From patchwork Thu Apr 11 18:01:16 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 10896581 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 6F1C617E0 for ; Thu, 11 Apr 2019 18:01:59 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 61D3B28D7E for ; Thu, 11 Apr 2019 18:01:59 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5556228D88; Thu, 11 Apr 2019 18:01:59 +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=-5.3 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 30C8B28D7E for ; Thu, 11 Apr 2019 18:01:58 +0000 (UTC) Received: (qmail 11684 invoked by uid 550); 11 Apr 2019 18:01:41 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 11540 invoked from network); 11 Apr 2019 18:01:40 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=5UVcalT/69dnaWJbEUHGU/qZgqR3xSJfEBAdMd0KbXI=; b=KTMfuuhGOAqwrTLGNljYi6CKR+25P7Qtg0HJTwZl7qsUCJ7pVzOJAMuZilvmtF9cYV PRZf1Nh2XYnUoC1vE1eByRDwxWPvOH4MOC1bBwuKqkUsdrM9zqXpwAhR0iplvRAFngZO 97eydYlVTVEXHobFBzWWFIR0rBhW4vy3vY9H8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=5UVcalT/69dnaWJbEUHGU/qZgqR3xSJfEBAdMd0KbXI=; b=MNOQUGCXEGw1L+uKX2jbKiIUedH4ZTrytcMwJz3E2rkaaZmhhlTDr4uzttiRCKGU0P ViTB5J1PYvObNlVBqY7BSL0YdcvbGy7sCvWmtrKDH8ew1J4WB22n9AzbroGlz71AjEj3 Ft7o2fV0s3EXJkpHoVcCoL+B3LZV3USJ/K5rZ9C0RXBsAFbysWVErrEGCXzODUXIML4g PYwWZQQ/OM9h0nxC8xc36L1oojOhMp5jD4E6WT9YXyxpkTbXpOih7bm8aY7VlQvvJIWe c/VMEcyk7kSoxbx6DBYK0t8RpEMEvwQYAq9shXKLXhxsJ64XSTUCpKrLdlpalbDtUdsa RPBg== X-Gm-Message-State: APjAAAVkoBaUHuNFIkTp1JDNugiZqevOmQt36B/63iksmiwmqP/9fxKQ yEfFAcyPu0lnbVOQo+ZFsPnSZQ== X-Google-Smtp-Source: APXvYqzZVkmGbK/kgGkS3PLIBPjakP/68xlKHi3tGLgH2Y/iUp33a3mnIFCATqNKZ2EmHv7KCzngQg== X-Received: by 2002:a63:2b4c:: with SMTP id r73mr49317982pgr.181.1555005688308; Thu, 11 Apr 2019 11:01:28 -0700 (PDT) From: Kees Cook To: Alexander Potapenko Cc: Kees Cook , Masahiro Yamada , James Morris , Alexander Popov , Nick Desaulniers , Kostya Serebryany , Dmitry Vyukov , Sandeep Patil , Laura Abbott , Randy Dunlap , Michal Marek , Emese Revfy , "Serge E. Hallyn" , kernel-hardening@lists.openwall.com, linux-security-module@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/3] security: Move stackleak config to Kconfig.hardening Date: Thu, 11 Apr 2019 11:01:16 -0700 Message-Id: <20190411180117.27704-3-keescook@chromium.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190411180117.27704-1-keescook@chromium.org> References: <20190411180117.27704-1-keescook@chromium.org> X-Virus-Scanned: ClamAV using ClamSMTP This moves the stackleak plugin options to Kconfig.hardening's memory initialization menu. Signed-off-by: Kees Cook --- scripts/gcc-plugins/Kconfig | 51 --------------------------------- security/Kconfig.hardening | 57 +++++++++++++++++++++++++++++++++++++ 2 files changed, 57 insertions(+), 51 deletions(-) diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig index 84d471dea2b7..e4cb58d5a73f 100644 --- a/scripts/gcc-plugins/Kconfig +++ b/scripts/gcc-plugins/Kconfig @@ -109,57 +109,6 @@ config GCC_PLUGIN_RANDSTRUCT_PERFORMANCE in structures. This reduces the performance hit of RANDSTRUCT at the cost of weakened randomization. -config GCC_PLUGIN_STACKLEAK - bool "Erase the kernel stack before returning from syscalls" - depends on GCC_PLUGINS - depends on HAVE_ARCH_STACKLEAK - help - This option makes the kernel erase the kernel stack before - returning from system calls. That reduces the information which - kernel stack leak bugs can reveal and blocks some uninitialized - stack variable attacks. - - The tradeoff is the performance impact: on a single CPU system kernel - compilation sees a 1% slowdown, other systems and workloads may vary - and you are advised to test this feature on your expected workload - before deploying it. - - This plugin was ported from grsecurity/PaX. More information at: - * https://grsecurity.net/ - * https://pax.grsecurity.net/ - -config STACKLEAK_TRACK_MIN_SIZE - int "Minimum stack frame size of functions tracked by STACKLEAK" - default 100 - range 0 4096 - depends on GCC_PLUGIN_STACKLEAK - help - The STACKLEAK gcc plugin instruments the kernel code for tracking - the lowest border of the kernel stack (and for some other purposes). - It inserts the stackleak_track_stack() call for the functions with - a stack frame size greater than or equal to this parameter. - If unsure, leave the default value 100. - -config STACKLEAK_METRICS - bool "Show STACKLEAK metrics in the /proc file system" - depends on GCC_PLUGIN_STACKLEAK - depends on PROC_FS - help - If this is set, STACKLEAK metrics for every task are available in - the /proc file system. In particular, /proc//stack_depth - shows the maximum kernel stack consumption for the current and - previous syscalls. Although this information is not precise, it - can be useful for estimating the STACKLEAK performance impact for - your workloads. - -config STACKLEAK_RUNTIME_DISABLE - bool "Allow runtime disabling of kernel stack erasing" - depends on GCC_PLUGIN_STACKLEAK - help - This option provides 'stack_erasing' sysctl, which can be used in - runtime to control kernel stack erasing for kernels built with - CONFIG_GCC_PLUGIN_STACKLEAK. - config GCC_PLUGIN_ARM_SSP_PER_TASK bool depends on GCC_PLUGINS && ARM diff --git a/security/Kconfig.hardening b/security/Kconfig.hardening index 01a119437dfc..3dd7a28c3822 100644 --- a/security/Kconfig.hardening +++ b/security/Kconfig.hardening @@ -88,6 +88,63 @@ config GCC_PLUGIN_STRUCTLEAK_VERBOSE initialized. Since not all existing initializers are detected by the plugin, this can produce false positive warnings. +config GCC_PLUGIN_STACKLEAK + bool "Poison kernel stack before returning from syscalls" + depends on GCC_PLUGINS + depends on HAVE_ARCH_STACKLEAK + help + This option makes the kernel erase the kernel stack before + returning from system calls. This has the effect of leaving + the stack initialized to the poison value, which both reduces + the lifetime of any sensitive stack contents and reduces + potential for uninitialized stack variable exploits or information + exposures (it does not cover functions reaching the same stack + depth as prior functions during the same syscall). This blocks + most uninitialized stack variable attacks, with the performance + impact being driven by the depth of the stack usage, rather than + the function calling complexity. + + The performance impact on a single CPU system kernel compilation + sees a 1% slowdown, other systems and workloads may vary and you + are advised to test this feature on your expected workload before + deploying it. + + This plugin was ported from grsecurity/PaX. More information at: + * https://grsecurity.net/ + * https://pax.grsecurity.net/ + +config STACKLEAK_TRACK_MIN_SIZE + int "Minimum stack frame size of functions tracked by STACKLEAK" + default 100 + range 0 4096 + depends on GCC_PLUGIN_STACKLEAK + help + The STACKLEAK gcc plugin instruments the kernel code for tracking + the lowest border of the kernel stack (and for some other purposes). + It inserts the stackleak_track_stack() call for the functions with + a stack frame size greater than or equal to this parameter. + If unsure, leave the default value 100. + +config STACKLEAK_METRICS + bool "Show STACKLEAK metrics in the /proc file system" + depends on GCC_PLUGIN_STACKLEAK + depends on PROC_FS + help + If this is set, STACKLEAK metrics for every task are available in + the /proc file system. In particular, /proc//stack_depth + shows the maximum kernel stack consumption for the current and + previous syscalls. Although this information is not precise, it + can be useful for estimating the STACKLEAK performance impact for + your workloads. + +config STACKLEAK_RUNTIME_DISABLE + bool "Allow runtime disabling of kernel stack erasing" + depends on GCC_PLUGIN_STACKLEAK + help + This option provides 'stack_erasing' sysctl, which can be used in + runtime to control kernel stack erasing for kernels built with + CONFIG_GCC_PLUGIN_STACKLEAK. + endmenu endmenu