ip6_tunnel: must reload ipv6h in ip6ip6_tnl_xmit() (21b995a9) · Commits · 戴 / test

Since ip6_tnl_parse_tlv_enc_lim() can call pskb_may_pull(), we must reload any pointer that was related to skb->head (or skb->data), or risk use after free. Fixes: ("gre: Support GRE over IPv6") Signed-off-by:

Eric Dumazet <edumazet@google.com> Cc: Dmitry Kozlov <xeb@mail.ru> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/ipv6/ip6_gre.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -582,6 +582,9 @@ static inline int ip6gre_xmit_ipv6(struct sk_buff skb, struct net_device dev)
		return -1;

		offset = ip6_tnl_parse_tlv_enc_lim(skb, skb_network_header(skb));
		/* ip6_tnl_parse_tlv_enc_lim() might have reallocated skb->head */
		ipv6h = ipv6_hdr(skb);

		if (offset > 0) {
		struct ipv6_tlv_tnl_enc_lim *tel;
		tel = (struct ipv6_tlv_tnl_enc_lim *)&skb_network_header(skb)[offset];

net/ipv6/ip6_tunnel.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -1303,6 +1303,8 @@ ip6ip6_tnl_xmit(struct sk_buff skb, struct net_device dev)
		fl6.flowlabel = key->label;
		} else {
		offset = ip6_tnl_parse_tlv_enc_lim(skb, skb_network_header(skb));
		/* ip6_tnl_parse_tlv_enc_lim() might have reallocated skb->head */
		ipv6h = ipv6_hdr(skb);
		if (offset > 0) {
		struct ipv6_tlv_tnl_enc_lim *tel;

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