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| author |   Eric Dumazet <edumazet@google.com> | 2019-03-10 10:36:40 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2019-03-10 11:05:52 -0700 |
| commit | 59cbf56fcd98ba2a715b6e97c4e43f773f956393 (patch) | |
| tree | b1f6b37fd3c5ca066ff1a9f4732a528d2bc02598 /drivers/net | |
| parent | net/x25: fix use-after-free in x25_device_event() (diff) | |
| download | linux-dev-59cbf56fcd98ba2a715b6e97c4e43f773f956393.tar.xz linux-dev-59cbf56fcd98ba2a715b6e97c4e43f773f956393.zip | |
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')
| -rw-r--r-- | drivers/net/vxlan.c | 11 |
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); u64_stats_update_begin(&stats->syncp); stats->rx_packets++; @@ -1738,6 +1746,9 @@ static int vxlan_rcv(struct sock *sk, struct sk_buff *skb) u64_stats_update_end(&stats->syncp); gro_cells_receive(&vxlan->gro_cells, skb); + + rcu_read_unlock(); + return 0; drop: |