From f15ca723c1ebe6c1a06bc95fda6b62cd87b44559 Mon Sep 17 00:00:00 2001 From: Nicolas Dichtel Date: Thu, 25 Jan 2018 19:03:03 +0100 Subject: net: don't call update_pmtu unconditionally Some dst_ops (e.g. md_dst_ops)) doesn't set this handler. It may result to: "BUG: unable to handle kernel NULL pointer dereference at (null)" Let's add a helper to check if update_pmtu is available before calling it. Fixes: 52a589d51f10 ("geneve: update skb dst pmtu on tx path") Fixes: a93bf0ff4490 ("vxlan: update skb dst pmtu on tx path") CC: Roman Kapl CC: Xin Long Signed-off-by: Nicolas Dichtel Signed-off-by: David S. Miller --- drivers/infiniband/ulp/ipoib/ipoib_cm.c | 3 +-- drivers/net/geneve.c | 4 ++-- drivers/net/vxlan.c | 6 ++---- include/net/dst.h | 8 ++++++++ net/ipv4/ip_tunnel.c | 3 +-- net/ipv4/ip_vti.c | 2 +- net/ipv6/ip6_tunnel.c | 6 ++---- net/ipv6/ip6_vti.c | 2 +- net/ipv6/sit.c | 4 ++-- 9 files changed, 20 insertions(+), 18 deletions(-) diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c index 2c13123bfd69..71ea9e26666c 100644 --- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c +++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c @@ -1456,8 +1456,7 @@ void ipoib_cm_skb_too_long(struct net_device *dev, struct sk_buff *skb, struct ipoib_dev_priv *priv = ipoib_priv(dev); int e = skb_queue_empty(&priv->cm.skb_queue); - if (skb_dst(skb)) - skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu); + skb_dst_update_pmtu(skb, mtu); skb_queue_tail(&priv->cm.skb_queue, skb); if (e) diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c index 0a48b3073d3d..64fda2e1040e 100644 --- a/drivers/net/geneve.c +++ b/drivers/net/geneve.c @@ -829,7 +829,7 @@ static int geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev, int mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr) - GENEVE_BASE_HLEN - info->options_len - 14; - skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu); + skb_dst_update_pmtu(skb, mtu); } sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true); @@ -875,7 +875,7 @@ static int geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev, int mtu = dst_mtu(dst) - sizeof(struct ipv6hdr) - GENEVE_BASE_HLEN - info->options_len - 14; - skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu); + skb_dst_update_pmtu(skb, mtu); } sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true); diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index 31f4b7911ef8..c3e34e3c82a7 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -2158,8 +2158,7 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev, if (skb_dst(skb)) { int mtu = dst_mtu(ndst) - VXLAN_HEADROOM; - skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, - skb, mtu); + skb_dst_update_pmtu(skb, mtu); } tos = ip_tunnel_ecn_encap(tos, old_iph, skb); @@ -2200,8 +2199,7 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev, if (skb_dst(skb)) { int mtu = dst_mtu(ndst) - VXLAN6_HEADROOM; - skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, - skb, mtu); + skb_dst_update_pmtu(skb, mtu); } tos = ip_tunnel_ecn_encap(tos, old_iph, skb); diff --git a/include/net/dst.h b/include/net/dst.h index b091fd536098..d49d607dd2b3 100644 --- a/include/net/dst.h +++ b/include/net/dst.h @@ -521,4 +521,12 @@ static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst) } #endif +static inline void skb_dst_update_pmtu(struct sk_buff *skb, u32 mtu) +{ + struct dst_entry *dst = skb_dst(skb); + + if (dst && dst->ops->update_pmtu) + dst->ops->update_pmtu(dst, NULL, skb, mtu); +} + #endif /* _NET_DST_H */ diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c index 5ddb1cb52bd4..6d21068f9b55 100644 --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -520,8 +520,7 @@ static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb, else mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu; - if (skb_dst(skb)) - skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu); + skb_dst_update_pmtu(skb, mtu); if (skb->protocol == htons(ETH_P_IP)) { if (!skb_is_gso(skb) && diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c index 949f432a5f04..51b1669334fe 100644 --- a/net/ipv4/ip_vti.c +++ b/net/ipv4/ip_vti.c @@ -200,7 +200,7 @@ static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev, mtu = dst_mtu(dst); if (skb->len > mtu) { - skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu); + skb_dst_update_pmtu(skb, mtu); if (skb->protocol == htons(ETH_P_IP)) { icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu)); diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index 9a7cf355bc8c..1ee5584c3555 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -642,8 +642,7 @@ ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, if (rel_info > dst_mtu(skb_dst(skb2))) goto out; - skb_dst(skb2)->ops->update_pmtu(skb_dst(skb2), NULL, skb2, - rel_info); + skb_dst_update_pmtu(skb2, rel_info); } icmp_send(skb2, rel_type, rel_code, htonl(rel_info)); @@ -1131,8 +1130,7 @@ route_lookup: mtu = 576; } - if (skb_dst(skb) && !t->parms.collect_md) - skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu); + skb_dst_update_pmtu(skb, mtu); if (skb->len - t->tun_hlen - eth_hlen > mtu && !skb_is_gso(skb)) { *pmtu = mtu; err = -EMSGSIZE; diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c index dbb74f3c57a7..8c184f84f353 100644 --- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -483,7 +483,7 @@ vti6_xmit(struct sk_buff *skb, struct net_device *dev, struct flowi *fl) mtu = dst_mtu(dst); if (!skb->ignore_df && skb->len > mtu) { - skb_dst(skb)->ops->update_pmtu(dst, NULL, skb, mtu); + skb_dst_update_pmtu(skb, mtu); if (skb->protocol == htons(ETH_P_IPV6)) { if (mtu < IPV6_MIN_MTU) diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c index d7dc23c1b2ca..3873d3877135 100644 --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -934,8 +934,8 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb, df = 0; } - if (tunnel->parms.iph.daddr && skb_dst(skb)) - skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu); + if (tunnel->parms.iph.daddr) + skb_dst_update_pmtu(skb, mtu); if (skb->len > mtu && !skb_is_gso(skb)) { icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); -- cgit v1.2.3-59-g8ed1b