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Tue, 05 Mar 2024 02:12:27 -0800 (PST) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id mm12-20020a1709030a0c00b001dc96d1a662sm10134092plb.197.2024.03.05.02.12.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 Mar 2024 02:12:26 -0800 (PST) Date: Tue, 5 Mar 2024 02:12:26 -0800 From: Kees Cook To: Christian Brauner Cc: Adrian Ratiu , linux-fsdevel@vger.kernel.org, kernel@collabora.com, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Guenter Roeck , Doug Anderson , Jann Horn , Andrew Morton , Randy Dunlap , Mike Frysinger Subject: Re: [PATCH v2] proc: allow restricting /proc/pid/mem writes Message-ID: <202403050211.86A44769@keescook> References: <20240301213442.198443-1-adrian.ratiu@collabora.com> <20240304-zugute-abtragen-d499556390b3@brauner> <202403040943.9545EBE5@keescook> <20240305-attentat-robust-b0da8137b7df@brauner> <202403050134.784D787337@keescook> <20240305-kontakt-ticken-77fc8f02be1d@brauner> Precedence: bulk X-Mailing-List: linux-security-module@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: <20240305-kontakt-ticken-77fc8f02be1d@brauner> On Tue, Mar 05, 2024 at 10:58:25AM +0100, Christian Brauner wrote: > Since the write handler for /proc//mem does raise FOLL_FORCE > unconditionally it likely would implicitly. But I'm not familiar enough > with FOLL_FORCE to say for sure. I should phrase the question better. :) Is the supervisor writing into read-only regions of the child process? -- Kees Cook