From: Julia Lawall <julia.lawall@lip6.fr>
To: Joe Perches <joe@perches.com>
Cc: David Laight <David.Laight@ACULAB.COM>,
cocci <cocci@systeme.lip6.fr>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [Cocci] [Fwd: [PATCH 1/2] string: Add stracpy and stracpy_pad mechanisms]
Date: Wed, 24 Jul 2019 06:45:23 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.21.1907240644580.2560@hadrien> (raw)
In-Reply-To: <d2b2b528b9f296dfeb1d92554be024245abd678e.camel@perches.com>
On Wed, 24 Jul 2019, Joe Perches wrote:
> On Wed, 2019-07-24 at 10:28 +0000, David Laight wrote:
> > From: Joe Perches
> > > Sent: 24 July 2019 05:38
> > > On Tue, 2019-07-23 at 23:27 -0500, Julia Lawall wrote:
> > > > On Tue, 23 Jul 2019, Joe Perches wrote:
> > > > > On Tue, 2019-07-23 at 22:54 -0500, Julia Lawall wrote:
> > > > > > A seantic patch and the resulting output for the case where the third
> > > > > > arugument is a constant is attached. Likewise the resulting output on a
> > > > > > recent linux-next.
> []
> > > > > There is a problem with conversions with assignments
> > > > > of strlcpy() so ideally the cocci script should make sure
> > > > > any return value was not used before conversion.
> > > > >
> > > > > This is not a provably good conversion:
> > > > >
> > > > > drivers/s390/char/sclp_ftp.c
> > > > > @@ -114,8 +114,7 @@ static int sclp_ftp_et7(const struct hmc
> > > > > sccb->evbuf.mdd.ftp.length = ftp->len;
> > > > > sccb->evbuf.mdd.ftp.bufaddr = virt_to_phys(ftp->buf);
> > > > >
> > > > > - len = strlcpy(sccb->evbuf.mdd.ftp.fident, ftp->fname,
> > > > > - HMCDRV_FTP_FIDENT_MAX);
> > > > > + len = stracpy(sccb->evbuf.mdd.ftp.fident, ftp->fname);
> []
> > > Any use of the strlcpy return value should not be converted
> > > because the logic after an assignment or use of the return value
> > > can not be assured to have the same behavior.
> >
> > Most of the code probably expects the length to be that copied
> > (so is broken if the string is truncated).
>
> Fortunately there are relatively few uses of the return
> value of strlcpy so it's not a large problem set.
>
> Slightly unrepresentative counts:
>
> $ git grep -P "^\s+strlcpy\b" | wc -l
> 1681
> $ git grep -P "=\s*strlcpy\b" | wc -l
> 28
OK, it's easy to check for in any case. Thanks.
julia
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next prev parent reply other threads:[~2019-07-24 11:45 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <7ab8957eaf9b0931a59eff6e2bd8c5169f2f6c41.1563841972.git.joe@perches.com>
2019-07-23 0:46 ` [Cocci] [Fwd: [PATCH 1/2] string: Add stracpy and stracpy_pad mechanisms] Joe Perches
2019-07-23 20:52 ` Julia Lawall
2019-07-23 23:42 ` Joe Perches
2019-07-24 3:54 ` Julia Lawall
2019-07-24 4:19 ` Joe Perches
2019-07-24 4:27 ` Julia Lawall
2019-07-24 4:37 ` Joe Perches
2019-07-24 10:28 ` David Laight
2019-07-24 10:43 ` Joe Perches
2019-07-24 11:45 ` Julia Lawall [this message]
2019-07-25 1:42 ` Julia Lawall
2019-07-25 7:46 ` [Cocci] [PATCH 1/2] string: Add stracpy and stracpy_pad mechanisms Markus Elfring
2019-07-25 11:34 ` Julia Lawall
2019-07-25 12:40 ` [Cocci] [1/2] " Markus Elfring
2019-07-25 13:45 ` [Cocci] [PATCH 1/2] " Markus Elfring
2019-07-25 13:48 ` Julia Lawall
2019-07-25 14:48 ` [Cocci] [1/2] " Markus Elfring
2019-07-25 13:50 ` [Cocci] [Fwd: [PATCH 1/2] string: Add stracpy and stracpy_pad mechanisms] Joe Perches
2019-07-25 13:58 ` Julia Lawall
2019-07-25 14:12 ` Joe Perches
2019-07-25 22:51 ` Julia Lawall
2019-07-26 6:15 ` [Cocci] [1/2] string: Add stracpy and stracpy_pad mechanisms Markus Elfring
2019-07-29 14:07 ` [Cocci] [Fwd: [PATCH 1/2] string: Add stracpy and stracpy_pad mechanisms] Julia Lawall
2019-07-29 16:28 ` Joe Perches
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