From 09395e2a0e93b2cf4258cb1de91887948796bb68 Mon Sep 17 00:00:00 2001 From: Denis Ovsienko Date: Mon, 26 Sep 2011 13:18:36 +0400 Subject: ospf6d: CVE-2011-3324 (DD LSA assertion) This vulnerability (CERT-FI #514839) was reported by CROSS project. When Database Description LSA header list contains trailing zero octets, ospf6d tries to process this data as an LSA header. This triggers an assertion in the code and ospf6d shuts down. * ospf6_lsa.c * ospf6_lsa_is_changed(): handle header-only argument(s) appropriately, do not treat LSA length underrun as a fatal error. --- ospf6d/ospf6_lsa.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'ospf6d/ospf6_lsa.c') diff --git a/ospf6d/ospf6_lsa.c b/ospf6d/ospf6_lsa.c index 588b9462..e65752d8 100644 --- a/ospf6d/ospf6_lsa.c +++ b/ospf6d/ospf6_lsa.c @@ -163,9 +163,19 @@ ospf6_lsa_is_changed (struct ospf6_lsa *lsa1, return 1; if (ntohs (lsa1->header->length) != ntohs (lsa2->header->length)) return 1; + /* Going beyond LSA headers to compare the payload only makes sense, when both LSAs aren't header-only. */ + if (CHECK_FLAG (lsa1->flag, OSPF6_LSA_HEADERONLY) != CHECK_FLAG (lsa2->flag, OSPF6_LSA_HEADERONLY)) + { + zlog_warn ("%s: only one of two (%s, %s) LSAs compared is header-only", __func__, lsa1->name, lsa2->name); + return 1; + } + if (CHECK_FLAG (lsa1->flag, OSPF6_LSA_HEADERONLY)) + return 0; length = OSPF6_LSA_SIZE (lsa1->header) - sizeof (struct ospf6_lsa_header); - assert (length > 0); + /* Once upper layer verifies LSAs received, length underrun should become a warning. */ + if (length <= 0) + return 0; return memcmp (OSPF6_LSA_HEADER_END (lsa1->header), OSPF6_LSA_HEADER_END (lsa2->header), length); -- cgit v1.2.1