diff --git a/database/tags.c b/database/tags.c
line changes: +5/-0
index dc6bac8..0d7a27f
--- a/database/tags.c
+++ b/database/tags.c

@@ -106,6 +106,11 @@ struct blergref * tag_list(const char *tag, uint64_t offset, int *count, int dir
 
 	if (!valid_tag_name(tag + 1))
 		return NULL;
+
+	if (!(direction == 1 || direction == -1)) {
+		fprintf(stderr, "Invalid direction: %d\n", direction);
+		return NULL;
+	}
 	
 	switch(tag[0]) {
 	case '#':