iwlwifi: pcie: validate RX descriptor length

Validate the maximum RX descriptor length against the size
of the buffers we gave the device - if it doesn't fit then
the hardware messed up.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20201209231352.6378fb435cc0.Ib07485f3dc5999c74b03f21e7a808c50a05e353c@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
index 94299f2..ed200f5 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
@@ -1335,6 +1335,13 @@ static void iwl_pcie_rx_handle_rb(struct iwl_trans *trans,
 
                len = iwl_rx_packet_len(pkt);
                len += sizeof(u32); /* account for status word */
+
+               offset += ALIGN(len, FH_RSCSR_FRAME_ALIGN);
+
+               /* check that what the device tells us made sense */
+               if (offset > max_len)
+                       break;
+
                trace_iwlwifi_dev_rx(trans->dev, trans, pkt, len);
                trace_iwlwifi_dev_rx_data(trans->dev, trans, pkt, len);
 
@@ -1392,7 +1399,6 @@ static void iwl_pcie_rx_handle_rb(struct iwl_trans *trans,
                page_stolen |= rxcb._page_stolen;
                if (trans->trans_cfg->device_family >= IWL_DEVICE_FAMILY_AX210)
                        break;
-               offset += ALIGN(len, FH_RSCSR_FRAME_ALIGN);
        }
 
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