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Date:   Tue, 13 Apr 2021 17:42:21 +0200
From:   Andrea Parri <parri.andrea@gmail.com>
To:     Dan Carpenter <dan.carpenter@oracle.com>
Cc:     "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Dexuan Cui <decui@microsoft.com>, linux-hyperv@vger.kernel.org,
        linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] Drivers: hv: vmbus: Use after free in __vmbus_open()
Message-ID: <20210413154221.GA2369@anparri>
References: <YHV3XLCot6xBS44r@mwanda>
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In-Reply-To: <YHV3XLCot6xBS44r@mwanda>
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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@oracle.com>

I had this 'queued' in my list,

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

  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
>