Received-SPF: pass (google.com: domain of linux-kernel+bounces-92061-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
Date: Tue, 5 Mar 2024 02:12:26 -0800
From: Kees Cook <keescook@chromium.org>
To: Christian Brauner <brauner@kernel.org>
Cc: Adrian Ratiu <adrian.ratiu@collabora.com>,
	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 <groeck@chromium.org>,
	Doug Anderson <dianders@chromium.org>, Jann Horn <jannh@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	Mike Frysinger <vapier@chromium.org>
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
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/<pid>/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