From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) (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 1AC9E12C544; Fri, 6 Jun 2025 14:41:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.89.141.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749220864; cv=none; b=FtVm5q8xnxIISyUMdVISYJo6+pH5Dh3Daq94aOxrHzVtOWfUN2b5tx6naKjv4353McB6qfI8AeCqrQvRaTqkjgCearloPzhxG6adYufldmxtduscBNrUM++W5MdBa/EPGjHrny6hTivo1Yya9UDmQT1hvC6DF0GLBpBwuBNA3VQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749220864; c=relaxed/simple; bh=i6yRDhrgT2/zq3iSXDElxzAsOnMwawV20rQ7HStxa3M=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=MlhEage/+ho0C29RRaCbgYNSDfNXDI2H8k5qq+RlRt+KxcTEkTdEeRSu7pM2nXUVYiW1yerD7KHHuuqDmSqQJ7+a8HfwBNNw8+ux9whjvcIV0kK7nYA/Hl0UMZOhgZd0PZrq8NRMM6KxtWiRnRdnx8gI3Detvjpvr1dilYgRKJ0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk; spf=none smtp.mailfrom=ftp.linux.org.uk; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b=vEgwYKXW; arc=none smtp.client-ip=62.89.141.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=ftp.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b="vEgwYKXW" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=BUMSe0tFWJRLz9VwcNCfytngVWsj4oVCG4RF0FGla5Y=; b=vEgwYKXWIxvqi2qfBNwslK5vx9 VsPxPYEQeWsRX5tCPp3P5OFJxKugVlpqYPEFHnzLNTOKVEBcYfIYdwZ0BrM6RYJECMp9T8jN3lO4+ Jsl6UzNw/pudNpkER7f6ou//01Wf16scHrGG1fChyR4eUJnVC0U3gIMew+NcR9Ab6zh2f2STtFwFt F87GCBGHHwS8dTqGei+wOgXnT6Q8DCvLPuVgW6wgUncgyHXcf6ASCgolmOMJoCmXEeBQmmmGsuojL wX/aYEHk8mYjsJQE7NIDj3oWM3g5GZLWQh7SXZgrygHk/5mFP7McpL1BN6do31ucnXBs7Sb5XBz8L hjZcZM/A==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uNYFe-0000000HDKS-17Ib; Fri, 06 Jun 2025 14:40:58 +0000 Date: Fri, 6 Jun 2025 15:40:58 +0100 From: Al Viro To: Song Liu Cc: bpf@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, kernel-team@meta.com, andrii@kernel.org, eddyz87@gmail.com, ast@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev, brauner@kernel.org, jack@suse.cz, kpsingh@kernel.org, mattbobrowski@google.com, amir73il@gmail.com, repnop@google.com, jlayton@kernel.org, josef@toxicpanda.com, mic@digikod.net, gnoack@google.com, m@maowtm.org Subject: Re: [PATCH v2 bpf-next 1/4] namei: Introduce new helper function path_walk_parent() Message-ID: <20250606144058.GW299672@ZenIV> References: <20250603065920.3404510-1-song@kernel.org> <20250603065920.3404510-2-song@kernel.org> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250603065920.3404510-2-song@kernel.org> Sender: Al Viro On Mon, Jun 02, 2025 at 11:59:17PM -0700, Song Liu wrote: > This helper walks an input path to its parent. Logic are added to handle > walking across mount tree. > > This will be used by landlock, and BPF LSM. Unless I'm misreading that, it does *NOT* walk to parent - it treats step into mountpoint as a separate step. NAK in that form - it's simply a wrong primitive.