net: atlantic: verify hw_head_ lies within TX buffer ring

Bounds check hw_head index provided by NIC to verify it lies
within the TX buffer ring.

Reported-by: Aashay Shringarpure <aashay@google.com>
Reported-by: Yi Chou <yich@google.com>
Reported-by: Shervin Oloumi <enlightened@google.com>
Signed-off-by: Grant Grundler <grundler@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c b/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c
index d875ce3..15ede72 100644 (file)
--- a/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c
+++ b/drivers/net/ethernet/aquantia/atlantic/hw_atl/hw_atl_b0.c
@@ -889,6 +889,13 @@ int hw_atl_b0_hw_ring_tx_head_update(struct aq_hw_s *self,
                err = -ENXIO;
                goto err_exit;
        }
+
+       /* Validate that the new hw_head_ is reasonable. */
+       if (hw_head_ >= ring->size) {
+               err = -ENXIO;
+               goto err_exit;
+       }
+
        ring->hw_head = hw_head_;
        err = aq_hw_err_from_flags(self);