From patchwork Mon Dec 10 21:29:34 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Michal_Such=C3=A1nek?= X-Patchwork-Id: 10722567 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3EF4F3E9D for ; Mon, 10 Dec 2018 21:29:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2EE612A243 for ; Mon, 10 Dec 2018 21:29:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 234042A263; Mon, 10 Dec 2018 21:29:53 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AA1452A296 for ; Mon, 10 Dec 2018 21:29:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728059AbeLJV3w (ORCPT ); Mon, 10 Dec 2018 16:29:52 -0500 Received: from mx2.suse.de ([195.135.220.15]:35798 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728088AbeLJV3w (ORCPT ); Mon, 10 Dec 2018 16:29:52 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 951F3AF59 for ; Mon, 10 Dec 2018 21:29:50 +0000 (UTC) From: Michal Suchanek To: linux-modules@vger.kernel.org Cc: Michal Suchanek Subject: [PATCH v2 3/3] depmod: shut up gcc insufficinet buffer warning. Date: Mon, 10 Dec 2018 22:29:34 +0100 Message-Id: X-Mailer: git-send-email 2.19.2 In-Reply-To: References: MIME-Version: 1.0 Sender: owner-linux-modules@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP In a couple of places depmod concatenates the module directory and filename with snprintf. This can technically overflow creating an unterminated string if module directory name is long. Use openat instead as is done elsewhere in depmod. This avoids the snprintf, the extra buffer on stack, and the gcc warning. It may even fix a corner case when the module direcotry name is just under PATH_MAX. Signed-off-by: Michal Suchanek --- tools/depmod.c | 51 ++++++++++++++++++++++++++++++++++---------------- 1 file changed, 35 insertions(+), 16 deletions(-) diff --git a/tools/depmod.c b/tools/depmod.c index 3b6d16e76160..fb76f823c016 100644 --- a/tools/depmod.c +++ b/tools/depmod.c @@ -1389,19 +1389,42 @@ static int depmod_modules_build_array(struct depmod *depmod) return 0; } +static FILE * dfdopen(const char * dname, const char * filename, int flags, const char * mode) + { + int fd, dfd; + FILE * ret; + + dfd = open(dname, O_RDONLY); + if (dfd < 0) { + WRN("could not open directory %s: %m\n", dname); + return NULL; + } + + fd = openat(dfd, filename, flags); + if (fd < 0) { + WRN("could not open %s at %s: %m\n", filename, dname); + ret = NULL; + } else { + ret = fdopen(fd, mode); + if (!ret) + WRN("could not associate stream with %s: %m\n", filename); + } + close(dfd); + return ret; +} + + + static void depmod_modules_sort(struct depmod *depmod) { - char order_file[PATH_MAX], line[PATH_MAX]; + char line[PATH_MAX]; + const char * order_file = "modules.order"; FILE *fp; unsigned idx = 0, total = 0; - snprintf(order_file, sizeof(order_file), "%s/modules.order", - depmod->cfg->dirname); - fp = fopen(order_file, "r"); - if (fp == NULL) { - WRN("could not open %s: %m\n", order_file); + fp = dfdopen(depmod->cfg->dirname, order_file, O_RDONLY, "r"); + if (fp == NULL) return; - } while (fgets(line, sizeof(line), fp) != NULL) { size_t len = strlen(line); @@ -1409,8 +1432,8 @@ static void depmod_modules_sort(struct depmod *depmod) if (len == 0) continue; if (line[len - 1] != '\n') { - ERR("%s:%u corrupted line misses '\\n'\n", - order_file, idx); + ERR("%s/%s:%u corrupted line misses '\\n'\n", + depmod->cfg->dirname, order_file, idx); goto corrupted; } } @@ -2287,18 +2310,14 @@ static int output_builtin_bin(struct depmod *depmod, FILE *out) { FILE *in; struct index_node *idx; - char infile[PATH_MAX], line[PATH_MAX], modname[PATH_MAX]; + char line[PATH_MAX], modname[PATH_MAX]; if (out == stdout) return 0; - snprintf(infile, sizeof(infile), "%s/modules.builtin", - depmod->cfg->dirname); - in = fopen(infile, "r"); - if (in == NULL) { - WRN("could not open %s: %m\n", infile); + in = dfdopen(depmod->cfg->dirname, "modules.builtin", O_RDONLY, "r"); + if (in == NULL) return 0; - } idx = index_create(); if (idx == NULL) {