diff options
Diffstat (limited to 'net/netfilter/nf_nat_proto_sctp.c')
| -rw-r--r-- | net/netfilter/nf_nat_proto_sctp.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/net/netfilter/nf_nat_proto_sctp.c b/net/netfilter/nf_nat_proto_sctp.c index 31d358691af0..804e8a0ab36e 100644 --- a/net/netfilter/nf_nat_proto_sctp.c +++ b/net/netfilter/nf_nat_proto_sctp.c @@ -33,8 +33,16 @@ sctp_manip_pkt(struct sk_buff *skb, enum nf_nat_manip_type maniptype) { sctp_sctphdr_t *hdr; + int hdrsize = 8; - if (!skb_make_writable(skb, hdroff + sizeof(*hdr))) + /* This could be an inner header returned in imcp packet; in such + * cases we cannot update the checksum field since it is outside + * of the 8 bytes of transport layer headers we are guaranteed. + */ + if (skb->len >= hdroff + sizeof(*hdr)) + hdrsize = sizeof(*hdr); + + if (!skb_make_writable(skb, hdroff + hdrsize)) return false; hdr = (struct sctphdr *)(skb->data + hdroff); @@ -47,6 +55,9 @@ sctp_manip_pkt(struct sk_buff *skb, hdr->dest = tuple->dst.u.sctp.port; } + if (hdrsize < sizeof(*hdr)) + return true; + if (skb->ip_summed != CHECKSUM_PARTIAL) { hdr->checksum = sctp_compute_cksum(skb, hdroff); skb->ip_summed = CHECKSUM_NONE; |