Hi Andrey, On Mon, Oct 24, 2016 at 05:30:04PM +0200, Andrey Konovalov wrote: > The problem is that sctp_walk_errors walks the chunk before its length > is checked for overflow. Exactly. The check is done too late, for the 2nd and subsequent chunks only. Please try the following patch, thanks. Note: not even compile tested. ---8<--- diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c index 026e3bca4a94..8ec20a64a3f8 100644 --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -3422,6 +3422,12 @@ sctp_disposition_t sctp_sf_ootb(struct net *net, return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands); + /* Report violation if chunk len overflows */ + ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); + if (ch_end > skb_tail_pointer(skb)) + return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, + commands); + /* Now that we know we at least have a chunk header, * do things that are type appropriate. */ @@ -3453,12 +3459,6 @@ sctp_disposition_t sctp_sf_ootb(struct net *net, } } - /* Report violation if chunk len overflows */ - ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); - if (ch_end > skb_tail_pointer(skb)) - return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, - commands); - ch = (sctp_chunkhdr_t *) ch_end; } while (ch_end < skb_tail_pointer(skb)); -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
