Patch "ip6_tunnel: must reload ipv6h in ip6ip6_tnl_xmit()" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    ip6_tunnel: must reload ipv6h in ip6ip6_tnl_xmit()

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ip6_tunnel-must-reload-ipv6h-in-ip6ip6_tnl_xmit.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Mon Jul  3 13:22:04 CEST 2017
From: Eric Dumazet <edumazet@google.com>
Date: Mon, 23 Jan 2017 16:43:05 -0800
Subject: ip6_tunnel: must reload ipv6h in ip6ip6_tnl_xmit()

From: Eric Dumazet <edumazet@google.com>


[ Upstream commit 21b995a9cb093fff33ec91d7cb3822b882a90a1e ]

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: c12b395a4664 ("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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ipv6/ip6_gre.c    |    3 +++
 net/ipv6/ip6_tunnel.c |    2 ++
 2 files changed, 5 insertions(+)

--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -582,6 +582,9 @@ static inline int ip6gre_xmit_ipv6(struc
 		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];
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1313,6 +1313,8 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, str
 		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;
 


Patches currently in stable-queue which might be from edumazet@google.com are

queue-4.9/ip6_tunnel-must-reload-ipv6h-in-ip6ip6_tnl_xmit.patch
queue-4.9/gianfar-do-not-reuse-pages-from-emergency-reserve.patch
queue-4.9/fix-an-intermittent-pr_emerg-warning-about-lo-becoming-free.patch
queue-4.9/netfilter-xt_tcpmss-add-more-sanity-tests-on-tcph-doff.patch
queue-4.9/ipv6-release-dst-on-error-in-ip6_dst_lookup_tail.patch
queue-4.9/igmp-acquire-pmc-lock-for-ip_mc_clear_src.patch