diff --git a/daemon/call_interfaces.c b/daemon/call_interfaces.c
index 6180a48e6..33bf187b9 100644
--- a/daemon/call_interfaces.c
+++ b/daemon/call_interfaces.c
@@ -950,7 +950,7 @@ static const char *call_offer_answer_ng(bencode_item_t *input,
 		goto out;
 
 	if (chopper->output->len)
-		bencode_dictionary_add_string(output, "sdp", chopper->output->str);
+		bencode_dictionary_add_string_len(output, "sdp", chopper->output->str, chopper->output->len);
 
 	errstr = NULL;
 out:
diff --git a/include/bencode.h b/include/bencode.h
index 0b27ca1ed..70eb1f4a1 100644
--- a/include/bencode.h
+++ b/include/bencode.h
@@ -126,6 +126,7 @@ bencode_item_t *bencode_dictionary_add_len(bencode_item_t *dict, const char *key
  * bencode_buffer_t object. */
 INLINE bencode_item_t *bencode_dictionary_add_string(bencode_item_t *dict, const char *key, const char *val);
 INLINE bencode_item_t *bencode_dictionary_add_string_dup(bencode_item_t *dict, const char *key, const char *val);
+INLINE bencode_item_t *bencode_dictionary_add_string_len(bencode_item_t *dict, const char *key, const char *val, int len);
 
 /* Ditto, but for a "str" object */
 INLINE bencode_item_t *bencode_dictionary_add_str(bencode_item_t *dict, const char *key, const str *val);
@@ -407,6 +408,12 @@ INLINE bencode_item_t *bencode_dictionary_add_string(bencode_item_t *dict, const
 	return bencode_dictionary_add(dict, key, bencode_string(bencode_item_buffer(dict), val));
 }
 
+INLINE bencode_item_t *bencode_dictionary_add_string_len(bencode_item_t *dict, const char *key, const char *val, int len) {
+	if (!val)
+		return NULL;
+	return bencode_dictionary_add(dict, key, bencode_string_len(bencode_item_buffer(dict), val, len));
+}
+
 INLINE bencode_item_t *bencode_dictionary_add_string_dup(bencode_item_t *dict, const char *key, const char *val) {
 	if (!val)
 		return NULL;