CID 316504: Untrusted loop bound (TAINTED_SCALAR)

*** CID 316504:    (TAINTED_SCALAR)
/lib/dns/rdata/generic/rrsig_46.c: 233 in totext_rrsig()
227     
228     	/*
229     	 * Time signed.
230     	 */
231     	when = uint32_fromregion(&sr);
232     	isc_region_consume(&sr, 4);
>>>     CID 316504:    (TAINTED_SCALAR)
>>>     Passing tainted expression "when" to "dns_time32_totext", which uses it as a loop boundary.
233     	RETERR(dns_time32_totext(when, target));
234     	RETERR(str_totext(" ", target));
235     
236     	/*
237     	 * Footprint.
238     	 */
/lib/dns/rdata/generic/rrsig_46.c: 225 in totext_rrsig()
219     
220     	/*
221     	 * Sig exp.
222     	 */
223     	exp = uint32_fromregion(&sr);
224     	isc_region_consume(&sr, 4);
>>>     CID 316504:    (TAINTED_SCALAR)
>>>     Passing tainted expression "exp" to "dns_time32_totext", which uses it as a loop boundary.
225     	RETERR(dns_time32_totext(exp, target));
226     	RETERR(str_totext(" ", target));
227     
228     	/*
229     	 * Time signed.
230     	 */