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=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL 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 0A352C7618F for ; Thu, 18 Jul 2019 19:44:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C58CF2184B for ; Thu, 18 Jul 2019 19:44:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ZkbTGs7F" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391439AbfGRToX (ORCPT ); Thu, 18 Jul 2019 15:44:23 -0400 Received: from mail-pg1-f202.google.com ([209.85.215.202]:43280 "EHLO mail-pg1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391312AbfGRToW (ORCPT ); Thu, 18 Jul 2019 15:44:22 -0400 Received: by mail-pg1-f202.google.com with SMTP id p29so9018990pgm.10 for ; Thu, 18 Jul 2019 12:44:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=597mNbti9AE4jskQLQ5sdKqhsrWUg3noqnu7lsx00Ik=; b=ZkbTGs7FpCCiRrttiRilxiosF826QIW9kfAEaMUPuIIsni9gHspwmsJZINkI68V1h+ thby5knIHW5YcyoqCtJTb28itY6d4hcSzENtydyHVroBQPbRu5BDoYVVNE9cD46wMWvC +Ds1ahXGoXfrchTMurL0hVloEDiYdIsBPqw/lZef45ZqW+QAsGyd+tD+Ksk6OxWbnRr9 s4QFsT1vI+rA6XNKsTFnpILQZgUtcf3RnYdK+jYdpErSbDlB1BZhDxxbLbzdHtOFv4+w NdD0YMfgj2C/se3LHFetW4Zb+7rs60QWm2t7nDKuPII9tZvkOc9iCGzEcoAvACnBvA40 A6TQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=597mNbti9AE4jskQLQ5sdKqhsrWUg3noqnu7lsx00Ik=; b=DSwedB/EVrUPL6CuoDbI/qIgulkfvYSPUC9qpg/03Sfjf3dqxGbYSv1RqCxm+fw1ZA PuhrmnO2diJ9gzwRgeaPfJvpWjDz/DR1ZLqA0dq2cE5ubYil5kAxQ7txd5vQ31qcXrQP XWuF7cSnwuUgGYtBaJiDbHo18hEcx1IiJMufjAe52TJSooBVpekcAYHbkihdeH272Po1 exsKW630lPbGJJPUsPD6XSEnzdShNhNQvvBtYcY9cdux3LBTDeXdo2wRKDZdJYl+dDKe R4V+8YKZs0IXPks6l+q58/4tn2tnR29HV5k1qJmPtDZFMSQUY8y0PDWd703fK7tKkKLW NWOw== X-Gm-Message-State: APjAAAVaKJvXqFqm2xI8NsTMxLnqNjvskgLMILOG6rBuuZfuVSzbdCfq nTIChwuhx7olpgDEW3UpJqGXZBc+YAHBiTMZgpD6jA== X-Google-Smtp-Source: APXvYqxC8oXMhGBSsruKuBX7m7e9PA7Cmox+WxmN9bWO2QCRGCC8FVz1afN0q1rtFmZ+/IoG9TgL/daj+aJpQTz6+ZTZyA== X-Received: by 2002:a65:464d:: with SMTP id k13mr44644813pgr.99.1563479061158; Thu, 18 Jul 2019 12:44:21 -0700 (PDT) Date: Thu, 18 Jul 2019 12:43:47 -0700 In-Reply-To: <20190718194415.108476-1-matthewgarrett@google.com> Message-Id: <20190718194415.108476-2-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190718194415.108476-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.22.0.510.g264f2c817a-goog Subject: [PATCH V36 01/29] security: Support early LSMs From: Matthew Garrett To: jmorris@namei.org Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Matthew Garrett , Matthew Garrett , Kees Cook Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The lockdown module is intended to allow for kernels to be locked down early in boot - sufficiently early that we don't have the ability to kmalloc() yet. Add support for early initialisation of some LSMs, and then add them to the list of names when we do full initialisation later. Early LSMs are initialised in link order and cannot be overridden via boot parameters, and cannot make use of kmalloc() (since the allocator isn't initialised yet). Signed-off-by: Matthew Garrett Acked-by: Kees Cook --- include/asm-generic/vmlinux.lds.h | 8 ++++- include/linux/lsm_hooks.h | 6 ++++ include/linux/security.h | 1 + init/main.c | 1 + security/security.c | 50 ++++++++++++++++++++++++++----- 5 files changed, 57 insertions(+), 9 deletions(-) diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index ca42182992a5..6cc6174a2a4c 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -215,8 +215,13 @@ __start_lsm_info = .; \ KEEP(*(.lsm_info.init)) \ __end_lsm_info = .; +#define EARLY_LSM_TABLE() . = ALIGN(8); \ + __start_early_lsm_info = .; \ + KEEP(*(.early_lsm_info.init)) \ + __end_early_lsm_info = .; #else #define LSM_TABLE() +#define EARLY_LSM_TABLE() #endif #define ___OF_TABLE(cfg, name) _OF_TABLE_##cfg(name) @@ -616,7 +621,8 @@ ACPI_PROBE_TABLE(irqchip) \ ACPI_PROBE_TABLE(timer) \ EARLYCON_TABLE() \ - LSM_TABLE() + LSM_TABLE() \ + EARLY_LSM_TABLE() #define INIT_TEXT \ *(.init.text .init.text.*) \ diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index df1318d85f7d..aebb0e032072 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -2104,12 +2104,18 @@ struct lsm_info { }; extern struct lsm_info __start_lsm_info[], __end_lsm_info[]; +extern struct lsm_info __start_early_lsm_info[], __end_early_lsm_info[]; #define DEFINE_LSM(lsm) \ static struct lsm_info __lsm_##lsm \ __used __section(.lsm_info.init) \ __aligned(sizeof(unsigned long)) +#define DEFINE_EARLY_LSM(lsm) \ + static struct lsm_info __early_lsm_##lsm \ + __used __section(.early_lsm_info.init) \ + __aligned(sizeof(unsigned long)) + #ifdef CONFIG_SECURITY_SELINUX_DISABLE /* * Assuring the safety of deleting a security module is up to diff --git a/include/linux/security.h b/include/linux/security.h index 5f7441abbf42..66a2fcbe6ab0 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -195,6 +195,7 @@ int unregister_blocking_lsm_notifier(struct notifier_block *nb); /* prototypes */ extern int security_init(void); +extern int early_security_init(void); /* Security operations */ int security_binder_set_context_mgr(struct task_struct *mgr); diff --git a/init/main.c b/init/main.c index ff5803b0841c..0fefca3fd43c 100644 --- a/init/main.c +++ b/init/main.c @@ -593,6 +593,7 @@ asmlinkage __visible void __init start_kernel(void) boot_cpu_init(); page_address_init(); pr_notice("%s", linux_banner); + early_security_init(); setup_arch(&command_line); mm_init_cpumask(&init_mm); setup_command_line(command_line); diff --git a/security/security.c b/security/security.c index 250ee2d76406..90f1e291c800 100644 --- a/security/security.c +++ b/security/security.c @@ -33,6 +33,7 @@ /* How many LSMs were built into the kernel? */ #define LSM_COUNT (__end_lsm_info - __start_lsm_info) +#define EARLY_LSM_COUNT (__end_early_lsm_info - __start_early_lsm_info) struct security_hook_heads security_hook_heads __lsm_ro_after_init; static BLOCKING_NOTIFIER_HEAD(blocking_lsm_notifier_chain); @@ -277,6 +278,8 @@ static void __init ordered_lsm_parse(const char *order, const char *origin) static void __init lsm_early_cred(struct cred *cred); static void __init lsm_early_task(struct task_struct *task); +static int lsm_append(const char *new, char **result); + static void __init ordered_lsm_init(void) { struct lsm_info **lsm; @@ -323,6 +326,26 @@ static void __init ordered_lsm_init(void) kfree(ordered_lsms); } +int __init early_security_init(void) +{ + int i; + struct hlist_head *list = (struct hlist_head *) &security_hook_heads; + struct lsm_info *lsm; + + for (i = 0; i < sizeof(security_hook_heads) / sizeof(struct hlist_head); + i++) + INIT_HLIST_HEAD(&list[i]); + + for (lsm = __start_early_lsm_info; lsm < __end_early_lsm_info; lsm++) { + if (!lsm->enabled) + lsm->enabled = &lsm_enabled_true; + prepare_lsm(lsm); + initialize_lsm(lsm); + } + + return 0; +} + /** * security_init - initializes the security framework * @@ -330,14 +353,18 @@ static void __init ordered_lsm_init(void) */ int __init security_init(void) { - int i; - struct hlist_head *list = (struct hlist_head *) &security_hook_heads; + struct lsm_info *lsm; pr_info("Security Framework initializing\n"); - for (i = 0; i < sizeof(security_hook_heads) / sizeof(struct hlist_head); - i++) - INIT_HLIST_HEAD(&list[i]); + /* + * Append the names of the early LSM modules now that kmalloc() is + * available + */ + for (lsm = __start_early_lsm_info; lsm < __end_early_lsm_info; lsm++) { + if (lsm->enabled) + lsm_append(lsm->name, &lsm_names); + } /* Load LSMs in specified order. */ ordered_lsm_init(); @@ -384,7 +411,7 @@ static bool match_last_lsm(const char *list, const char *lsm) return !strcmp(last, lsm); } -static int lsm_append(char *new, char **result) +static int lsm_append(const char *new, char **result) { char *cp; @@ -422,8 +449,15 @@ void __init security_add_hooks(struct security_hook_list *hooks, int count, hooks[i].lsm = lsm; hlist_add_tail_rcu(&hooks[i].list, hooks[i].head); } - if (lsm_append(lsm, &lsm_names) < 0) - panic("%s - Cannot get early memory.\n", __func__); + + /* + * Don't try to append during early_security_init(), we'll come back + * and fix this up afterwards. + */ + if (slab_is_available()) { + if (lsm_append(lsm, &lsm_names) < 0) + panic("%s - Cannot get early memory.\n", __func__); + } } int call_blocking_lsm_notifier(enum lsm_event event, void *data) -- 2.22.0.510.g264f2c817a-goog