[PATCH 6.18 248/396] vxlan: use pskb_network_may_pull() for transmit path header pulls

6.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eric Dumazet <[email protected]>

commit b9553558b48db54ac9273e6b98d7263ef5c1a329 upstream.

In vxlan_xmit(), arp_reduce(), and vxlan_mdb_entry_skb_get(), pskb_may_pull() was
being called to verify the availability of network layer headers (ARP, IPv6/ND,
IP/IPv6 MDB keys).

However, during transmit skb->data points to the MAC header, so skb_network_offset(skb)
is ETH_HLEN (14 bytes). Using pskb_may_pull(skb, len) only checks len bytes from skb->data
rather than skb_network_offset(skb) + len, which can leave part of the network header
in non-linear frags.

Replace these remaining pskb_may_pull() calls with pskb_network_may_pull() to properly
account for the MAC header offset.

Fixes: e4f67addf158 ("add DOVE extensions for VXLAN")
Fixes: f564f45c4518 ("vxlan: add ipv6 proxy support")
Fixes: 0f83e69f44bf ("vxlan: Add MDB data path support")
Signed-off-by: Eric Dumazet <[email protected]>
Cc: [email protected]
Reviewed-by: Vadim Fedorenko <[email protected]>
Reviewed-by: Ido Schimmel <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 drivers/net/vxlan/vxlan_core.c |    6 +++---
 drivers/net/vxlan/vxlan_mdb.c  |    4 ++--
 2 files changed, 5 insertions(+), 5 deletions(-)

--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -1852,7 +1852,7 @@ static int arp_reduce(struct net_device
 	if (dev->flags & IFF_NOARP)
 		goto out;
 
-	if (!pskb_may_pull(skb, arp_hdr_len(dev))) {
+	if (!pskb_network_may_pull(skb, arp_hdr_len(dev))) {
 		dev_dstats_tx_dropped(dev);
 		vxlan_vnifilter_count(vxlan, vni, NULL,
 				      VXLAN_VNI_STATS_TX_DROPS, 0);
@@ -2765,8 +2765,8 @@ static netdev_tx_t vxlan_xmit(struct sk_
 			return arp_reduce(dev, skb, vni);
 #if IS_ENABLED(CONFIG_IPV6)
 		else if (ntohs(eth->h_proto) == ETH_P_IPV6 &&
-			 pskb_may_pull(skb, sizeof(struct ipv6hdr) +
-					    sizeof(struct nd_msg)) &&
+			 pskb_network_may_pull(skb, sizeof(struct ipv6hdr) +
+						    sizeof(struct nd_msg)) &&
 			 ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) {
 			struct nd_msg *m = (struct nd_msg *)(ipv6_hdr(skb) + 1);
 
--- a/drivers/net/vxlan/vxlan_mdb.c
+++ b/drivers/net/vxlan/vxlan_mdb.c
@@ -1631,7 +1631,7 @@ struct vxlan_mdb_entry *vxlan_mdb_entry_
 
 	switch (skb->protocol) {
 	case htons(ETH_P_IP):
-		if (!pskb_may_pull(skb, sizeof(struct iphdr)))
+		if (!pskb_network_may_pull(skb, sizeof(struct iphdr)))
 			return NULL;
 		group.dst.sa.sa_family = AF_INET;
 		group.dst.sin.sin_addr.s_addr = ip_hdr(skb)->daddr;
@@ -1640,7 +1640,7 @@ struct vxlan_mdb_entry *vxlan_mdb_entry_
 		break;
 #if IS_ENABLED(CONFIG_IPV6)
 	case htons(ETH_P_IPV6):
-		if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
+		if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
 			return NULL;
 		group.dst.sa.sa_family = AF_INET6;
 		group.dst.sin6.sin6_addr = ipv6_hdr(skb)->daddr;