CID 316507: Insecure data handling (TAINTED_SCALAR)

*** CID 316507:  Insecure data handling  (TAINTED_SCALAR)
/lib/dns/rdata/generic/nsec3param_51.c: 241 in tostruct_nsec3param()
235     	region.length = rdata->length;
236     	nsec3param->hash = uint8_consume_fromregion(&region);
237     	nsec3param->flags = uint8_consume_fromregion(&region);
238     	nsec3param->iterations = uint16_consume_fromregion(&region);
239     
240     	nsec3param->salt_length = uint8_consume_fromregion(&region);
>>>     CID 316507:  Insecure data handling  (TAINTED_SCALAR)
>>>     Passing tainted expression "nsec3param->salt_length" to "mem_maybedup", which uses it as an offset.
241     	nsec3param->salt = mem_maybedup(mctx, region.base,
242     					nsec3param->salt_length);
243     	if (nsec3param->salt == NULL) {
244     		return (ISC_R_NOMEMORY);
245     	}
246     	isc_region_consume(&region, nsec3param->salt_length);