diff options
Diffstat (limited to 'proto/ospf/packet.c')
| -rw-r--r-- | proto/ospf/packet.c | 30 |
1 files changed, 22 insertions, 8 deletions
diff --git a/proto/ospf/packet.c b/proto/ospf/packet.c index c6b233f..23785fe 100644 --- a/proto/ospf/packet.c +++ b/proto/ospf/packet.c @@ -75,13 +75,25 @@ ospf_pkt_finalize(struct ospf_iface *ifa, struct ospf_packet *pkt) pkt->checksum = 0; + /* Perhaps use random value to prevent replay attacks after + reboot when system does not have independent RTC? */ if (!ifa->csn) - ifa->csn = (u32) time(NULL); + { + ifa->csn = (u32) now; + ifa->csn_use = now; + } + + /* We must have sufficient delay between sending a packet and increasing + CSN to prevent reordering of packets (in a network) with different CSNs */ + if ((now - ifa->csn_use) > 1) + ifa->csn++; + + ifa->csn_use = now; pkt->u.md5.keyid = passwd->id; pkt->u.md5.len = OSPF_AUTH_CRYPT_SIZE; pkt->u.md5.zero = 0; - pkt->u.md5.csn = htonl(ifa->csn++); + pkt->u.md5.csn = htonl(ifa->csn); tail = ((void *)pkt) + ntohs(pkt->length); MD5Init(&ctxt); MD5Update(&ctxt, (char *) pkt, ntohs(pkt->length)); @@ -184,12 +196,14 @@ ospf_pkt_checkauth(struct ospf_neighbor *n, struct ospf_iface *ifa, struct ospf_ if (n) { - if(ntohs(pkt->u.md5.csn) < n->csn) - { - OSPF_TRACE(D_PACKETS, "OSPF_auth: lower sequence number"); - return 0; - } - n->csn = ntohs(pkt->u.md5.csn); + u32 rcv_csn = ntohl(pkt->u.md5.csn); + if(rcv_csn < n->csn) + { + OSPF_TRACE(D_PACKETS, "OSPF_auth: lower sequence number (rcv %d, old %d)", rcv_csn, n->csn); + return 0; + } + + n->csn = rcv_csn; } MD5Init(&ctxt); |