From: Dima Chumak dchumak@nvidia.com
[ Upstream commit b1c2f6312c5005c928a72e668bf305a589d828d4 ]
The result of __dev_get_by_index() is not checked for NULL and then gets dereferenced immediately.
Also, __dev_get_by_index() must be called while holding either RTNL lock or @dev_base_lock, which isn't satisfied by mlx5e_hairpin_get_mdev() or its callers. This makes the underlying hlist_for_each_entry() loop not safe, and can have adverse effects in itself.
Fix by using dev_get_by_index() and handling nullptr return value when ifindex device is not found. Update mlx5e_hairpin_get_mdev() callers to check for possible PTR_ERR() result.
Fixes: 77ab67b7f0f9 ("net/mlx5e: Basic setup of hairpin object") Addresses-Coverity: ("Dereference null return value") Signed-off-by: Dima Chumak dchumak@nvidia.com Reviewed-by: Vlad Buslov vladbu@nvidia.com Reviewed-by: Roi Dayan roid@nvidia.com Signed-off-by: Saeed Mahameed saeedm@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- .../net/ethernet/mellanox/mlx5/core/en_tc.c | 33 +++++++++++++++++-- 1 file changed, 31 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c index 9d26463f3fa5..5abc15a92cfa 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c @@ -444,12 +444,32 @@ static void mlx5e_detach_mod_hdr(struct mlx5e_priv *priv, static struct mlx5_core_dev *mlx5e_hairpin_get_mdev(struct net *net, int ifindex) { + struct mlx5_core_dev *mdev; struct net_device *netdev; struct mlx5e_priv *priv;
- netdev = __dev_get_by_index(net, ifindex); + netdev = dev_get_by_index(net, ifindex); + if (!netdev) + return ERR_PTR(-ENODEV); + priv = netdev_priv(netdev); - return priv->mdev; + mdev = priv->mdev; + dev_put(netdev); + + /* Mirred tc action holds a refcount on the ifindex net_device (see + * net/sched/act_mirred.c:tcf_mirred_get_dev). So, it's okay to continue using mdev + * after dev_put(netdev), while we're in the context of adding a tc flow. + * + * The mdev pointer corresponds to the peer/out net_device of a hairpin. It is then + * stored in a hairpin object, which exists until all flows, that refer to it, get + * removed. + * + * On the other hand, after a hairpin object has been created, the peer net_device may + * be removed/unbound while there are still some hairpin flows that are using it. This + * case is handled by mlx5e_tc_hairpin_update_dead_peer, which is hooked to + * NETDEV_UNREGISTER event of the peer net_device. + */ + return mdev; }
static int mlx5e_hairpin_create_transport(struct mlx5e_hairpin *hp) @@ -648,6 +668,10 @@ mlx5e_hairpin_create(struct mlx5e_priv *priv, struct mlx5_hairpin_params *params
func_mdev = priv->mdev; peer_mdev = mlx5e_hairpin_get_mdev(dev_net(priv->netdev), peer_ifindex); + if (IS_ERR(peer_mdev)) { + err = PTR_ERR(peer_mdev); + goto create_pair_err; + }
pair = mlx5_core_hairpin_create(func_mdev, peer_mdev, params); if (IS_ERR(pair)) { @@ -786,6 +810,11 @@ static int mlx5e_hairpin_flow_add(struct mlx5e_priv *priv, int err;
peer_mdev = mlx5e_hairpin_get_mdev(dev_net(priv->netdev), peer_ifindex); + if (IS_ERR(peer_mdev)) { + NL_SET_ERR_MSG_MOD(extack, "invalid ifindex of mirred device"); + return PTR_ERR(peer_mdev); + } + if (!MLX5_CAP_GEN(priv->mdev, hairpin) || !MLX5_CAP_GEN(peer_mdev, hairpin)) { NL_SET_ERR_MSG_MOD(extack, "hairpin is not supported"); return -EOPNOTSUPP;