Merge branch 'ip6_payload_len' into 'master'

Drop bogus IPv6 messages

See merge request slirp/libslirp!44

1 files changed, 8 insertions, 1 deletions

diff --git a/src/ip6_input.c b/src/ip6_input.c
index dfcbfd6..a83e4f8 100644
--- a/src/ip6_input.c
+++ b/src/ip6_input.c
@@ -44,11 +44,18 @@ void ip6_input(struct mbuf *m)
         goto bad;
     }
 
-    if (ntohs(ip6->ip_pl) > slirp->if_mtu) {
+    if (ntohs(ip6->ip_pl) + sizeof(struct ip6) > slirp->if_mtu) {
         icmp6_send_error(m, ICMP6_TOOBIG, 0);
         goto bad;
     }
 
+    // Check if the message size is big enough to hold what's
+    // set in the payload length header. If not this is an invalid
+    // packet
+    if (m->m_len < ntohs(ip6->ip_pl) + sizeof(struct ip6)) {
+        goto bad;
+    }
+
     /* check ip_ttl for a correct ICMP reply */
     if (ip6->ip_hl == 0) {
         icmp6_send_error(m, ICMP6_TIMXCEED, ICMP6_TIMXCEED_INTRANS);