From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751467AbdGQMxM (ORCPT ); Mon, 17 Jul 2017 08:53:12 -0400 Received: from lb3-smtp-cloud2.xs4all.net ([194.109.24.29]:53488 "EHLO lb3-smtp-cloud2.xs4all.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751384AbdGQMxJ (ORCPT ); Mon, 17 Jul 2017 08:53:09 -0400 Subject: Re: [PATCH 14/22] [media] usbvision-i2c: fix format overflow warning To: Arnd Bergmann , linux-kernel@vger.kernel.org, Mauro Carvalho Chehab References: <20170714120720.906842-1-arnd@arndb.de> <20170714120720.906842-15-arnd@arndb.de> Cc: Greg Kroah-Hartman , Linus Torvalds , Guenter Roeck , akpm@linux-foundation.org, netdev@vger.kernel.org, "David S . Miller" , "James E . J . Bottomley" , "Martin K . Petersen" , linux-scsi@vger.kernel.org, x86@kernel.org, Sakari Ailus , linux-media@vger.kernel.org From: Hans Verkuil Message-ID: Date: Mon, 17 Jul 2017 14:53:01 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: <20170714120720.906842-15-arnd@arndb.de> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14/07/17 14:07, Arnd Bergmann wrote: > gcc-7 notices that we copy a fixed length string into another > string of the same size, with additional characters: > > drivers/media/usb/usbvision/usbvision-i2c.c: In function 'usbvision_i2c_register': > drivers/media/usb/usbvision/usbvision-i2c.c:190:36: error: '%d' directive writing between 1 and 11 bytes into a region of size between 0 and 47 [-Werror=format-overflow=] > sprintf(usbvision->i2c_adap.name, "%s-%d-%s", i2c_adap_template.name, > ^~~~~~~~~~ > drivers/media/usb/usbvision/usbvision-i2c.c:190:2: note: 'sprintf' output between 4 and 76 bytes into a destination of size 48 > > We know this is fine as the template name is always "usbvision", so > we can easily avoid the warning by using this as the format string > directly. Hmm, how about replacing sprintf by snprintf? That feels a lot safer (this is very old code, it's not surprising it is still using sprintf). Regards, Hans > > Signed-off-by: Arnd Bergmann > --- > drivers/media/usb/usbvision/usbvision-i2c.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/media/usb/usbvision/usbvision-i2c.c b/drivers/media/usb/usbvision/usbvision-i2c.c > index fdf6b6e285da..aae9f69884da 100644 > --- a/drivers/media/usb/usbvision/usbvision-i2c.c > +++ b/drivers/media/usb/usbvision/usbvision-i2c.c > @@ -187,8 +187,8 @@ int usbvision_i2c_register(struct usb_usbvision *usbvision) > > usbvision->i2c_adap = i2c_adap_template; > > - sprintf(usbvision->i2c_adap.name, "%s-%d-%s", i2c_adap_template.name, > - usbvision->dev->bus->busnum, usbvision->dev->devpath); > + sprintf(usbvision->i2c_adap.name, "usbvision-%d-%s", > + usbvision->dev->bus->busnum, usbvision->dev->devpath); > PDEBUG(DBG_I2C, "Adaptername: %s", usbvision->i2c_adap.name); > usbvision->i2c_adap.dev.parent = &usbvision->dev->dev; > >