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[173.164.112.133]) by smtp.gmail.com with ESMTPSA id q23-v6sm22030901pfd.44.2018.10.01.17.55.19 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 01 Oct 2018 17:55:25 -0700 (PDT) From: Kees Cook 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 Subject: [PATCH security-next v4 31/32] LSM: Separate idea of "major" LSM from "exclusive" LSM Date: Mon, 1 Oct 2018 17:55:04 -0700 Message-Id: <20181002005505.6112-32-keescook@chromium.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181002005505.6112-1-keescook@chromium.org> References: <20181002005505.6112-1-keescook@chromium.org> Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org In order to both support old "security=" Legacy Major LSM selection, and handling real exclusivity, this creates LSM_FLAG_EXCLUSIVE and updates the selection logic to handle them. Signed-off-by: Kees Cook Reviewed-by: Casey Schaufler --- include/linux/lsm_hooks.h | 1 + security/apparmor/lsm.c | 2 +- security/security.c | 12 ++++++++++++ security/selinux/hooks.c | 2 +- security/smack/smack_lsm.c | 2 +- security/tomoyo/tomoyo.c | 2 +- 6 files changed, 17 insertions(+), 4 deletions(-) diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 36e7a716fdfe..2c9cf89a20ad 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -2040,6 +2040,7 @@ extern void security_add_hooks(struct security_hook_list *hooks, int count, char *lsm); #define LSM_FLAG_LEGACY_MAJOR BIT(0) +#define LSM_FLAG_EXCLUSIVE BIT(1) enum lsm_order { LSM_ORDER_FIRST = -1, /* This is only for capabilities. */ diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c index 4cd96a66ed6f..4eb74a6f2020 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -1599,7 +1599,7 @@ static int __init apparmor_init(void) DEFINE_LSM(apparmor) = { .name = "apparmor", - .flags = LSM_FLAG_LEGACY_MAJOR, + .flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE, .enabled = &apparmor_enabled, .init = apparmor_init, }; diff --git a/security/security.c b/security/security.c index 813dab3b5b97..7d542e78b7e8 100644 --- a/security/security.c +++ b/security/security.c @@ -52,6 +52,7 @@ static __initconst const char * const builtin_lsm_order = CONFIG_LSM_ORDER; /* Ordered list of LSMs to initialize. */ static __initdata struct lsm_info **ordered_lsms; +static __initdata struct lsm_info *exclusive; static __initdata bool debug; #define init_debug(...) \ @@ -196,6 +197,12 @@ static bool __init lsm_allowed(struct lsm_info *lsm) if (!is_enabled(lsm)) return false; + /* Not allowed if another exclusive LSM already initialized. */ + if ((lsm->flags & LSM_FLAG_EXCLUSIVE) && exclusive) { + init_debug("exclusive disabled: %s\n", lsm->name); + return false; + } + return true; } @@ -211,6 +218,11 @@ static void __init maybe_initialize_lsm(struct lsm_info *lsm) if (enabled) { int ret; + if ((lsm->flags & LSM_FLAG_EXCLUSIVE) && !exclusive) { + exclusive = lsm; + init_debug("exclusive: %s\n", lsm->name); + } + init_debug("initializing %s\n", lsm->name); ret = lsm->init(); WARN(ret, "%s failed to initialize: %d\n", lsm->name, ret); diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 8f5eea097612..c070d3761ddc 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -7181,7 +7181,7 @@ void selinux_complete_init(void) all processes and objects when they are created. */ DEFINE_LSM(selinux) = { .name = "selinux", - .flags = LSM_FLAG_LEGACY_MAJOR, + .flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE, .enabled = &selinux_enabled, .init = selinux_init, }; diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index f243044d5a55..92e4baa342f8 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -4881,6 +4881,6 @@ static __init int smack_init(void) */ DEFINE_LSM(smack) = { .name = "smack", - .flags = LSM_FLAG_LEGACY_MAJOR, + .flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE, .init = smack_init, }; diff --git a/security/tomoyo/tomoyo.c b/security/tomoyo/tomoyo.c index a46f6bc1e97c..daff7d7897ad 100644 --- a/security/tomoyo/tomoyo.c +++ b/security/tomoyo/tomoyo.c @@ -550,6 +550,6 @@ static int __init tomoyo_init(void) DEFINE_LSM(tomoyo) = { .name = "tomoyo", - .flags = LSM_FLAG_LEGACY_MAJOR, + .flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE, .init = tomoyo_init, }; -- 2.17.1