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 622622765DC; Thu, 23 Oct 2025 10:46:53 +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=1761216413; cv=none; b=J7acZ53Z08PuI0EZ94hojatEirftDrp9WXg5qkcBAkfJI3/SU8yJrIKpyeY84JfavYr9Pt7eA0VXrrfIZwTupibz/vbKJo1ZYsX43B99IwVxUTGis1V6vBqP55s2JalCr2mzwYIvKwLJIlZ/fojSOYLZjU0FUWhvb267sYP92JA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761216413; c=relaxed/simple; bh=4Nycx1ORZclwlAUuSrDPm+Q6EH8JvLo9+c1zBeefgcA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=CbHMTTQpLwl2OGBKFVjSqqSs5a7Kl03vI7CkwY/b+MOtlAdKnt80XVYlnIPw9fy+aqVGiGgUv0Eo8R0gZ4Ef4lHRZpI4TgpCPRs7CkHjpL98MI/jN8P97crQHkOOD1X62f310tNVtCXmzuyO8cpNGs/fohkpICcaRYMV4zVVX9k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MLokn6j7; 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="MLokn6j7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CD9B7C4CEE7; Thu, 23 Oct 2025 10:46:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761216412; bh=4Nycx1ORZclwlAUuSrDPm+Q6EH8JvLo9+c1zBeefgcA=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=MLokn6j7bsPTtDKzR8pqjp2OIR+OMKA1rj3J/6jxNvlhgcsOoQ+moyQ5GdMJY0dDs Znmt5H3FHjRCN/E5Q2OiSn3Lge5IHCXD/l7T7/WJ6bkLphXMC2HXV8rhysZfDX6Sr+ rNUl8sN5/1gEAa9ysrMEafdWcYQ0VQhevGk1H7BhaFT8iiTd5n9BTY4verf1aGvcpu 2n7qQ7sTY81LVQ1UhGF1Gtff22NCJXEfiZHTApKvHY7cQr6tmKVbYlAGr+xV9kWFbP 87li730Z1OQYtoHcpFjViMqnavqolBedQ+OYK4M6H1LebiK34NEzwo7Gy1V6/AuNf7 96d0cS8eISSpA== Message-ID: <5b287ec6-72ff-4707-9040-3c84efc58b94@kernel.org> Date: Thu, 23 Oct 2025 12:46:45 +0200 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 01/32] pidfs: validate extensible ioctls To: Christian Brauner , Jan Kara , Amir Goldstein , linux-fsdevel@vger.kernel.org Cc: Josef Bacik , Jeff Layton , Mike Yuan , =?UTF-8?Q?Zbigniew_J=C4=99drzejewski-Szmek?= , Lennart Poettering , Daan De Meyer , Aleksa Sarai , Alexander Viro , Jens Axboe , Tejun Heo , Johannes Weiner , =?UTF-8?Q?Michal_Koutn=C3=BD?= , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Chuck Lever , linux-nfs@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, netdev@vger.kernel.org References: <20250910-work-namespace-v1-0-4dd56e7359d8@kernel.org> <20250910-work-namespace-v1-1-4dd56e7359d8@kernel.org> Content-Language: en-US From: Jiri Slaby Autocrypt: addr=jirislaby@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 10. 09. 25, 16:36, Christian Brauner wrote: > Validate extensible ioctls stricter than we do now. > > Signed-off-by: Christian Brauner > --- > fs/pidfs.c | 2 +- > include/linux/fs.h | 14 ++++++++++++++ > 2 files changed, 15 insertions(+), 1 deletion(-) > > diff --git a/fs/pidfs.c b/fs/pidfs.c > index edc35522d75c..0a5083b9cce5 100644 > --- a/fs/pidfs.c > +++ b/fs/pidfs.c > @@ -440,7 +440,7 @@ static bool pidfs_ioctl_valid(unsigned int cmd) > * erronously mistook the file descriptor for a pidfd. > * This is not perfect but will catch most cases. > */ > - return (_IOC_TYPE(cmd) == _IOC_TYPE(PIDFD_GET_INFO)); > + return extensible_ioctl_valid(cmd, PIDFD_GET_INFO, PIDFD_INFO_SIZE_VER0); Hi, this turned EINVAL (from pidfd_info()) into ENOTTY (from pidfd_ioctl()) for at least LTP's: struct pidfd_info_invalid { uint32_t dummy; }; #define PIDFD_GET_INFO_SHORT _IOWR(PIDFS_IOCTL_MAGIC, 11, struct pidfd_info_invalid) ioctl(pidfd, PIDFD_GET_INFO_SHORT, info_invalid) == EINVAL at: https://github.com/linux-test-project/ltp/blob/9bb94efa39bb1b08f37e56c7437db5fa13ddcae2/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c#L46 Is this expected? > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -4023,4 +4023,18 @@ static inline bool vfs_empty_path(int dfd, const char __user *path) > > int generic_atomic_write_valid(struct kiocb *iocb, struct iov_iter *iter); > > +static inline bool extensible_ioctl_valid(unsigned int cmd_a, > + unsigned int cmd_b, size_t min_size) > +{ > + if (_IOC_DIR(cmd_a) != _IOC_DIR(cmd_b)) > + return false; > + if (_IOC_TYPE(cmd_a) != _IOC_TYPE(cmd_b)) > + return false; > + if (_IOC_NR(cmd_a) != _IOC_NR(cmd_b)) > + return false; > + if (_IOC_SIZE(cmd_a) < min_size) > + return false; > + return true; > +} > + > #endif /* _LINUX_FS_H */ > thanks, -- js suse labs