From patchwork Thu Apr 4 00:32:32 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Garrett X-Patchwork-Id: 10884685 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A68F51800 for ; Thu, 4 Apr 2019 00:35:08 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 97277262F2 for ; Thu, 4 Apr 2019 00:35:08 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8AC5E289AF; Thu, 4 Apr 2019 00:35:08 +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=-15.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, USER_IN_DEF_DKIM_WL autolearn=ham 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 ACDDF262F2 for ; Thu, 4 Apr 2019 00:35:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726858AbfDDAdV (ORCPT ); Wed, 3 Apr 2019 20:33:21 -0400 Received: from mail-oi1-f201.google.com ([209.85.167.201]:47708 "EHLO mail-oi1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726847AbfDDAdV (ORCPT ); Wed, 3 Apr 2019 20:33:21 -0400 Received: by mail-oi1-f201.google.com with SMTP id j5so337146oif.14 for ; Wed, 03 Apr 2019 17:33:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=m5EpQp8h0Y4rOl6Y1bbFAZQnIUUjTzjUqWwPJEltX0Y=; b=ocjKRk2uUtqZ4iOJV2jedYJKPEapKDEzvfWc8HY+i+xFfEyayOYqbLWPu8Z3xN6v7m 7vE6H9PK8L1J2QZZhJeDyD0kawGilYXs+t0n4wzbstR/VqOE7iCdQ/AhSVLMB8zkTEkP hED0gN06yC/q53ohr6GM0JuqFX+wx9Lc4u4EgwAuwiiKvzPNJDyAx3lCJYmK9/Vx+bq8 F0vaeAYBmLnAM+aAWf44QmkFfIRr3tMYARd7EInNJb2QflHlEqzW4rXTX9RM+klXPMzl q1PsBfL5YaDXc14Lm2QkznhvbIaNW7bGY4Luc6wiotRneuT0jRSaYY9bEDbhEFKYRmWi drbQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=m5EpQp8h0Y4rOl6Y1bbFAZQnIUUjTzjUqWwPJEltX0Y=; b=TCWUEVpBRHv7sXXuZEF2N2/5yu6gZS7tOxYv20o6fnqiuWqPtHhZxqr6MPMIggFezO iD9mXW/psAlb9EaUBGIhv4nV144SPRTK5eEz5jITzE1PRTu7xQ7mvRjUBDiNBT8XSQ1L G5EuvjFn8JyN62LmClwfvp3INd1wa4Qr8yBWpPuCA4lnNDq4yfRZ8NIm3LQZ1Lz5JV5y e2zA12E29eayxFYCjSHQaP5nZOaovGBGhUv6fAUr16xh4cIsahEvqGIlTMGJOZDlzCAe fE5SqBsA5S7dQhJj6iaHm272FQtpsolJggv8T8JZx8hy44uPabx7i54tV/00YeRYzphx JELg== X-Gm-Message-State: APjAAAVlI9BG/EyEARoUwD93UK9O+JkIJflkdr8lXefNVfzMa5i69tH7 nhm72CtRWN4NfGxSidSXXA93IoOxNn14l0YjwI3+tw== X-Google-Smtp-Source: APXvYqwi6dSpI9p/5yHXUp5zHUlVc9aBYPhvQtpRQtFUwPCGKLeTlUt0GbyXS3R2mPTpVRAld1ySv5RUcgaNvopbDpSu3Q== X-Received: by 2002:aca:abd7:: with SMTP id u206mr329089oie.36.1554338000165; Wed, 03 Apr 2019 17:33:20 -0700 (PDT) Date: Wed, 3 Apr 2019 17:32:32 -0700 In-Reply-To: <20190404003249.14356-1-matthewgarrett@google.com> Message-Id: <20190404003249.14356-11-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190404003249.14356-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.21.0.392.gf8f6787159e-goog Subject: [PATCH V32 10/27] PCI: Lock down BAR access when the kernel is locked down From: Matthew Garrett To: jmorris@namei.org Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, linux-api@vger.kernel.org, luto@kernel.org, Matthew Garrett , Matthew Garrett , Bjorn Helgaas , linux-pci@vger.kernel.org Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Matthew Garrett Any hardware that can potentially generate DMA has to be locked down in order to avoid it being possible for an attacker to modify kernel code, allowing them to circumvent disabled module loading or module signing. Default to paranoid - in future we can potentially relax this for sufficiently IOMMU-isolated devices. Signed-off-by: David Howells Signed-off-by: Matthew Garrett Acked-by: Bjorn Helgaas cc: linux-pci@vger.kernel.org --- drivers/pci/pci-sysfs.c | 9 +++++++++ drivers/pci/proc.c | 9 ++++++++- drivers/pci/syscall.c | 3 ++- 3 files changed, 19 insertions(+), 2 deletions(-) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 9ecfe13157c0..59d02088945e 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -905,6 +905,9 @@ static ssize_t pci_write_config(struct file *filp, struct kobject *kobj, loff_t init_off = off; u8 *data = (u8 *) buf; + if (kernel_is_locked_down("Direct PCI access", LOCKDOWN_INTEGRITY)) + return -EPERM; + if (off > dev->cfg_size) return 0; if (off + count > dev->cfg_size) { @@ -1167,6 +1170,9 @@ static int pci_mmap_resource(struct kobject *kobj, struct bin_attribute *attr, enum pci_mmap_state mmap_type; struct resource *res = &pdev->resource[bar]; + if (kernel_is_locked_down("Direct PCI access", LOCKDOWN_INTEGRITY)) + return -EPERM; + if (res->flags & IORESOURCE_MEM && iomem_is_exclusive(res->start)) return -EINVAL; @@ -1242,6 +1248,9 @@ static ssize_t pci_write_resource_io(struct file *filp, struct kobject *kobj, struct bin_attribute *attr, char *buf, loff_t off, size_t count) { + if (kernel_is_locked_down("Direct PCI access", LOCKDOWN_INTEGRITY)) + return -EPERM; + return pci_resource_io(filp, kobj, attr, buf, off, count, true); } diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c index 6fa1627ce08d..85769f222b6d 100644 --- a/drivers/pci/proc.c +++ b/drivers/pci/proc.c @@ -117,6 +117,9 @@ static ssize_t proc_bus_pci_write(struct file *file, const char __user *buf, int size = dev->cfg_size; int cnt; + if (kernel_is_locked_down("Direct PCI access", LOCKDOWN_INTEGRITY)) + return -EPERM; + if (pos >= size) return 0; if (nbytes >= size) @@ -196,6 +199,9 @@ static long proc_bus_pci_ioctl(struct file *file, unsigned int cmd, #endif /* HAVE_PCI_MMAP */ int ret = 0; + if (kernel_is_locked_down("Direct PCI access", LOCKDOWN_INTEGRITY)) + return -EPERM; + switch (cmd) { case PCIIOC_CONTROLLER: ret = pci_domain_nr(dev->bus); @@ -237,7 +243,8 @@ static int proc_bus_pci_mmap(struct file *file, struct vm_area_struct *vma) struct pci_filp_private *fpriv = file->private_data; int i, ret, write_combine = 0, res_bit = IORESOURCE_MEM; - if (!capable(CAP_SYS_RAWIO)) + if (!capable(CAP_SYS_RAWIO) || + kernel_is_locked_down("Direct PCI access", LOCKDOWN_INTEGRITY)) return -EPERM; if (fpriv->mmap_state == pci_mmap_io) { diff --git a/drivers/pci/syscall.c b/drivers/pci/syscall.c index d96626c614f5..0669cb09e792 100644 --- a/drivers/pci/syscall.c +++ b/drivers/pci/syscall.c @@ -90,7 +90,8 @@ SYSCALL_DEFINE5(pciconfig_write, unsigned long, bus, unsigned long, dfn, u32 dword; int err = 0; - if (!capable(CAP_SYS_ADMIN)) + if (!capable(CAP_SYS_ADMIN) || + kernel_is_locked_down("Direct PCI access", LOCKDOWN_INTEGRITY)) return -EPERM; dev = pci_get_domain_bus_and_slot(0, bus, dfn);