From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from janus.otherwize.co.uk (janus.otherwize.co.uk [185.73.44.80]) (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 3E24A1D63D1; Mon, 16 Feb 2026 00:55:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.73.44.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771203346; cv=none; b=WcnTO/r8ufBxcspusayFUYcovnrZsFctsUkJoyZMtyRQmOeuOaFp/kn1u25jTMLpZkFuYVZvv4jwacBj8k0CVYb/jPRnnlmjwfHYGyyXtbRom6A7L+6Sxj/hq4MCH17R2KI74oW9dR3rHhFyf1MDPNsE7Towhclgr7HJQ0Fuy2o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771203346; c=relaxed/simple; bh=fvkR0Wh8KtO0lrdxTcYcUHxzWKd3DSAIhWmKgWV6eIA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=OzIYUNmkVnlFkuQKs+ARDtzGIQbExhsE0YtKXN0NyexH5AgbB4kszc2xPjD04tTwTNNgNWUAEgccMR1pbAyy9BxCqoJ1uLM8xpyawOiR5MSBEZ5Ez82NR3wpHmy/SrEy/lB3i/2reY02egvm1KumluJXV0qNm95sdkGeSXv86U8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=dgl.cx; spf=pass smtp.mailfrom=dgl.cx; arc=none smtp.client-ip=185.73.44.80 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=dgl.cx Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=dgl.cx Received: from melos.hm.i.d.cx (melos.hm.i.d.cx [10.1.91.149]) by janus.otherwize.co.uk (OpenSMTPD) with ESMTP id 3d60e48d; Mon, 16 Feb 2026 00:49:03 +0000 (UTC) Received: from localhost (melos.hm.i.d.cx [local]) by melos.hm.i.d.cx (OpenSMTPD) with ESMTPA id 53709845; Mon, 16 Feb 2026 11:48:27 +1100 (AEDT) Date: Mon, 16 Feb 2026 11:48:27 +1100 From: David Leadbeater To: Shyam Prasad N Cc: lsf-pc@lists.linux-foundation.org, linux-fsdevel , keyrings@vger.kernel.org, CIFS , linux-nfs@vger.kernel.org, brauner@kernel.org, David Howells Subject: Re: [LSF/MM/BPF TOPIC] Namespace-aware upcalls from kernel filesystems Message-ID: References: Precedence: bulk X-Mailing-List: linux-nfs@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: On Sat, Feb 14, 2026 at 03:36:22PM +0530, Shyam Prasad N wrote: > I tried to prototype a namespace aware upcall mechanism for kernel keys here: > https://www.spinics.net/lists/keyrings/msg17581.html > But it has not been successful so far. I'm seeking reviews on this > approach from security point of view. I have more context from the containers side, but to me this doesn't appear safe. Entering the right namespaces isn't enough to safely run code within a container. The container runtime may have set up seccomp or other limits which this upcall won't respect. I would like to see a solution to this though, we currently have custom callback code to make this work. I'm not familiar enough with the interfaces but an approach where something registers also seems desirable because it is able to preserve backwards compatibility, which changing the namespace the upcall runs in doesn't. David