Re: [PATCH] Drivers: hv: vmbus: Use after free in __vmbus_open()

[Andrea Parri]

On Tue, Apr 13, 2021 at 01:50:04PM +0300, Dan Carpenter wrote:
> The "open_info" variable is added to the &vmbus_connection.chn_msg_list,
> but the error handling frees "open_info" without removing it from the
> list.  This will result in a use after free.  First remove it from the
> list, and then free it.
> 
> Fixes: 6f3d791f3006 ("Drivers: hv: vmbus: Fix rescind handling issues")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

I had this 'queued' in my list,

Reviewed-by: Andrea Parri <parri.andrea@xxxxxxxxx>

  Andrea


> ---
> From static analysis.  Untested etc.  There is almost certainly a good
> reason to add it to the list before checking "newchannel->rescind" but I
> don't know the code well enough to know what the reason is.
> 
>  drivers/hv/channel.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
> index db30be8f9cce..1c5a418c1962 100644
> --- a/drivers/hv/channel.c
> +++ b/drivers/hv/channel.c
> @@ -653,7 +653,7 @@ static int __vmbus_open(struct vmbus_channel *newchannel,
>  
>  	if (newchannel->rescind) {
>  		err = -ENODEV;
> -		goto error_free_info;
> +		goto error_clean_msglist;
>  	}
>  
>  	err = vmbus_post_msg(open_msg,
> -- 
> 2.30.2
>