From patchwork Thu Oct 24 21:20:01 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?b?TWljaGHFgiDFgXlzemN6ZWs=?= X-Patchwork-Id: 1183574 X-Patchwork-Delegate: shemminger@vyatta.com Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=bofc.pl Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 46zgCb42Tcz9sPk for ; Fri, 25 Oct 2019 08:21:15 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728930AbfJXVUJ (ORCPT ); Thu, 24 Oct 2019 17:20:09 -0400 Received: from cache12.mydevil.net ([128.204.216.223]:63766 "EHLO cache12.mydevil.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727838AbfJXVUJ (ORCPT ); Thu, 24 Oct 2019 17:20:09 -0400 From: =?utf-8?b?TWljaGHFgiDFgXlzemN6ZWs=?= To: netdev@vger.kernel.org Cc: =?utf-8?b?TWljaGHFgiDFgXlzemN6ZWs=?= Subject: [PATCH iproute2] libnetlink.c, ss.c: properly handle fread() error Date: Thu, 24 Oct 2019 23:20:01 +0200 Message-Id: <20191024212001.7020-1-michal.lyszczek@bofc.pl> X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 X-AV-Check: Passed X-System-Sender: michal.lyszczek@bofc.pl X-Spam-Flag: NO X-Spam-Status: NO, score=0.8 required=5.0, tests=(BAYES_50=0.8, NO_RELAYS=-0.001, URIBL_BLOCKED=0.001) autolearn=disabled version=3.4.2 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org fread(3) returns size_t data type which is unsigned, thus check `if (fread(...) < 0)' is always false. To check if fread(3) has failed, user should check if return is 0 and then check error indicator with ferror(3). Signed-off-by: Michał Łyszczek --- lib/libnetlink.c | 6 +++--- misc/ss.c | 7 ++++--- 2 files changed, 7 insertions(+), 6 deletions(-) diff --git a/lib/libnetlink.c b/lib/libnetlink.c index 6ce8b199..76c383f9 100644 --- a/lib/libnetlink.c +++ b/lib/libnetlink.c @@ -1174,7 +1174,7 @@ int rtnl_listen(struct rtnl_handle *rtnl, int rtnl_from_file(FILE *rtnl, rtnl_listen_filter_t handler, void *jarg) { - int status; + size_t status; char buf[16384]; struct nlmsghdr *h = (struct nlmsghdr *)buf; @@ -1184,7 +1184,7 @@ int rtnl_from_file(FILE *rtnl, rtnl_listen_filter_t handler, status = fread(&buf, 1, sizeof(*h), rtnl); - if (status < 0) { + if (status == 0 && ferror(rtnl)) { if (errno == EINTR) continue; perror("rtnl_from_file: fread"); @@ -1204,7 +1204,7 @@ int rtnl_from_file(FILE *rtnl, rtnl_listen_filter_t handler, status = fread(NLMSG_DATA(h), 1, NLMSG_ALIGN(l), rtnl); - if (status < 0) { + if (status == 0 && ferror(rtnl)) { perror("rtnl_from_file: fread"); return -1; } diff --git a/misc/ss.c b/misc/ss.c index 363b4c8d..769332e9 100644 --- a/misc/ss.c +++ b/misc/ss.c @@ -3329,12 +3329,13 @@ static int tcp_show_netlink_file(struct filter *f) } while (1) { - int status, err2; + int err2; + size_t status; struct nlmsghdr *h = (struct nlmsghdr *)buf; struct sockstat s = {}; status = fread(buf, 1, sizeof(*h), fp); - if (status < 0) { + if (status == 0 && ferror(fp)) { perror("Reading header from $TCPDIAG_FILE"); break; } @@ -3345,7 +3346,7 @@ static int tcp_show_netlink_file(struct filter *f) status = fread(h+1, 1, NLMSG_ALIGN(h->nlmsg_len-sizeof(*h)), fp); - if (status < 0) { + if (status == 0 && ferror(fp)) { perror("Reading $TCPDIAG_FILE"); break; }