From 7115e632f90952454ab6426e0d2151327162a30f Mon Sep 17 00:00:00 2001 From: Wei Yongjun Date: Thu, 19 Jun 2008 16:07:48 -0700 Subject: [PATCH] sctp: Validate Initiate Tag when handling ICMP message This patch add to validate initiate tag and chunk type if verification tag is 0 when handling ICMP message. RFC 4960, Appendix C. ICMP Handling ICMP6) An implementation MUST validate that the Verification Tag contained in the ICMP message matches the Verification Tag of the peer. If the Verification Tag is not 0 and does NOT match, discard the ICMP message. If it is 0 and the ICMP message contains enough bytes to verify that the chunk type is an INIT chunk and that the Initiate Tag matches the tag of the peer, continue with ICMP7. If the ICMP message is too short or the chunk type or the Initiate Tag does not match, silently discard the packet. Signed-off-by: Wei Yongjun Signed-off-by: Vlad Yasevich Signed-off-by: David S. Miller --- net/sctp/input.c | 27 +++++++++++++++++++++++++-- 1 file changed, 25 insertions(+), 2 deletions(-) diff --git a/net/sctp/input.c b/net/sctp/input.c index ca6b022b1df2..d354a23972d4 100644 --- a/net/sctp/input.c +++ b/net/sctp/input.c @@ -430,6 +430,9 @@ struct sock *sctp_err_lookup(int family, struct sk_buff *skb, struct sock *sk = NULL; struct sctp_association *asoc; struct sctp_transport *transport = NULL; + struct sctp_init_chunk *chunkhdr; + __u32 vtag = ntohl(sctphdr->vtag); + int len = skb->len - ((void *)sctphdr - (void *)skb->data); *app = NULL; *tpp = NULL; @@ -451,8 +454,28 @@ struct sock *sctp_err_lookup(int family, struct sk_buff *skb, sk = asoc->base.sk; - if (ntohl(sctphdr->vtag) != asoc->c.peer_vtag) { - ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); + /* RFC 4960, Appendix C. ICMP Handling + * + * ICMP6) An implementation MUST validate that the Verification Tag + * contained in the ICMP message matches the Verification Tag of + * the peer. If the Verification Tag is not 0 and does NOT + * match, discard the ICMP message. If it is 0 and the ICMP + * message contains enough bytes to verify that the chunk type is + * an INIT chunk and that the Initiate Tag matches the tag of the + * peer, continue with ICMP7. If the ICMP message is too short + * or the chunk type or the Initiate Tag does not match, silently + * discard the packet. + */ + if (vtag == 0) { + chunkhdr = (struct sctp_init_chunk *)((void *)sctphdr + + sizeof(struct sctphdr)); + if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t) + + sizeof(__be32) || + chunkhdr->chunk_hdr.type != SCTP_CID_INIT || + ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) { + goto out; + } + } else if (vtag != asoc->c.peer_vtag) { goto out; }