2022-04-22 17:40:40

by Andrea Parri

Subject: [PATCH 1/5] hv_sock: Check hv_pkt_iter_first_raw()'s return value

The function returns NULL if the ring buffer doesn't contain enough
readable bytes to constitute a packet descriptor. The ring buffer's
write_index is in memory which is shared with the Hyper-V host, an
erroneous or malicious host could thus change its value and overturn
the result of hvs_stream_has_data().

Signed-off-by: Andrea Parri (Microsoft) <[email protected]>
---
net/vmw_vsock/hyperv_transport.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
index e111e13b66604..943352530936e 100644
--- a/net/vmw_vsock/hyperv_transport.c
+++ b/net/vmw_vsock/hyperv_transport.c
@@ -603,6 +603,8 @@ static ssize_t hvs_stream_dequeue(struct vsock_sock *vsk, struct msghdr *msg,

if (need_refill) {
hvs->recv_desc = hv_pkt_iter_first_raw(hvs->chan);
+ if (!hvs->recv_desc)
+ return -ENOBUFS;
ret = hvs_update_recv_data(hvs);
if (ret)
return ret;
--
2.25.1

2022-04-22 17:46:55

by Michael Kelley (LINUX)

Subject: RE: [PATCH 1/5] hv_sock: Check hv_pkt_iter_first_raw()'s return value

From: Andrea Parri (Microsoft) <[email protected]> Sent: Wednesday, April 20, 2022 1:07 PM
>
> The function returns NULL if the ring buffer doesn't contain enough
> readable bytes to constitute a packet descriptor. The ring buffer's
> write_index is in memory which is shared with the Hyper-V host, an
> erroneous or malicious host could thus change its value and overturn
> the result of hvs_stream_has_data().
>
> Signed-off-by: Andrea Parri (Microsoft) <[email protected]>
> ---
> net/vmw_vsock/hyperv_transport.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
> index e111e13b66604..943352530936e 100644
> --- a/net/vmw_vsock/hyperv_transport.c
> +++ b/net/vmw_vsock/hyperv_transport.c
> @@ -603,6 +603,8 @@ static ssize_t hvs_stream_dequeue(struct vsock_sock *vsk,
> struct msghdr *msg,
>
> if (need_refill) {
> hvs->recv_desc = hv_pkt_iter_first_raw(hvs->chan);
> + if (!hvs->recv_desc)
> + return -ENOBUFS;
> ret = hvs_update_recv_data(hvs);
> if (ret)
> return ret;
> --
> 2.25.1

Reviewed-by: Michael Kelley <[email protected]>

2022-04-22 22:26:13

by Stefano Garzarella

Subject: Re: [PATCH 1/5] hv_sock: Check hv_pkt_iter_first_raw()'s return value

On Wed, Apr 20, 2022 at 10:07:16PM +0200, Andrea Parri (Microsoft) wrote:
>The function returns NULL if the ring buffer doesn't contain enough
>readable bytes to constitute a packet descriptor. The ring buffer's
>write_index is in memory which is shared with the Hyper-V host, an
>erroneous or malicious host could thus change its value and overturn
>the result of hvs_stream_has_data().
>
>Signed-off-by: Andrea Parri (Microsoft) <[email protected]>
>---
> net/vmw_vsock/hyperv_transport.c | 2 ++
> 1 file changed, 2 insertions(+)
>
>diff --git a/net/vmw_vsock/hyperv_transport.c b/net/vmw_vsock/hyperv_transport.c
>index e111e13b66604..943352530936e 100644
>--- a/net/vmw_vsock/hyperv_transport.c
>+++ b/net/vmw_vsock/hyperv_transport.c
>@@ -603,6 +603,8 @@ static ssize_t hvs_stream_dequeue(struct vsock_sock *vsk, struct msghdr *msg,
>
> if (need_refill) {
> hvs->recv_desc = hv_pkt_iter_first_raw(hvs->chan);
>+ if (!hvs->recv_desc)
>+ return -ENOBUFS;
> ret = hvs_update_recv_data(hvs);
> if (ret)
> return ret;
>--
>2.25.1
>

Reviewed-by: Stefano Garzarella <[email protected]>