lib: Check prefix length from zebra is sensible
* zclient.c: prefix length on router-id and interface address add
messages not sanity checked. fix.
* */*_zebra.c: Prefix length on zebra route read was not checked, and
clients use it to write to storage. An evil zebra could overflow
client structures by sending overly long prefixlen.
Prompted by discussions with:
Donald Sharp <sharpd@cumulusnetworks.com>
diff --git a/ospf6d/ospf6_zebra.c b/ospf6d/ospf6_zebra.c
index 30b6fc6..0caf001 100644
--- a/ospf6d/ospf6_zebra.c
+++ b/ospf6d/ospf6_zebra.c
@@ -227,7 +227,7 @@
/* IPv6 prefix. */
memset (&p, 0, sizeof (struct prefix_ipv6));
p.family = AF_INET6;
- p.prefixlen = stream_getc (s);
+ p.prefixlen = MIN(IPV6_MAX_PREFIXLEN, stream_getc (s));
stream_get (&p.prefix, s, PSIZE (p.prefixlen));
/* Nexthop, ifindex, distance, metric. */