From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 74CE836AF5; Tue, 7 Jan 2025 01:17:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736212633; cv=none; b=QfvFw/V0AUAZAvanOahre3xoKkIAdhUmyhV/eWw+OSIsLtYkVL3W7KmRKHeXxVroK6N1CQ7n5FdRXwv+YddtnaYsmJk/d01DbN91V8xrYt/ZsQjPBx+sU3hj+eYd5C6p4io1MRIJ7BGHFY3PF09vmnmb7u2PU6mLUDY04zcmBb8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736212633; c=relaxed/simple; bh=kAVrCQjzZghGx/Mh/TnXhecmI2ef0AhPGBvN/Aj8emc=; h=Date:From:To:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=oB4obopmq3BbtryVfpww9eIbbGS/OD4C5G2q03EMOGE3PNVGfGHSIGRo/PbGHcIGubf1MGLPGx+XpYxqlahPCS9Y1Q2lagbkEFHlyX8+i04sB7W1tf14P7Oa2eE07cw5oHGuJhSKgdJDiQzXSTEolYzMu0s6Lu5efBFe/8NXaB0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dpk+LaIM; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="dpk+LaIM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 06360C4CED2; Tue, 7 Jan 2025 01:17:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1736212633; bh=kAVrCQjzZghGx/Mh/TnXhecmI2ef0AhPGBvN/Aj8emc=; h=Date:From:To:Subject:References:In-Reply-To:From; b=dpk+LaIMK1A26bZlbRyuwn8ixb/Il4rYdg9BPZKr+WqFHmKjCt/rXJ+T4CbdMT+P8 eXzNTGgu3STjCmzu+4POglK+Uq/mZPr57XZl7bi3IAHy4qB8O/+HvsGt1vgbBHn8Vz m6xN1oK+YJ4ZhknXWuE6ui1fuABxFC+YFlezOjDLBshBGhd8bX59qfC03Vu03iz3Vi /XUAJiFgOL+bmIZHZvPzsdz5HdaX1zPxR+e2SmmOPNj5no7M1B4+lEkJxLX8wucN3t Z/c0h5GGHRtU9pryz7ailccg7DjIM2y6NFXWW1iOeEzinRwJ7vlz2g4yUsPL1MHVfV va1n5a+DihdAA== Date: Mon, 6 Jan 2025 17:17:10 -0800 From: Kees Cook To: "Liam R. Howlett" , jeffxu@chromium.org, akpm@linux-foundation.org, jannh@google.com, torvalds@linux-foundation.org, adhemerval.zanella@linaro.org, oleg@redhat.com, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, linux-mm@kvack.org, jorgelo@chromium.org, sroettger@google.com, ojeda@kernel.org, adobriyan@gmail.com, anna-maria@linutronix.de, mark.rutland@arm.com, linus.walleij@linaro.org, Jason@zx2c4.com, deller@gmx.de, rdunlap@infradead.org, davem@davemloft.net, hch@lst.de, peterx@redhat.com, hca@linux.ibm.com, f.fainelli@gmail.com, gerg@kernel.org, dave.hansen@linux.intel.com, mingo@kernel.org, ardb@kernel.org, mhocko@suse.com, 42.hyeyoo@gmail.com, peterz@infradead.org, ardb@google.com, enh@google.com, rientjes@google.com, groeck@chromium.org, mpe@ellerman.id.au, Vlastimil Babka , Lorenzo Stoakes , Andrei Vagin , Dmitry Safonov <0x7f454c46@gmail.com>, Mike Rapoport , Alexander Mikhalitsyn Subject: Re: [PATCH v4 1/1] exec: seal system mappings Message-ID: <202501061713.823E772F@keescook> References: <20241125202021.3684919-1-jeffxu@google.com> <20241125202021.3684919-2-jeffxu@google.com> <202412171248.409B10D@keescook> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Jan 03, 2025 at 03:48:23PM -0500, Liam R. Howlett wrote: > So we have at least two userspace uses that this will breaks: checkpoint > restore and now gVisor, but who knows what else? How many config > options before we decide this can't be just on by default? See my reply to Lorenzo, but I'm not arguing for it to be enabled by default. I was trying to show how we traditionally handle these kinds of features: putting their enablement behind a Kconfig and boot param that work together. That way distro kernels have it _available_ without making it _enabled_, and specialty kernels can have in enabled by default (and can disable it at boot if needed too). -- Kees Cook