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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 33487C43143 for ; Mon, 1 Oct 2018 21:22:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EF541208AE for ; Mon, 1 Oct 2018 21:22:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EF541208AE Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=canonical.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726362AbeJBECE (ORCPT ); Tue, 2 Oct 2018 00:02:04 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:51321 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725878AbeJBECE (ORCPT ); Tue, 2 Oct 2018 00:02:04 -0400 Received: from static-50-53-48-205.bvtn.or.frontiernet.net ([50.53.48.205] helo=[192.168.192.153]) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1g75dw-0007zj-8e; Mon, 01 Oct 2018 21:22:16 +0000 Subject: Re: [PATCH security-next v3 16/29] LSM: Prepare for arbitrary LSM enabling To: Kees Cook , James Morris Cc: Casey Schaufler , Tetsuo Handa , Paul Moore , Stephen Smalley , "Schaufler, Casey" , LSM , Jonathan Corbet , linux-doc@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org References: <20180925001832.18322-1-keescook@chromium.org> <20180925001832.18322-17-keescook@chromium.org> From: John Johansen Openpgp: preference=signencrypt Autocrypt: addr=john.johansen@canonical.com; 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Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180925001832.18322-17-keescook@chromium.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/24/2018 05:18 PM, Kees Cook wrote: > Before now, all the LSMs that did not specify an "enable" variable in their > struct lsm_info were considered enabled by default. This prepares to make > LSM enabling more explicit. For all LSMs without an explicit "enable" > variable, a hard-coded storage location is chosen, and all LSMs without > an external "enable" state have their state explicitly set to "enabled". > > This code appears more complex than it needs to be (comma-separated > list parsing and "set" function parameter) because its use will be > expanded on in the following patches to provide more explicit enabling. > > Signed-off-by: Kees Cook Reviewed-by: John Johansen > --- > security/security.c | 69 ++++++++++++++++++++++++++++++++++++++++++--- > 1 file changed, 65 insertions(+), 4 deletions(-) > > diff --git a/security/security.c b/security/security.c > index 056b36cf6245..a8107d54b3d3 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -54,17 +54,46 @@ static bool debug __initdata; > > static bool __init is_enabled(struct lsm_info *lsm) > { > - if (!lsm->enabled || *lsm->enabled) > - return true; > + if (WARN_ON(!lsm->enabled)) > + return false; > > - return false; > + return *lsm->enabled; > } > > /* Mark an LSM's enabled flag, if it exists. */ > -static void __init set_enabled(struct lsm_info *lsm, bool enabled) > +static int lsm_enabled_true __initdata = 1; > +static int lsm_enabled_false __initdata = 0; > + > +static void __init default_enabled(struct lsm_info *lsm, bool enabled) > { > + /* If storage location already set, skip this one. */ > if (lsm->enabled) > + return; > + > + /* > + * When an LSM hasn't configured an enable variable, we can use > + * a hard-coded location for storing the default enabled state. > + */ > + if (enabled) > + lsm->enabled = &lsm_enabled_true; > + else > + lsm->enabled = &lsm_enabled_false; > +} > + > +static void __init set_enabled(struct lsm_info *lsm, bool enabled) > +{ > + if (WARN_ON(!lsm->enabled)) > + return; > + > + if (lsm->enabled == &lsm_enabled_true) { > + if (!enabled) > + lsm->enabled = &lsm_enabled_false; > + } else if (lsm->enabled == &lsm_enabled_false) { > + if (enabled) > + lsm->enabled = &lsm_enabled_true; > + } else { > *lsm->enabled = enabled; > + } > } > > /* Is an LSM allowed to be initialized? */ > @@ -127,6 +156,35 @@ static void __init major_lsm_init(void) > } > } > > +static void __init parse_lsm_enable(const char *str, > + void (*set)(struct lsm_info *, bool), > + bool enabled) > +{ > + char *sep, *name, *next; > + > + if (!str) > + return; > + > + sep = kstrdup(str, GFP_KERNEL); > + next = sep; > + while ((name = strsep(&next, ",")) != NULL) { > + struct lsm_info *lsm; > + > + for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { > + if (strcmp(name, "all") == 0 || > + strcmp(name, lsm->name) == 0) > + set(lsm, enabled); > + } > + } > + kfree(sep); > +} > + > +static void __init prepare_lsm_enable(void) > +{ > + /* Prepare defaults. */ > + parse_lsm_enable("all", default_enabled, true); > +} > + > /** > * security_init - initializes the security framework > * > @@ -143,6 +201,9 @@ int __init security_init(void) > i++) > INIT_HLIST_HEAD(&list[i]); > > + /* Figure out which LSMs are enabled and disabled. */ > + prepare_lsm_enable(); > + > /* > * Load minor LSMs, with the capability module always first. > */ >