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Date:   Sat, 12 Dec 2020 19:09:01 +0100
From:   Andrea Parri <parri.andrea@gmail.com>
To:     Sasha Levin <sashal@kernel.org>
Cc:     linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        linux-scsi@vger.kernel.org,
        Saruhan Karademir <skarade@microsoft.com>,
        devel@linuxdriverproject.org
Subject: Re: [PATCH AUTOSEL 5.9 15/23] scsi: storvsc: Validate length of
 incoming packet in storvsc_on_channel_callback()
Message-ID: <20201212180901.GA19225@andrea>
References: <20201212160804.2334982-1-sashal@kernel.org>
 <20201212160804.2334982-15-sashal@kernel.org>
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Hi Sasha,

On Sat, Dec 12, 2020 at 11:07:56AM -0500, Sasha Levin wrote:
> From: "Andrea Parri (Microsoft)" <parri.andrea@gmail.com>
> 
> [ Upstream commit 3b8c72d076c42bf27284cda7b2b2b522810686f8 ]

FYI, we found that this commit introduced a regression and posted a
revert:

  https://lkml.kernel.org/r/20201211131404.21359-1-parri.andrea@gmail.com

Same comment for the AUTOSEL 5.4, 4.19 and 4.14 you've just posted.

  Andrea


> 
> Check that the packet is of the expected size at least, don't copy data
> past the packet.
> 
> Link: https://lore.kernel.org/r/20201118145348.109879-1-parri.andrea@gmail.com
> Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
> Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
> Cc: linux-scsi@vger.kernel.org
> Reported-by: Saruhan Karademir <skarade@microsoft.com>
> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
>  drivers/scsi/storvsc_drv.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
> index 8f5f5dc863a4a..6779ee4edfee3 100644
> --- a/drivers/scsi/storvsc_drv.c
> +++ b/drivers/scsi/storvsc_drv.c
> @@ -1246,6 +1246,11 @@ static void storvsc_on_channel_callback(void *context)
>  		request = (struct storvsc_cmd_request *)
>  			((unsigned long)desc->trans_id);
>  
> +		if (hv_pkt_datalen(desc) < sizeof(struct vstor_packet) - vmscsi_size_delta) {
> +			dev_err(&device->device, "Invalid packet len\n");
> +			continue;
> +		}
> +
>  		if (request == &stor_device->init_request ||
>  		    request == &stor_device->reset_request) {
>  			memcpy(&request->vstor_packet, packet,
> -- 
> 2.27.0
>