From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id CD34FA04DD; Wed, 28 Oct 2020 17:27:52 +0100 (CET) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 6F296BC64; Wed, 28 Oct 2020 17:27:26 +0100 (CET) Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by dpdk.org (Postfix) with ESMTP id A39E272E2; Wed, 28 Oct 2020 17:27:22 +0100 (CET) IronPort-SDR: u0f3lWtKy2GxQSOvYyK6oOb6g5xg+5b5YUkaCDcAEJ+dKxXPOmeIpGo8XxC5Fu6Htek2clZKiS C9hMWKxf5lUA== X-IronPort-AV: E=McAfee;i="6000,8403,9788"; a="165699149" X-IronPort-AV: E=Sophos;i="5.77,427,1596524400"; d="scan'208";a="165699149" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Oct 2020 09:27:22 -0700 IronPort-SDR: 2EZT8twnFPfNigHiliRcA6Wy0lO2XrhMN5jRukhU8Hl++BuNPOEGJLQ4d7Ih0RaaS98sGrTwKA qYu5qT8SZOIg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.77,427,1596524400"; d="scan'208";a="334787986" Received: from silpixa00399126.ir.intel.com ([10.237.222.4]) by orsmga002.jf.intel.com with ESMTP; 28 Oct 2020 09:27:20 -0700 From: Bruce Richardson To: dev@dpdk.org Cc: Bruce Richardson , stable@dpdk.org, Stephen Hemminger , Radu Nicolau , Anatoly Burakov Date: Wed, 28 Oct 2020 16:27:01 +0000 Message-Id: <20201028162702.969509-3-bruce.richardson@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201028162702.969509-1-bruce.richardson@intel.com> References: <20200814110045.217724-1-bruce.richardson@intel.com> <20201028162702.969509-1-bruce.richardson@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [dpdk-dev] [PATCH v3 2/3] examples/mp_server: fix snprintf overflow X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" When producing a printable mac address the buffer was appropriately sized for holding the mac address exactly, but the actual snprintf included a '\n' character at the end, which means that the snprintf technically is getting truncated i.e. the \n would not be added due to lack of space. This gets flagged as a problem by modern versions of gcc, e.g. on Ubuntu 20.04. main.c:77:37: warning: ‘__builtin___snprintf_chk’ output truncated before the last format character [-Wformat-truncation=] 77 | "%02x:%02x:%02x:%02x:%02x:%02x\n", | ^ Since the \n is getting stripped anyway, we can fix the issue by just removing it. In the process we can switch to using the standard ethernet address formating function from rte_ether.h. Fixes: af75078fece3 ("first public release") Cc: stable@dpdk.org Cc: Stephen Hemminger Signed-off-by: Bruce Richardson Acked-by: Radu Nicolau --- V2: switched code to use standard formatting function --- .../client_server_mp/mp_server/main.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/examples/multi_process/client_server_mp/mp_server/main.c b/examples/multi_process/client_server_mp/mp_server/main.c index ec7f6b11f..b18e12dd4 100644 --- a/examples/multi_process/client_server_mp/mp_server/main.c +++ b/examples/multi_process/client_server_mp/mp_server/main.c @@ -59,12 +59,17 @@ static struct client_rx_buf *cl_rx_buf; static const char * get_printable_mac_addr(uint16_t port) { - static const char err_address[] = "00:00:00:00:00:00"; - static char addresses[RTE_MAX_ETHPORTS][sizeof(err_address)]; + static const struct rte_ether_addr null_mac; /* static defaults to 0 */ + static char err_address[32]; + static char addresses[RTE_MAX_ETHPORTS][32]; int ret; - if (unlikely(port >= RTE_MAX_ETHPORTS)) + if (unlikely(port >= RTE_MAX_ETHPORTS)) { + if (err_address[0] == '\0') + rte_ether_format_addr(err_address, + sizeof(err_address), &null_mac); return err_address; + } if (unlikely(addresses[port][0]=='\0')){ struct rte_ether_addr mac; ret = rte_eth_macaddr_get(port, &mac); @@ -73,10 +78,8 @@ get_printable_mac_addr(uint16_t port) port, rte_strerror(-ret)); return err_address; } - snprintf(addresses[port], sizeof(addresses[port]), - "%02x:%02x:%02x:%02x:%02x:%02x\n", - mac.addr_bytes[0], mac.addr_bytes[1], mac.addr_bytes[2], - mac.addr_bytes[3], mac.addr_bytes[4], mac.addr_bytes[5]); + rte_ether_format_addr(addresses[port], + sizeof(addresses[port]), &mac); } return addresses[port]; } -- 2.25.1