From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4D313C43381 for ; Thu, 7 Mar 2019 00:00:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1508220663 for ; Thu, 7 Mar 2019 00:00:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="fgEDghp9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726531AbfCFX77 (ORCPT ); Wed, 6 Mar 2019 18:59:59 -0500 Received: from mail-vk1-f201.google.com ([209.85.221.201]:36226 "EHLO mail-vk1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726488AbfCFX7z (ORCPT ); Wed, 6 Mar 2019 18:59:55 -0500 Received: by mail-vk1-f201.google.com with SMTP id b202so7435130vke.3 for ; Wed, 06 Mar 2019 15:59:54 -0800 (PST) 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=ACqFRhtJUfbHBZBPOu5dDkAx0/TaxY9Rwhxh4VD+UBs=; b=fgEDghp9aUPPq5LIQbGaL6nEH0coUYCSyYuTyRdQ1gO7leMx3wv+kvJFbiZsfJbaov pklDS/Qt+yxsTTHks6MoVO6lWCuAdTGqQMzj/XCnPMZ5UPnexaPpwiiChv19uM9BCsLb n9YirvJwxBiFfS9eJUPeX1s7SaKQQ2dx44MkksoVzcAyWjumoAoWdn1t2PQ4sFbpQjQv v6PPsY0oLcsXMY6ctV6rr7aTkf2/sZpJgGo917exFXjIF4tDC6TPaOHRkVBab0nCoNQe KYu6vYBfWFa8zDnkCuY6BcGyBAU7/dXYU0DzBrLh18YqVlZ8UvtOrAE4Sd4uraIBBuDv 8uQw== 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=ACqFRhtJUfbHBZBPOu5dDkAx0/TaxY9Rwhxh4VD+UBs=; b=SZXUKx8Ex+hgqXNnrCBA23jOvh1NmKardDMQGSAqjSPg11cFICxHTfURt8xPfTX8+3 VJaTSfJcZEiqtJF/4AwlwhisgVW719e5t9yT4MEVBr6AgJpkGpoHDQOYLiDDYzMJ7BWi sscXeKBbS2A2NJcDvwQE3lD5mTaT5b159I1QsFGbuA0q1sWsypAewhLZcjf7S6JPuz1R +LwZWzInCbPAiGxH8MlQT7wxF77CaERoEtNSD7Gt6qwiMh6Zx3uZt4HMCzvDmx7JeVBq F8v453BlaNcut4ExWLl4T/XKdWdGHDxMUoZyixENQG5UR10TIJK/AXJnNwXEeWEeElK2 trtQ== X-Gm-Message-State: APjAAAXLjFiIc8wbHArBeGwyLqkVKdOIhkjboOJLl303EK+ZRQ0f1EEZ Mv0ghTjq9AIxRW2oANyqAIUtj6Y/4l3afX2o/hx69Q== X-Google-Smtp-Source: APXvYqzUBqNd8/YUx2fDLnRpZCWhP0/NfK79PxMtzpWY5W8/fAB2exucG4GxQ+dIl9GStj1lAczoDSn+eRiRXxQ2c8jgmQ== X-Received: by 2002:ab0:778d:: with SMTP id x13mr6862246uar.7.1551916794166; Wed, 06 Mar 2019 15:59:54 -0800 (PST) Date: Wed, 6 Mar 2019 15:58:57 -0800 In-Reply-To: <20190306235913.6631-1-matthewgarrett@google.com> Message-Id: <20190306235913.6631-12-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190306235913.6631-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.21.0.352.gf09ad66450-goog Subject: [PATCH 11/27] 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 Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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: Matthew Garrett Signed-off-by: David Howells Acked-by: Bjorn Helgaas Reviewed-by: "Lee, Chun-Yi" cc: linux-pci@vger.kernel.org Signed-off-by: Matthew Garrett --- 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..40c14574fcf8 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")) + 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")) + 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")) + 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..1549cdd0710e 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")) + 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")) + 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")) return -EPERM; if (fpriv->mmap_state == pci_mmap_io) { diff --git a/drivers/pci/syscall.c b/drivers/pci/syscall.c index d96626c614f5..b8a08d3166a1 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")) return -EPERM; dev = pci_get_domain_bus_and_slot(0, bus, dfn); -- 2.21.0.352.gf09ad66450-goog