From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1768181AbcHROVk (ORCPT ); Thu, 18 Aug 2016 10:21:40 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:37582 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1767644AbcHROSE (ORCPT ); Thu, 18 Aug 2016 10:18:04 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ben Hutchings , Rusty Russell Subject: [PATCH 4.7 184/186] module: Invalidate signatures on force-loaded modules Date: Thu, 18 Aug 2016 16:00:01 +0200 Message-Id: <20160818135940.072763589@linuxfoundation.org> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20160818135932.219369981@linuxfoundation.org> References: <20160818135932.219369981@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ben Hutchings commit bca014caaa6130e57f69b5bf527967aa8ee70fdd upstream. Signing a module should only make it trusted by the specific kernel it was built for, not anything else. Loading a signed module meant for a kernel with a different ABI could have interesting effects. Therefore, treat all signatures as invalid when a module is force-loaded. Signed-off-by: Ben Hutchings Signed-off-by: Rusty Russell Signed-off-by: Greg Kroah-Hartman --- kernel/module.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) --- a/kernel/module.c +++ b/kernel/module.c @@ -2687,13 +2687,18 @@ static inline void kmemleak_load_module( #endif #ifdef CONFIG_MODULE_SIG -static int module_sig_check(struct load_info *info) +static int module_sig_check(struct load_info *info, int flags) { int err = -ENOKEY; const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1; const void *mod = info->hdr; - if (info->len > markerlen && + /* + * Require flags == 0, as a module with version information + * removed is no longer the module that was signed + */ + if (flags == 0 && + info->len > markerlen && memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) { /* We truncate the module to discard the signature */ info->len -= markerlen; @@ -2712,7 +2717,7 @@ static int module_sig_check(struct load_ return err; } #else /* !CONFIG_MODULE_SIG */ -static int module_sig_check(struct load_info *info) +static int module_sig_check(struct load_info *info, int flags) { return 0; } @@ -3498,7 +3503,7 @@ static int load_module(struct load_info long err; char *after_dashes; - err = module_sig_check(info); + err = module_sig_check(info, flags); if (err) goto free_copy;