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authorEric Dumazet <edumazet@google.com>2017-01-23 16:43:05 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-07-05 14:40:23 +0200
commitb07bf2364605dc7d78401b7eb02a533b0b6ddc05 (patch)
treefbf40c24c669b40f6a8bf029f7a643c84d976426
parent7fdc81f6e1a9b3f520e40cfc4ebccc94858da62d (diff)
ip6_tunnel: must reload ipv6h in ip6ip6_tnl_xmit()
[ 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>
-rw-r--r--net/ipv6/ip6_gre.c3
-rw-r--r--net/ipv6/ip6_tunnel.c2
2 files changed, 5 insertions, 0 deletions
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 0a5922055da2..a5fdc1aa7a9a 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -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];
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 116b4da06820..63fad2467a7e 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1313,6 +1313,8 @@ 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;