linux-kernel - Re: [PATCH v2 1/3] nvmem: core: make default user binary file root-access only

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Message-ID: <20151007161228.GD9669@kroah.com>
Date:	Wed, 7 Oct 2015 17:12:28 +0100
From:	Greg KH <gregkh@...uxfoundation.org>
To:	Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Cc:	maxime.ripard@...e-electrons.com, linux-kernel@...r.kernel.org,
	andrew@...n.ch, wxt@...k-chips.com, stefan.wahren@...e.com,
	pantelis.antoniou@...sulko.com, maitysanchayan@...il.com,
	p.zabel@...gutronix.de, s.hauer@...gutronix.de,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 1/3] nvmem: core: make default user binary file
 root-access only

On Wed, Oct 07, 2015 at 02:18:47PM +0100, Srinivas Kandagatla wrote:
> 
> 
> On 07/10/15 13:55, Greg KH wrote:
> >On Wed, Oct 07, 2015 at 12:00:47PM +0100, Srinivas Kandagatla wrote:
> >>As required by many providers like at24/at25/mxs-ocotp/qfprom and may be
> >>other providers would want to allow root-only to read the nvmem content.
> >>So making the defaults to be root-only access would address the request
> >>and also provide flexibility to providers to specify there own permissions
> >>on top of the root-only using the perm flag in nvmem_config.
> >
> >Eeek, no, don't mess with different permissions, that's not ok, be
> >consistent and only allow root write access, that's why we have static
> >build-time checks to ensure you get this correct and do not accidentally
> >let a "normal" user access to things they shouldn't have access to.
> Thanks for your inputs,
> 
> Code as it is in mainline would provide a write permission to root-only and
> read to all the group.
> 
> Fixing/removing the group read permissions should stop normal user accessing
> the binary file.

Great, send a simple patch that does this and I'll be glad to queue it
up.

thanks,

greg k-h
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