RE: [PATCH] hv_netvsc: Validate number of allocated sub-channels

[Michael Kelley]

From: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx> Sent: Wednesday, November 18, 2020 7:33 AM
> 
> Lack of validation could lead to out-of-bound reads and information
> leaks (cf. usage of nvdev->chan_table[]).  Check that the number of
> allocated sub-channels fits into the expected range.
> 
> Suggested-by: Saruhan Karademir <skarade@xxxxxxxxxxxxx>
> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx>
> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
> Cc: netdev@xxxxxxxxxxxxxxx
> ---
> Based on hyperv-next.
> 
>  drivers/net/hyperv/rndis_filter.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
> index 3835d9bea1005..c5a709f67870f 100644
> --- a/drivers/net/hyperv/rndis_filter.c
> +++ b/drivers/net/hyperv/rndis_filter.c
> @@ -1226,6 +1226,11 @@ int rndis_set_subchannel(struct net_device *ndev,
>  		return -EIO;
>  	}
> 
> +	/* Check that number of allocated sub channel is within the expected range */
> +	if (init_packet->msg.v5_msg.subchn_comp.num_subchannels > nvdev->num_chn - 1) {
> +		netdev_err(ndev, "invalid number of allocated sub channel\n");
> +		return -EINVAL;
> +	}
>  	nvdev->num_chn = 1 +
>  		init_packet->msg.v5_msg.subchn_comp.num_subchannels;
> 
> --
> 2.25.1

Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>