From: Dima Chumak dchumak@nvidia.com

commit fe7738eb3ca3631a75844e790f6cb576c0fe7b00 upstream.

The result of __dev_get_by_index() is not checked for NULL, which then passed to mlx5e_attach_encap() and gets dereferenced.

Also, in case of a successful lookup, the net_device reference count is not incremented, which may result in net_device pointer becoming invalid at any time during mlx5e_attach_encap() execution.

Fix by using dev_get_by_index(), which does proper reference counting on the net_device pointer. Also, handle nullptr return value when mirred device is not found.

It's safe to call dev_put() on the mirred net_device pointer, right after mlx5e_attach_encap() call, because it's not being saved/copied down the call chain.

Fixes: 3c37745ec614 ("net/mlx5e: Properly deal with encap flows add/del under neigh update") Addresses-Coverity: ("Dereference null return value") Signed-off-by: Dima Chumak dchumak@nvidia.com Reviewed-by: Vlad Buslov vladbu@nvidia.com Signed-off-by: Saeed Mahameed saeedm@nvidia.com Signed-off-by: Nikita Zhandarovich n.zhandarovich@fintech.ru --- drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c index ce710f22b1ff..fbfce2b3baeb 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c @@ -1307,9 +1307,9 @@ mlx5e_tc_add_fdb_flow(struct mlx5e_priv *priv, struct netlink_ext_ack *extack) { struct mlx5_eswitch *esw = priv->mdev->priv.eswitch; - struct net_device *out_dev, *encap_dev = NULL; struct mlx5e_tc_flow_parse_attr *parse_attr; struct mlx5_flow_attr *attr = flow->attr; + struct net_device *encap_dev = NULL; struct mlx5_esw_flow_attr *esw_attr; struct mlx5_fc *counter = NULL; struct mlx5e_rep_priv *rpriv; @@ -1354,16 +1354,22 @@ mlx5e_tc_add_fdb_flow(struct mlx5e_priv *priv, esw_attr = attr->esw_attr;

for (out_index = 0; out_index < MLX5_MAX_FLOW_FWD_VPORTS; out_index++) { + struct net_device *out_dev; int mirred_ifindex;

if (!(esw_attr->dests[out_index].flags & MLX5_ESW_DEST_ENCAP)) continue;

mirred_ifindex = parse_attr->mirred_ifindex[out_index]; - out_dev = __dev_get_by_index(dev_net(priv->netdev), - mirred_ifindex); + out_dev = dev_get_by_index(dev_net(priv->netdev), mirred_ifindex); + if (!out_dev) { + NL_SET_ERR_MSG_MOD(extack, "Requested mirred device not found"); + err = -ENODEV; + return err; + } err = mlx5e_attach_encap(priv, flow, out_dev, out_index, extack, &encap_dev, &encap_valid); + dev_put(out_dev); if (err) return err;