Attempt to address issue #46

Makefile.in

@@ -31,6 +31,9 @@ uninstall:
 doc: 
 	cd doc && $(MAKE) $@
 
+example:
+	cd src && $(MAKE) $@
+
 test:
 	cd src && $(MAKE) $@
 

src/general.c

@@ -341,6 +341,11 @@ getdns_general(struct getdns_context *context,
          return GETDNS_RETURN_INVALID_PARAMETER;
     }
 
+    extcheck = validate_dname(name);
+    if (extcheck != GETDNS_RETURN_GOOD) {
+        return extcheck;
+    }
+
 	extcheck = validate_extensions(extensions);
 	if (extcheck != GETDNS_RETURN_GOOD)
 		return extcheck;

src/sync.c

@@ -71,6 +71,11 @@ getdns_general_sync(struct getdns_context *context,
 	getdns_return_t response_status;
     RETURN_IF_NULL(context, GETDNS_RETURN_BAD_CONTEXT);
     RETURN_IF_NULL(response, GETDNS_RETURN_INVALID_PARAMETER);
+    RETURN_IF_NULL(name, GETDNS_RETURN_INVALID_PARAMETER);
+    response_status = validate_dname(name);
+    if (response_status != GETDNS_RETURN_GOOD) {
+        return response_status;
+    }
 	response_status = validate_extensions(extensions);
 	if (response_status == GETDNS_RETURN_GOOD) {
 		response_status = getdns_general_ub(context->unbound_sync,

src/util-internal.c

@@ -677,4 +677,49 @@ validate_extensions(struct getdns_dict * extensions)
 	return GETDNS_RETURN_GOOD;
 }				/* validate_extensions */
 
+getdns_return_t
+validate_dname(const char* dname) {
+    int len;
+    int label_len;
+    const char* s;
+    if (dname == NULL) {
+        return GETDNS_RETURN_INVALID_PARAMETER;
+    }
+    len = strlen(dname);
+    if (len >= GETDNS_MAX_DNAME_LEN || len == 0) {
+        return GETDNS_RETURN_BAD_DOMAIN_NAME;
+    }
+    if (len == 1 && dname[0] == '.') {
+        /* root is ok */
+        return GETDNS_RETURN_GOOD;
+    }
+    label_len = 0;
+    for (s = dname; *s; ++s) {
+        switch (*s) {
+            case '.':
+                if (label_len > GETDNS_MAX_LABEL_LEN ||
+                    label_len == 0) {
+                    return GETDNS_RETURN_BAD_DOMAIN_NAME;
+                }
+                label_len = 0;
+                break;
+            default:
+                if ((*s >= 'a' && *s <= 'z') ||
+                    (*s >= 'A' && *s <= 'Z') ||
+                    (*s >= '0' && *s <= '9')) {
+                    label_len++;
+                } else if (*s == '-' && label_len != 0) {
+                    label_len++;
+                } else {
+                    return GETDNS_RETURN_BAD_DOMAIN_NAME;
+                }
+                break;
+        }
+    }
+    if (label_len > GETDNS_MAX_LABEL_LEN) {
+        return GETDNS_RETURN_BAD_DOMAIN_NAME;
+    }
+    return GETDNS_RETURN_GOOD;
+}
+
 /* util-internal.c */

src/util-internal.h

@@ -41,6 +41,9 @@
 #include <ldns/ldns.h>
 #include "context.h"
 
+#define GETDNS_MAX_DNAME_LEN 255
+#define GETDNS_MAX_LABEL_LEN 63
+
 /**
  * add an item to the tail of a list - note that this was not in the getdns API
  * description but the list_set functions seem to be designed to modify an existing
@@ -96,6 +99,8 @@ getdns_return_t getdns_dict_util_get_string(struct getdns_dict * dict, char *nam
     char **result);
 char *reverse_address(struct getdns_bindata *address_data);
 
+getdns_return_t validate_dname(const char* dname);
+
 /**
  * detect unrecognized extension strings or invalid extension formats
  * TODO: this could be optimized by searching a sorted list