From patchwork Tue Aug 20 00:17:37 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Garrett X-Patchwork-Id: 11102439 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 036A41398 for ; Tue, 20 Aug 2019 00:20:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CD9DB22CF5 for ; Tue, 20 Aug 2019 00:20:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="SlxH5uYa" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728817AbfHTASP (ORCPT ); Mon, 19 Aug 2019 20:18:15 -0400 Received: from mail-qt1-f201.google.com ([209.85.160.201]:33387 "EHLO mail-qt1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728731AbfHTASO (ORCPT ); Mon, 19 Aug 2019 20:18:14 -0400 Received: by mail-qt1-f201.google.com with SMTP id z15so5529122qts.0 for ; Mon, 19 Aug 2019 17:18:13 -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=i0tvJnPgM16fE/v88Mj7Ir2tHD98e473SFHYbAwN8qU=; b=SlxH5uYas+8Abm7SbQD1UL42mj14y/X4v46a1Kndi4jsQz5j91H+emmjpnbnKJqySS OqNq0UId1K/QgByJQcuXNTME8U5pe7GBkSZs3Pu8nZ3x4Zi0M29Y4/s3KgjIfFzJTbLo jh22sxA3oKcb6oBCsSPQj85hmZAk6DVsiIzPqHT6/FzFm0s6m0Kcp1+WXd5skg9j+9yZ gTm6S68VNzGzn+6hDx76u9ibDiVTNc/+69dh8Lqw4kq6U1beKKmMz0/S+/Z29M9nYIoc 1x4ywaYx0P54AauCOlG2tBZ6t1q5tQI9xFhNZTTficSAnRM3iDCuk7ruvOFb122+JiS2 E97g== 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=i0tvJnPgM16fE/v88Mj7Ir2tHD98e473SFHYbAwN8qU=; b=iygFlwvYfjiQ1KqOFr1CgagO5MpsDHqMBAg8HYdzFtzbRp0qjXEvZtUt9IMMGXSbRI Wtdu1aZM8cFwh537D0UJANXY/fMgnpkbx9RAvTLe+baGF4OsDyxFBMIwq4SKpfov30Xg zfBp6HaBYwYmbMaqCOTBSu/WrQeJEYqjy6az+Wx/eskKmWw9NuA+GW/D0ot8n/44U2Kj Lxllrx32wynnvXBwtcmhI80ZJmaD7XoFy8m8oQIMACB3WS12zmhkgFkf5At7n3SQPZvd D58YXcKgP+ZhHw+H39OUACDpzgQgZc4IXSftPSmXgZUsVi7UbZtswTWZGBPk/vK2C6wf oPIw== X-Gm-Message-State: APjAAAXtYBKn50kwpAT81m1m7DWn1h2xlQM4OYEoQAvI2IJ7AMoG+hVZ lRREB+KI6aW4yAmludzN8np5ZYTc/+YHIvvkFvhOkw== X-Google-Smtp-Source: APXvYqyVwptPHKk2lGhsl1pUB9XAtwzz5s8x+rZmR9WdC5AJePpuUYNu/MBTLLOGeKZ2RPDbBkHAPr1bJZ8jjQVydWx2RQ== X-Received: by 2002:ae9:d8c7:: with SMTP id u190mr7965911qkf.461.1566260292656; Mon, 19 Aug 2019 17:18:12 -0700 (PDT) Date: Mon, 19 Aug 2019 17:17:37 -0700 In-Reply-To: <20190820001805.241928-1-matthewgarrett@google.com> Message-Id: <20190820001805.241928-2-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190820001805.241928-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.23.0.rc1.153.gdeed80330f-goog Subject: [PATCH V40 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 , Stephen Rothwell Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: 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). (Fixed by Stephen Rothwell to include a stub to fix builds when !CONFIG_SECURITY) Signed-off-by: Matthew Garrett Acked-by: Kees Cook Acked-by: Casey Schaufler Cc: Stephen Rothwell --- include/asm-generic/vmlinux.lds.h | 8 ++++- include/linux/lsm_hooks.h | 6 ++++ include/linux/security.h | 6 ++++ init/main.c | 1 + security/security.c | 50 ++++++++++++++++++++++++++----- 5 files changed, 62 insertions(+), 9 deletions(-) diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 088987e9a3ea..c1807d14daa3 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -208,8 +208,13 @@ __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) @@ -609,7 +614,8 @@ 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 47f58cfb6a19..b02e8bb6654d 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 659071c2e57c..c5dd90981c98 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -195,6 +195,7 @@ int unregister_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); @@ -423,6 +424,11 @@ static inline int security_init(void) return 0; } +static inline int early_security_init(void) +{ + return 0; +} + static inline int security_binder_set_context_mgr(struct task_struct *mgr) { return 0; diff --git a/init/main.c b/init/main.c index 66a196c5e4c3..598effd29a0a 100644 --- a/init/main.c +++ b/init/main.c @@ -569,6 +569,7 @@ 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 f493db0bf62a..ef4a0111c8b4 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 ATOMIC_NOTIFIER_HEAD(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_lsm_notifier(enum lsm_event event, void *data)