path: root/drivers/net/vxlan.c
diff options
authorEric Dumazet <edumazet@google.com>2019-02-07 12:27:38 -0800
committerDavid S. Miller <davem@davemloft.net>2019-02-11 12:39:51 -0800
commit4179cb5a4c924cd233eaadd081882425bc98f44e (patch)
tree83dc255e437ace38c17db611fd8052cb8db1dfd8 /drivers/net/vxlan.c
parentDocumentation: bring operstate documentation up-to-date (diff)
vxlan: test dev->flags & IFF_UP before calling netif_rx()
netif_rx() 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. 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. Note this patch also fixes a small issue that came with commit ce6502a8f957 ("vxlan: fix a use after free in vxlan_encap_bypass"), since the dev->stats.rx_dropped change was done on the wrong device. Fixes: d342894c5d2f ("vxlan: virtual extensible lan") Fixes: ce6502a8f957 ("vxlan: fix a use after free in vxlan_encap_bypass") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Petr Machata <petrm@mellanox.com> Cc: Ido Schimmel <idosch@mellanox.com> Cc: Roopa Prabhu <roopa@cumulusnetworks.com> Cc: Stefano Brivio <sbrivio@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/vxlan.c')
1 files changed, 11 insertions, 3 deletions
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 5209ee9aac47..2aae11feff0c 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -2219,7 +2219,7 @@ static void vxlan_encap_bypass(struct sk_buff *skb, struct vxlan_dev *src_vxlan,
struct pcpu_sw_netstats *tx_stats, *rx_stats;
union vxlan_addr loopback;
union vxlan_addr *remote_ip = &dst_vxlan->default_dst.remote_ip;
- struct net_device *dev = skb->dev;
+ struct net_device *dev;
int len = skb->len;
tx_stats = this_cpu_ptr(src_vxlan->dev->tstats);
@@ -2239,9 +2239,15 @@ static void vxlan_encap_bypass(struct sk_buff *skb, struct vxlan_dev *src_vxlan,
+ rcu_read_lock();
+ dev = skb->dev;
+ if (unlikely(!(dev->flags & IFF_UP))) {
+ kfree_skb(skb);
+ goto drop;
+ }
if (dst_vxlan->cfg.flags & VXLAN_F_LEARN)
- vxlan_snoop(skb->dev, &loopback, eth_hdr(skb)->h_source, 0,
- vni);
+ vxlan_snoop(dev, &loopback, eth_hdr(skb)->h_source, 0, vni);
@@ -2254,8 +2260,10 @@ static void vxlan_encap_bypass(struct sk_buff *skb, struct vxlan_dev *src_vxlan,
rx_stats->rx_bytes += len;
} else {
+ rcu_read_unlock();
static int encap_bypass_if_local(struct sk_buff *skb, struct net_device *dev,