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From: David Laight <David.Laight@ACULAB.COM>
To: 'Kees Cook' <keescook@chromium.org>,
	Justin Stitt <justinstitt@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>,
	"Darrick J. Wong" <djwong@kernel.org>,
	"linux-xfs@vger.kernel.org" <linux-xfs@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-hardening@vger.kernel.org"
	<linux-hardening@vger.kernel.org>
Subject: RE: [PATCH] xfs: replace deprecated strncpy with strscpy_pad
Date: Mon, 15 Apr 2024 11:22:41 +0000	[thread overview]
Message-ID: <1a75240d27bb4f2abe3cfae49b2f7605@AcuMS.aculab.com> (raw)
In-Reply-To: <202404110829.D3A5A56@keescook>

From: Kees Cook
> Sent: 11 April 2024 16:32
> 
> On Wed, Apr 10, 2024 at 01:45:21PM -0700, Justin Stitt wrote:
> > On Tue, Apr 9, 2024 at 9:22 AM Kees Cook <keescook@chromium.org> wrote:
> > > >
> > > > -     /* 1 larger than sb_fname, so this ensures a trailing NUL char */
> > > > -     memset(label, 0, sizeof(label));
> > > >       spin_lock(&mp->m_sb_lock);
> > > > -     strncpy(label, sbp->sb_fname, XFSLABEL_MAX);
> > > > +     strscpy_pad(label, sbp->sb_fname);
> > >
> > > Is sbp->sb_fname itself NUL-terminated? This looks like another case of
> > > needing the memtostr() helper?
> > >
> >
> > I sent a patch [1].
> >
> > Obviously it depends on your implementation patch landing first; what
> > tree should it go to?
> 
> This "flavor" of conversion may need to wait a release? There's no
> urgency on the conversion, and there are plenty more to do for this
> cycle. ;)

In this case:
	char label[sizeof (sbp->fb_fname) + 1];
	memcpy(label, sbp->sb_fname, sizeof (sbp->sb_fname));
	label[sizeof (sbp->fname)] = 0;
is probably the clearest code.
(it is [12] - so no point faffing with the copy.)

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

      reply	other threads:[~2024-04-15 11:23 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-05 19:52 [PATCH] xfs: replace deprecated strncpy with strscpy_pad Justin Stitt
2024-04-09 16:22 ` Kees Cook
2024-04-10 20:45   ` Justin Stitt
2024-04-11 15:31     ` Kees Cook
2024-04-15 11:22       ` David Laight [this message]

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