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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>
This commit is contained in:
Eric Dumazet 2012-07-08 21:45:10 +00:00 committed by David S. Miller
parent 96ca7ffe74
commit 91c68ce2b2
2 changed files with 8 additions and 4 deletions
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8
net/core/dev.c
View File

@ -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)

4
net/core/netprio_cgroup.c
View File

@ -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();