Messages in this thread Patch in this message | | | Subject | [PATCH] net: cgroup: fix out of bounds accesses | From | Eric Dumazet <> | Date | Mon, 09 Jul 2012 09:45:10 +0200 |
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From: Eric Dumazet <edumazet@google.com>
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> --- net/core/dev.c | 8 ++++++-- net/core/netprio_cgroup.c | 4 ++-- 2 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c index 84f01ba..0f28a9e 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -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) diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c index aa907ed..3e953ea 100644 --- a/net/core/netprio_cgroup.c +++ b/net/core/netprio_cgroup.c @@ -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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