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Commit 91c68ce2 authored Jul 08, 2012 by Eric Dumazet Committed by David S. Miller Jul 09, 2012

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: Eric Dumazet <edumazet@google.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Acked-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: David 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();