diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c index c77a4c3fbe75..d3c677e9bff2 100644 --- a/net/ipv4/ip_tunnel_core.c +++ b/net/ipv4/ip_tunnel_core.c @@ -280,7 +280,6 @@ static int iptunnel_pmtud_build_icmp(struct sk_buff *skb, int mtu) */ static int iptunnel_pmtud_check_icmp(struct sk_buff *skb, int mtu) { - const struct icmphdr *icmph = icmp_hdr(skb); const struct iphdr *iph = ip_hdr(skb); if (mtu < 576 || iph->frag_off != htons(IP_DF)) @@ -291,9 +290,17 @@ static int iptunnel_pmtud_check_icmp(struct sk_buff *skb, int mtu) ipv4_is_lbcast(iph->saddr) || ipv4_is_multicast(iph->saddr)) return 0; - if (iph->protocol == IPPROTO_ICMP && icmp_is_err(icmph->type)) - return 0; + if (iph->protocol == IPPROTO_ICMP) { + const struct icmphdr *icmph; + if (!pskb_network_may_pull(skb, iph->ihl * 4 + + offsetofend(struct icmphdr, type))) + return 0; + iph = ip_hdr(skb); + icmph = (void *)iph + iph->ihl * 4; + if (icmp_is_err(icmph->type)) + return 0; + } return iptunnel_pmtud_build_icmp(skb, mtu); }