From patchwork Thu Jan 17 00:32:59 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rick Edgecombe X-Patchwork-Id: 10767399 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 885C014E5 for ; Thu, 17 Jan 2019 00:37:05 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7A06F2EA06 for ; Thu, 17 Jan 2019 00:37:05 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6D3072EBCE; Thu, 17 Jan 2019 00:37:05 +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=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 8DBF42EA06 for ; Thu, 17 Jan 2019 00:37:04 +0000 (UTC) Received: (qmail 2034 invoked by uid 550); 17 Jan 2019 00:34:09 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 1756 invoked from network); 17 Jan 2019 00:34:03 -0000 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,488,1539673200"; d="scan'208";a="292166062" 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> X-Virus-Scanned: ClamAV using ClamSMTP 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)