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Sat, 13 Dec 2025 13:59:12 -0500 (EST) Received: by fw12.qyliss.net (Postfix, from userid 1000) id EC40578F6F74; Sat, 13 Dec 2025 19:59:05 +0100 (CET) From: Alyssa Ross To: Alejandro Colomar Cc: Christian Brauner , Al Viro , linux-kernel@vger.kernel.org, linux-man@vger.kernel.org Subject: Re: [PATCH] man/man2/setns.2: clarify type of nsfs fd required In-Reply-To: References: <20251213175853.555517-1-hi@alyssa.is> Date: Sat, 13 Dec 2025 19:59:04 +0100 Message-ID: <87qzsy5htz.fsf@alyssa.is> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" --=-=-= Content-Type: text/plain Alejandro Colomar writes: > Hi Alyssa, > > On Sat, Dec 13, 2025 at 06:58:53PM +0100, Alyssa Ross wrote: >> I was surprised to discover than an O_PATH file descriptor was >> insufficient. > > How did you discover it? Could you please link to relevant information > (or kernel sources)? By trying it! Presumably it's the fd_empty() check at the beginning of the syscall implementation in nsproxy.c. >> Since the mode of nsfs files is always 0444, tell >> callers to always a file descriptor opened for reading. > > Missing 'use'? Yes. Feel free to add it. --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEARYKAB0WIQQGoGac7QfI+H5ZtFCZddwkt31pFQUCaT23eAAKCRCZddwkt31p FbScAQDIsOCpRdX43v6dqChYFvnSEgc2YAZNxVxR5JdmDFQNgAD+KbmE3vT6ie9o 2h6Wcc9KTs89L+OblOUfg/wqDYCsUw0= =qkaZ -----END PGP SIGNATURE----- --=-=-=--