s4 dns: Correctly handle A questions for CNAMEs

[garming/samba-autobuild/.git] / source4 / dns_server / dns_query.c

diff --git a/source4/dns_server/dns_query.c b/source4/dns_server/dns_query.c
index 0e630582280d39113be86d7c9ef7fed0a3f0d01f..40df3a1ff0f1580484697ae4d95e2d888108797e 100644 (file)
--- a/source4/dns_server/dns_query.c
+++ b/source4/dns_server/dns_query.c
@@ -231,11 +231,11 @@ static WERROR handle_question(struct dns_server *dns,
                              const struct dns_name_question *question,
                              struct dns_res_rec **answers, uint16_t *ancount)
 {
-       struct dns_res_rec *ans;
+       struct dns_res_rec *ans = *answers;
        WERROR werror;
        unsigned int ri;
        struct dnsp_DnssrvRpcRecord *recs;
-       uint16_t rec_count, ai = 0;
+       uint16_t rec_count, ai = *ancount;
        struct ldb_dn *dn = NULL;
 
        werror = dns_name2dn(dns, mem_ctx, question->name, &dn);
@@ -244,16 +244,67 @@ static WERROR handle_question(struct dns_server *dns,
        werror = dns_lookup_records(dns, mem_ctx, dn, &recs, &rec_count);
        W_ERROR_NOT_OK_RETURN(werror);
 
-       ans = talloc_zero_array(mem_ctx, struct dns_res_rec, rec_count);
-       W_ERROR_HAVE_NO_MEMORY(ans);
+       ans = talloc_realloc(mem_ctx, ans, struct dns_res_rec, rec_count + ai);
+       if (ans == NULL) {
+               return WERR_NOMEM;
+       }
 
        for (ri = 0; ri < rec_count; ri++) {
+               if ((recs[ri].wType == DNS_TYPE_CNAME) &&
+                   ((question->question_type == DNS_QTYPE_A) ||
+                    (question->question_type == DNS_QTYPE_AAAA))) {
+                       struct dns_name_question *new_q =
+                               talloc(mem_ctx, struct dns_name_question);
+
+                       if (new_q == NULL) {
+                               return WERR_NOMEM;
+                       }
+
+                       /* We reply with one more record, so grow the array */
+                       ans = talloc_realloc(mem_ctx, ans, struct dns_res_rec,
+                                            rec_count + 1);
+                       if (ans == NULL) {
+                               TALLOC_FREE(new_q);
+                               return WERR_NOMEM;
+                       }
+
+                       /* First put in the CNAME record */
+                       werror = create_response_rr(question, &recs[ri], &ans, &ai);
+                       if (!W_ERROR_IS_OK(werror)) {
+                               return werror;
+                       }
+
+                       /* And then look up the name it points at.. */
+
+                       /* First build up the new question */
+                       new_q->question_type = question->question_type;
+                       new_q->question_class = question->question_class;
+                       if (new_q->question_type == DNS_QTYPE_A) {
+                               new_q->name = talloc_strdup(new_q, recs[ri].data.ipv4);
+                       } else if (new_q->question_type == DNS_QTYPE_AAAA) {
+                               new_q->name = talloc_strdup(new_q, recs[ri].data.ipv6);
+                       }
+                       if (new_q->name == NULL) {
+                               TALLOC_FREE(new_q);
+                               return WERR_NOMEM;
+                       }
+                       /* and then call the lookup again */
+                       werror = handle_question(dns, mem_ctx, new_q, &ans, &ai);
+                       if (!W_ERROR_IS_OK(werror)) {
+                               return werror;
+                       }
+
+
+                       continue;
+               }
                if ((question->question_type != DNS_QTYPE_ALL) &&
                    (recs[ri].wType != question->question_type)) {
                        continue;
                }
                werror = create_response_rr(question, &recs[ri], &ans, &ai);
-               W_ERROR_NOT_OK_RETURN(werror);
+               if (!W_ERROR_IS_OK(werror)) {
+                       return werror;
+               }
        }
 
        if (ai == 0) {