ip6_gre: fix endianness errors in ip6gre_err

info is in network byte order, change it back to host byte order
before use. In particular, the current code sets the MTU of the tunnel
to a wrong (too big) value.

Fixes: c12b395a4664 ("gre: Support GRE over IPv6")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 13cda4c6313b..01ccc28a686f 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -417,7 +417,7 @@ static void ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
                 if (code == ICMPV6_HDR_FIELD)
                         teli = ip6_tnl_parse_tlv_enc_lim(skb, skb->data);
 
-                if (teli && teli == info - 2) {
+                if (teli && teli == be32_to_cpu(info) - 2) {
                         tel = (struct ipv6_tlv_tnl_enc_lim *) &skb->data[teli];
                         if (tel->encap_limit == 0) {
                                 net_warn_ratelimited("%s: Too small encapsulation limit or routing loop in tunnel!\n",
@@ -429,7 +429,7 @@ static void ip6gre_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
                 }
                 break;
         case ICMPV6_PKT_TOOBIG:
-                mtu = info - offset;
+                mtu = be32_to_cpu(info) - offset;
                 if (mtu < IPV6_MIN_MTU)
                         mtu = IPV6_MIN_MTU;
                 t->dev->mtu = mtu;