ipv4: remove BUG_ON() from fib_compute_spec_dst (9fc12023) · Commits · 戴 / test

Remove BUG_ON() from fib_compute_spec_dst routine and check in_dev pointer during flowi4 data structure initialization. fib_compute_spec_dst routine can be run concurrently with device removal where ip_ptr net_device pointer is set to NULL. This can happen if userspace enables pkt info on UDP rx socket and the device is removed while traffic is flowing Fixes: ("ipv4: Create and use fib_compute_spec_dst() helper") Signed-off-by:

Lorenzo Bianconi <lorenzo.bianconi@redhat.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/ipv4/fib_frontend.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -292,19 +292,19 @@ __be32 fib_compute_spec_dst(struct sk_buff *skb)
		return ip_hdr(skb)->daddr;

		in_dev = __in_dev_get_rcu(dev);
		BUG_ON(!in_dev);

		net = dev_net(dev);

		scope = RT_SCOPE_UNIVERSE;
		if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) {
		bool vmark = in_dev && IN_DEV_SRC_VMARK(in_dev);
		struct flowi4 fl4 = {
		.flowi4_iif = LOOPBACK_IFINDEX,
		.flowi4_oif = l3mdev_master_ifindex_rcu(dev),
		.daddr = ip_hdr(skb)->saddr,
		.flowi4_tos = RT_TOS(ip_hdr(skb)->tos),
		.flowi4_scope = scope,
		.flowi4_mark = IN_DEV_SRC_VMARK(in_dev) ? skb->mark : 0,
		.flowi4_mark = vmark ? skb->mark : 0,
		};
		if (!fib_lookup(net, &fl4, &res, 0))
		return FIB_RES_PREFSRC(net, res);

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