static int dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
u8 type, u8 code, int offset, __be32 info)
{
- const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
+ const struct ipv6hdr *hdr;
const struct dccp_hdr *dh;
struct dccp_sock *dp;
struct ipv6_pinfo *np;
__u64 seq;
struct net *net = dev_net(skb->dev);
- /* Only need dccph_dport & dccph_sport which are the first
- * 4 bytes in dccp header.
+ /* For the first __dccp_basic_hdr_len() check, we only need dh->dccph_x,
+ * which is in byte 7 of the dccp header.
* Our caller (icmpv6_notify()) already pulled 8 bytes for us.
+ *
+ * Later on, we want to access the sequence number fields, which are
+ * beyond 8 bytes, so we have to pskb_may_pull() ourselves.
*/
- BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_sport) > 8);
- BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_dport) > 8);
+ dh = (struct dccp_hdr *)(skb->data + offset);
+ if (!pskb_may_pull(skb, offset + __dccp_basic_hdr_len(dh)))
+ return -EINVAL;
+ hdr = (const struct ipv6hdr *)skb->data;
dh = (struct dccp_hdr *)(skb->data + offset);
sk = __inet6_lookup_established(net, &dccp_hashinfo,