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Wed, 31 Jan 2024 20:51:43 +0000 (UTC) From: Jonathan Corbet To: Jeff Xu Cc: akpm@linux-foundation.org, keescook@chromium.org, jannh@google.com, sroettger@google.com, willy@infradead.org, gregkh@linuxfoundation.org, torvalds@linux-foundation.org, usama.anjum@collabora.com, rdunlap@infradead.org, jeffxu@google.com, jorgelo@chromium.org, groeck@chromium.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, pedro.falcato@gmail.com, dave.hansen@intel.com, linux-hardening@vger.kernel.org, deraadt@openbsd.org Subject: Re: [PATCH v7 0/4] Introduce mseal() In-Reply-To: References: <20240122152905.2220849-1-jeffxu@chromium.org> <87a5ong41h.fsf@meer.lwn.net> Date: Wed, 31 Jan 2024 13:51:42 -0700 Message-ID: <87le854469.fsf@meer.lwn.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: CC20B120026 X-Rspam-User: X-Stat-Signature: id7wqp3em48podcwf8p1fhwz7dxrk76d X-Rspamd-Server: rspam01 X-HE-Tag: 1706734305-291046 X-HE-Meta: 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 5Rn7HQ1j xXkKIearXl4T24iNSNGxJV+Y0wAnxuQseDbhewvZkGroOSbf2NjqWCUrNfyHmQeoRCxAc9fXcMRD9bkQhVpDjNV2r1Jy3VsLnZIHh/ak7E6AETo+cWmMf5vWEtdk/0EKcBKb6uVNsxV/gG8mvb4MWzhfUA60mm526UzTdHhw+pFC9K/PN/22Dd9Nmhs+Y1MiVzh3CgeXA+dLDbqt8K1XRbDMvP00p14DPqAp4j11P0+1ztVzbh96n1L0oItm6xiaKvhRgDp72V0lBKq76U13DziVshtFrCOGqXYRB8xOQLx9rXT4GHhRwf/PJIde6WwYcq/qMU29+LDWVgOMyNiKy9sJ6S31SOUQSnnh05aJQvc8aVUcGvpS95wn70z5kT0QX71QTliPp2cledkE= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Jeff Xu writes: > On Mon, Jan 29, 2024 at 2:37=E2=80=AFPM Jonathan Corbet = wrote: >> >> jeffxu@chromium.org writes: >> >> > Although the initial version of this patch series is targeting the >> > Chrome browser as its first user, it became evident during upstream >> > discussions that we would also want to ensure that the patch set >> > eventually is a complete solution for memory sealing and compatible >> > with other use cases. The specific scenario currently in mind is >> > glibc's use case of loading and sealing ELF executables. To this end, >> > Stephen is working on a change to glibc to add sealing support to the >> > dynamic linker, which will seal all non-writable segments at startup. >> > Once this work is completed, all applications will be able to >> > automatically benefit from these new protections. >> >> Is this work posted somewhere? Having a second - and more generally >> useful - user for this API would do a lot to show that the design is, in >> fact, right and useful beyond the Chrome browser. >> > Stephen conducted a PoC last year, it will be published once it is comple= te. > We're super excited about introducing this as a general safety measure > for all of Linux! We're excited too, something like mseal() seems like a good thing to have. My point, though, is that it would be good to see this second (and more general) user of the API *before* merging it. As others have noted, once mseal() is in a released kernel, it will be difficult to change if adjustments turn out to be necessary. Thanks, jon