From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932569AbcCINIp (ORCPT ); Wed, 9 Mar 2016 08:08:45 -0500 Received: from mail-lb0-f171.google.com ([209.85.217.171]:34047 "EHLO mail-lb0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932401AbcCINIg (ORCPT ); Wed, 9 Mar 2016 08:08:36 -0500 Subject: Re: [RFC 7/7] USB: usbatm: avoid fragile and inefficient snprintf use To: Rasmus Villemoes , Kees Cook , Andrew Morton , Duncan Sands , Greg Kroah-Hartman References: <1457469654-17059-1-git-send-email-linux@rasmusvillemoes.dk> <1457469654-17059-8-git-send-email-linux@rasmusvillemoes.dk> Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org From: Sergei Shtylyov Message-ID: <56E02052.80507@cogentembedded.com> Date: Wed, 9 Mar 2016 16:08:34 +0300 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <1457469654-17059-8-git-send-email-linux@rasmusvillemoes.dk> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello. On 3/8/2016 11:40 PM, Rasmus Villemoes wrote: > Passing overlapping source and destination is fragile, and in this > case we can even simplify the code and avoid the huge stack buffer by > using the %p extension for printing a small hex dump. > > Signed-off-by: Rasmus Villemoes > --- > drivers/usb/atm/usbatm.c | 11 ++++------- > 1 file changed, 4 insertions(+), 7 deletions(-) > > diff --git a/drivers/usb/atm/usbatm.c b/drivers/usb/atm/usbatm.c > index db322d9ccb6e..fb47f9883056 100644 > --- a/drivers/usb/atm/usbatm.c > +++ b/drivers/usb/atm/usbatm.c > @@ -1331,15 +1331,12 @@ MODULE_VERSION(DRIVER_VERSION); > static int usbatm_print_packet(struct usbatm_data *instance, > const unsigned char *data, int len) > { > - unsigned char buffer[256]; > - int i = 0, j = 0; > + int i, j; > > for (i = 0; i < len;) { > - buffer[0] = '\0'; > - sprintf(buffer, "%.3d :", i); > - for (j = 0; (j < 16) && (i < len); j++, i++) > - sprintf(buffer, "%s %2.2x", buffer, data[i]); > - dev_dbg(&instance->usb_intf->dev, "%s", buffer); > + j = min(16, len-i); Kernel style assumes spaces on either side of the operators, like below, no? > + dev_dbg(&instance->usb_intf->dev, "%.3d : %*ph", i, j, data + i); > + i += j; > } > return i; > } MBR, Sergei