linux-kernel - Re: [PATCH] staging/rtl8712: Remove all strcpy() uses in favor of strscpy()

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Message-ID: <20210726081148.GF1931@kadam>
Date:   Mon, 26 Jul 2021 11:11:48 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Len Baker <len.baker@....com>
Cc:     David Laight <David.Laight@...LAB.COM>,
        Larry Finger <Larry.Finger@...inger.net>,
        Florian Schilhabel <florian.c.schilhabel@...glemail.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Pavel Skripkin <paskripkin@...il.com>,
        "linux-staging@...ts.linux.dev" <linux-staging@...ts.linux.dev>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] staging/rtl8712: Remove all strcpy() uses in favor of
 strscpy()

On Fri, Jul 23, 2021 at 05:15:10PM +0200, Len Baker wrote:
> Hi,
> 
> On Wed, Jul 21, 2021 at 11:06:24AM +0300, Dan Carpenter wrote:
> > On Mon, Jul 19, 2021 at 03:24:38PM +0000, David Laight wrote:
> > > From: Dan Carpenter
> > > > Sent: 19 July 2021 06:38
> > > ...
> > > > Not related to your patch but this code is bad.  What it does is the
> > > > "ifname" can be set as a module parameter.  So instead of testing if it
> > > > has been set, it uses the checking inside dev_alloc_name() to see if we
> > > > can allocate what the user requested.  If not then set it to "wlan%d".
> > > > If we cannot allocate what the user wants then we should return an
> > > > error.
> > > >
> > > > It should do:
> > > >
> > > > 	if (ifname[0] == '\0')
> > > > 		strscpy(ifname, "wlan%d", sizeof(ifname));
> > > >
> > > > 	ret = dev_alloc_name(pnetdev, ifname);
> > > > 	if (ret < 0) {
> > > > 		dev_err(pnetdev, "allocating device name failed.\n");
> > > > 		return NULL;
> > > > 	}
> > >
> > > I know only root can set module parameters, but having one
> > > that contains a string used as a printf format seems
> > > dangerous at best.
> > >
> > > Isn't it best to let userspace rename the interfaces later on?
> >
> > Yeah.  I think you're right.
> 
> Sorry, but I don't understand if the code needs to be improved or not.
> Is the code shown by Dan not correct?

We should remove the ifname[] array and the module option completely.

regards,
dan carpenter