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[2003:cb:c71f:6900:2b25:fc69:599e:3986]) by smtp.gmail.com with ESMTPSA id 16-20020a05600c021000b003f1940fe278sm7185780wmi.7.2023.05.05.00.35.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 05 May 2023 00:36:00 -0700 (PDT) Message-ID: Date: Fri, 5 May 2023 09:35:59 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH] sysctl: add config to make randomize_va_space RO To: Michael McCracken , linux-kernel@vger.kernel.org Cc: kernel-hardening@lists.openwall.com, serge@hallyn.com, tycho@tycho.pizza, Luis Chamberlain , Kees Cook , Iurii Zaikin , Andrew Morton , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org References: <20230504213002.56803-1-michael.mccracken@gmail.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20230504213002.56803-1-michael.mccracken@gmail.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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: On 04.05.23 23:30, Michael McCracken wrote: > Add config RO_RANDMAP_SYSCTL to set the mode of the randomize_va_space > sysctl to 0444 to disallow all runtime changes. This will prevent > accidental changing of this value by a root service. > > The config is disabled by default to avoid surprises. Can you elaborate why we care about "accidental changing of this value by a root service"? We cannot really stop root from doing a lot of stupid things (e.g., erase the root fs), so why do we particularly care here? -- Thanks, David / dhildenb