From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Thu, 3 Apr 2014 19:51:42 +0300
Subject: [PATCH] vmstate: fix buffer overflow in target-arm/machine.c

CVE-2013-4531

cpreg_vmstate_indexes is a VARRAY_INT32. A negative value for
cpreg_vmstate_array_len will cause a buffer overflow.

VMSTATE_INT32_LE was supposed to protect against this
but doesn't because it doesn't validate that input is
non-negative.

Fix this macro to valide the value appropriately.

The only other user of VMSTATE_INT32_LE doesn't
ever use negative numbers so it doesn't care.

Reported-by: Anthony Liguori <anthony@codemonkey.ws>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
(cherry picked from commit d2ef4b61fe6d33d2a5dcf100a9b9440de341ad62)
---
 savevm.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/savevm.c b/savevm.c
index 9f7f668..ffc1a7c 100644
--- a/savevm.c
+++ b/savevm.c
@@ -1104,17 +1104,20 @@ const VMStateInfo vmstate_info_int32_equal = {
     .put  = put_int32,
 };
 
-/* 32 bit int. See that the received value is the less or the same
-   than the one in the field */
+/* 32 bit int. Check that the received value is non-negative
+ * and less than or equal to the one in the field.
+ */
 
 static int get_int32_le(QEMUFile *f, void *pv, size_t size)
 {
-    int32_t *old = pv;
-    int32_t new;
-    qemu_get_sbe32s(f, &new);
+    int32_t *cur = pv;
+    int32_t loaded;
+    qemu_get_sbe32s(f, &loaded);
 
-    if (*old <= new)
+    if (loaded >= 0 && loaded <= *cur) {
+        *cur = loaded;
         return 0;
+    }
     return -EINVAL;
 }