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Tue, 30 Jun 2026 00:26:04 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface Precedence: bulk X-Mailing-List: linux-api@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ThreadId: AG8qDlxFSDr7 Date: Tue, 30 Jun 2026 00:25:44 -0400 From: "John Ericson" To: "Andy Lutomirski" , "Christian Brauner" Cc: "Li Chen" , "Cong Wang" , linux-arch , LKML , linux-fsdevel , linux-api , "Arnd Bergmann" , "Thomas Gleixner" , "Ingo Molnar" , "Borislav Petkov" , "Dave Hansen" , "H. Peter Anvin" , "Jan Kara" , "Jonathan Corbet" , "Shuah Khan" , "Al Viro" , "Kees Cook" , "Sergei Zimmerman" , "Farid Zakaria" Message-Id: In-Reply-To: References: <20260629-hauer-erhitzen-sobald-96d3dff68707@brauner> Subject: Re: [RFC] Null Namespaces Content-Type: text/plain Content-Transfer-Encoding: 7bit On Mon, Jun 29, 2026, at 5:06 PM, Andy Lutomirski wrote: > But if this happens, maybe we could finally land one of the patches to > enable unprivileged chroot? It's been tried a few times. > If we had a way to make an OFD to a directory that forced > RESOLVE_BENEATH (or RESOLVE_IN_ROOT) and that propagated that > restriction to anything you open using it, and if an unprivileged > process could chroot itself to nullfs, then we would be getting quite > close to what Capsicum can do. I just want to briefly say that I agree that these are both things worth pursuing. Once the root and working directories are sorted out (whether by nullfs or by making those optional in `fs_struct`, see my other email), I am fine putting my yet-unsubmitted patches for the null namespaces themselves on hold and addressing these things instead. I can indeed see it may be useful to wrap up such loose ends in VFS-land while we are here, before switching gears to other namespaces and other subsystems. John