644
index 0000000000000..2170b8e1a3277
--- /dev/null
+++ b/system/xen/xsa/xsa410-4.16-04.patch
@@ -0,0 +1,62 @@
+From: Jan Beulich <jbeulich@suse.com>
+Subject: x86/HAP: adjust monitor table related error handling
+
+hap_make_monitor_table() will return INVALID_MFN if it encounters an
+error condition, but hap_update_paging_modes() wasn’t handling this
+value, resulting in an inappropriate value being stored in
+monitor_table. This would subsequently misguide at least
+hap_vcpu_teardown(). Avoid this by bailing early.
+
+Further, when a domain has/was already crashed or (perhaps less
+important as there's no such path known to lead here) is already dying,
+avoid calling domain_crash() on it again - that's at best confusing.
+
+This is part of CVE-2022-33746 / XSA-410.
+
+Signed-off-by: Jan Beulich <jbeulich@suse.com>
+Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
+
+--- a/xen/arch/x86/mm/hap/hap.c
++++ b/xen/arch/x86/mm/hap/hap.c
+@@ -39,6 +39,7 @@
+ #include <asm/domain.h>
+ #include <xen/numa.h>
+ #include <asm/hvm/nestedhvm.h>
++#include <public/sched.h>
+ 
+ #include "private.h"
+ 
+@@ -405,8 +406,13 @@ static mfn_t hap_make_monitor_table(stru
+     return m4mfn;
+ 
+  oom:
+-    printk(XENLOG_G_ERR "out of memory building monitor pagetable\n");
+-    domain_crash(d);
++    if ( !d->is_dying &&
++         (!d->is_shutting_down || d->shutdown_code != SHUTDOWN_crash) )
++    {
++        printk(XENLOG_G_ERR "%pd: out of memory building monitor pagetable\n",
++               d);
++        domain_crash(d);
++    }
+     return INVALID_MFN;
+ }
+ 
+@@ -766,6 +772,9 @@ static void hap_update_paging_modes(stru
+     if ( pagetable_is_null(v->arch.hvm.monitor_table) )
+     {
+         mfn_t mmfn = hap_make_monitor_table(v);
++
++        if ( mfn_eq(mmfn, INVALID_MFN) )
++            goto unlock;
+         v->arch.hvm.monitor_table = pagetable_from_mfn(mmfn);
+         make_cr3(v, mmfn);
+         hvm_update_host_cr3(v);
+@@ -774,6 +783,7 @@ static void hap_update_paging_modes(stru
+     /* CR3 is effectively updated by a mode change. Flush ASIDs, etc. */
+     hap_update_cr3(v, 0, false);
+ 
++ unlock:
+     paging_unlock(d);
+     put_gfn(d, cr3_gfn);
+ }