sfc: don't try and read ef10 data on non-ef10 NIC

The MAC stats command takes a port ID, which doesn't exist on
pre-ef10 NICs (5000- and 6000- series). This is extracted from the
NIC specific data; we misinterpret this as the ef10 data structure,
causing us to read potentially unallocated data. With a KASAN kernel
this can cause errors with:
   BUG: KASAN: slab-out-of-bounds in efx_mcdi_mac_stats

Fixes: 0a2ab4d988d7 ("sfc: set the port-id when calling MC_CMD_MAC_STATS")
Reported-by: Stefano Brivio <sbrivio@redhat.com>
Tested-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Bert Kenward <bkenward@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/sfc/mcdi_port.c b/drivers/net/ethernet/sfc/mcdi_port.c
index c905971..990a63d 100644 (file)
--- a/drivers/net/ethernet/sfc/mcdi_port.c
+++ b/drivers/net/ethernet/sfc/mcdi_port.c
@@ -938,7 +938,6 @@ enum efx_stats_action {
 static int efx_mcdi_mac_stats(struct efx_nic *efx,
                              enum efx_stats_action action, int clear)
 {
-       struct efx_ef10_nic_data *nic_data = efx->nic_data;
        MCDI_DECLARE_BUF(inbuf, MC_CMD_MAC_STATS_IN_LEN);
        int rc;
        int change = action == EFX_STATS_PULL ? 0 : 1;
@@ -960,7 +959,12 @@ static int efx_mcdi_mac_stats(struct efx_nic *efx,
                              MAC_STATS_IN_PERIODIC_NOEVENT, 1,
                              MAC_STATS_IN_PERIOD_MS, period);
        MCDI_SET_DWORD(inbuf, MAC_STATS_IN_DMA_LEN, dma_len);
-       MCDI_SET_DWORD(inbuf, MAC_STATS_IN_PORT_ID, nic_data->vport_id);
+
+       if (efx_nic_rev(efx) >= EFX_REV_HUNT_A0) {
+               struct efx_ef10_nic_data *nic_data = efx->nic_data;
+
+               MCDI_SET_DWORD(inbuf, MAC_STATS_IN_PORT_ID, nic_data->vport_id);
+       }
 
        rc = efx_mcdi_rpc_quiet(efx, MC_CMD_MAC_STATS, inbuf, sizeof(inbuf),
                                NULL, 0, NULL);