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From: Stephen Suryaputra <ssuryaextr@gmail.com>
Date: Mon, 16 Apr 2018 13:42:16 -0400
Subject: ipv6: Count interface receive statistics on the ingress netdev
Patch-mainline: v4.18-rc1
Git-commit: bdb7cc643fc9db8d6ed9a2b9e524e27ac5882029
References: CVE-2018-5391 bsc#1103097

The statistics such as InHdrErrors should be counted on the ingress
netdev rather than on the dev from the dst, which is the egress.

Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Michal Kubecek <mkubecek@suse.cz>

---
 include/net/addrconf.h          | 14 +++++++++
 net/ipv6/exthdrs.c              | 56 +++++++++++++--------------------
 net/ipv6/ip6_input.c            |  2 +-
 net/ipv6/ip6_output.c           | 18 +++++------
 net/ipv6/reassembly.c           |  6 ++--
 net/ipv6/route.c                |  3 +-
 net/netfilter/ipvs/ip_vs_xmit.c |  5 +--
 7 files changed, 52 insertions(+), 52 deletions(-)

--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -309,6 +309,20 @@ static inline struct inet6_dev *__in6_dev_get(const struct net_device *dev)
 	return rcu_dereference_rtnl(dev->ip6_ptr);
 }
 
+/**
+ * __in6_dev_get_safely - get inet6_dev pointer from netdevice
+ * @dev: network device
+ *
+ * This is a safer version of __in6_dev_get
+ */
+static inline struct inet6_dev *__in6_dev_get_safely(const struct net_device *dev)
+{
+	if (likely(dev))
+		return rcu_dereference_rtnl(dev->ip6_ptr);
+	else
+		return NULL;
+}
+
 /**
  * in6_dev_get - get inet6_dev pointer from netdevice
  * @dev: network device
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -255,16 +255,18 @@ static const struct tlvtype_proc tlvprocdestopt_lst[] = {
 
 static int ipv6_destopt_rcv(struct sk_buff *skb)
 {
+	struct inet6_dev *idev = __in6_dev_get(skb->dev);
 	struct inet6_skb_parm *opt = IP6CB(skb);
 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 	__u16 dstbuf;
 #endif
 	struct dst_entry *dst = skb_dst(skb);
+	struct net *net = dev_net(skb->dev);
 
 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 	    !pskb_may_pull(skb, (skb_transport_offset(skb) +
 				 ((skb_transport_header(skb)[1] + 1) << 3)))) {
-		__IP6_INC_STATS(dev_net(dst->dev), ip6_dst_idev(dst),
+		__IP6_INC_STATS(dev_net(dst->dev), idev,
 				IPSTATS_MIB_INHDRERRORS);
 		kfree_skb(skb);
 		return -1;
@@ -286,8 +288,7 @@ static int ipv6_destopt_rcv(struct sk_buff *skb)
 		return 1;
 	}
 
-	__IP6_INC_STATS(dev_net(dst->dev),
-			ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
+	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 	return -1;
 }
 
@@ -383,8 +384,7 @@ static int ipv6_srh_rcv(struct sk_buff *skb)
 	}
 
 	if (hdr->segments_left >= (hdr->hdrlen >> 1)) {
-		__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
-				IPSTATS_MIB_INHDRERRORS);
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 				  ((&hdr->segments_left) -
 				   skb_network_header(skb)));
@@ -423,8 +423,7 @@ static int ipv6_srh_rcv(struct sk_buff *skb)
 
 	if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
 		if (ipv6_hdr(skb)->hop_limit <= 1) {
-			__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
-					IPSTATS_MIB_INHDRERRORS);
+			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 			icmpv6_send(skb, ICMPV6_TIME_EXCEED,
 				    ICMPV6_EXC_HOPLIMIT, 0);
 			kfree_skb(skb);
@@ -448,10 +447,10 @@ static int ipv6_srh_rcv(struct sk_buff *skb)
 /* called with rcu_read_lock() */
 static int ipv6_rthdr_rcv(struct sk_buff *skb)
 {
+	struct inet6_dev *idev = __in6_dev_get(skb->dev);
 	struct inet6_skb_parm *opt = IP6CB(skb);
 	struct in6_addr *addr = NULL;
 	struct in6_addr daddr;
-	struct inet6_dev *idev;
 	int n, i;
 	struct ipv6_rt_hdr *hdr;
 	struct rt0_hdr *rthdr;
@@ -465,8 +464,7 @@ static int ipv6_rthdr_rcv(struct sk_buff *skb)
 	if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 	    !pskb_may_pull(skb, (skb_transport_offset(skb) +
 				 ((skb_transport_header(skb)[1] + 1) << 3)))) {
-		__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
-				IPSTATS_MIB_INHDRERRORS);
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 		kfree_skb(skb);
 		return -1;
 	}
@@ -475,8 +473,7 @@ static int ipv6_rthdr_rcv(struct sk_buff *skb)
 
 	if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
 	    skb->pkt_type != PACKET_HOST) {
-		__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
-				IPSTATS_MIB_INADDRERRORS);
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 		kfree_skb(skb);
 		return -1;
 	}
@@ -494,7 +491,7 @@ static int ipv6_rthdr_rcv(struct sk_buff *skb)
 			 * processed by own
 			 */
 			if (!addr) {
-				__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
+				__IP6_INC_STATS(net, idev,
 						IPSTATS_MIB_INADDRERRORS);
 				kfree_skb(skb);
 				return -1;
@@ -520,8 +517,7 @@ static int ipv6_rthdr_rcv(struct sk_buff *skb)
 			goto unknown_rh;
 		/* Silently discard invalid RTH type 2 */
 		if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
-			__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
-					IPSTATS_MIB_INHDRERRORS);
+			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 			kfree_skb(skb);
 			return -1;
 		}
@@ -539,8 +535,7 @@ static int ipv6_rthdr_rcv(struct sk_buff *skb)
 	n = hdr->hdrlen >> 1;
 
 	if (hdr->segments_left > n) {
-		__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
-				IPSTATS_MIB_INHDRERRORS);
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 				  ((&hdr->segments_left) -
 				   skb_network_header(skb)));
@@ -576,14 +571,12 @@ static int ipv6_rthdr_rcv(struct sk_buff *skb)
 		if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
 				     (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
 				     IPPROTO_ROUTING) < 0) {
-			__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
-					IPSTATS_MIB_INADDRERRORS);
+			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 			kfree_skb(skb);
 			return -1;
 		}
 		if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
-			__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
-					IPSTATS_MIB_INADDRERRORS);
+			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 			kfree_skb(skb);
 			return -1;
 		}
@@ -594,8 +587,7 @@ static int ipv6_rthdr_rcv(struct sk_buff *skb)
 	}
 
 	if (ipv6_addr_is_multicast(addr)) {
-		__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
-				IPSTATS_MIB_INADDRERRORS);
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 		kfree_skb(skb);
 		return -1;
 	}
@@ -614,8 +606,7 @@ static int ipv6_rthdr_rcv(struct sk_buff *skb)
 
 	if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
 		if (ipv6_hdr(skb)->hop_limit <= 1) {
-			__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
-					IPSTATS_MIB_INHDRERRORS);
+			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 			icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
 				    0);
 			kfree_skb(skb);
@@ -630,7 +621,7 @@ static int ipv6_rthdr_rcv(struct sk_buff *skb)
 	return -1;
 
 unknown_rh:
-	__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
+	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 	icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 			  (&hdr->type) - skb_network_header(skb));
 	return -1;
@@ -722,34 +713,31 @@ static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
 {
 	const unsigned char *nh = skb_network_header(skb);
+	struct inet6_dev *idev = __in6_dev_get_safely(skb->dev);
 	struct net *net = ipv6_skb_net(skb);
 	u32 pkt_len;
 
 	if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
 		net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
 				    nh[optoff+1]);
-		__IP6_INC_STATS(net, ipv6_skb_idev(skb),
-				IPSTATS_MIB_INHDRERRORS);
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 		goto drop;
 	}
 
 	pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
 	if (pkt_len <= IPV6_MAXPLEN) {
-		__IP6_INC_STATS(net, ipv6_skb_idev(skb),
-				IPSTATS_MIB_INHDRERRORS);
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
 		return false;
 	}
 	if (ipv6_hdr(skb)->payload_len) {
-		__IP6_INC_STATS(net, ipv6_skb_idev(skb),
-				IPSTATS_MIB_INHDRERRORS);
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
 		return false;
 	}
 
 	if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
-		__IP6_INC_STATS(net, ipv6_skb_idev(skb),
-				IPSTATS_MIB_INTRUNCATEDPKTS);
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INTRUNCATEDPKTS);
 		goto drop;
 	}
 
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -336,7 +336,7 @@ int ip6_mc_input(struct sk_buff *skb)
 	bool deliver;
 
 	__IP6_UPD_PO_STATS(dev_net(skb_dst(skb)->dev),
-			 ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INMCAST,
+			 __in6_dev_get_safely(skb->dev), IPSTATS_MIB_INMCAST,
 			 skb->len);
 
 	hdr = ipv6_hdr(skb);
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -414,6 +414,7 @@ static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
 
 int ip6_forward(struct sk_buff *skb)
 {
+	struct inet6_dev *idev = __in6_dev_get_safely(skb->dev);
 	struct dst_entry *dst = skb_dst(skb);
 	struct ipv6hdr *hdr = ipv6_hdr(skb);
 	struct inet6_skb_parm *opt = IP6CB(skb);
@@ -433,8 +434,7 @@ int ip6_forward(struct sk_buff *skb)
 		goto drop;
 
 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
-		__IP6_INC_STATS(net, ip6_dst_idev(dst),
-				IPSTATS_MIB_INDISCARDS);
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
 		goto drop;
 	}
 
@@ -465,8 +465,7 @@ int ip6_forward(struct sk_buff *skb)
 		/* Force OUTPUT device used as source address */
 		skb->dev = dst->dev;
 		icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0);
-		__IP6_INC_STATS(net, ip6_dst_idev(dst),
-				IPSTATS_MIB_INHDRERRORS);
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 
 		kfree_skb(skb);
 		return -ETIMEDOUT;
@@ -479,15 +478,13 @@ int ip6_forward(struct sk_buff *skb)
 		if (proxied > 0)
 			return ip6_input(skb);
 		else if (proxied < 0) {
-			__IP6_INC_STATS(net, ip6_dst_idev(dst),
-					IPSTATS_MIB_INDISCARDS);
+			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
 			goto drop;
 		}
 	}
 
 	if (!xfrm6_route_forward(skb)) {
-		__IP6_INC_STATS(net, ip6_dst_idev(dst),
-				IPSTATS_MIB_INDISCARDS);
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
 		goto drop;
 	}
 	dst = skb_dst(skb);
@@ -544,8 +541,7 @@ int ip6_forward(struct sk_buff *skb)
 		/* Again, force OUTPUT device used as source address */
 		skb->dev = dst->dev;
 		icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
-		__IP6_INC_STATS(net, ip6_dst_idev(dst),
-				IPSTATS_MIB_INTOOBIGERRORS);
+		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INTOOBIGERRORS);
 		__IP6_INC_STATS(net, ip6_dst_idev(dst),
 				IPSTATS_MIB_FRAGFAILS);
 		kfree_skb(skb);
@@ -569,7 +565,7 @@ int ip6_forward(struct sk_buff *skb)
 		       ip6_forward_finish);
 
 error:
-	__IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_INADDRERRORS);
+	__IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 drop:
 	kfree_skb(skb);
 	return -EINVAL;
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -178,7 +178,7 @@ static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 			((u8 *)(fhdr + 1) - (u8 *)(ipv6_hdr(skb) + 1)));
 
 	if ((unsigned int)end > IPV6_MAXPLEN) {
-		__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
+		__IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev),
 				IPSTATS_MIB_INHDRERRORS);
 		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 				  ((u8 *)&fhdr->frag_off -
@@ -213,7 +213,7 @@ static int ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 			/* RFC2460 says always send parameter problem in
 			 * this case. -DaveM
 			 */
-			__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
+			__IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev),
 					IPSTATS_MIB_INHDRERRORS);
 			icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 					  offsetof(struct ipv6hdr, payload_len));
@@ -541,7 +541,7 @@ static int ipv6_frag_rcv(struct sk_buff *skb)
 	return -1;
 
 fail_hdr:
-	__IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
+	__IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev),
 			IPSTATS_MIB_INHDRERRORS);
 	icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb_network_header_len(skb));
 	return -1;
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2649,7 +2649,8 @@ static int ip6_pkt_drop(struct sk_buff *skb, u8 code, int ipstats_mib_noroutes)
 	case IPSTATS_MIB_INNOROUTES:
 		type = ipv6_addr_type(&ipv6_hdr(skb)->daddr);
 		if (type == IPV6_ADDR_ANY) {
-			IP6_INC_STATS(dev_net(dst->dev), ip6_dst_idev(dst),
+			IP6_INC_STATS(dev_net(dst->dev),
+				      __in6_dev_get_safely(skb->dev),
 				      IPSTATS_MIB_INADDRERRORS);
 			break;
 		}
--- a/net/netfilter/ipvs/ip_vs_xmit.c
+++ b/net/netfilter/ipvs/ip_vs_xmit.c
@@ -266,12 +266,13 @@ static inline bool decrement_ttl(struct netns_ipvs *ipvs,
 
 		/* check and decrement ttl */
 		if (ipv6_hdr(skb)->hop_limit <= 1) {
+			struct inet6_dev *idev = __in6_dev_get_safely(skb->dev);
+
 			/* Force OUTPUT device used as source address */
 			skb->dev = dst->dev;
 			icmpv6_send(skb, ICMPV6_TIME_EXCEED,
 				    ICMPV6_EXC_HOPLIMIT, 0);
-			__IP6_INC_STATS(net, ip6_dst_idev(dst),
-					IPSTATS_MIB_INHDRERRORS);
+			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 
 			return false;
 		}