On Thu, 22 Mar 2018 12:01:14 -0700
Haiyang Zhang <haiya...@linuxonhyperv.com> wrote:
> From: Haiyang Zhang <haiya...@microsoft.com>
>
> This patch adds range checking for rx packet offset and length.
> It may only happen if there is a host side bug.
>
> Signed-off-by: Haiyang Zhang <haiya...@microsoft.com>
> ---
> drivers/net/hyperv/hyperv_net.h | 1 +
> drivers/net/hyperv/netvsc.c | 17 +++++++++++++++--
> 2 files changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
> index 0db3bd1ea06f..49c05ac894e5 100644
> --- a/drivers/net/hyperv/hyperv_net.h
> +++ b/drivers/net/hyperv/hyperv_net.h
> @@ -793,6 +793,7 @@ struct netvsc_device {
>
> /* Receive buffer allocated by us but manages by NetVSP */
> void *recv_buf;
> + u32 recv_buf_size; /* allocated bytes */
> u32 recv_buf_gpadl_handle;
> u32 recv_section_cnt;
> u32 recv_section_size;
> diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
> index 1ddb2c39b6e4..a6700d65f206 100644
> --- a/drivers/net/hyperv/netvsc.c
> +++ b/drivers/net/hyperv/netvsc.c
> @@ -289,6 +289,8 @@ static int netvsc_init_buf(struct hv_device *device,
> goto cleanup;
> }
>
> + net_device->recv_buf_size = buf_size;
> +
> /*
> * Establish the gpadl handle for this buffer on this
> * channel. Note: This call uses the vmbus connection rather
> @@ -1095,11 +1097,22 @@ static int netvsc_receive(struct net_device *ndev,
>
> /* Each range represents 1 RNDIS pkt that contains 1 ethernet frame */
> for (i = 0; i < count; i++) {
> - void *data = recv_buf
> - + vmxferpage_packet->ranges[i].byte_offset;
> + u32 offset = vmxferpage_packet->ranges[i].byte_offset;
> u32 buflen = vmxferpage_packet->ranges[i].byte_count;
> + void *data;
> int ret;
>
> + if (unlikely(offset + buflen > net_device->recv_buf_size)) {
> + status = NVSP_STAT_FAIL;
> + netif_err(net_device_ctx, rx_err, ndev,
> + "Packet offset:%u + len:%u too big\n",
> + offset, buflen);
> +
> + continue;
> + }
> +
If one part of the RNDIS packet is wrong then the whole receive
buffer is damaged. Just return, don't continue.
It could really just be a statistic and a one shot log message.
