Commit 91c68ce2 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: cgroup: fix out of bounds accesses 



dev->priomap is allocated by extend_netdev_table() called from
update_netdev_tables().
And this is only called if write_priomap() is called.

But if write_priomap() is not called, it seems we can have out of bounds
accesses in cgrp_destroy(), read_priomap() & skb_update_prio()

With help from Gao Feng

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Acked-by: default avatarGao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 96ca7ffe

net/core/dev.c

+6 −2
Original line number Diff line number Diff line
@@ -2444,8 +2444,12 @@ static void skb_update_prio(struct sk_buff *skb) 
{

	struct netprio_map *map = rcu_dereference_bh(skb->dev->priomap);



	if ((!skb->priority) && (skb->sk) && map)

		skb->priority = map->priomap[skb->sk->sk_cgrp_prioidx];

	if (!skb->priority && skb->sk && map) {

		unsigned int prioidx = skb->sk->sk_cgrp_prioidx;



		if (prioidx < map->priomap_len)

			skb->priority = map->priomap[prioidx];

	}

}

#else

#define skb_update_prio(skb)

net/core/netprio_cgroup.c

+2 −2
Original line number Diff line number Diff line
@@ -142,7 +142,7 @@ static void cgrp_destroy(struct cgroup *cgrp) 
	rtnl_lock();

	for_each_netdev(&init_net, dev) {

		map = rtnl_dereference(dev->priomap);

		if (map)

		if (map && cs->prioidx < map->priomap_len)

			map->priomap[cs->prioidx] = 0;

	}

	rtnl_unlock();
@@ -166,7 +166,7 @@ static int read_priomap(struct cgroup *cont, struct cftype *cft, 
	rcu_read_lock();

	for_each_netdev_rcu(&init_net, dev) {

		map = rcu_dereference(dev->priomap);

		priority = map ? map->priomap[prioidx] : 0;

		priority = (map && prioidx < map->priomap_len) ? map->priomap[prioidx] : 0;

		cb->fill(cb, dev->name, priority);

	}

	rcu_read_unlock();

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