Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752288AbaJLCLa (ORCPT ); Sat, 11 Oct 2014 22:11:30 -0400 Received: from mail-pd0-f179.google.com ([209.85.192.179]:60689 "EHLO mail-pd0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751927AbaJLCL3 (ORCPT ); Sat, 11 Oct 2014 22:11:29 -0400 Date: Sat, 11 Oct 2014 19:11:22 -0700 From: Guenter Roeck To: Mark D Rustad Cc: Rickard Strandqvist , Matt Mackall , Herbert Xu , Torsten Duwe , "Theodore Ts'o" , Jason Cooper , Amit Shah , Stephen Boyd , Paul Gortmaker , Kees Cook , Dan Carpenter , linux-kernel@vger.kernel.org Subject: Re: [PATCH] char: hw_random: core.c: Changed from using strncpy to strlcpy Message-ID: <20141012021122.GA10822@roeck-us.net> References: <1413067004-10925-1-git-send-email-rickard_strandqvist@spectrumdigital.se> <09FC08CC-027E-443A-83C3-CC4C1D978743@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <09FC08CC-027E-443A-83C3-CC4C1D978743@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 11, 2014 at 05:27:41PM -0700, Mark D Rustad wrote: > On Oct 11, 2014, at 3:36 PM, Rickard Strandqvist wrote: > > > Changed from using strncpy to strlcpy to simplify the code > > Actually you changed from using strncat to strlcat. > ... and changed the length parameter along the way, making the length check overall quite worthless and introducing a _real_ problem. Guenter > > Signed-off-by: Rickard Strandqvist > > --- > > drivers/char/hw_random/core.c | 12 ++++-------- > > 1 file changed, 4 insertions(+), 8 deletions(-) > > > > diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c > > index aa30a25..1500cfd 100644 > > --- a/drivers/char/hw_random/core.c > > +++ b/drivers/char/hw_random/core.c > > @@ -281,7 +281,6 @@ static ssize_t hwrng_attr_available_show(struct device *dev, > > char *buf) > > { > > int err; > > - ssize_t ret = 0; > > struct hwrng *rng; > > > > err = mutex_lock_interruptible(&rng_mutex); > > @@ -289,16 +288,13 @@ static ssize_t hwrng_attr_available_show(struct device *dev, > > return -ERESTARTSYS; > > buf[0] = '\0'; > > list_for_each_entry(rng, &rng_list, list) { > > - strncat(buf, rng->name, PAGE_SIZE - ret - 1); > > - ret += strlen(rng->name); > > - strncat(buf, " ", PAGE_SIZE - ret - 1); > > - ret++; > > + strlcat(buf, rng->name, PAGE_SIZE); > > + strlcat(buf, " ", PAGE_SIZE); > > } > > - strncat(buf, "\n", PAGE_SIZE - ret - 1); > > - ret++; > > + strlcat(buf, "\n", PAGE_SIZE); > > mutex_unlock(&rng_mutex); > > > > - return ret; > > + return strlen(buf); > > } > > > > static DEVICE_ATTR(rng_current, S_IRUGO | S_IWUSR, > > -- > > 1.7.10.4 > > -- > Mark Rustad, MRustad@gmail.com > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/