From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F3E96C43444 for ; Thu, 17 Jan 2019 00:34:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C1B892077B for ; Thu, 17 Jan 2019 00:34:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728923AbfAQAeG (ORCPT ); Wed, 16 Jan 2019 19:34:06 -0500 Received: from mga11.intel.com ([192.55.52.93]:47095 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730163AbfAQAdp (ORCPT ); Wed, 16 Jan 2019 19:33:45 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 16 Jan 2019 16:33:37 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,488,1539673200"; d="scan'208";a="292166062" Received: from rpedgeco-desk5.jf.intel.com ([10.54.75.79]) by orsmga005.jf.intel.com with ESMTP; 16 Jan 2019 16:33:36 -0800 From: Rick Edgecombe To: Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Borislav Petkov , Nadav Amit , Dave Hansen , Peter Zijlstra , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Nadav Amit , Rick Edgecombe Subject: [PATCH 17/17] module: Prevent module removal racing with text_poke() Date: Wed, 16 Jan 2019 16:32:59 -0800 Message-Id: <20190117003259.23141-18-rick.p.edgecombe@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190117003259.23141-1-rick.p.edgecombe@intel.com> References: <20190117003259.23141-1-rick.p.edgecombe@intel.com> Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: From: Nadav Amit It seems dangerous to allow code modifications to take place concurrently with module unloading. So take the text_mutex while the memory of the module is freed. Signed-off-by: Nadav Amit Signed-off-by: Rick Edgecombe --- kernel/module.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/module.c b/kernel/module.c index 1af5c8e19086..90cfc4988d98 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -64,6 +64,7 @@ #include #include #include +#include #include #include "module-internal.h" @@ -2157,6 +2158,9 @@ static void free_module(struct module *mod) synchronize_rcu(); mutex_unlock(&module_mutex); + /* Protect against patching of the module while it is being removed */ + mutex_lock(&text_mutex); + /* This may be empty, but that's OK */ module_arch_freeing_init(mod); module_memfree(mod->init_layout.base); @@ -2168,6 +2172,7 @@ static void free_module(struct module *mod) /* Finally, free the core (containing the module structure) */ module_memfree(mod->core_layout.base); + mutex_unlock(&text_mutex); } void *__symbol_get(const char *symbol) -- 2.17.1