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 0B33DDDBE; Thu, 7 Nov 2024 14:59:43 +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=1730991583; cv=none; b=nRHozvaFsS3incN1QHJkL0QDsw2MZ5BmDi4v3JUiJqRUC5Xi/77y0FjNDfgWnrl9S1BnjnHBWDNvFJEOjXsdKpq4xlAfzQiZB9bFIdHwhb3Li/R+k1HE6KnP9uhz2+R21SJb03I0+kVISL119yt4NPntGwv1SlFRHes+eGw01OA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730991583; c=relaxed/simple; bh=0uZRH9no1sDMwn1zq/WxGdvCuQAjLUJEK0XIIj3xt+I=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=AAM7y7rRFRdfnZenh9VJIIqAkK18ceHScFJUyExa11o+FhxlG87UV+koLQurFh50m+ThVvZ1uzNrlFYFKuSl4Z4KbZachkoVM1R88TtOJanJCtW7W5e7rxdTVJC7ph64Ndx037uGzLPUxlLA3vwxjbG9fCRz+2AcHsmL4S674rI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qND1QVkc; 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="qND1QVkc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B89A7C4CECD; Thu, 7 Nov 2024 14:59:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730991582; bh=0uZRH9no1sDMwn1zq/WxGdvCuQAjLUJEK0XIIj3xt+I=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=qND1QVkch2tu6qrqQ6YNdRUw2hf8r9HSt65E0Z2xbzy8I8LgG9uwNTJm8Gs6rHvFW Wr8YymkshkkrnML224h6HWmS/k1poxNnvH/XY+clYrcIxly8m2pe2aCiJMcxVyHuCn j/Vh848GmF2i50XEtR5VWS+dxT2zjhKr43gaQKHrEhN7QjXqfe4il6Wp4sPwEErTW/ UbyxHx48SJtdKUWloF8LG1KmIG7pfdWDeBjGsfXAVx63iNEIHgtYfmtNnpRUT9/cmh wgiycfUzDtzwWC3tAoVy/Dk8C0u7rZP9O1N9Pcd3VY/vVAb6pSyvOvS5DbqLg/AkVZ 2OmqvqLiw/hJw== Date: Thu, 7 Nov 2024 08:59:41 -0600 From: Bjorn Helgaas To: Leon Romanovsky Cc: Bjorn Helgaas , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , linux-pci@vger.kernel.org, Ariel Almog , Aditya Prabhune , Hannes Reinecke , Heiner Kallweit , Arun Easi , Jonathan Chocron , Bert Kenward , Matt Carlson , Kai-Heng Feng , Jean Delvare , Alex Williamson , linux-kernel@vger.kernel.org Subject: Re: [PATCH] PCI/sysfs: Fix read permissions for VPD attributes Message-ID: <20241107145941.GA1613712@bhelgaas> Precedence: bulk X-Mailing-List: linux-pci@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: <1d4df22e-3783-4081-b57b-ac03cd894cb5@app.fastmail.com> On Thu, Nov 07, 2024 at 01:31:44PM +0200, Leon Romanovsky wrote: > On Tue, Nov 5, 2024, at 18:26, Leon Romanovsky wrote: > > On Tue, Nov 05, 2024 at 09:24:55AM -0600, Bjorn Helgaas wrote: > >> On Tue, Nov 05, 2024 at 09:51:30AM +0200, Leon Romanovsky wrote: > >> > On Mon, Nov 04, 2024 at 06:10:27PM -0600, Bjorn Helgaas wrote: > >> > > On Sun, Nov 03, 2024 at 02:33:44PM +0200, Leon Romanovsky wrote: > >> > > > On Fri, Nov 01, 2024 at 11:47:37AM -0500, Bjorn Helgaas wrote: > >> > > > > On Fri, Nov 01, 2024 at 04:33:00PM +0200, Leon Romanovsky wrote: > >> > > > > > On Thu, Oct 31, 2024 at 06:22:52PM -0500, Bjorn Helgaas wrote: > >> > > > > > > On Tue, Oct 29, 2024 at 07:04:50PM -0500, Bjorn Helgaas wrote: > >> > > > > > > > On Mon, Oct 28, 2024 at 10:05:33AM +0200, Leon Romanovsky wrote: > >> > > > > > > > > From: Leon Romanovsky > >> > > > > > > > > > >> > > > > > > > > The Virtual Product Data (VPD) attribute is not > >> > > > > > > > > readable by regular user without root permissions. > >> > > > > > > > > Such restriction is not really needed, as data > >> > > > > > > > > presented in that VPD is not sensitive at all. > >> > > > > > > > > > >> > > > > > > > > This change aligns the permissions of the VPD > >> > > > > > > > > attribute to be accessible for read by all users, > >> > > > > > > > > while write being restricted to root only. > >> > ... > >> > >> > > What's the use case? How does an unprivileged user use the VPD > >> > > information? > >> > > >> > We have to add new field keyword=value in VA section of VPD, which > >> > will indicate very specific sub-model for devices used as a bridge. > >> > > >> > > I can certainly imagine using VPD for bug reporting, but that > >> > > would typically involve dmesg, dmidecode, lspci -vv, etc, all of > >> > > which already require privilege, so it's not clear to me how > >> > > public VPD info would help in that scenario. > >> > > >> > I'm targeting other scenario - monitoring tool, which doesn't need > >> > root permissions for reading data. It needs to distinguish between > >> > NIC sub-models. > >> > >> Maybe the driver could expose something in sysfs? Maybe the driver > >> needs to know the sub-model as well, and reading VPD once in the > >> driver would make subsequent userspace sysfs reads trivial and fast. > > > > Our PCI driver lays in netdev subsystem and they have long-standing > > position do not allow any custom sysfs files. To be fair, we (RDMA) > > don't allow custom sysfs files too. > > > > Driver doesn't need to know this information as it is extra key=value in > > existing [VA] field, while driver relies on multiple FW capabilities > > to enable/disable functionality. > > > > Current [VA] line: > > "[VA] Vendor specific: > > MLX:MN=MLNX:CSKU=V2:UUID=V3:PCI=V0:MODL=CX713106A" > > Future [VA] line: > > "[VA] Vendor specific: > > MLX:MN=MLNX:CSKU=V2:UUID=V3:PCI=V0:MODL=CX713106A,SMDL=SOMETHING" > > > > Also the idea that we will duplicate existing functionality doesn't > > sound like a good approach to me, and there is no way that it is > > possible to expose as subsystem specific file. > > > > What about to allow existing VPD sysfs file to be readable for everyone > > for our devices? > > And if this allow list grows to much, we will open it for all devices > > in the world? > > Bjorn, > > I don't see this patch in > https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git/log/?h=next > So what did you decide? How can we enable existing VPD access to > regular users? I think it's too risky to enable VPD to be readable by all users. Bjorn