From patchwork Wed Apr 29 15:52:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wen Yang X-Patchwork-Id: 11517811 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D471B1392 for ; Wed, 29 Apr 2020 15:52:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C04C821D79 for ; Wed, 29 Apr 2020 15:52:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726669AbgD2Pwc (ORCPT ); Wed, 29 Apr 2020 11:52:32 -0400 Received: from out30-45.freemail.mail.aliyun.com ([115.124.30.45]:59308 "EHLO out30-45.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726519AbgD2Pwc (ORCPT ); Wed, 29 Apr 2020 11:52:32 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R621e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04394;MF=wenyang@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0Tx1ibTk_1588175537; Received: from localhost(mailfrom:wenyang@linux.alibaba.com fp:SMTPD_---0Tx1ibTk_1588175537) by smtp.aliyun-inc.com(127.0.0.1); Wed, 29 Apr 2020 23:52:27 +0800 From: Wen Yang To: Lucas De Marchi Cc: Caspar Zhang , Wen Yang , Lucas De Marchi , Topi Miettinen , Alexey Gladkov , linux-modules@vger.kernel.org Subject: [PATCH] libkmod: introduce kmod_module_uniq_options() to improve the reliability of loading module Date: Wed, 29 Apr 2020 23:52:08 +0800 Message-Id: <20200429155208.97041-1-wenyang@linux.alibaba.com> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 Sender: owner-linux-modules@vger.kernel.org Precedence: bulk List-ID: As in commit 2045cdfa1b40 ("netfilter: nf_conntrack: Fix possible possible crash on module loading"), Loading the nf_conntrack module with doubled hashsize parameter, i.e. modprobe nf_conntrack hashsize=12345 hashsize=12345 causes NULL-ptr deref. If 'hashsize' specified twice, the nf_conntrack_set_hashsize() function will be called also twice. In addition, we may also construct the doubled hashsize parameter scenario by using the following configuration: $ cat /etc/modprobe.d/firewalld-sysctls.conf install nf_conntrack /usr/sbin/modprobe --ignore-install nf_conntrack $CMDLINE_OPTS && /usr/sbin/sysctl --quiet --pattern 'net[.]netfilter[.]nf_conntrack.*' --system $ cat /etc/modprobe.d/nf_conntrack.conf options nf_conntrack hashsize=187600 $ sudo modprobe nf_conntrack -v install /usr/sbin/modprobe --ignore-install nf_conntrack $CMDLINE_OPTS && /usr/sbin/sysctl --quiet --pattern 'net[.]netfilter[.]nf_conntrack.*' --system hashsize=187500 insmod /path/to/nf_conntrack.ko hashsize=187500 hashsize=187500 Passing multiple repeated parameters to the kernel may trigger kernel bugs and affect the performance of loading kernel modules. We introduce the nf_conntrack_set_hashsize() and hope to solve this problem. Signed-off-by: Wen Yang Cc: Lucas De Marchi Cc: Lucas De Marchi Cc: Topi Miettinen Cc: Alexey Gladkov Cc: linux-modules@vger.kernel.org --- libkmod/libkmod-module.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++ libkmod/libkmod.h | 1 + tools/insmod.c | 7 +++++ 3 files changed, 80 insertions(+) diff --git a/libkmod/libkmod-module.c b/libkmod/libkmod-module.c index 76a6dc3..f42beb8 100644 --- a/libkmod/libkmod-module.c +++ b/libkmod/libkmod-module.c @@ -1076,6 +1076,72 @@ static char *module_options_concat(const char *opt, const char *xopt) return r; } +static unsigned int module_options_cnt(const char *opts) +{ + int nr_opts = 0; + char *saveptr, *tok, *buf; + + if (!opts) + return 0; + + buf = strdup(opts); + for (tok = strtok_r(buf, " ", &saveptr); tok != NULL; + tok = strtok_r(NULL, " ", &saveptr), nr_opts++) {} + + free(buf); + return nr_opts; +} + +KMOD_EXPORT int kmod_module_uniq_options(char **opts) +{ + char *buf; + char **array; + bool duplicated; + char *saveptr, *tok; + int nr_opts, len, i, j; + + if (!opts || !*opts) + return 0; + + buf = strdup(*opts); + if (!buf) + return -ENOMEM; + + len = strlen(buf); + nr_opts = module_options_cnt(buf); + array = calloc(nr_opts, sizeof(char *)); + if (!buf) + return -ENOMEM; + + for (tok = strtok_r(buf, " ", &saveptr), i = 0; tok != NULL; + tok = strtok_r(NULL, " ", &saveptr), i++) { + array[i] = tok; + } + + (*opts)[0] = '\0'; + len = 0; + for (i = 0; i < nr_opts; i++) { + duplicated = false; + for (j = 0; j < i; j++) { + if (strcmp(array[i], array[j]) == 0) { + duplicated = true; + break; + } + } + + if (!duplicated) { + strcat(*opts, array[i]); + strcat(*opts, " "); + len += strlen(array[i]) + 1; + } + } + + (*opts)[len] = '\0'; + free(buf); + free(array); + return 0; +} + static int __kmod_module_get_probe_list(struct kmod_module *mod, bool required, bool ignorecmd, @@ -1322,6 +1388,12 @@ KMOD_EXPORT int kmod_module_probe_insert_module(struct kmod_module *mod, options = module_options_concat(moptions, m == mod ? extra_options : NULL); + err = kmod_module_uniq_options(&options); + if (err < 0) { + free(options); + return err; + } + if (cmd != NULL && !m->ignorecmd) { if (print_action != NULL) print_action(m, true, options ?: ""); diff --git a/libkmod/libkmod.h b/libkmod/libkmod.h index 3cab2e5..774e52a 100644 --- a/libkmod/libkmod.h +++ b/libkmod/libkmod.h @@ -186,6 +186,7 @@ int kmod_module_probe_insert_module(struct kmod_module *mod, const char *kmod_module_get_name(const struct kmod_module *mod); const char *kmod_module_get_path(const struct kmod_module *mod); const char *kmod_module_get_options(const struct kmod_module *mod); +int kmod_module_uniq_options(char **opts); const char *kmod_module_get_install_commands(const struct kmod_module *mod); const char *kmod_module_get_remove_commands(const struct kmod_module *mod); struct kmod_list *kmod_module_get_dependencies(const struct kmod_module *mod); diff --git a/tools/insmod.c b/tools/insmod.c index c422971..2dc0c22 100644 --- a/tools/insmod.c +++ b/tools/insmod.c @@ -132,6 +132,13 @@ static int do_insmod(int argc, char *argv[]) opts[optslen] = '\0'; } + err = kmod_module_uniq_options(&opts); + if (err < 0) { + ERR("kmod_module_uniq_options() failed!\n"); + free(opts); + return err; + } + ctx = kmod_new(NULL, &null_config); if (!ctx) { ERR("kmod_new() failed!\n");