From patchwork Wed Nov 16 21:48:36 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 9432849 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id AA2B360471 for ; Wed, 16 Nov 2016 21:50:18 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9A1AD29168 for ; Wed, 16 Nov 2016 21:50:18 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8F07A2916D; Wed, 16 Nov 2016 21:50:18 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4A18A29168 for ; Wed, 16 Nov 2016 21:50:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935535AbcKPVuD (ORCPT ); Wed, 16 Nov 2016 16:50:03 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39948 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S941057AbcKPVsi (ORCPT ); Wed, 16 Nov 2016 16:48:38 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6AC69C05166C; Wed, 16 Nov 2016 21:48:38 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-116-110.phx2.redhat.com [10.3.116.110]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id uAGLma7M030968; Wed, 16 Nov 2016 16:48:37 -0500 Organization: Red Hat UK Ltd. 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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 11/16] x86: Lock down IO port access when the kernel is locked down From: David Howells To: keyrings@vger.kernel.org Cc: dhowells@redhat.com, matthew.garrett@nebula.com, linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 16 Nov 2016 21:48:36 +0000 Message-ID: <147933291647.19316.6065544311010705130.stgit@warthog.procyon.org.uk> In-Reply-To: <147933283664.19316.12454053022687659937.stgit@warthog.procyon.org.uk> References: <147933283664.19316.12454053022687659937.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Wed, 16 Nov 2016 21:48:38 +0000 (UTC) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP From: Matthew Garrett IO port access would permit users to gain access to PCI configuration registers, which in turn (on a lot of hardware) give access to MMIO register space. This would potentially permit root to trigger arbitrary DMA, so lock it down by default. Signed-off-by: Matthew Garrett Signed-off-by: David Howells --- arch/x86/kernel/ioport.c | 5 +++-- drivers/char/mem.c | 4 ++++ 2 files changed, 7 insertions(+), 2 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c index 589b3193f102..2ee24e9ff6d8 100644 --- a/arch/x86/kernel/ioport.c +++ b/arch/x86/kernel/ioport.c @@ -15,6 +15,7 @@ #include #include #include +#include #include /* @@ -28,7 +29,7 @@ asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int turn_on) if ((from + num <= from) || (from + num > IO_BITMAP_BITS)) return -EINVAL; - if (turn_on && !capable(CAP_SYS_RAWIO)) + if (turn_on && (!capable(CAP_SYS_RAWIO) || kernel_is_locked_down())) return -EPERM; /* @@ -108,7 +109,7 @@ SYSCALL_DEFINE1(iopl, unsigned int, level) return -EINVAL; /* Trying to gain more privileges? */ if (level > old) { - if (!capable(CAP_SYS_RAWIO)) + if (!capable(CAP_SYS_RAWIO) || kernel_is_locked_down()) return -EPERM; } regs->flags = (regs->flags & ~X86_EFLAGS_IOPL) | diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 5bb1985ec484..17e22cb2db14 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -28,6 +28,7 @@ #include #include #include +#include #include @@ -580,6 +581,9 @@ static ssize_t write_port(struct file *file, const char __user *buf, unsigned long i = *ppos; const char __user *tmp = buf; + if (kernel_is_locked_down()) + return -EPERM; + if (!access_ok(VERIFY_READ, buf, count)) return -EFAULT; while (count-- > 0 && i < 65536) {