path: root/drivers/net
diff options
authorEric Dumazet <edumazet@google.com>2019-03-10 10:36:40 -0700
committerDavid S. Miller <davem@davemloft.net>2019-03-10 11:05:52 -0700
commit59cbf56fcd98ba2a715b6e97c4e43f773f956393 (patch)
treeb1f6b37fd3c5ca066ff1a9f4732a528d2bc02598 /drivers/net
parentnet/x25: fix use-after-free in x25_device_event() (diff)
vxlan: test dev->flags & IFF_UP before calling gro_cells_receive()
Same reasons than the ones explained in commit 4179cb5a4c92 ("vxlan: test dev->flags & IFF_UP before calling netif_rx()") netif_rx() or gro_cells_receive() must be called under a strict contract. At device dismantle phase, core networking clears IFF_UP and flush_all_backlogs() is called after rcu grace period to make sure no incoming packet might be in a cpu backlog and still referencing the device. A similar protocol is used for gro_cells infrastructure, as gro_cells_destroy() will be called only after a full rcu grace period is observed after IFF_UP has been cleared. Most drivers call netif_rx() from their interrupt handler, and since the interrupts are disabled at device dismantle, netif_rx() does not have to check dev->flags & IFF_UP Virtual drivers do not have this guarantee, and must therefore make the check themselves. Otherwise we risk use-after-free and/or crashes. Fixes: d342894c5d2f ("vxlan: virtual extensible lan") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net')
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 7610c51b33a0..077f1b9f2761 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1731,6 +1731,14 @@ static int vxlan_rcv(struct sock *sk, struct sk_buff *skb)
goto drop;
+ rcu_read_lock();
+ if (unlikely(!(vxlan->dev->flags & IFF_UP))) {
+ rcu_read_unlock();
+ atomic_long_inc(&vxlan->dev->rx_dropped);
+ goto drop;
+ }
stats = this_cpu_ptr(vxlan->dev->tstats);
@@ -1738,6 +1746,9 @@ static int vxlan_rcv(struct sock *sk, struct sk_buff *skb)
gro_cells_receive(&vxlan->gro_cells, skb);
+ rcu_read_unlock();
return 0;