From: Vlad Buslov <vladbu@nvidia.com>
Date: Mon, 31 Aug 2020 16:17:29 +0300
Subject: net/mlx5e: Protect encap route dev from concurrent release
Patch-mainline: v5.10-rc4
Git-commit: 78c906e430b13d30a8cfbdef4ccbbe1686841a9e
References: jsc#SLE-8464
In functions mlx5e_route_lookup_ipv{4|6}() route_dev can be arbitrary net
device and not necessary mlx5 eswitch port representor. As such, in order
to ensure that route_dev is not destroyed concurrent the code needs either
explicitly take reference to the device before releasing reference to
rtable instance or ensure that caller holds rtnl lock. First approach is
chosen as a fix since rtnl lock dependency was intentionally removed from
mlx5 TC layer.
To prevent unprotected usage of route_dev in encap code take a reference to
the device before releasing rt. Don't save direct pointer to the device in
mlx5_encap_entry structure and use ifindex instead. Modify users of
route_dev pointer to properly obtain the net device instance from its
ifindex.
Fixes: 61086f391044 ("net/mlx5e: Protect encap hash table with mutex")
Fixes: 6707f74be862 ("net/mlx5e: Update hw flows when encap source mac changed")
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/net/ethernet/mellanox/mlx5/core/en/rep/tc.c | 6 +
drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c | 72 ++++++++++++--------
drivers/net/ethernet/mellanox/mlx5/core/en_rep.h | 2
3 files changed, 52 insertions(+), 28 deletions(-)
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/rep/tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/rep/tc.c
@@ -107,12 +107,16 @@ void mlx5e_rep_update_flows(struct mlx5e
mlx5e_tc_encap_flows_del(priv, e, &flow_list);
if (neigh_connected && !(e->flags & MLX5_ENCAP_ENTRY_VALID)) {
+ struct net_device *route_dev;
+
ether_addr_copy(e->h_dest, ha);
ether_addr_copy(eth->h_dest, ha);
/* Update the encap source mac, in case that we delete
* the flows when encap source mac changed.
*/
- ether_addr_copy(eth->h_source, e->route_dev->dev_addr);
+ route_dev = __dev_get_by_index(dev_net(priv->netdev), e->route_dev_ifindex);
+ if (route_dev)
+ ether_addr_copy(eth->h_source, route_dev->dev_addr);
mlx5e_tc_encap_flows_add(priv, e, &flow_list);
}
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
@@ -77,13 +77,13 @@ static int get_route_and_out_devs(struct
return 0;
}
-static int mlx5e_route_lookup_ipv4(struct mlx5e_priv *priv,
- struct net_device *mirred_dev,
- struct net_device **out_dev,
- struct net_device **route_dev,
- struct flowi4 *fl4,
- struct neighbour **out_n,
- u8 *out_ttl)
+static int mlx5e_route_lookup_ipv4_get(struct mlx5e_priv *priv,
+ struct net_device *mirred_dev,
+ struct net_device **out_dev,
+ struct net_device **route_dev,
+ struct flowi4 *fl4,
+ struct neighbour **out_n,
+ u8 *out_ttl)
{
struct neighbour *n;
struct rtable *rt;
@@ -117,18 +117,28 @@ static int mlx5e_route_lookup_ipv4(struc
ip_rt_put(rt);
return ret;
}
+ dev_hold(*route_dev);
if (!(*out_ttl))
*out_ttl = ip4_dst_hoplimit(&rt->dst);
n = dst_neigh_lookup(&rt->dst, &fl4->daddr);
ip_rt_put(rt);
- if (!n)
+ if (!n) {
+ dev_put(*route_dev);
return -ENOMEM;
+ }
*out_n = n;
return 0;
}
+static void mlx5e_route_lookup_ipv4_put(struct net_device *route_dev,
+ struct neighbour *n)
+{
+ neigh_release(n);
+ dev_put(route_dev);
+}
+
static const char *mlx5e_netdev_kind(struct net_device *dev)
{
if (dev->rtnl_link_ops)
@@ -193,8 +203,8 @@ int mlx5e_tc_tun_create_header_ipv4(stru
fl4.saddr = tun_key->u.ipv4.src;
ttl = tun_key->ttl;
- err = mlx5e_route_lookup_ipv4(priv, mirred_dev, &out_dev, &route_dev,
- &fl4, &n, &ttl);
+ err = mlx5e_route_lookup_ipv4_get(priv, mirred_dev, &out_dev, &route_dev,
+ &fl4, &n, &ttl);
if (err)
return err;
@@ -223,7 +233,7 @@ int mlx5e_tc_tun_create_header_ipv4(stru
e->m_neigh.family = n->ops->family;
memcpy(&e->m_neigh.dst_ip, n->primary_key, n->tbl->key_len);
e->out_dev = out_dev;
- e->route_dev = route_dev;
+ e->route_dev_ifindex = route_dev->ifindex;
/* It's important to add the neigh to the hash table before checking
* the neigh validity state. So if we'll get a notification, in case the
@@ -278,7 +288,7 @@ int mlx5e_tc_tun_create_header_ipv4(stru
e->flags |= MLX5_ENCAP_ENTRY_VALID;
mlx5e_rep_queue_neigh_stats_work(netdev_priv(out_dev));
- neigh_release(n);
+ mlx5e_route_lookup_ipv4_put(route_dev, n);
return err;
destroy_neigh_entry:
@@ -286,18 +296,18 @@ destroy_neigh_entry:
free_encap:
kfree(encap_header);
release_neigh:
- neigh_release(n);
+ mlx5e_route_lookup_ipv4_put(route_dev, n);
return err;
}
#if IS_ENABLED(CONFIG_INET) && IS_ENABLED(CONFIG_IPV6)
-static int mlx5e_route_lookup_ipv6(struct mlx5e_priv *priv,
- struct net_device *mirred_dev,
- struct net_device **out_dev,
- struct net_device **route_dev,
- struct flowi6 *fl6,
- struct neighbour **out_n,
- u8 *out_ttl)
+static int mlx5e_route_lookup_ipv6_get(struct mlx5e_priv *priv,
+ struct net_device *mirred_dev,
+ struct net_device **out_dev,
+ struct net_device **route_dev,
+ struct flowi6 *fl6,
+ struct neighbour **out_n,
+ u8 *out_ttl)
{
struct dst_entry *dst;
struct neighbour *n;
@@ -318,15 +328,25 @@ static int mlx5e_route_lookup_ipv6(struc
return ret;
}
+ dev_hold(*route_dev);
n = dst_neigh_lookup(dst, &fl6->daddr);
dst_release(dst);
- if (!n)
+ if (!n) {
+ dev_put(*route_dev);
return -ENOMEM;
+ }
*out_n = n;
return 0;
}
+static void mlx5e_route_lookup_ipv6_put(struct net_device *route_dev,
+ struct neighbour *n)
+{
+ neigh_release(n);
+ dev_put(route_dev);
+}
+
int mlx5e_tc_tun_create_header_ipv6(struct mlx5e_priv *priv,
struct net_device *mirred_dev,
struct mlx5e_encap_entry *e)
@@ -348,8 +368,8 @@ int mlx5e_tc_tun_create_header_ipv6(stru
fl6.daddr = tun_key->u.ipv6.dst;
fl6.saddr = tun_key->u.ipv6.src;
- err = mlx5e_route_lookup_ipv6(priv, mirred_dev, &out_dev, &route_dev,
- &fl6, &n, &ttl);
+ err = mlx5e_route_lookup_ipv6_get(priv, mirred_dev, &out_dev, &route_dev,
+ &fl6, &n, &ttl);
if (err)
return err;
@@ -378,7 +398,7 @@ int mlx5e_tc_tun_create_header_ipv6(stru
e->m_neigh.family = n->ops->family;
memcpy(&e->m_neigh.dst_ip, n->primary_key, n->tbl->key_len);
e->out_dev = out_dev;
- e->route_dev = route_dev;
+ e->route_dev_ifindex = route_dev->ifindex;
/* It's importent to add the neigh to the hash table before checking
* the neigh validity state. So if we'll get a notification, in case the
@@ -433,7 +453,7 @@ int mlx5e_tc_tun_create_header_ipv6(stru
e->flags |= MLX5_ENCAP_ENTRY_VALID;
mlx5e_rep_queue_neigh_stats_work(netdev_priv(out_dev));
- neigh_release(n);
+ mlx5e_route_lookup_ipv6_put(route_dev, n);
return err;
destroy_neigh_entry:
@@ -441,7 +461,7 @@ destroy_neigh_entry:
free_encap:
kfree(encap_header);
release_neigh:
- neigh_release(n);
+ mlx5e_route_lookup_ipv6_put(route_dev, n);
return err;
}
#endif
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.h
@@ -187,7 +187,7 @@ struct mlx5e_encap_entry {
unsigned char h_dest[ETH_ALEN]; /* destination eth addr */
struct net_device *out_dev;
- struct net_device *route_dev;
+ int route_dev_ifindex;
struct mlx5e_tc_tunnel *tunnel;
int reformat_type;
u8 flags;