cname loop detection

smmapdfw/libsmmapdfw/htdns.c

@@ -298,7 +298,7 @@ static void** get_rrs(char *domain, int qtype) {
 
   cnt = sizeof(HEADER);
 
-#if 0
+#if 1
   syslog(LOG_DEBUG, "id: %d\n", answer->hdr.id);
   syslog(LOG_DEBUG, "qr: %d\n", answer->hdr.qr);
   syslog(LOG_DEBUG, "oc: %d\n", answer->hdr.opcode);
@@ -334,6 +334,7 @@ static void** get_rrs(char *domain, int qtype) {
     //if (type != qtype) 
     //  printf("answer type mismatch: %d != %d\n", type, qtype);
 /*     assert(type==qtype); */
+
     cnt += 2;
     class = get16(answer->buf, cnt);
     cnt += 2;
@@ -368,8 +369,14 @@ mx_rdata_t** get_mx_rrs(char *domain) {
 
   rdata_t **rdata = (rdata_t**) get_rrs(domain, T_MX);
 
-  if ((NULL == rdata) || (NULL == *rdata)) 
+  if (NULL == rdata) {
     return NULL;
+  }
+  
+  if (NULL == *rdata) {
+    free(rdata);
+    return NULL;
+  }
 
   rdata_t **rdata2;
   mx_rdata_t **mx_rdata = NULL;
@@ -389,32 +396,49 @@ mx_rdata_t** get_mx_rrs(char *domain) {
   free(rdata);
   
   /* terminate the new container */
+  if (mx_rdata != NULL)
     *((int**)(mx_rdata + i)) = NULL;
 
   return mx_rdata;
 }
 
-a_rdata_t** get_a_rrs(char *domain) {
+
+
+a_rdata_t** inner_get_a_rrs(char *domain, int *depth) {
+  printf("depth: %d, domain: %s\n", *depth, domain);
+  if (*depth > 5) {
+    printf("loop\n");
+    return NULL;
+  }
   if (domain == NULL)
     return NULL;
 
   cname_rdata_t **cname_rdata;
 
   rdata_t **rdata = (rdata_t**) get_rrs(domain, T_A);
-  if ((NULL == rdata) || (NULL == *rdata))
+
+  if (NULL == rdata) {
     return NULL;
+  }
+  
+  if (NULL == *rdata) {
+    free(rdata);
+    return NULL;
+  }
 
   rdata_t **rdata2;
   a_rdata_t **a_rdata = NULL;
   int i = 0; // one for the termination
   for (rdata2 = rdata; *rdata2 != NULL; rdata2++) {
+    printf("  depth: %d, rdata2: %p\n", *depth, rdata2);
     if ((*rdata2)->type == T_A) {
       a_rdata = (a_rdata_t**) htrealloc(a_rdata, sizeof(a_rdata_t*) * (i + 2));
       *(a_rdata + i) = *rdata2;
       i++;
     } else if ((*rdata2)->type == T_CNAME) {
       cname_rdata_t *cname_rdata = (cname_rdata_t*) *rdata2;
-      a_rdata_t **a_rdata_recurse = get_a_rrs(cname_rdata->cname);
+      (*depth)++;
+      a_rdata_t **a_rdata_recurse = inner_get_a_rrs(cname_rdata->cname, depth);
       if ((NULL != a_rdata_recurse) && (NULL != *a_rdata_recurse)) {
 	a_rdata_t **a_rdata2;
 	for (a_rdata2 = a_rdata_recurse; *a_rdata2 != NULL; a_rdata2++) {
@@ -423,7 +447,10 @@ a_rdata_t** get_a_rrs(char *domain) {
 	  i++;
 	}
 	free(a_rdata_recurse);
+      } else if (NULL != a_rdata_recurse) {
+	free(a_rdata_recurse);
       }
+      free_rdata(cname_rdata);
     } else {
       /* it's not, free it */
       free_rdata(*rdata2);
@@ -434,12 +461,18 @@ a_rdata_t** get_a_rrs(char *domain) {
   free(rdata);
   
   /* terminate the new container */
+  if (a_rdata != NULL)
     *((int**)(a_rdata + i)) = NULL;
 
   return a_rdata;
 }
 
 
+a_rdata_t** get_a_rrs(char *domain) {
+  int i = 0;
+  return inner_get_a_rrs(domain, &i);
+}
+
 
 
 #define min(A,B) ((A<B) ? A : B)