bnx2x: fix dump flag handling

bnx2x interprets the dump flag as an index of a register preset.
It is important to validate the index to avoid out of bounds
memory accesses.
Signed-off-by: NMichal Schmidt <mschmidt@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c

@@ -959,6 +959,9 @@ static int bnx2x_set_dump(struct net_device *dev, struct ethtool_dump *val)
 	struct bnx2x *bp = netdev_priv(dev);
 
 	/* Use the ethtool_dump "flag" field as the dump preset index */
+	if (val->flag < 1 || val->flag > DUMP_MAX_PRESETS)
+		return -EINVAL;
+
 	bp->dump_preset_idx = val->flag;
 	return 0;
 }

drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c

@@ -11636,6 +11636,8 @@ static int bnx2x_init_bp(struct bnx2x *bp)
 		bp->min_msix_vec_cnt = 2;
 	BNX2X_DEV_INFO("bp->min_msix_vec_cnt %d", bp->min_msix_vec_cnt);
 
+	bp->dump_preset_idx = 1;
+
 	return rc;
 }