From: Kees Cook <keescook@chromium.org>
To: Joe Perches <joe@perches.com>
Cc: David Laight <David.Laight@ACULAB.COM>,
Julia Lawall <julia.lawall@inria.fr>,
Alex Dewar <alex.dewar90@gmail.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
cocci <cocci@systeme.lip6.fr>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
"accessrunner-general@lists.sourceforge.net"
<accessrunner-general@lists.sourceforge.net>
Subject: Re: [Cocci] [PATCH] usb: atm: don't use snprintf() for sysfs attrs
Date: Thu, 27 Aug 2020 15:16:56 -0700 [thread overview]
Message-ID: <202008271516.ED209B68@keescook> (raw)
In-Reply-To: <ca08f34a5aaa3e9031a934296dd97fc806dab66f.camel@perches.com>
On Thu, Aug 27, 2020 at 03:11:57PM -0700, Joe Perches wrote:
> On Thu, 2020-08-27 at 22:03 +0000, David Laight wrote:
> > From: Joe Perches
> > > Sent: 27 August 2020 21:30
> > ...
> > > Perhaps what's necessary is to find any
> > > appropriate .show function and change
> > > any use of strcpy/sprintf within those
> > > function to some other name.
> > >
> > > For instance:
> > >
> > > drivers/isdn/mISDN/core.c-static ssize_t name_show(struct device *dev,
> > > drivers/isdn/mISDN/core.c- struct device_attribute *attr, char *buf)
> > > drivers/isdn/mISDN/core.c-{
> > > drivers/isdn/mISDN/core.c: strcpy(buf, dev_name(dev));
> > > drivers/isdn/mISDN/core.c- return strlen(buf);
> > > drivers/isdn/mISDN/core.c-}
> > > drivers/isdn/mISDN/core.c-static DEVICE_ATTR_RO(name);
> >
> > That form ends up calculating the string length twice.
> > Better would be:
> > len = strlen(msg);
> > memcpy(buf, msg, len);
> > return len;
>
> or given clang's requirement for stpcpy
>
> return stpcpy(buf, dev_name(dev)) - buf;
>
> (I do not advocate for this ;)
Heh. And humans aren't allowed to use stpcpy() in the kernel. :)
--
Kees Cook
next prev parent reply other threads:[~2020-08-27 22:17 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-24 22:23 [PATCH] usb: atm: don't use snprintf() for sysfs attrs Alex Dewar
2020-08-25 8:12 ` David Laight
2020-08-25 8:17 ` Alex Dewar
2020-08-25 9:07 ` David Laight
2020-08-25 8:24 ` Greg Kroah-Hartman
2020-08-27 16:49 ` Kees Cook
2020-08-27 17:45 ` Greg Kroah-Hartman
2020-08-27 6:42 ` Rasmus Villemoes
2020-08-27 7:15 ` Greg Kroah-Hartman
2020-08-27 13:18 ` Alex Dewar
2020-08-27 13:41 ` Rasmus Villemoes
2020-08-27 14:48 ` Alex Dewar
2020-08-27 16:58 ` Joe Perches
2020-08-27 19:42 ` [Cocci] " Julia Lawall
2020-08-27 20:29 ` Joe Perches
2020-08-27 21:00 ` Joe Perches
2020-08-27 21:29 ` Julia Lawall
2020-08-27 22:03 ` David Laight
2020-08-27 22:11 ` Joe Perches
2020-08-27 22:16 ` Kees Cook [this message]
2020-08-27 21:01 ` Denis Efremov
2020-08-27 21:36 ` Julia Lawall
2020-08-27 21:44 ` Joe Perches
2020-08-27 22:38 ` Denis Efremov
2020-08-27 22:48 ` Joe Perches
2020-08-27 22:20 ` Kees Cook
2020-08-27 22:45 ` Joe Perches
2020-08-28 4:12 ` Joe Perches
2020-08-28 7:58 ` Kees Cook
2020-08-28 8:10 ` Joe Perches
2020-08-28 8:22 ` Joe Perches
2020-08-28 7:39 ` David Laight
2020-08-27 21:54 ` David Laight
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