silence coverity

diff --git a/lib/isc/netaddr.c b/lib/isc/netaddr.c
index 0940df1713e5d07ea444546a24c597a3156415cb..acb44acebdc17be7ea3af29b54c9c0aef686a1f2 100644 (file)
--- a/lib/isc/netaddr.c
+++ b/lib/isc/netaddr.c
@@ -235,6 +235,7 @@ isc_netaddr_prefixok(const isc_netaddr_t *na, unsigned int prefixlen) {
        nbytes = prefixlen / 8;
        nbits = prefixlen % 8;
        if (nbits != 0) {
+               INSIST(nbytes < ipbytes);
                if ((p[nbytes] & (0xff>>nbits)) != 0U)
                        return (ISC_R_FAILURE);
                nbytes++;