From patchwork Tue Feb 11 17:16:00 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 865731 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 53F4626BD8E; Tue, 11 Feb 2025 17:16:46 +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=1739294207; cv=none; b=WbIq24LERrzj63/R1TncmQ5awwHzXg3af6FtEfkt+azeGfPe9Sp5ZZnbnCE28Bcb8wwVcAomPWrpZEV4W1eeuwM9sZZFrzt3bThGlj/IZCV0eEy8NMaOwq8k7yLyUS4FToGanlZWPG6dTb7E9tZQBE0jhmMVX1xyRVdQzcvrge0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739294207; c=relaxed/simple; bh=R8d5Ssr+h4DakuPRujcY1UcNTq2kza5I6mwLHnz1mt4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=HwaeXxnnj1cEm1wD4obGLBGRbqAb6bP/qwojZus1N6ftSxYXc1dErbs7RuhFF8puni6NKvjP1JLCiqwdyoM4TV52QIEjlSjg9uKWD1ScYBLXkApvafb2hzXR3LoNo2cSrM6DZL9Zuism8p63+ZmsF0jhHR3iziNA61ZWs3wuTlE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tVMJrP1C; 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="tVMJrP1C" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3B1FBC4CEE7; Tue, 11 Feb 2025 17:16:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739294206; bh=R8d5Ssr+h4DakuPRujcY1UcNTq2kza5I6mwLHnz1mt4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tVMJrP1CRNsyE+8u/InV9JqgmQua6GhyffEgl6CLXwuJc8lkm3oveZOhTRyQaC6BO EUA/cnNtE3XIj/ILxGOnN5R8/Gv/5i2lFecYVt+HXDAFKlgKtirg1xnlN9QY6YJxxa dDl0tSHBupZ9JEwjZcrxo61VG5DAWFNOX/G3wk/M5erTGlrOAbrRjkxF3QjZAnuQED ZzX08k75IFTvMkdSl7/KABgMto1KDtKERlMSptFh5mE8WWfUkakNo0aPWMzEEZTKQE PeYHB4hVIj0W3RSA/QYiaeE1+U6Y8ZXHp7/Lmlqwknuh9cfGuLA7+qSYRgrbc6F6bA erQBVPwHx70sg== From: Christian Brauner To: Zicheng Qu , Linus Torvalds Cc: Christian Brauner , jlayton@kernel.org, axboe@kernel.dk, joel.granados@kernel.org, tglx@linutronix.de, viro@zeniv.linux.org.uk, hch@lst.de, len.brown@intel.com, pavel@ucw.cz, pengfei.xu@intel.com, rafael@kernel.org, tanghui20@huawei.com, zhangqiao22@huawei.com, judy.chenhui@huawei.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, syzkaller-bugs@googlegroups.com, linux-pm@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH 2/2] acct: block access to kernel internal filesystems Date: Tue, 11 Feb 2025 18:16:00 +0100 Message-ID: <20250211-work-acct-v1-2-1c16aecab8b3@kernel.org> X-Mailer: git-send-email 2.47.2 In-Reply-To: <20250211-work-acct-v1-0-1c16aecab8b3@kernel.org> References: <20250211-work-acct-v1-0-1c16aecab8b3@kernel.org> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Mailer: b4 0.15-dev-d23a9 X-Developer-Signature: v=1; a=openpgp-sha256; l=1108; i=brauner@kernel.org; h=from:subject:message-id; bh=R8d5Ssr+h4DakuPRujcY1UcNTq2kza5I6mwLHnz1mt4=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMaSvbr3ok9HCnmjp5jU5uET2QFSa01nWeZzdH9/7Fb7i+ Cg6ySeto5SFQYyLQVZMkcWh3SRcbjlPxWajTA2YOaxMIEMYuDgFYCI3lzMy/FrnbrF949ozkVxH n8ZsUpL9meyjn3DK98O+zdc21R3Sc2H4K8n8Ve1HCJ+ceF6VecEj+5LeY2cUjLpbVK7fl1c4EHG BBQA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 There's no point in allowing anything kernel internal nor procfs or sysfs. Reported-by: Zicheng Qu Link: https://lore.kernel.org/r/20250127091811.3183623-1-quzicheng@huawei.com Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: Signed-off-by: Christian Brauner --- kernel/acct.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/kernel/acct.c b/kernel/acct.c index 48283efe8a12..6520baa13669 100644 --- a/kernel/acct.c +++ b/kernel/acct.c @@ -243,6 +243,20 @@ static int acct_on(struct filename *pathname) return -EACCES; } + /* Exclude kernel kernel internal filesystems. */ + if (file_inode(file)->i_sb->s_flags & (SB_NOUSER | SB_KERNMOUNT)) { + kfree(acct); + filp_close(file, NULL); + return -EINVAL; + } + + /* Exclude procfs and sysfs. */ + if (file_inode(file)->i_sb->s_iflags & SB_I_USERNS_VISIBLE) { + kfree(acct); + filp_close(file, NULL); + return -EINVAL; + } + if (!(file->f_mode & FMODE_CAN_WRITE)) { kfree(acct); filp_close(file, NULL);