From patchwork Wed Dec 30 20:11:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicolas Iooss X-Patchwork-Id: 11993643 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 65D4CC433DB for ; Wed, 30 Dec 2020 20:12:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 314822222A for ; Wed, 30 Dec 2020 20:12:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726285AbgL3UMg (ORCPT ); Wed, 30 Dec 2020 15:12:36 -0500 Received: from mx1.polytechnique.org ([129.104.30.34]:45584 "EHLO mx1.polytechnique.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726247AbgL3UMg (ORCPT ); Wed, 30 Dec 2020 15:12:36 -0500 Received: from localhost.localdomain (174.17.206.77.rev.sfr.net [77.206.17.174]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ssl.polytechnique.org (Postfix) with ESMTPSA id AF7E0560618 for ; Wed, 30 Dec 2020 21:11:54 +0100 (CET) From: Nicolas Iooss To: selinux@vger.kernel.org Subject: [PATCH 3/4] libsepol/cil: do not add a stack variable to a list Date: Wed, 30 Dec 2020 21:11:40 +0100 Message-Id: <20201230201141.3455302-3-nicolas.iooss@m4x.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201230201141.3455302-1-nicolas.iooss@m4x.org> References: <20201230201141.3455302-1-nicolas.iooss@m4x.org> MIME-Version: 1.0 X-AV-Checked: ClamAV using ClamSMTP at svoboda.polytechnique.org (Wed Dec 30 21:11:55 2020 +0100 (CET)) X-Org-Mail: nicolas.iooss.2010@polytechnique.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org OSS-Fuzz found a heap use-after-free when the CIL compiler destroys its database after failing to compile the following policy: (validatetrans x (eq t3 (a))) This is caused by the fact that the validatetrans AST object references a stack variable local to __cil_fill_constraint_leaf_expr, when parsing the list "(a)": struct cil_list *sub_list; cil_fill_list(current->next->next->cl_head, leaf_expr_flavor, &sub_list); cil_list_append(*leaf_expr, CIL_LIST, &sub_list); Drop the & sign to really add the list like it is supposed to be. Fixes: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28507 Signed-off-by: Nicolas Iooss --- libsepol/cil/src/cil_build_ast.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libsepol/cil/src/cil_build_ast.c b/libsepol/cil/src/cil_build_ast.c index 0c9015cef578..4caff3cb3c98 100644 --- a/libsepol/cil/src/cil_build_ast.c +++ b/libsepol/cil/src/cil_build_ast.c @@ -2714,7 +2714,7 @@ static int __cil_fill_constraint_leaf_expr(struct cil_tree_node *current, enum c } else if (r_flavor == CIL_LIST) { struct cil_list *sub_list; cil_fill_list(current->next->next->cl_head, leaf_expr_flavor, &sub_list); - cil_list_append(*leaf_expr, CIL_LIST, &sub_list); + cil_list_append(*leaf_expr, CIL_LIST, sub_list); } else { cil_list_append(*leaf_expr, CIL_CONS_OPERAND, (void *)r_flavor); }