From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752859AbdJSOwC (ORCPT ); Thu, 19 Oct 2017 10:52:02 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53698 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752231AbdJSOv7 (ORCPT ); Thu, 19 Oct 2017 10:51:59 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 49BEB356E3 Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=dhowells@redhat.com Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 11/27] x86: Lock down IO port access when the kernel is locked down From: David Howells To: linux-security-module@vger.kernel.org Cc: gnomes@lxorguk.ukuu.org.uk, linux-efi@vger.kernel.org, matthew.garrett@nebula.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, jforbes@redhat.com Date: Thu, 19 Oct 2017 15:51:56 +0100 Message-ID: <150842471673.7923.7676307847318724274.stgit@warthog.procyon.org.uk> In-Reply-To: <150842463163.7923.11081723749106843698.stgit@warthog.procyon.org.uk> References: <150842463163.7923.11081723749106843698.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Thu, 19 Oct 2017 14:51:59 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. This also implicitly locks down the KDADDIO, KDDELIO, KDENABIO and KDDISABIO console ioctls. Signed-off-by: Matthew Garrett Signed-off-by: David Howells Reviewed-by: Thomas Gleixner cc: x86@kernel.org --- arch/x86/kernel/ioport.c | 6 ++++-- drivers/char/mem.c | 2 ++ 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c index 9c3cf0944bce..2c0f058651c5 100644 --- a/arch/x86/kernel/ioport.c +++ b/arch/x86/kernel/ioport.c @@ -30,7 +30,8 @@ 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("ioperm"))) return -EPERM; /* @@ -120,7 +121,8 @@ 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("iopl")) return -EPERM; } regs->flags = (regs->flags & ~X86_EFLAGS_IOPL) | diff --git a/drivers/char/mem.c b/drivers/char/mem.c index b7c36898b689..0875b3d47773 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -768,6 +768,8 @@ static loff_t memory_lseek(struct file *file, loff_t offset, int orig) static int open_port(struct inode *inode, struct file *filp) { + if (kernel_is_locked_down("Direct ioport access")) + return -EPERM; return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; } From mboxrd@z Thu Jan 1 00:00:00 1970 From: dhowells@redhat.com (David Howells) Date: Thu, 19 Oct 2017 15:51:56 +0100 Subject: [PATCH 11/27] x86: Lock down IO port access when the kernel is locked down In-Reply-To: <150842463163.7923.11081723749106843698.stgit@warthog.procyon.org.uk> References: <150842463163.7923.11081723749106843698.stgit@warthog.procyon.org.uk> Message-ID: <150842471673.7923.7676307847318724274.stgit@warthog.procyon.org.uk> To: linux-security-module@vger.kernel.org List-Id: linux-security-module.vger.kernel.org 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. This also implicitly locks down the KDADDIO, KDDELIO, KDENABIO and KDDISABIO console ioctls. Signed-off-by: Matthew Garrett Signed-off-by: David Howells Reviewed-by: Thomas Gleixner cc: x86 at kernel.org --- arch/x86/kernel/ioport.c | 6 ++++-- drivers/char/mem.c | 2 ++ 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c index 9c3cf0944bce..2c0f058651c5 100644 --- a/arch/x86/kernel/ioport.c +++ b/arch/x86/kernel/ioport.c @@ -30,7 +30,8 @@ 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("ioperm"))) return -EPERM; /* @@ -120,7 +121,8 @@ 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("iopl")) return -EPERM; } regs->flags = (regs->flags & ~X86_EFLAGS_IOPL) | diff --git a/drivers/char/mem.c b/drivers/char/mem.c index b7c36898b689..0875b3d47773 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -768,6 +768,8 @@ static loff_t memory_lseek(struct file *file, loff_t offset, int orig) static int open_port(struct inode *inode, struct file *filp) { + if (kernel_is_locked_down("Direct ioport access")) + return -EPERM; return capable(CAP_SYS_RAWIO) ? 0 : -EPERM; } -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html