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Date: Tue, 18 Jun 2013 11:53:42 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v1 1/1] qom: Fix class cast of NULL classes
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To: peter.crosthwaite@xilinx.com
Cc: aliguori@us.ibm.com, qemu-devel@nongnu.org, "1.5.x" <qemu-stable@nongnu.org>

Il 18/06/2013 11:18, peter.crosthwaite@xilinx.com ha scritto:
> From: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
> 
> Its clear from the implementation that class casting is supposed to work
> with a NULL class argument. Guard all dereferences of the class argument
> against NULL accordingly.
> 
> Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>

Cc: qemu-stable@nongnu.org


> ---
> 
>  qom/object.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/qom/object.c b/qom/object.c
> index 803b94b..b7ecb9f 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -531,14 +531,14 @@ ObjectClass *object_class_dynamic_cast_assert(ObjectClass *class,
>  #ifdef CONFIG_QOM_CAST_DEBUG
>      int i;
>  
> -    for (i = 0; i < OBJECT_CLASS_CAST_CACHE; i++) {
> +    for (i = 0; class && i < OBJECT_CLASS_CAST_CACHE; i++) {
>          if (class->cast_cache[i] == typename) {
>              ret = class;
>              goto out;
>          }
>      }
>  #else
> -    if (!class->interfaces) {
> +    if (!class || !class->interfaces) {
>          return class;
>      }
>  #endif
> @@ -551,7 +551,7 @@ ObjectClass *object_class_dynamic_cast_assert(ObjectClass *class,
>      }
>  
>  #ifdef CONFIG_QOM_CAST_DEBUG
> -    if (ret == class) {
> +    if (class && ret == class) {
>          for (i = 1; i < OBJECT_CLASS_CAST_CACHE; i++) {
>              class->cast_cache[i - 1] = class->cast_cache[i];
>          }
>