Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934183Ab3ICXuv (ORCPT ); Tue, 3 Sep 2013 19:50:51 -0400 Received: from cavan.codon.org.uk ([93.93.128.6]:33641 "EHLO cavan.codon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934138Ab3ICXud (ORCPT ); Tue, 3 Sep 2013 19:50:33 -0400 From: Matthew Garrett To: linux-kernel@vger.kernel.org Cc: linux-efi@vger.kernel.org, keescook@chromium.org, hpa@zytor.com, Matthew Garrett Subject: [PATCH V3 08/11] kexec: Disable at runtime if the kernel enforces module loading restrictions Date: Tue, 3 Sep 2013 19:50:15 -0400 Message-Id: <1378252218-18798-9-git-send-email-matthew.garrett@nebula.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1378252218-18798-1-git-send-email-matthew.garrett@nebula.com> References: <1378252218-18798-1-git-send-email-matthew.garrett@nebula.com> X-SA-Do-Not-Run: Yes X-SA-Exim-Connect-IP: 2001:470:1f07:1371:6267:20ff:fec3:2318 X-SA-Exim-Mail-From: matthew.garrett@nebula.com X-SA-Exim-Scanned: No (on cavan.codon.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1253 Lines: 43 kexec permits the loading and execution of arbitrary code in ring 0, which is something that module signing enforcement is meant to prevent. It makes sense to disable kexec in this situation. Signed-off-by: Matthew Garrett --- kernel/kexec.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/kexec.c b/kernel/kexec.c index 59f7b55..3e2b63a 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -32,6 +32,7 @@ #include #include #include +#include #include #include @@ -943,6 +944,13 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments, return -EPERM; /* + * kexec can be used to circumvent module loading restrictions, so + * prevent loading in that case + */ + if (secure_modules()) + return -EPERM; + + /* * Verify we have a legal set of flags * This leaves us room for future extensions. */ -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/