From mboxrd@z Thu Jan 1 00:00:00 1970 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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 9548EC07E95 for ; Tue, 13 Jul 2021 20:00:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 67E806101D for ; Tue, 13 Jul 2021 20:00:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234290AbhGMUDi (ORCPT ); Tue, 13 Jul 2021 16:03:38 -0400 Received: from mx1.polytechnique.org ([129.104.30.34]:49086 "EHLO mx1.polytechnique.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229944AbhGMUDi (ORCPT ); Tue, 13 Jul 2021 16:03:38 -0400 Received: from mail-io1-f46.google.com (mail-io1-f46.google.com [209.85.166.46]) (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 0744C564798 for ; Tue, 13 Jul 2021 22:00:46 +0200 (CEST) Received: by mail-io1-f46.google.com with SMTP id x10so9938697ion.9 for ; Tue, 13 Jul 2021 13:00:45 -0700 (PDT) X-Gm-Message-State: AOAM531onmcuulg9IczbkBXLlAnBub0fRRHIgyTns5S6JenHWsZ371bM bCP2tPRWKNbZLO/7p4I6GIA0AkMc+8GXrZO5m54= X-Google-Smtp-Source: ABdhPJwnNXbtDpGG5SV2fpTjy8K4Kk5DlVD4gh0g2IrRQCdTrNhkDJRZG6gsstznXFMB7meHrLoDsPgveXkxZ8Y8JFE= X-Received: by 2002:a6b:f81a:: with SMTP id o26mr4496240ioh.56.1626206445180; Tue, 13 Jul 2021 13:00:45 -0700 (PDT) MIME-Version: 1.0 References: <20210712135038.9405-1-jwcart2@gmail.com> In-Reply-To: From: Nicolas Iooss Date: Tue, 13 Jul 2021 22:00:34 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2] libsepol/cil: Fix handling category sets in an expression To: James Carter Cc: SElinux list Content-Type: text/plain; charset="UTF-8" X-AV-Checked: ClamAV using ClamSMTP at svoboda.polytechnique.org (Tue Jul 13 22:00:46 2021 +0200 (CEST)) X-Org-Mail: nicolas.iooss.2010@polytechnique.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org On Mon, Jul 12, 2021 at 10:06 PM Nicolas Iooss wrote: > > On Mon, Jul 12, 2021 at 3:50 PM James Carter wrote: > > > > There are two problems that need to be addressed when resolving an > > expression with category sets. > > > > 1. Only expand anonymous category sets in an expression. > > > > Commit 982ec302b67f3c7f8df667dadb67352b1e4a6d18 (libsepol/cil: > > Account for anonymous category sets in an expression) attempted to > > properly handle anonymous category sets when resolving category > > expressions. Unfortunately, it did not check whether a category set > > was actually an anonymous category set and expanded all category > > sets in an expression. If a category set refers to itself in the > > expression, then everything from the name of the category set to the > > end of the expression is ignored. > > > > For example, the rule "(categoryset cs (c0 cs c1 c2))", would be > > equivalent to the rule "(categoryset cs (c0))" as everything from > > "cs" to the end would be dropped. The secilc-fuzzer found that the > > rule "(categoryset cat (not cat))" would cause a segfault since > > "(not)" is not a valid expression and it is assumed to be valid > > during later evaluation because syntax checking has already been > > done. > > > > Instead, check whether or not the category set is anonymous before > > expanding it when resolving an expression. > > > > 2. Category sets cannot be used in a category range > > > > A category range can be used to specify a large number of categories. > > The range "(range c0 c1023)" refers to 1024 categories. Only categories > > and category aliases can be used in a range. Determining if an > > identifier is a category, an alias, or a set can only be done after > > resolving the identifer. > > > > Keep track of the current operator as an expression is being resolved > > and if the expression involves categories and a category set is > > encountered, then return an error if the expression is a category > > range. > > > > Signed-off-by: James Carter > > Acked-by: Nicolas Iooss > > Thanks! > Nicolas Merged. Thanks! Nicolas > > --- > > libsepol/cil/src/cil_resolve_ast.c | 28 +++++++++++++++++++++------- > > 1 file changed, 21 insertions(+), 7 deletions(-) > > > > diff --git a/libsepol/cil/src/cil_resolve_ast.c b/libsepol/cil/src/cil_resolve_ast.c > > index 145d4e74..18007324 100644 > > --- a/libsepol/cil/src/cil_resolve_ast.c > > +++ b/libsepol/cil/src/cil_resolve_ast.c > > @@ -3228,6 +3228,7 @@ int cil_resolve_expr(enum cil_flavor expr_type, struct cil_list *str_expr, struc > > struct cil_symtab_datum *res_datum = NULL; > > enum cil_sym_index sym_index = CIL_SYM_UNKNOWN; > > struct cil_list *datum_sub_expr; > > + enum cil_flavor op = CIL_NONE; > > > > switch (str_expr->flavor) { > > case CIL_BOOL: > > @@ -3263,14 +3264,24 @@ int cil_resolve_expr(enum cil_flavor expr_type, struct cil_list *str_expr, struc > > } > > if (sym_index == CIL_SYM_CATS && NODE(res_datum)->flavor == CIL_CATSET) { > > struct cil_catset *catset = (struct cil_catset *)res_datum; > > - if (!catset->cats->datum_expr) { > > - rc = cil_resolve_expr(expr_type, catset->cats->str_expr, &catset->cats->datum_expr, parent, extra_args); > > - if (rc != SEPOL_OK) { > > - goto exit; > > + if (op == CIL_RANGE) { > > + cil_tree_log(parent, CIL_ERR, "Category set not allowed in category range"); > > + rc = SEPOL_ERR; > > + goto exit; > > + } > > + if (!res_datum->name) { > > + /* Anonymous category sets need to be resolved when encountered */ > > + if (!catset->cats->datum_expr) { > > + rc = cil_resolve_expr(expr_type, catset->cats->str_expr, &catset->cats->datum_expr, parent, extra_args); > > + if (rc != SEPOL_OK) { > > + goto exit; > > + } > > } > > + cil_copy_list(catset->cats->datum_expr, &datum_sub_expr); > > + cil_list_append(*datum_expr, CIL_LIST, datum_sub_expr); > > + } else { > > + cil_list_append(*datum_expr, CIL_DATUM, res_datum); > > } > > - cil_copy_list(catset->cats->datum_expr, &datum_sub_expr); > > - cil_list_append(*datum_expr, CIL_LIST, datum_sub_expr); > > } else { > > if (sym_index == CIL_SYM_TYPES && (expr_type == CIL_CONSTRAIN || expr_type == CIL_VALIDATETRANS)) { > > cil_type_used(res_datum, CIL_ATTR_CONSTRAINT); > > @@ -3287,9 +3298,12 @@ int cil_resolve_expr(enum cil_flavor expr_type, struct cil_list *str_expr, struc > > break; > > } > > default: > > + if (curr->flavor == CIL_OP) { > > + op = (enum cil_flavor)(uintptr_t)curr->data; > > + } > > cil_list_append(*datum_expr, curr->flavor, curr->data); > > break; > > - } > > + } > > } > > return SEPOL_OK; > > > > -- > > 2.31.1 > >