From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phil Sutter Subject: [nft PATCH] parser_bison: Allow parens on RHS of relational_expr Date: Mon, 28 Nov 2016 18:51:43 +0100 Message-ID: <20161128175143.25201-1-phil@nwl.cc> Cc: netfilter-devel@vger.kernel.org To: Pablo Neira Ayuso Return-path: Received: from orbyte.nwl.cc ([151.80.46.58]:51162 "EHLO mail.nwl.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752225AbcK1Rvy (ORCPT ); Mon, 28 Nov 2016 12:51:54 -0500 Sender: netfilter-devel-owner@vger.kernel.org List-ID: This is useful to allow a construct such as: | tcp flags & (syn|fin) == (syn|fin) Before, only the parentheses on the left side were allowed, but via a quite funny path through the parser: * expr might be a concat_expr * concat_expr might be a basic_expr * basic_expr is an inclusive_or_expr * inclusive_or_expr might be an exclusive_or_expr * exclusive_or_expr might be an and_expr * and_expr might be 'and_expr AMPERSAND shift_expr' -> here we eliminate 'flags &' in above statement * shift_expr might be a primary_expr * primary_expr might be '( basic_expr )' Commit a3e60492a684b ("parser: restrict relational rhs expression recursion") introduced rhs_expr to disallow recursion on RHS, so just reverting that change for relational_expr is a no go. Allowing rhs_expr to be '( rhs_expr )' though seems way too intrusive to me since it's being used in all kinds of places, so this patch is the safest way to allow the above I could come up with. Signed-off-by: Phil Sutter --- src/parser_bison.y | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/src/parser_bison.y b/src/parser_bison.y index 91955c187f3f0..73a0eda9a5d87 100644 --- a/src/parser_bison.y +++ b/src/parser_bison.y @@ -2254,6 +2254,10 @@ relational_expr : expr /* implicit */ rhs_expr { $$ = relational_expr_alloc(&@2, $2, $1, $3); } + | expr relational_op '(' rhs_expr ')' + { + $$ = relational_expr_alloc(&@2, $2, $1, $4); + } ; list_rhs_expr : basic_rhs_expr COMMA basic_rhs_expr -- 2.10.0