Re: [Xen-devel] Xen 4.0.0-rc7 problem/hang with vt-d DMAR parsing

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

>>> Weidong Han <weidong.han@xxxxxxxxx> 25.03.10 10:05 >>>
>Ok. Updated the patch according to your suggestion. Thanks.

Looks good to me, and I would ack it if I didn't (sorry, only now)
notice that it can't be against -unstable: The patch seems to be
against code which doesn't have an ACPI_DMAR_RHSA case in
acpi_parse_dmar(). Quite odd...

Jan

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

diff -r a4eac162dcb9 xen/drivers/passthrough/vtd/dmar.c
--- a/xen/drivers/passthrough/vtd/dmar.c    Thu Mar 25 01:05:03 2010 +0800
+++ b/xen/drivers/passthrough/vtd/dmar.c    Fri Mar 26 01:59:55 2010 +0800
@@ -659,26 +659,71 @@ static int __init acpi_parse_dmar(struct
     while ( ((unsigned long)entry_header) <
             (((unsigned long)dmar) + table->length) )
     {
+        if ( entry_header->length < sizeof(struct acpi_dmar_entry_header) )
+        {
+            dprintk(XENLOG_ERR VTDPREFIX,
+                    "Invalid ACPI DMAR entry length: 0x%x\n",
+                    entry_header->length);
+            ret = -EINVAL;
+            break;
+        }
+
         switch ( entry_header->type )
         {
         case ACPI_DMAR_DRHD:
             if ( iommu_verbose )
                 dprintk(VTDPREFIX, "found ACPI_DMAR_DRHD:\n");
+
+            if ( entry_header->length < sizeof(struct acpi_table_drhd) )
+            {
+                dprintk(XENLOG_ERR VTDPREFIX,
+                        "  Invalid length: 0x%x\n", entry_header->length);
+                ret = -EINVAL;
+                break;
+            }
+
             ret = acpi_parse_one_drhd(entry_header);
             break;
         case ACPI_DMAR_RMRR:
             if ( iommu_verbose )
                 dprintk(VTDPREFIX, "found ACPI_DMAR_RMRR:\n");
+
+            if ( entry_header->length < sizeof(struct acpi_table_rmrr) )
+            {
+                dprintk(XENLOG_ERR VTDPREFIX,
+                        "  Invalid length: 0x%x\n", entry_header->length);
+                ret = -EINVAL;
+                break;
+            }
+
             ret = acpi_parse_one_rmrr(entry_header);
             break;
         case ACPI_DMAR_ATSR:
             if ( iommu_verbose )
                 dprintk(VTDPREFIX, "found ACPI_DMAR_ATSR:\n");
+
+            if ( entry_header->length < sizeof(struct acpi_table_atsr) )
+            {
+                dprintk(XENLOG_ERR VTDPREFIX,
+                        "  Invalid length: 0x%x\n", entry_header->length);
+                ret = -EINVAL;
+                break;
+            }
+
             ret = acpi_parse_one_atsr(entry_header);
             break;
         default:



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