ip6_gre: fix endianness errors in ip6gre_err

commit d1e158e2d7a0a91110b206653f0e02376e809150 upstream.

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>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 0baac7127c571dae042b7a01fe73afa845148808..07506e7a89177c00deb5eca564d8458b2855bf84 100644 (file)
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -414,7 +414,7 @@ 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",
@@ -426,7 +426,7 @@ 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;