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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 AB3CEC10F11 for ; Wed, 24 Apr 2019 15:26:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7A33921901 for ; Wed, 24 Apr 2019 15:26:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731374AbfDXPZz (ORCPT ); Wed, 24 Apr 2019 11:25:55 -0400 Received: from mail-lf1-f65.google.com ([209.85.167.65]:38272 "EHLO mail-lf1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731065AbfDXPZz (ORCPT ); Wed, 24 Apr 2019 11:25:55 -0400 Received: by mail-lf1-f65.google.com with SMTP id v1so2553752lfg.5; Wed, 24 Apr 2019 08:25:51 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:reply-to:subject:to:cc:references:from:openpgp :autocrypt:message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=nKE/xyq4imc55KQfJ9wehrfi/E+X6DNeYp3aVRnme5Q=; b=FKk4zyLzQ7H6ikaMj8GxU8oy1OVIvRFV2oaVehYi0qhMWBRQZsLenj0CAGc5ymABGq LwcqFVJ/1PBI64atxM2rkLdGKfDcU7CXiIHP47iAOKEAWdTGCJT+WbKr58Jjg8QBydrX SFLd02A6ULeM2iLASEPUWJc9d9kkfPFQB12l5QNVnANGe1TDOEiK0LbnCetIZ7njNvn0 CQ+kOldUfM6PM157eW66zKnwHf7EoF/g7IwBuLIxIGJSJPOdlmH8u4VpYU04q4+qpF1Y uc4Wz5XpGJq46F7MEeqjy0zChxs3D9S8XEnnjrDPcajp59wU+juEI8IGpACFPhEnU5Q+ BXsw== X-Gm-Message-State: APjAAAU3/KemJCJAgpR0icArQEw4LkD+7kpBvXnxyBVXtJgXihEKgRWa 9edKyIzDrr41OX/6LVb7MbyQik9j X-Google-Smtp-Source: APXvYqycMvsfU0Yy0POsr+lKHb0Fg84V3epzIvyE4SNRIp0Ee9Wq4yxNkk8EtJV2i5FeCIUACl/4zg== X-Received: by 2002:a19:6619:: with SMTP id a25mr17514901lfc.21.1556119550508; Wed, 24 Apr 2019 08:25:50 -0700 (PDT) Received: from [192.168.42.211] ([213.87.153.202]) by smtp.gmail.com with ESMTPSA id s16sm3911082lji.61.2019.04.24.08.25.46 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Apr 2019 08:25:48 -0700 (PDT) Reply-To: alex.popov@linux.com Subject: Re: [PATCH v3 2/3] security: Move stackleak config to Kconfig.hardening To: Kees Cook , Alexander Potapenko Cc: Masahiro Yamada , James Morris , Nick Desaulniers , Kostya Serebryany , Dmitry Vyukov , Sandeep Patil , Laura Abbott , Randy Dunlap , Michal Marek , Emese Revfy , "Serge E. Hallyn" , Kernel Hardening , linux-security-module , Linux Kbuild mailing list , Linux Kernel Mailing List References: <20190423194925.32151-1-keescook@chromium.org> <20190423194925.32151-3-keescook@chromium.org> From: Alexander Popov Openpgp: preference=signencrypt Autocrypt: addr=alex.popov@linux.com; prefer-encrypt=mutual; keydata= mQINBFX15q4BEADZartsIW3sQ9R+9TOuCFRIW+RDCoBWNHhqDLu+Tzf2mZevVSF0D5AMJW4f UB1QigxOuGIeSngfmgLspdYe2Kl8+P8qyfrnBcS4hLFyLGjaP7UVGtpUl7CUxz2Hct3yhsPz ID/rnCSd0Q+3thrJTq44b2kIKqM1swt/F2Er5Bl0B4o5WKx4J9k6Dz7bAMjKD8pHZJnScoP4 dzKPhrytN/iWM01eRZRc1TcIdVsRZC3hcVE6OtFoamaYmePDwWTRhmDtWYngbRDVGe3Tl8bT 7BYN7gv7Ikt7Nq2T2TOfXEQqr9CtidxBNsqFEaajbFvpLDpUPw692+4lUbQ7FL0B1WYLvWkG cVysClEyX3VBSMzIG5eTF0Dng9RqItUxpbD317ihKqYL95jk6eK6XyI8wVOCEa1V3MhtvzUo WGZVkwm9eMVZ05GbhzmT7KHBEBbCkihS+TpVxOgzvuV+heCEaaxIDWY/k8u4tgbrVVk+tIVG 99v1//kNLqd5KuwY1Y2/h2MhRrfxqGz+l/f/qghKh+1iptm6McN//1nNaIbzXQ2Ej34jeWDa xAN1C1OANOyV7mYuYPNDl5c9QrbcNGg3D6gOeGeGiMn11NjbjHae3ipH8MkX7/k8pH5q4Lhh Ra0vtJspeg77CS4b7+WC5jlK3UAKoUja3kGgkCrnfNkvKjrkEwARAQABtCZBbGV4YW5kZXIg UG9wb3YgPGFsZXgucG9wb3ZAbGludXguY29tPokCQAQTAQoAKgIbIwIeAQIXgAULCQgHAwUV CgkICwUWAgMBAAUJB8+UXAUCWgsUegIZAQAKCRCODp3rvH6PqqpOEACX+tXHOgMJ6fGxaNJZ HkKRFR/9AGP1bxp5QS528Sd6w17bMMQ87V5NSFUsTMPMcbIoO73DganKQ3nN6tW0ZvDTKpRt pBUCUP8KPqNvoSs3kkskaQgNQ3FXv46YqPZ7DoYj9HevY9NUyGLwCTEWD2ER5zKuNbI2ek82 j4rwdqXn9kqqBf1ExAoEsszeNHzTKRl2d+bXuGDcOdpnOi7avoQfwi/O0oapR+goxz49Oeov YFf1EVaogHjDBREaqiqJ0MSKexfVBt8RD9ev9SGSIMcwfhgUHhMTX2JY/+6BXnUbzVcHD6HR EgqVGn/0RXfJIYmFsjH0Z6cHy34Vn+aqcGa8faztPnmkA/vNfhw8k5fEE7VlBqdEY8YeOiza hHdpaUi4GofNy/GoHIqpz16UulMjGB5SBzgsYKgCO+faNBrCcBrscWTl1aJfSNJvImuS1JhB EQnl/MIegxyBBRsH68x5BCffERo4FjaG0NDCmZLjXPOgMvl3vRywHLdDZThjAea3pwdGUq+W C77i7tnnUqgK7P9i+nEKwNWZfLpfjYgH5JE/jOgMf4tpHvO6fu4AnOffdz3kOxDyi+zFLVcz rTP5b46aVjI7D0dIDTIaCKUT+PfsLnJmP18x7dU/gR/XDcUaSEbWU3D9u61AvxP47g7tN5+a 5pFIJhJ44JLk6I5H/bkCDQRV9eauARAArcUVf6RdT14hkm0zT5TPc/3BJc6PyAghV/iCoPm8 kbzjKBIK80NvGodDeUV0MnQbX40jjFdSI0m96HNt86FtifQ3nwuW/BtS8dk8+lakRVwuTgMb hJWmXqKMFdVRCbjdyLbZWpdPip0WGND6p5i801xgPRmI8P6e5e4jBO4Cx1ToIFyJOzD/jvtb UhH9t5/naKUGa5BD9gSkguooXVOFvPdvKQKca19S7bb9hzjySh63H4qlbhUrG/7JGhX+Lr3g DwuAGrrFIV0FaVyIPGZ8U2fjLKpcBC7/lZJv0jRFpZ9CjHefILxt7NGxPB9hk2iDt2tE6jSl GNeloDYJUVItFmG+/giza2KrXmDEFKl+/mwfjRI/+PHR8PscWiB7S1zhsVus3DxhbM2mAK4x mmH4k0wNfgClh0Srw9zCU2CKJ6YcuRLi/RAAiyoxBb9wnSuQS5KkxoT32LRNwfyMdwlEtQGp WtC/vBI13XJVabx0Oalx7NtvRCcX1FX9rnKVjSFHX5YJ48heAd0dwRVmzOGL/EGywb1b9Q3O IWe9EFF8tmWV/JHs2thMz492qTHA5pm5JUsHQuZGBhBU+GqdOkdkFvujcNu4w7WyuEITBFAh 5qDiGkvY9FU1OH0fWQqVU/5LHNizzIYN2KjU6529b0VTVGb4e/M0HglwtlWpkpfQzHMAEQEA AYkCJQQYAQIADwUCVfXmrgIbDAUJCWYBgAAKCRCODp3rvH6PqrZtEACKsd/UUtpKmy4mrZwl 053nWp7+WCE+S9ke7CFytmXoMWf1CIrcQTk5cmdBmB4E0l3sr/DgKlJ8UrHTdRLcZZnbVqur +fnmVeQy9lqGkaIZvx/iXVYUqhT3+DNj9Zkjrynbe5pLsrGyxYWfsPRVL6J4mQatChadjuLw 7/WC6PBmWkRA2SxUVpxFEZlirpbboYWLSXk9I3JmS5/iJ+P5kHYiB0YqYkd1twFXXxixv1GB Zi/idvWTK7x6/bUh0AAGTKc5zFhyR4DJRGROGlFTAYM3WDoa9XbrHXsggJDLNoPZJTj9DMww u28SzHLvR3t2pY1dT61jzKNDLoE3pjvzgLKF/Olif0t7+m0IPKY+8umZvUEhJ9CAUcoFPCfG tEbL6t1xrcsT7dsUhZpkIX0Qc77op8GHlfNd/N6wZUt19Vn9G8B6xrH+dinc0ylUc4+4yxt6 6BsiEzma6Ah5jexChYIwaB5Oi21yjc6bBb4l6z01WWJQ052OGaOBzi+tS5iGmc5DWH4/pFqX OIkgJVVgjPv2y41qV66QJJEi2wT4WUKLY1zA9s6KXbt8dVSzJsNFvsrAoFdtzc8v6uqCo0/W f0Id8MBKoqN5FniTHWNxYX6b2dFwq8i5Rh6Oxc6q75Kg8279+co3/tLCkU6pGga28K7tUP2z h9AUWENlnWJX/YhP8IkCJQQYAQoADwIbDAUCWgsSOgUJB9eShwAKCRCODp3rvH6PqtoND/41 ozCKAS4WWBBCU6AYLm2SoJ0EGhg1kIf9VMiqy5PKlSrAnW5yl4WJQcv5wER/7EzvZ49Gj8aG uRWfz3lyQU8dH2KG6KLilDFCZF0mViEo2C7O4QUx5xmbpMUq41fWjY947Xvd3QDisc1T1/7G uNBAALEZdqzwnKsT9G27e9Cd3AW3KsLAD4MhsALFARg6OuuwDCbLl6k5fu++26PEqORGtpJQ rRBWan9ZWb/Y57P126IVIylWiH6vt6iEPlaEHBU8H9+Z0WF6wJ5rNz9gR6GhZhmo1qsyNedD 1HzOsXQhvCinsErpZs99VdZSF3d54dac8ypH4hvbjSmXZjY3Sblhyc6RLYlru5UXJFh7Hy+E TMuCg3hIVbdyFSDkvxVlvhHgUSf8+Uk3Ya4MO4a5l9ElUqxpSqYH7CvuwkG+mH5mN8tK3CCd +aKPCxUFfil62DfTa7YgLovr7sHQB+VMQkNDPXleC+amNqJb423L8M2sfCi9gw/lA1ha6q80 ydgbcFEkNjqz4OtbrSwEHMy/ADsUWksYuzVbw7/pQTc6OAskESBr5igP7B/rIACUgiIjdOVB ktD1IQcezrDcuzVCIpuq8zC6LwLm7V1Tr6zfU9FWwnqzoQeQZH4QlP7MBuOeswCpxIl07mz9 jXz/74kjFsyRgZA+d6a1pGtOwITEBxtxxg== Message-ID: <84ed0a4b-b1e5-ae86-56c1-40a212734667@linux.com> Date: Wed, 24 Apr 2019 18:25:45 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190423194925.32151-3-keescook@chromium.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On 23.04.2019 22:49, Kees Cook wrote: > This moves the stackleak plugin options to Kconfig.hardening's memory > initialization menu. > > Signed-off-by: Kees Cook Hello Kees, I see the changes in STACKLEAK help, looks good to me. For this patch - Reviewed-by: Alexander Popov By the way, for your information, GCC_PLUGIN_STRUCTLEAK help is now unreachable from 'make menuconfig'. Best regards, Alexander > --- > 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 352f03878a1e..80220ed26a35 100644 > --- a/scripts/gcc-plugins/Kconfig > +++ b/scripts/gcc-plugins/Kconfig > @@ -108,57 +108,6 @@ 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 19881341f1c2..a96d4a43ca65 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 >