From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io1-f68.google.com ([209.85.166.68]:34587 "EHLO mail-io1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727051AbeJBHpI (ORCPT ); Tue, 2 Oct 2018 03:45:08 -0400 Received: by mail-io1-f68.google.com with SMTP id k19-v6so304390iom.1 for ; Mon, 01 Oct 2018 18:04:37 -0700 (PDT) From: Kees Cook Subject: [PATCH security-next v4 25/32] LSM: Introduce CONFIG_LSM_ORDER Date: Mon, 1 Oct 2018 17:54:58 -0700 Message-ID: <20181002005505.6112-26-keescook@chromium.org> In-Reply-To: <20181002005505.6112-1-keescook@chromium.org> References: <20181002005505.6112-1-keescook@chromium.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: James Morris Cc: Kees Cook , Casey Schaufler , John Johansen , 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 Message-ID: <20181002005458.scrPdDGj2h0d0MI123_AeAqoXUkHqLigEnE7HVmOR2Y@z> This provides a way to declare LSM initialization order via Kconfig. Signed-off-by: Kees Cook Reviewed-by: Casey Schaufler --- security/Kconfig | 16 ++++++++++++++++ security/security.c | 40 +++++++++++++++++++++++++++++++++++++--- 2 files changed, 53 insertions(+), 3 deletions(-) diff --git a/security/Kconfig b/security/Kconfig index 1e57619fd561..c68520d97fd7 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -286,5 +286,21 @@ config LSM_ENABLE changed with the "lsm.enable=" and "lsm.disable=" boot parameters. + Note that any enabled exclusive LSM modules will be initialized + based on LSM ordering, automatically disabling any following + exclusive LSMs. See CONFIG_LSM_ORDER for more details on + changing LSM initialization order. + +config LSM_ORDER + string "Default initialization order of builtin LSMs" + default "integrity" + help + A comma-separated list of LSMs, in initialization order. + Any LSMs left off this list will be link-order initialized + after any listed LSMs. Any LSMs listed here but not built in + the kernel will be ignored. + + If unsure, leave this as the default. + endmenu diff --git a/security/security.c b/security/security.c index 8706b42b4d44..0510bb8e0af0 100644 --- a/security/security.c +++ b/security/security.c @@ -47,6 +47,7 @@ static __initdata const char *chosen_lsm_disable; static __initdata const char *chosen_major_lsm; static __initconst const char * const builtin_lsm_enable = CONFIG_LSM_ENABLE; +static __initconst const char * const builtin_lsm_order = CONFIG_LSM_ORDER; /* Ordered list of LSMs to initialize. */ static __initdata struct lsm_info **ordered_lsms; @@ -122,14 +123,47 @@ static void __init append_ordered_lsm(struct lsm_info *lsm, const char *from) is_enabled(lsm) ? "en" : "dis"); } -/* Populate ordered LSMs list from hard-coded list of LSMs. */ +/* Populate ordered LSMs list from given string. */ +static void __init parse_lsm_order(const char *order, const char *origin) +{ + struct lsm_info *lsm; + char *sep, *name, *next; + + if (!order) + return; + + sep = kstrdup(order, GFP_KERNEL); + next = sep; + /* Walk the list, looking for matching LSMs. */ + while ((name = strsep(&next, ",")) != NULL) { + bool found = false; + + for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { + if ((lsm->flags & LSM_FLAG_LEGACY_MAJOR) == 0 && + strcmp(lsm->name, name) == 0) { + append_ordered_lsm(lsm, origin); + found = true; + } + } + + if (!found) + init_debug("%s ignored: %s\n", origin, name); + } + kfree(sep); +} + +/* Populate ordered LSMs list from builtin list of LSMs. */ static void __init prepare_lsm_order(void) { struct lsm_info *lsm; + /* Parse order from builtin list. */ + parse_lsm_order(builtin_lsm_order, "builtin"); + + /* Add any missing LSMs, in link order. */ for (lsm = __start_lsm_info; lsm < __end_lsm_info; lsm++) { - if (strcmp(lsm->name, "integrity") == 0) - append_ordered_lsm(lsm, "builtin"); + if ((lsm->flags & LSM_FLAG_LEGACY_MAJOR) == 0) + append_ordered_lsm(lsm, "link-time"); } } -- 2.17.1