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pshelardavem330
pshelar
authored and
davem330
committed
geneve: avoid using stale geneve socket.
This patch is similar to earlier vxlan patch. Geneve device close operation frees geneve socket. This operation can race with geneve-xmit function which dereferences geneve socket. Following patch uses RCU mechanism to avoid this situation. Signed-off-by: Pravin B Shelar <pshelar@ovn.org> Acked-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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‎drivers/net/geneve.c

Lines changed: 34 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -58,9 +58,9 @@ struct geneve_dev {
5858
struct hlist_node hlist; /* vni hash table */
5959
struct net *net; /* netns for packet i/o */
6060
struct net_device *dev; /* netdev for geneve tunnel */
61-
struct geneve_sock *sock4; /* IPv4 socket used for geneve tunnel */
61+
struct geneve_sock __rcu *sock4; /* IPv4 socket used for geneve tunnel */
6262
#if IS_ENABLED(CONFIG_IPV6)
63-
struct geneve_sock *sock6; /* IPv6 socket used for geneve tunnel */
63+
struct geneve_sock __rcu *sock6; /* IPv6 socket used for geneve tunnel */
6464
#endif
6565
u8 vni[3]; /* virtual network ID for tunnel */
6666
u8 ttl; /* TTL override */
@@ -543,9 +543,19 @@ static void __geneve_sock_release(struct geneve_sock *gs)
543543

544544
static void geneve_sock_release(struct geneve_dev *geneve)
545545
{
546-
__geneve_sock_release(geneve->sock4);
546+
struct geneve_sock *gs4 = rtnl_dereference(geneve->sock4);
547547
#if IS_ENABLED(CONFIG_IPV6)
548-
__geneve_sock_release(geneve->sock6);
548+
struct geneve_sock *gs6 = rtnl_dereference(geneve->sock6);
549+
550+
rcu_assign_pointer(geneve->sock6, NULL);
551+
#endif
552+
553+
rcu_assign_pointer(geneve->sock4, NULL);
554+
synchronize_net();
555+
556+
__geneve_sock_release(gs4);
557+
#if IS_ENABLED(CONFIG_IPV6)
558+
__geneve_sock_release(gs6);
549559
#endif
550560
}
551561

@@ -586,10 +596,10 @@ static int geneve_sock_add(struct geneve_dev *geneve, bool ipv6)
586596
gs->flags = geneve->flags;
587597
#if IS_ENABLED(CONFIG_IPV6)
588598
if (ipv6)
589-
geneve->sock6 = gs;
599+
rcu_assign_pointer(geneve->sock6, gs);
590600
else
591601
#endif
592-
geneve->sock4 = gs;
602+
rcu_assign_pointer(geneve->sock4, gs);
593603

594604
hash = geneve_net_vni_hash(geneve->vni);
595605
hlist_add_head_rcu(&geneve->hlist, &gs->vni_list[hash]);
@@ -603,9 +613,7 @@ static int geneve_open(struct net_device *dev)
603613
bool metadata = geneve->collect_md;
604614
int ret = 0;
605615

606-
geneve->sock4 = NULL;
607616
#if IS_ENABLED(CONFIG_IPV6)
608-
geneve->sock6 = NULL;
609617
if (ipv6 || metadata)
610618
ret = geneve_sock_add(geneve, true);
611619
#endif
@@ -720,6 +728,9 @@ static struct rtable *geneve_get_v4_rt(struct sk_buff *skb,
720728
struct rtable *rt = NULL;
721729
__u8 tos;
722730

731+
if (!rcu_dereference(geneve->sock4))
732+
return ERR_PTR(-EIO);
733+
723734
memset(fl4, 0, sizeof(*fl4));
724735
fl4->flowi4_mark = skb->mark;
725736
fl4->flowi4_proto = IPPROTO_UDP;
@@ -772,11 +783,15 @@ static struct dst_entry *geneve_get_v6_dst(struct sk_buff *skb,
772783
{
773784
bool use_cache = ip_tunnel_dst_cache_usable(skb, info);
774785
struct geneve_dev *geneve = netdev_priv(dev);
775-
struct geneve_sock *gs6 = geneve->sock6;
776786
struct dst_entry *dst = NULL;
777787
struct dst_cache *dst_cache;
788+
struct geneve_sock *gs6;
778789
__u8 prio;
779790

791+
gs6 = rcu_dereference(geneve->sock6);
792+
if (!gs6)
793+
return ERR_PTR(-EIO);
794+
780795
memset(fl6, 0, sizeof(*fl6));
781796
fl6->flowi6_mark = skb->mark;
782797
fl6->flowi6_proto = IPPROTO_UDP;
@@ -842,7 +857,7 @@ static netdev_tx_t geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev,
842857
struct ip_tunnel_info *info)
843858
{
844859
struct geneve_dev *geneve = netdev_priv(dev);
845-
struct geneve_sock *gs4 = geneve->sock4;
860+
struct geneve_sock *gs4;
846861
struct rtable *rt = NULL;
847862
const struct iphdr *iip; /* interior IP header */
848863
int err = -EINVAL;
@@ -853,6 +868,10 @@ static netdev_tx_t geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev,
853868
bool xnet = !net_eq(geneve->net, dev_net(geneve->dev));
854869
u32 flags = geneve->flags;
855870

871+
gs4 = rcu_dereference(geneve->sock4);
872+
if (!gs4)
873+
goto tx_error;
874+
856875
if (geneve->collect_md) {
857876
if (unlikely(!info || !(info->mode & IP_TUNNEL_INFO_TX))) {
858877
netdev_dbg(dev, "no tunnel metadata\n");
@@ -932,9 +951,9 @@ static netdev_tx_t geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
932951
struct ip_tunnel_info *info)
933952
{
934953
struct geneve_dev *geneve = netdev_priv(dev);
935-
struct geneve_sock *gs6 = geneve->sock6;
936954
struct dst_entry *dst = NULL;
937955
const struct iphdr *iip; /* interior IP header */
956+
struct geneve_sock *gs6;
938957
int err = -EINVAL;
939958
struct flowi6 fl6;
940959
__u8 prio, ttl;
@@ -943,6 +962,10 @@ static netdev_tx_t geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
943962
bool xnet = !net_eq(geneve->net, dev_net(geneve->dev));
944963
u32 flags = geneve->flags;
945964

965+
gs6 = rcu_dereference(geneve->sock6);
966+
if (!gs6)
967+
goto tx_error;
968+
946969
if (geneve->collect_md) {
947970
if (unlikely(!info || !(info->mode & IP_TUNNEL_INFO_TX))) {
948971
netdev_dbg(dev, "no tunnel metadata\n");

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