Commit 582737f9 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'net-ipv4-fix-circular-list-infinite-loop' 



Florian Westphal says:

====================
net: ipv4: fix circular-list infinite loop

Tariq and Ran reported a regression caused by net-next commit
2638eb8b ("net: ipv4: provide __rcu annotation for ifa_list").

This happens when net.ipv4.conf.$dev.promote_secondaries sysctl is
enabled -- we can arrange for ifa->next to point at ifa, so next
process that tries to walk the list loops forever.

Fix this and extend rtnetlink.sh with a small test case for this.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 5b9469a2 bb2bd090

net/ipv4/devinet.c

+2 −1
Original line number Diff line number Diff line
@@ -428,8 +428,9 @@ no_promotions: 
		if (prev_prom) {

			struct in_ifaddr *last_sec;



			last_sec = rtnl_dereference(last_prim->ifa_next);

			rcu_assign_pointer(prev_prom->ifa_next, next_sec);



			last_sec = rtnl_dereference(last_prim->ifa_next);

			rcu_assign_pointer(promote->ifa_next, last_sec);

			rcu_assign_pointer(last_prim->ifa_next, promote);

		}

tools/testing/selftests/net/rtnetlink.sh

+20 −0
Original line number Diff line number Diff line
@@ -269,6 +269,25 @@ kci_test_addrlft() 
	echo "PASS: preferred_lft addresses have expired"

}



kci_test_promote_secondaries()

{

	promote=$(sysctl -n net.ipv4.conf.$devdummy.promote_secondaries)



	sysctl -q net.ipv4.conf.$devdummy.promote_secondaries=1



	for i in $(seq 2 254);do

		IP="10.23.11.$i"

		ip -f inet addr add $IP/16 brd + dev "$devdummy"

		ifconfig "$devdummy" $IP netmask 255.255.0.0

	done



	ip addr flush dev "$devdummy"



	[ $promote -eq 0 ] && sysctl -q net.ipv4.conf.$devdummy.promote_secondaries=0



	echo "PASS: promote_secondaries complete"

}



kci_test_addrlabel()

{

	ret=0
@@ -1161,6 +1180,7 @@ kci_test_rtnl() 
	kci_test_polrouting

	kci_test_route_get

	kci_test_addrlft

	kci_test_promote_secondaries

	kci_test_tc

	kci_test_gre

	kci_test_gretap

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