From: Denis Ovsienko <infrastation@yandex.ru>
Date: Mon, 26 Sep 2011 09:17:52 +0000 (+0400)
Subject: ospfd: CVE-2011-3325 part 1 (OSPF header underrun)
X-Git-Tag: frr-2.0-rc1~2060
X-Git-Url: https://git.puffer.fish/?a=commitdiff_plain;h=61ab0301606053192f45c188bc48afc837518770;p=mirror%2Ffrr.git

ospfd: CVE-2011-3325 part 1 (OSPF header underrun)

This vulnerability (CERT-FI #514838) was reported by CROSS project.

When only 14 first bytes of a Hello packet is delivered, ospfd crashes.

* ospf_packet.c
  * ospf_read(): add size check
---

diff --git a/ospfd/ospf_packet.c b/ospfd/ospf_packet.c
index be137d9116..57278788dc 100644
--- a/ospfd/ospf_packet.c
+++ b/ospfd/ospf_packet.c
@@ -2430,10 +2430,19 @@ ospf_read (struct thread *thread)
       return 0;
     }
 
-  /* Adjust size to message length. */
+  /* Advance from IP header to OSPF header (iph->ip_hl has been verified
+     by ospf_recv_packet() to be correct). */
   stream_forward_getp (ibuf, iph->ip_hl * 4);
-  
-  /* Get ospf packet header. */
+
+  /* Make sure the OSPF header is really there. */
+  if (stream_get_endp (ibuf) - stream_get_getp (ibuf) < OSPF_HEADER_SIZE)
+  {
+    zlog_debug ("ospf_read: ignored OSPF packet with undersized (%u bytes) header",
+                stream_get_endp (ibuf) - stream_get_getp (ibuf));
+    return -1;
+  }
+
+  /* Now it is safe to access all fields of OSPF packet header. */
   ospfh = (struct ospf_header *) STREAM_PNT (ibuf);
 
   /* associate packet with ospf interface */