[PATCH] state: Fix "pack" returning freed data for DTB backend

[PATCH] state: Fix "pack" returning freed data for DTB backend

[Ian Abbott]

`state_backend_format_dtb_pack()` passes a buffer containing state
packed in flattened DTB format back to its caller via its `buf`
parameter.  It then frees the buffer before returning.  This means the
caller (`state_save()`) will be working on freed buffer contents before
freeing the buffer a second time itself.  Fix it by removing the
spurious call to `free()`.

This should fix a bug reported by Norbert Wiedmann in
<http://lists.infradead.org/pipermail/barebox/2017-April/029980.html>.

Cc: Norbert Wiedmann <info@n-wiedmann.de>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
---
As reported by Norbert, there is an identical bug in the "dt-utils"
package.
---
 common/state/backend_format_dtb.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/common/state/backend_format_dtb.c b/common/state/backend_format_dtb.c
index 55fa1fc59..e88cda499 100644
--- a/common/state/backend_format_dtb.c
+++ b/common/state/backend_format_dtb.c
@@ -120,8 +120,6 @@ static int state_backend_format_dtb_pack(struct state_backend_format *format,
 		of_delete_node(fdtb->root);
 	fdtb->root = root;
 
-	free(fdt);
-
 	return 0;
 }
 
-- 
2.11.0


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Re: [PATCH] state: Fix "pack" returning freed data for DTB backend

[Sascha Hauer]

On Fri, Apr 21, 2017 at 10:53:25AM +0100, Ian Abbott wrote:
> `state_backend_format_dtb_pack()` passes a buffer containing state
> packed in flattened DTB format back to its caller via its `buf`
> parameter.  It then frees the buffer before returning.  This means the
> caller (`state_save()`) will be working on freed buffer contents before
> freeing the buffer a second time itself.  Fix it by removing the
> spurious call to `free()`.
> 
> This should fix a bug reported by Norbert Wiedmann in
> <http://lists.infradead.org/pipermail/barebox/2017-April/029980.html>.
> 
> Cc: Norbert Wiedmann <info@n-wiedmann.de>
> Signed-off-by: Ian Abbott <abbotti@mev.co.uk>

Applied, thanks

Sascha

> ---
> As reported by Norbert, there is an identical bug in the "dt-utils"
> package.
> ---
>  common/state/backend_format_dtb.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/common/state/backend_format_dtb.c b/common/state/backend_format_dtb.c
> index 55fa1fc59..e88cda499 100644
> --- a/common/state/backend_format_dtb.c
> +++ b/common/state/backend_format_dtb.c
> @@ -120,8 +120,6 @@ static int state_backend_format_dtb_pack(struct state_backend_format *format,
>  		of_delete_node(fdtb->root);
>  	fdtb->root = root;
>  
> -	free(fdt);
> -
>  	return 0;
>  }
>  
> -- 
> 2.11.0
> 
> 
> _______________________________________________
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> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox
> 

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