[Xen-devel] [PATCH] libxc/restore: Fix data auditing in handle_x86_pv_vcpu_blob()

* [Xen-devel] [PATCH] libxc/restore: Fix data auditing in handle_x86_pv_vcpu_blob()
@ 2019-12-19 20:42 Andrew Cooper
  2019-12-20 12:08 ` Ian Jackson
  0 siblings, 1 reply; 2+ messages in thread
From: Andrew Cooper @ 2019-12-19 20:42 UTC (permalink / raw
  To: Xen-devel; +Cc: Andrew Cooper, Wei Liu, Ian Jackson

The current logic only works by chance, in that XSAVE records also tend to be
a multiple of 128.  Implement the missing logic for XSAVE.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Ian Jackson <Ian.Jackson@citrix.com>
CC: Wei Liu <wl@xen.org>
---
 tools/libxc/xc_sr_restore_x86_pv.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tools/libxc/xc_sr_restore_x86_pv.c b/tools/libxc/xc_sr_restore_x86_pv.c
index 1a26f2205f..116a004726 100644
--- a/tools/libxc/xc_sr_restore_x86_pv.c
+++ b/tools/libxc/xc_sr_restore_x86_pv.c
@@ -825,6 +825,15 @@ static int handle_x86_pv_vcpu_blob(struct xc_sr_context *ctx,
         break;
 
     case REC_TYPE_X86_PV_VCPU_XSAVE:
+        if ( blobsz < 128 )
+        {
+            ERROR("%s record too short: min %zu, got %u",
+                  rec_name, sizeof(*vhdr) + 128, rec->length);
+            goto out;
+        }
+        break;
+
+    case REC_TYPE_X86_PV_VCPU_MSRS:
         if ( blobsz % sizeof(xen_domctl_vcpu_msr_t) != 0 )
         {
             ERROR("%s record payload size %zu expected to be a multiple of %zu",
-- 
2.11.0


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