json: disallow empty concatenation

Disallow empty concatenation in set declaration in json.

 internal:0:0-0: Error: Empty concatenation
 internal:0:0-0: Error: Invalid set type.
 internal:0:0-0: Error: Parsing command array at index 1 failed.

Joint work with Florian Westphal.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/src/parser_json.c b/src/parser_json.c
index dd085d78..04d76274 100644
--- a/src/parser_json.c
+++ b/src/parser_json.c
@@ -1729,6 +1729,13 @@ static struct expr *json_parse_dtype_expr(struct json_ctx *ctx, json_t *root)
 			}
 			compound_expr_add(expr, i);
 		}
+
+		if (list_empty(&expr->expressions)) {
+			json_error(ctx, "Empty concatenation");
+			expr_free(expr);
+			return NULL;
+		}
+
 		return expr;
 	} else if (json_is_object(root)) {
 		const char *key;