slirp/arp: do not special-case bogus IP addresses

Do not special-case addresses with zero host part, as we do not
necessarily know how big it is, and the guest can fake them anyway.
Silently avoid having 0.0.0.0 as a destination, however.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
[Edgar: Minor change to subject]
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/slirp.c b/slirp.c
index f002b0a..0a143da 100644
--- a/slirp.c
+++ b/slirp.c
@@ -772,6 +772,11 @@ int if_encap(Slirp *slirp, struct mbuf *ifm)
         return 1;
     }
 
+    if (iph->ip_dst.s_addr == 0) {
+        /* 0.0.0.0 can not be a destination address, something went wrong,
+         * avoid making it worse */
+        return 1;
+    }
     if (!arp_table_search(slirp, iph->ip_dst.s_addr, ethaddr)) {
         uint8_t arp_req[ETH_HLEN + sizeof(struct arphdr)];
         struct ethhdr *reh = (struct ethhdr *)arp_req;