diff --git a/ldns/buffer.h b/ldns/buffer.h
index 79ae0f5c..1e536bfd 100644
--- a/ldns/buffer.h
+++ b/ldns/buffer.h
@@ -356,11 +356,13 @@ ldns_buffer_available(const ldns_buffer *buffer, size_t count)
  * \param[in] data pointer to the data to write to the buffer
  * \param[in] count the number of bytes of data to write
  */
-INLINE void
+INLINE size_t
 ldns_buffer_write_at(ldns_buffer *buffer, size_t at, const void *data, size_t count)
 {
-	assert(ldns_buffer_available_at(buffer, at, count));
-	memcpy(buffer->_data + at, data, count);
+	size_t avail = ldns_buffer_remaining_at(buffer, at);
+	size_t copy = count < avail ? count : avail;
+	memcpy(buffer->_data + at, data, copy);
+	return copy;
 }
 
 /**
@@ -372,8 +374,8 @@ ldns_buffer_write_at(ldns_buffer *buffer, size_t at, const void *data, size_t co
 INLINE void
 ldns_buffer_write(ldns_buffer *buffer, const void *data, size_t count)
 {
-	ldns_buffer_write_at(buffer, buffer->_position, data, count);
-	buffer->_position += count;
+	size_t copied = ldns_buffer_write_at(buffer, buffer->_position, data, count);
+	buffer->_position += copied;
 }
 
 /**
diff --git a/str2host.c b/str2host.c
index 8a325921..6f5aca7f 100644
--- a/str2host.c
+++ b/str2host.c
@@ -392,7 +392,7 @@ ldns_str2rdf_dname(ldns_rdf **d, const char *str)
 	/* root label */
 	if (1 == len && *str == '.') {
 		*d = ldns_rdf_new_frm_data(LDNS_RDF_TYPE_DNAME, 1, "\0");
-		return LDNS_STATUS_OK;
+		return *d?LDNS_STATUS_OK:LDNS_STATUS_MEM_ERR;
 	}
 
 	/* get on with the rest */
@@ -457,7 +457,7 @@ ldns_str2rdf_dname(ldns_rdf **d, const char *str)
 	len++;
 
 	*d = ldns_rdf_new_frm_data(LDNS_RDF_TYPE_DNAME, len, buf);
-	return LDNS_STATUS_OK;
+	return *d?LDNS_STATUS_OK:LDNS_STATUS_MEM_ERR;
 }
 
 ldns_status