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[173.79.60.52]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-90c939314d2sm4857616d6.25.2026.08.21.21.19.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 Aug 2026 21:19:01 -0700 (PDT) Date: Sat, 22 Aug 2026 00:18:58 -0400 From: Gregory Price To: "Darrick J. Wong" Cc: John Groves , John Groves , Miklos Szeredi , Dan Williams , Bernd Schubert , Alison Schofield , John Groves , Jonathan Corbet , Jake Edge , Shuah Khan , Vishal Verma , Dave Jiang , Matthew Wilcox , Jan Kara , Alexander Viro , David Hildenbrand , Christian Brauner , Randy Dunlap , Jeff Layton , Amir Goldstein , Jonathan Cameron , Stefan Hajnoczi , Joanne Koong , Josef Bacik , Bagas Sanjaya , Chen Linxuan , James Morse , Fuad Tabba , Sean Christopherson , Shivank Garg , Ackerley Tng , Andrew Morton , Namjae Jeon , Lorenzo Stoakes , Greg Kroah-Hartman , Ira Weiny , Pasha Tatashin , Haren Myneni , Pratyush Yadav , Giovanni Cabiddu , Jiri Slaby , Ethan Nelson-Moore , Gabriel Whigham , Aravind Ramesh , Ajay Joshi , "venkataravis@micron.com" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "nvdimm@lists.linux.dev" , "linux-cxl@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "fuse-devel@lists.linux.dev" Subject: Re: [PATCH v13 10/12] famfs: Add runtime operation-permission (opts) framework Message-ID: References: <0100019fed5850ec-2bdfb17a-3086-44ea-8fdd-777d3ce12a33-000000@email.amazonses.com> <20260810202539.96378-1-john@jagalactic.com> <0100019fed5a5210-a09f1bdb-c705-44fc-8108-a7e7995a7af0-000000@email.amazonses.com> <20260822000728.GB6047@frogsfrogsfrogs> Precedence: bulk X-Mailing-List: linux-fsdevel@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: <20260822000728.GB6047@frogsfrogsfrogs> On Fri, Aug 21, 2026 at 05:07:28PM -0700, Darrick J. Wong wrote: > > But what prevents a malicious program that is /not/ the famfs client > software but has CAP_SYS_ADMIN from doing that? > Such a program can already unmount famfs, rebind the device to device_dax, and mmap the whole range directly. MAP_CREATE isn't handing it reach it didn't have. ~Gregory