From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S969541AbdDSVOo (ORCPT ); Wed, 19 Apr 2017 17:14:44 -0400 Received: from lb2-smtp-cloud6.xs4all.net ([194.109.24.28]:57909 "EHLO lb2-smtp-cloud6.xs4all.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967284AbdDSVOl (ORCPT ); Wed, 19 Apr 2017 17:14:41 -0400 Subject: Re: [PATCH] [media] rainshadow-cec: use strlcat instead of strncat To: Arnd Bergmann , Mauro Carvalho Chehab References: <20170419171543.3274995-1-arnd@arndb.de> Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org From: Hans Verkuil Message-ID: Date: Wed, 19 Apr 2017 23:14:38 +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: <20170419171543.3274995-1-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 19/04/17 19:15, Arnd Bergmann wrote: > gcc warns about an obviously incorrect use of strncat(): > > drivers/media/usb/rainshadow-cec/rainshadow-cec.c: In function 'rain_cec_adap_transmit': > drivers/media/usb/rainshadow-cec/rainshadow-cec.c:299:4: error: specified bound 48 equals the size of the destination [-Werror=stringop-overflow=] > > It seems that strlcat was intended here, and using that makes the > code correct. Oops! You're right, it should be strlcat. Which gcc version do you use? Mine (6.3.0) didn't give an error (or warning, for that matter). Regards, Hans > > Fixes: 0f314f6c2e77 ("[media] rainshadow-cec: new RainShadow Tech HDMI CEC driver") > Signed-off-by: Arnd Bergmann > --- > drivers/media/usb/rainshadow-cec/rainshadow-cec.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/media/usb/rainshadow-cec/rainshadow-cec.c b/drivers/media/usb/rainshadow-cec/rainshadow-cec.c > index 541ca543f71f..dc1f64f904cd 100644 > --- a/drivers/media/usb/rainshadow-cec/rainshadow-cec.c > +++ b/drivers/media/usb/rainshadow-cec/rainshadow-cec.c > @@ -296,7 +296,7 @@ static int rain_cec_adap_transmit(struct cec_adapter *adap, u8 attempts, > cec_msg_destination(msg), msg->msg[1]); > for (i = 2; i < msg->len; i++) { > snprintf(hex, sizeof(hex), "%02x", msg->msg[i]); > - strncat(cmd, hex, sizeof(cmd)); > + strlcat(cmd, hex, sizeof(cmd)); > } > } > mutex_lock(&rain->write_lock); >