Re: [PATCH net] sctp: fix ICMP processing if skb is non-linear

hello Xin Long,
On Sat, 2017-05-20 at 02:40 +0800, Xin Long wrote:

On Fri, May 19, 2017 at 11:34 PM, Davide Caratti [off-list ref] wrote:

quoted

@@ -515,14 +515,23 @@ struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb,
         * or the chunk type or the Initiate Tag does not match, silently
         * discard the packet.
         */
+       offset = skb_transport_offset(skb);
+       sctphdr = skb_header_pointer(skb, offset, sizeof(_sctphdr), &_sctphdr);
+       if (unlikely(!sctphdr))
+               goto out;
+
+       vtag = ntohl(sctphdr->vtag);
        if (vtag == 0) {
-               chunkhdr = (void *)sctphdr + sizeof(struct sctphdr);
-               if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t)
-                         + sizeof(__be32) ||
+               offset += sizeof(_sctphdr);

will be nice to delete this line, and use

quoted

+               /* chunk header + first 4 octects of init header */
+               chunkhdr = skb_header_pointer(skb, offset,

chunkhdr = skb_header_pointer(skb, offset + sizeof(_sctphdr), ;)
wdyt?

that's right, 'offset' does not need the re-assignment: I will post the v2
soon. Thanks!