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-rw-r--r--net/ipv4/ip_tunnel.c28
1 files changed, 21 insertions, 7 deletions
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 24961b304..328f9068c 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -540,6 +540,20 @@ static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb,
return 0;
}
+static void ip_tunnel_adj_headroom(struct net_device *dev, unsigned int headroom)
+{
+ /* we must cap headroom to some upperlimit, else pskb_expand_head
+ * will overflow header offsets in skb_headers_offset_update().
+ */
+ static const unsigned int max_allowed = 512;
+
+ if (headroom > max_allowed)
+ headroom = max_allowed;
+
+ if (headroom > READ_ONCE(dev->needed_headroom))
+ WRITE_ONCE(dev->needed_headroom, headroom);
+}
+
void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
u8 proto, int tunnel_hlen)
{
@@ -614,13 +628,13 @@ void ip_md_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
}
headroom += LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len;
- if (headroom > READ_ONCE(dev->needed_headroom))
- WRITE_ONCE(dev->needed_headroom, headroom);
-
- if (skb_cow_head(skb, READ_ONCE(dev->needed_headroom))) {
+ if (skb_cow_head(skb, headroom)) {
ip_rt_put(rt);
goto tx_dropped;
}
+
+ ip_tunnel_adj_headroom(dev, headroom);
+
iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, proto, tos, ttl,
df, !net_eq(tunnel->net, dev_net(dev)));
return;
@@ -800,16 +814,16 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
max_headroom = LL_RESERVED_SPACE(rt->dst.dev) + sizeof(struct iphdr)
+ rt->dst.header_len + ip_encap_hlen(&tunnel->encap);
- if (max_headroom > READ_ONCE(dev->needed_headroom))
- WRITE_ONCE(dev->needed_headroom, max_headroom);
- if (skb_cow_head(skb, READ_ONCE(dev->needed_headroom))) {
+ if (skb_cow_head(skb, max_headroom)) {
ip_rt_put(rt);
dev->stats.tx_dropped++;
kfree_skb(skb);
return;
}
+ ip_tunnel_adj_headroom(dev, max_headroom);
+
iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
df, !net_eq(tunnel->net, dev_net(dev)));
return;