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) <parri.and...@gmail.com>
---
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 <sgarz...@redhat.com>

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