From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by dpdk.space (Postfix) with ESMTP id C2430A05D3 for ; Fri, 26 Apr 2019 14:47:45 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 7D2F31B1EE; Fri, 26 Apr 2019 14:47:45 +0200 (CEST) Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by dpdk.org (Postfix) with ESMTP id 44F091B1EE; Fri, 26 Apr 2019 14:47:43 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 26 Apr 2019 05:47:43 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,397,1549958400"; d="scan'208";a="153974662" Received: from aburakov-mobl1.ger.corp.intel.com (HELO [10.251.92.20]) ([10.251.92.20]) by orsmga002.jf.intel.com with ESMTP; 26 Apr 2019 05:47:41 -0700 To: Bruce Richardson Cc: David Hunt , dev@dpdk.org, stable@dpdk.org References: <20190426084337.3921-1-david.hunt@intel.com> <20190426112422.15719-1-david.hunt@intel.com> <339cb6ac-9c56-b9cb-28e8-950ad2cd70b4@intel.com> <20190426123117.GA1695@bricha3-MOBL.ger.corp.intel.com> From: "Burakov, Anatoly" Message-ID: Date: Fri, 26 Apr 2019 13:47:41 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190426123117.GA1695@bricha3-MOBL.ger.corp.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH v2] examples/vm_power_manager: fix string null termination X-BeenThere: stable@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches for DPDK stable branches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: stable-bounces@dpdk.org Sender: "stable" On 26-Apr-19 1:31 PM, Bruce Richardson wrote: > On Fri, Apr 26, 2019 at 12:56:08PM +0100, Burakov, Anatoly wrote: >> On 26-Apr-19 12:24 PM, David Hunt wrote: >>> coverity complains about a null-termination after a read, >>> so we terminate after exiting the do-while loop. The position >>> is conditional on whether idx is within the buffer or at the >>> end of the buffer. >>> >>> Coverity issue: 337680 >>> Fixes: a63504a90f ("examples/power: add JSON string handling") >>> CC: stable@dpdk.org >>> >>> Signed-off-by: David Hunt >>> >>> --- >>> v2: >>> * Move null termination outside of do-while. >>> --- >>> examples/vm_power_manager/channel_monitor.c | 2 ++ >>> 1 file changed, 2 insertions(+) >>> >>> diff --git a/examples/vm_power_manager/channel_monitor.c b/examples/vm_power_manager/channel_monitor.c >>> index 971e4f2bc..03fdcd15a 100644 >>> --- a/examples/vm_power_manager/channel_monitor.c >>> +++ b/examples/vm_power_manager/channel_monitor.c >>> @@ -822,6 +822,8 @@ read_json_packet(struct channel_info *chan_info) >>> break; >>> } while (indent > 0); >>> + json_data[idx + (idx < MAX_JSON_STRING_LEN - 1)] = '\0'; >>> + >> >> I don't think you need this complicated logic here. You start at idx = 0, so >> even if you receive 0 bytes, you'll terminate buffer at index 0. You also >> break when idx reaches (MAX_JSON_STRING_LEN - 1), so it's also safe to do >> json_data[idx] after the loop. In all other cases, you still increment idx >> before breaking out (e.g. when reaching indent == 0), so it's also safe to >> do json_data[idx] in those cases. >> > +1 to that. > > An alternative and simpler option might be to memset the who array to zero > before you start anyway. That'll cost us few extra cycles on a non-performance critical path full of syscalls, surely we can't have that! :) > > /Bruce > -- Thanks, Anatoly