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authorEric Dumazet <edumazet@google.com>2019-03-10 10:36:40 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-03-19 13:14:09 +0100
commit9b0e9c285be4e51ccca5d09f9f7894e5637a735d (patch)
tree73c09b7db838a332191aa05821f3afcb0d128d30 /drivers/net
parent40852d58feb5cf1fb0aafd257cba175e528f75ee (diff)
vxlan: test dev->flags & IFF_UP before calling gro_cells_receive()
[ Upstream commit 59cbf56fcd98ba2a715b6e97c4e43f773f956393 ] 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/net')
-rw-r--r--drivers/net/vxlan.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 373713faa1f5..56332ca8b70c 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1380,6 +1380,14 @@ 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++;
@@ -1387,6 +1395,9 @@ 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: