From patchwork Thu Aug 8 00:06:53 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Garrett X-Patchwork-Id: 11082991 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7DD4A13B1 for ; Thu, 8 Aug 2019 00:09:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6D72828AAE for ; Thu, 8 Aug 2019 00:09:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5E38328AC8; Thu, 8 Aug 2019 00:09:51 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,RCVD_IN_DNSWL_HI,USER_IN_DEF_DKIM_WL autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B9A4D28AAE for ; Thu, 8 Aug 2019 00:09:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730525AbfHHAH2 (ORCPT ); Wed, 7 Aug 2019 20:07:28 -0400 Received: from mail-pl1-f202.google.com ([209.85.214.202]:48497 "EHLO mail-pl1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730149AbfHHAH2 (ORCPT ); Wed, 7 Aug 2019 20:07:28 -0400 Received: by mail-pl1-f202.google.com with SMTP id i33so54388702pld.15 for ; Wed, 07 Aug 2019 17:07:28 -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=51dHsz2VCo9w+VP1Zvpve034pgyEZM98AQeW9IXg4Ow=; b=qaPMZFsxPYlh8hN7E8ZioYbLyoR2pnDjpUUdmvY82bDBN4zqlIczR0U1yBwpU333HZ aSch76HNl1DW8kctots8Mrj8L3EbKtrh9q4nuhBYvc0Z1EOR/JIfl3aZpyWr+C23mn72 g9HOt17EpcIbJ7QlgWlERG14acM/xEk9FLARVuCHKSudxWmSL5xub/4seyB3pD+D3Va5 DVqZ6FgAeJwHubIPsuex5xOBBNoVqePDedbxGWuOHDJNcURe/7+XlN/ThGoh9NoRdDTI wPFHD2qhLBeMr4Yw29yn97s9LTZi5I4xogrV35LxyTlNL3QoHVm+JfRun+A3NQUgNb5z L03g== 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=51dHsz2VCo9w+VP1Zvpve034pgyEZM98AQeW9IXg4Ow=; b=BBrRejfQuaqHMBkhSztkV0grjfJ1dPqwg2A12ZbdexnocTvSjx7tn8vdYswNngVWlf 06xQtjMqBAkvvHrsDBRd47/DYj9pQwJlW6tUBAil2rZft5y9eqAcrVnY6VNrGrAm11sM 6UVknVHCQchOepLZ9Htjn3qvUeZFRYxsDyOX5aMIMrJ+aCVW2Jksd1z9oXLYhuL1yjnP JzqFDPOApRzKPX44i0OpkGu5cKqBxsOQBPB7XR3wBx4G26NjMXoJjqEfTtKIR27CXYFT bZlS9MFL/LZIrFDUHd5DQGeRin7r3tJ9TL/rmeO9NXfSZrBN2RNeuVKhP8KFJ3yqfvy1 ANtw== X-Gm-Message-State: APjAAAV1ydi06v7Hf6rFQ8m51S0/O8KOXgdrtc8J217kiEnKmkwCC37n wedY6JMfBQu/H78Eys6R8slwAjfL/JlhSES2LPkJXw== X-Google-Smtp-Source: APXvYqyXtNAxynYmxfxirHWyIQHSssxHGPLAILeIiaUiKtIaz1Su7soR9o0OnZUQglCEnNkTXXxrxUaj34yGnQgmX6KI1A== X-Received: by 2002:a65:52ca:: with SMTP id z10mr10274165pgp.424.1565222847365; Wed, 07 Aug 2019 17:07:27 -0700 (PDT) Date: Wed, 7 Aug 2019 17:06:53 -0700 In-Reply-To: <20190808000721.124691-1-matthewgarrett@google.com> Message-Id: <20190808000721.124691-2-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190808000721.124691-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.22.0.770.g0f2c4a37fd-goog Subject: [PATCH V38 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 , Casey Schaufler Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP 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 Acked-by: Casey Schaufler --- 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 cd28f63bfbc7..dae64600ccbf 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) @@ -627,7 +632,8 @@ ACPI_PROBE_TABLE(timer) \ THERMAL_TABLE(governor) \ 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 96f8d5af52d6..565af7b963e1 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)