3.16.52-rc1 review patch. If anyone has any objections, please let me know.
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From: Xin Long lucien.xin@gmail.com
commit 76cc0d3282d4b933fa144fa41fbc5318e0fdca24 upstream.
Now in ip6gre_header before packing the ipv6 header, it skb_push t->hlen which only includes encap_hlen + tun_hlen. It means greh and inner header would be over written by ipv6 stuff and ipv6h might have no chance to set up.
Jianlin found this issue when using remote any on ip6_gre, the packets he captured on gre dev are truncated:
22:50:26.210866 Out ethertype IPv6 (0x86dd), length 120: truncated-ip6 -\ 8128 bytes missing!(flowlabel 0x92f40, hlim 0, next-header Options (0) \ payload length: 8192) ::1:2000:0 > ::1:0:86dd: HBH [trunc] ip-proto-128 \ 8184
It should also skb_push ipv6hdr so that ipv6h points to the right position to set ipv6 stuff up.
This patch is to skb_push hlen + sizeof(*ipv6h) and also fix some indents in ip6gre_header.
Fixes: c12b395a4664 ("gre: Support GRE over IPv6") Reported-by: Jianlin Shi jishi@redhat.com Signed-off-by: Xin Long lucien.xin@gmail.com Signed-off-by: David S. Miller davem@davemloft.net [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -1172,21 +1172,23 @@ static int ip6gre_tunnel_change_mtu(stru }
static int ip6gre_header(struct sk_buff *skb, struct net_device *dev, - unsigned short type, - const void *daddr, const void *saddr, unsigned int len) + unsigned short type, const void *daddr, + const void *saddr, unsigned int len) { struct ip6_tnl *t = netdev_priv(dev); - struct ipv6hdr *ipv6h = (struct ipv6hdr *)skb_push(skb, t->hlen); - __be16 *p = (__be16 *)(ipv6h+1); + struct ipv6hdr *ipv6h; + __be16 *p;
+ ipv6h = (struct ipv6hdr *)skb_push(skb, t->hlen + sizeof(*ipv6h)); ip6_flow_hdr(ipv6h, 0, t->fl.u.ip6.flowlabel); ipv6h->hop_limit = t->parms.hop_limit; ipv6h->nexthdr = NEXTHDR_GRE; ipv6h->saddr = t->parms.laddr; ipv6h->daddr = t->parms.raddr;
- p[0] = t->parms.o_flags; - p[1] = htons(type); + p = (__be16 *)(ipv6h + 1); + p[0] = t->parms.o_flags; + p[1] = htons(type);
/* * Set the source hardware address.