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Revision 78c906e430b13d30a8cfbdef4ccbbe1686841a9e authored by Vlad Buslov on 31 August 2020, 13:17:29 UTC, committed by Saeed Mahameed on 05 November 2020, 20:17:05 UTC 
net/mlx5e: Protect encap route dev from concurrent release
 
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>
1 parent e68e28b
Raw File
metrics.c 
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/types.h>
#include <net/ip.h>
#include <net/net_namespace.h>
#include <net/tcp.h>

static int ip_metrics_convert(struct net *net, struct nlattr *fc_mx,
			      int fc_mx_len, u32 *metrics,
			      struct netlink_ext_ack *extack)
{
	bool ecn_ca = false;
	struct nlattr *nla;
	int remaining;

	if (!fc_mx)
		return 0;

	nla_for_each_attr(nla, fc_mx, fc_mx_len, remaining) {
		int type = nla_type(nla);
		u32 val;

		if (!type)
			continue;
		if (type > RTAX_MAX) {
			NL_SET_ERR_MSG(extack, "Invalid metric type");
			return -EINVAL;
		}

		if (type == RTAX_CC_ALGO) {
			char tmp[TCP_CA_NAME_MAX];

			nla_strlcpy(tmp, nla, sizeof(tmp));
			val = tcp_ca_get_key_by_name(net, tmp, &ecn_ca);
			if (val == TCP_CA_UNSPEC) {
				NL_SET_ERR_MSG(extack, "Unknown tcp congestion algorithm");
				return -EINVAL;
			}
		} else {
			if (nla_len(nla) != sizeof(u32)) {
				NL_SET_ERR_MSG_ATTR(extack, nla,
						    "Invalid attribute in metrics");
				return -EINVAL;
			}
			val = nla_get_u32(nla);
		}
		if (type == RTAX_ADVMSS && val > 65535 - 40)
			val = 65535 - 40;
		if (type == RTAX_MTU && val > 65535 - 15)
			val = 65535 - 15;
		if (type == RTAX_HOPLIMIT && val > 255)
			val = 255;
		if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK)) {
			NL_SET_ERR_MSG(extack, "Unknown flag set in feature mask in metrics attribute");
			return -EINVAL;
		}
		metrics[type - 1] = val;
	}

	if (ecn_ca)
		metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;

	return 0;
}

struct dst_metrics *ip_fib_metrics_init(struct net *net, struct nlattr *fc_mx,
					int fc_mx_len,
					struct netlink_ext_ack *extack)
{
	struct dst_metrics *fib_metrics;
	int err;

	if (!fc_mx)
		return (struct dst_metrics *)&dst_default_metrics;

	fib_metrics = kzalloc(sizeof(*fib_metrics), GFP_KERNEL);
	if (unlikely(!fib_metrics))
		return ERR_PTR(-ENOMEM);

	err = ip_metrics_convert(net, fc_mx, fc_mx_len, fib_metrics->metrics,
				 extack);
	if (!err) {
		refcount_set(&fib_metrics->refcnt, 1);
	} else {
		kfree(fib_metrics);
		fib_metrics = ERR_PTR(err);
	}

	return fib_metrics;
}
EXPORT_SYMBOL_GPL(ip_fib_metrics_init);
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