From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 33F263B8BBF; Mon, 16 Mar 2026 16:53:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773680027; cv=none; b=ICIylsjkMUGwURsg0ZTx78iSx8h6qrRqZnAWCEhyjFSDOXtgE0JqEDKoppcxq8gL5rg5wKg53tL/FUfjB8tqVLrry1hhYZwEEX8zFoCkNJUMCyeNkZpaPb0S0frIsxqFHaWJdKlgf2EVBWf4GUwA+BOI+q0XsQ8Y2ecqXsmMT9c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773680027; c=relaxed/simple; bh=XGmk+bJYmHJVxnVa2fQvb/Pqvfns2aI1x7zCbX8yktc=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=Z8TqJMw0XzElN6nH0zjs513JBDlVCUuE7y6IOLSpOuLh5abCwNAFDPMhm3ij5aDl8/wEw302IJQClCn1uC3op3XUs+bGx+6zeePD3jtr1wPf+LTEl96Pd20Ae/pShTx4Wp+O21YsAiOGEndrSdOgahHzpj4Mx31dR7FLQI1lXL8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=R832Orfs; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="R832Orfs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 292E7C19421; Mon, 16 Mar 2026 16:53:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773680026; bh=XGmk+bJYmHJVxnVa2fQvb/Pqvfns2aI1x7zCbX8yktc=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=R832OrfsM9tquLmCOCzbAg5RHBExZBgmcHa+SJSvN7T3/P/Vsa4nvBcb1g7+BmmH9 U2DxOMN9f+mlDaX6MrhB6Mj8wj8CnSxmcdiYjLf7+m8xCRGSTcHT4rKpGtU6kV7BRw 1f6gXApOrW01lYc4GaKu0tU4D08BeY5uxiwYFSJbUPsplSYAe1eSfcfsvUVkl1Ncwd 0KG6UZQ4M9KEL27YkV/V2UsedyUlJSosy5Vhx7/NhC/OK9WEOWGrjK/eKzoj5bZa0X 77Cc01pEIrWAUvD0kuC/KeAokOmKF8nIvi/Q/lzEoqnEp6cIr97+rHAOEzkylLgss6 zX0Jr1Spvs5vQ== Message-ID: <5fcc2a6e6d92dae0601c6b3b8faa8b2f83981afb.camel@kernel.org> Subject: Re: [PATCH v5 1/4] openat2: new OPENAT2_REGULAR flag support From: Jeff Layton To: Dorjoy Chowdhury , linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, ceph-devel@vger.kernel.org, gfs2@lists.linux.dev, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, v9fs@lists.linux.dev, linux-kselftest@vger.kernel.org, viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz, chuck.lever@oracle.com, alex.aring@gmail.com, arnd@arndb.de, adilger@dilger.ca, mjguzik@gmail.com, smfrench@gmail.com, richard.henderson@linaro.org, mattst88@gmail.com, linmag7@gmail.com, tsbogend@alpha.franken.de, James.Bottomley@HansenPartnership.com, deller@gmx.de, davem@davemloft.net, andreas@gaisler.com, idryomov@gmail.com, amarkuze@redhat.com, slava@dubeyko.com, agruenba@redhat.com, trondmy@kernel.org, anna@kernel.org, sfrench@samba.org, pc@manguebit.org, ronniesahlberg@gmail.com, sprasad@microsoft.com, tom@talpey.com, bharathsm@microsoft.com, shuah@kernel.org, miklos@szeredi.hu, hansg@kernel.org Date: Mon, 16 Mar 2026 12:53:40 -0400 In-Reply-To: <20260307140726.70219-2-dorjoychy111@gmail.com> References: <20260307140726.70219-1-dorjoychy111@gmail.com> <20260307140726.70219-2-dorjoychy111@gmail.com> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 0OX6MYPtv76hka8lW4mnRmZqqx3UtfHX/hF/zH24Gj7A6sYKYLCU3YrI2Ogiu7/ksKcl7goQjpvtV YrOOI5VGLHge0awt7bhMCTM9KAfPc+xL/ZxAMVWd3NCk5SamL2cE99UWgtvNOIYU8m6EjTLhsj8sn 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DfX/sn9XcfoVZIxMpCRE750zvJvcCUz9HojsrMQ1NFc7MFT1z3MOW2/RlzPcog7xvR5ENPH19ojRD CHqumUHRry+RF0lH00clzX/W8OrQJZtoBPXv9ahka/Vp7kEulcBJr1cH5Wz/WprhsIM7U9pse1f1g Yy9YbXtWctUz8uvDR7shsQxAhX3qO7DilMtuGo1v97I/Kx4gXQ52syh/w6EBny71CZrOgD6kJwPVV AaM1LRC28muq91WCFhs/nzHozpbzcheyGtMUI2Ao4K6mnY+3zIuXPygZMFr9KXE6fF7HzKxKuZMJO aEZCiDOq0anx6FmOzs5E6Jqdpo/mtI8beK+BE7Va6ni7YrQlnT0i3vaTVMTiCThbqsB20VrbMjlhp f8lfK1XVNbRq/R7GZ9zHESlsa35ha60yd/j3pu5hT2xyy8krV8vGhHvnJ1XRMJBAB/UYb6FyC7S+m QZIQXVeAA+smfTT0tDrisj1U5x6ZB9b3nBg65kc= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.3 (3.58.3-1.fc43) Precedence: bulk X-Mailing-List: gfs2@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Sat, 2026-03-07 at 20:06 +0600, Dorjoy Chowdhury wrote: > This flag indicates the path should be opened if it's a regular file. > This is useful to write secure programs that want to avoid being > tricked into opening device nodes with special semantics while thinking > they operate on regular files. This is a requested feature from the > uapi-group[1]. >=20 > A corresponding error code EFTYPE has been introduced. For example, if > openat2 is called on path /dev/null with OPENAT2_REGULAR in the flag > param, it will return -EFTYPE. EFTYPE is already used in BSD systems > like FreeBSD, macOS. >=20 > When used in combination with O_CREAT, either the regular file is > created, or if the path already exists, it is opened if it's a regular > file. Otherwise, -EFTYPE is returned. >=20 > When OPENAT2_REGULAR is combined with O_DIRECTORY, -EINVAL is returned > as it doesn't make sense to open a path that is both a directory and a > regular file. >=20 > [1]: https://uapi-group.org/kernel-features/#ability-to-only-open-regular= -files >=20 > Signed-off-by: Dorjoy Chowdhury > --- > arch/alpha/include/uapi/asm/errno.h | 2 ++ > arch/alpha/include/uapi/asm/fcntl.h | 1 + > arch/mips/include/uapi/asm/errno.h | 2 ++ > arch/parisc/include/uapi/asm/errno.h | 2 ++ > arch/parisc/include/uapi/asm/fcntl.h | 1 + > arch/sparc/include/uapi/asm/errno.h | 2 ++ > arch/sparc/include/uapi/asm/fcntl.h | 1 + > fs/ceph/file.c | 4 ++++ > fs/gfs2/inode.c | 6 ++++++ > fs/namei.c | 4 ++++ > fs/nfs/dir.c | 4 ++++ > fs/open.c | 4 +++- > fs/smb/client/dir.c | 14 +++++++++++++- > include/linux/fcntl.h | 2 ++ > include/uapi/asm-generic/errno.h | 2 ++ > include/uapi/asm-generic/fcntl.h | 4 ++++ > tools/arch/alpha/include/uapi/asm/errno.h | 2 ++ > tools/arch/mips/include/uapi/asm/errno.h | 2 ++ > tools/arch/parisc/include/uapi/asm/errno.h | 2 ++ > tools/arch/sparc/include/uapi/asm/errno.h | 2 ++ > tools/include/uapi/asm-generic/errno.h | 2 ++ > 21 files changed, 63 insertions(+), 2 deletions(-) >=20 >=20 I pointed Claude at this patch and got this back. Both issues that it found will need to be fixed: Analysis Summary Commit: 7e7fa2653ca57 - openat2: new OPENAT2_REGULAR flag support This patch adds a new OPENAT2_REGULAR flag for openat2() that restricts o= pens to regular files only, returning a new EFTYPE errno for non-regular files. It adds filesystem-specific checks in= ceph, gfs2, nfs, and cifs atomic_open paths, plus a VFS-level fallback in do_open(). Issues found: 1. OPENAT2_REGULAR leaks into f_flags - do_dentry_open() strips open-time= -only flags (O_CREAT|O_EXCL|O_NOCTTY|O_TRUNC) but does not strip OPENAT2_REGULAR. When a regular file is successfully o= pened via openat2() with this flag, the bit persists in file->f_flags and will be returned by fcntl(fd, F_GETFL). 2. BUILD_BUG_ON not updated - The compile-time guard checks upper_32_bits= (VALID_OPEN_FLAGS) but the code now accepts VALID_OPENAT2_FLAGS. The guard should cover the expanded flag set. Verified correct: - All hex=E2=86=92octal conversions in MIPS and SPARC fcntl.h are numeric= ally correct - Legacy open()/openat() properly strips OPENAT2_REGULAR via build_open_h= ow() masking with VALID_OPEN_FLAGS - All filesystem cleanup paths (ceph, gfs2, nfs, cifs) properly handle re= sources when returning -EFTYPE - O_DIRECTORY + OPENAT2_REGULAR mutual exclusion is correct - O_PATH + OPENAT2_REGULAR is properly rejected by O_PATH_FLAGS check Ruled out: - NFS -ENOTDIR to -EFTYPE conversion: in atomic_open context, parent path= is VFS-resolved, server errors relate to target - CIFS resource leak: out_err label properly closes server handle and cal= ls iput() - OPENAT2_REGULAR + O_TMPFILE: silently accepted but tmpfiles are always = regular, so harmless FINAL REGRESSIONS FOUND: 2 FINAL TOKENS USED: ~45000 False positives eliminated: NFS -ENOTDIR conversion, CIFS resource leak, = O_TMPFILE interaction Cheers, --=20 Jeff Layton