From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754366AbcHUQFA (ORCPT ); Sun, 21 Aug 2016 12:05:00 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:55499 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932361AbcHUPdE (ORCPT ); Sun, 21 Aug 2016 11:33:04 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ben Hutchings , Rusty Russell , Greg Kroah-Hartman , Willy Tarreau Subject: [PATCH 3.10 172/180] module: Invalidate signatures on force-loaded modules Date: Sun, 21 Aug 2016 17:31:42 +0200 Message-Id: <1471793510-13022-173-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1471793510-13022-1-git-send-email-w@1wt.eu> References: <1471793510-13022-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Signed-off-by: Willy Tarreau --- kernel/module.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/kernel/module.c b/kernel/module.c index f8a4f48..2c87e52 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2475,13 +2475,18 @@ static inline void kmemleak_load_module(const struct module *mod, #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; @@ -2503,7 +2508,7 @@ static int module_sig_check(struct load_info *info) 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; } @@ -3228,7 +3233,7 @@ static int load_module(struct load_info *info, const char __user *uargs, struct module *mod; long err; - err = module_sig_check(info); + err = module_sig_check(info, flags); if (err) goto free_copy; -- 2.8.0.rc2.1.gbe9624a