[Qemu-devel] Re: [PATCH] add VMSTATE_BOOL

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Nov 09, 2010 at 12:50:11PM +0100, Gerd Hoffmann wrote:
>   Hi,
> 
> >>>>+static int get_bool(QEMUFile *f, void *pv, size_t size)
> >>>>+{
> >>>>+    bool *v = pv;
> >>>>+    *v = qemu_get_byte(f);
> >>>>+    return 0;
> 
> >I think we should verify that value is 0 or 1 and fail
> >migration otherwise, to make it more robust.
> 
> I still think such a check doesn't belong into the migration code as
> such a bug would exist without migration too.  And if anything we
> should check on save not on load, otherwise qemu can write out
> savevm images which it will refuse to load.  I wouldn't call this
> "robust".
> 
> cheers,
>   Gerd

I think we should verify on load: e.g. the image could have
got corrupted. What, exactly, do you want to check on save?

---

savevm: validate bool values on load

We always save 0 or 1 values for booleans.  Validate on input to
increase the chance of detecting input corruption.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

---

diff --git a/savevm.c b/savevm.c
index 4e49765..da2fdfa 100644
--- a/savevm.c
+++ b/savevm.c
@@ -680,7 +680,12 @@ uint64_t qemu_get_be64(QEMUFile *f)
 static int get_bool(QEMUFile *f, void *pv, size_t size)
 {
     bool *v = pv;
-    *v = qemu_get_byte(f);
+    uint8_t b;
+    b = qemu_get_byte(f);
+    if (b != (uint8_t)true && b != (uint8_t)false) {
+        return -EINVAL;
+    }
+    *v = b;
     return 0;
 }