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/ospfd/ospf_zebra.c b/ospfd/ospf_zebra.c
index cf2ea81..4531f13 100644
--- a/ospfd/ospf_zebra.c
+++ b/ospfd/ospf_zebra.c
@@ -845,7 +845,7 @@
/* IPv4 prefix. */
memset (&p, 0, sizeof (struct prefix_ipv4));
p.family = AF_INET;
- p.prefixlen = stream_getc (s);
+ p.prefixlen = MIN(IPV4_MAX_PREFIXLEN, stream_getc (s));
stream_get (&p.prefix, s, PSIZE (p.prefixlen));
if (IPV4_NET127(ntohl(p.prefix.s_addr)))