Re: [PATCH] RDMA/nes: do not leak uninitialized resp.reserved to userspace

[Leon Romanovsky]

On Mon, Sep 04, 2017 at 12:23:16PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> resp.reserved has not been initialized and so the copy_to_user (via
> ib_copy_to_udata) is copying uninitialized data from the stack back
> to user space which is a potential information leak. Fix this by
> setting resp.reserved to zero.
>
> Fixes: 3c2d774cad5b ("RDMA/nes: Add a driver for NetEffect RNICs")
> Cc: <stable@xxxxxxxxxxxxxxx> [2.6.24+]
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> ---
>  drivers/infiniband/hw/nes/nes_verbs.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/infiniband/hw/nes/nes_verbs.c b/drivers/infiniband/hw/nes/nes_verbs.c
> index f0dc5f4aa177..052c3822dfed 100644
> --- a/drivers/infiniband/hw/nes/nes_verbs.c
> +++ b/drivers/infiniband/hw/nes/nes_verbs.c
> @@ -1666,6 +1666,7 @@ static struct ib_cq *nes_create_cq(struct ib_device *ibdev,
>  		resp.cq_id = nescq->hw_cq.cq_number;
>  		resp.cq_size = nescq->hw_cq.cq_size;
>  		resp.mmap_db_index = 0;
> +		resp.reserved = 0;

Right and it is better to initialize the "struct nes_create_cq_resp resp" to zero
at the beginning of the function.

Thanks


>  		if (ib_copy_to_udata(udata, &resp, sizeof resp - sizeof resp.reserved)) {
>  			nes_free_resource(nesadapter, nesadapter->allocated_cqs, cq_num);
>  			kfree(nescq);
> --
> 2.14.1
>
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