File bind-CVE-2021-25214.patch of Package bind.37294

Index: bind-9.9.9-P1/lib/dns/xfrin.c
===================================================================
--- bind-9.9.9-P1.orig/lib/dns/xfrin.c
+++ bind-9.9.9-P1/lib/dns/xfrin.c
@@ -478,6 +478,19 @@ xfr_rr(dns_xfrin_ctx_t *xfr, dns_name_t
 	if (rdata->type == dns_rdatatype_none ||
 	    dns_rdatatype_ismeta(rdata->type))
 		FAIL(DNS_R_FORMERR);
+	/*
+	 * Immediately reject the entire transfer if the RR that is currently
+	 * being processed is an SOA record that is not placed at the zone
+	 * apex.
+	 */
+	if (rdata->type == dns_rdatatype_soa &&
+	    !dns_name_equal(&xfr->name, name)) {
+		char namebuf[DNS_NAME_FORMATSIZE];
+		dns_name_format(name, namebuf, sizeof(namebuf));
+		xfrin_log(xfr, ISC_LOG_DEBUG(3), "SOA name mismatch: '%s'",
+			  namebuf);
+		FAIL(DNS_R_NOTZONETOP);
+	}
 
  redo:
 	switch (xfr->state) {