Check message id against expected id, fail / revert to AXFR on mismatch.

Skip check for second and subsequent messages if the query is AXFR.

diff --git a/lib/dns/xfrin.c b/lib/dns/xfrin.c
index 7aecd075847f733d7b520beea6de5b6af6b872fa..3fb75cbd09db3372d30cf1830f91d486d55d4614 100644 (file)
--- a/lib/dns/xfrin.c
+++ b/lib/dns/xfrin.c
@@ -15,12 +15,13 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: xfrin.c,v 1.101 2000/10/12 21:51:53 mws Exp $ */
+/* $Id: xfrin.c,v 1.102 2000/10/16 04:26:08 marka Exp $ */
 
 #include <config.h>
 
 #include <isc/mem.h>
 #include <isc/print.h>
+#include <isc/random.h>
 #include <isc/string.h>                /* Required for HP/UX (and others?) */
 #include <isc/task.h>
 #include <isc/timer.h>
@@ -103,6 +104,9 @@ struct dns_xfrin_ctx {
        dns_name_t              name;           /* Name of zone to transfer */
        dns_rdataclass_t        rdclass;
 
+       isc_boolean_t           checkid;
+       dns_messageid_t         id;
+
        /*
         * Requested transfer type (dns_rdatatype_axfr or
         * dns_rdatatype_ixfr).  The actual transfer type
@@ -452,6 +456,8 @@ xfr_rr(dns_xfrin_ctx_t *xfr, dns_name_t *name, isc_uint32_t ttl,
                                  xfr->ixfr.request_serial, xfr->end_serial);
                        FAIL(DNS_R_UPTODATE);
                }
+               if (xfr->reqtype == dns_rdatatype_axfr)
+                       xfr->checkid = ISC_FALSE;
                xfr->state = XFRST_FIRSTDATA;
                break;
 
@@ -660,6 +666,7 @@ xfrin_create(isc_mem_t *mctx,
        isc_result_t result;
        isc_interval_t maxinterval, idleinterval;
        isc_time_t expires;
+       isc_uint32_t tmp;
 
        xfr = isc_mem_get(mctx, sizeof(*xfr));
        if (xfr == NULL)
@@ -681,6 +688,9 @@ xfrin_create(isc_mem_t *mctx,
 
        dns_name_init(&xfr->name, NULL);
        xfr->rdclass = rdclass;
+       isc_random_get(&tmp);
+       xfr->checkid = ISC_TRUE;
+       xfr->id = tmp &0xffff;
        xfr->reqtype = reqtype;
 
        /* sockaddr */
@@ -911,7 +921,9 @@ xfrin_send_request(dns_xfrin_ctx_t *xfr) {
                dns_message_addname(msg, msgsoaname, DNS_SECTION_AUTHORITY);
        }
 
-       msg->id = ('b' << 8) | '9'; /* Arbitrary */
+       xfr->checkid = ISC_TRUE;
+       xfr->id++;
+       msg->id = xfr->id;
 
        CHECK(render(msg, &xfr->qbuffer));
 
@@ -1050,9 +1062,12 @@ xfrin_recv_done(isc_task_t *task, isc_event_t *ev) {
        result = dns_message_parse(msg, &tcpmsg->buffer,
                                   DNS_MESSAGEPARSE_PRESERVEORDER);
 
-       if (result != ISC_R_SUCCESS || msg->rcode != dns_rcode_noerror) {
+       if (result != ISC_R_SUCCESS || msg->rcode != dns_rcode_noerror ||
+           (xfr->checkid && msg->id != xfr->id)) {
                if (result == ISC_R_SUCCESS)
                        result = ISC_RESULTCLASS_DNSRCODE + msg->rcode; /*XXX*/
+               if (result == ISC_R_SUCCESS || result == DNS_R_NOERROR)
+                       result = DNS_R_UNEXPECTEDID;
                if (xfr->reqtype == dns_rdatatype_axfr ||
                    xfr->reqtype == dns_rdatatype_soa)
                        FAIL(result);