From patchwork Wed Mar 6 23:58:57 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Garrett X-Patchwork-Id: 10842013 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 7821A14DE for ; Wed, 6 Mar 2019 23:59:59 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 64A392E746 for ; Wed, 6 Mar 2019 23:59:59 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 58A5B2E7D1; Wed, 6 Mar 2019 23:59:59 +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=-14.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 E16F82E746 for ; Wed, 6 Mar 2019 23:59:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726445AbfCFX75 (ORCPT ); Wed, 6 Mar 2019 18:59:57 -0500 Received: from mail-vk1-f201.google.com ([209.85.221.201]:49133 "EHLO mail-vk1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726487AbfCFX7z (ORCPT ); Wed, 6 Mar 2019 18:59:55 -0500 Received: by mail-vk1-f201.google.com with SMTP id j1so7389546vkj.15 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=tRV0eiJ7E0YvXh11gaT5OMgRH+eIZiUUocpYd6mRX/glfTBkAkxqJy51zK1dFe+Y01 bbTPQK8fDe6IPHgmK7E/SE/1EAgxiAqoHuQ8joaCXxUBtbAysY1jV85AnrmuLZa3wxzp 7FWNDxg29b4xOui6ROTF8bJW6zEqAKyaxb8WqpbcKmHyK79lSy1C90xUqtHWPQLMT74T omt53MPJQczYL0LO5C4N9HF2uE5vDtZ4RxbvxQIMlAomfkvcu58CrdyqxuFU+o7HTIfn 30z0jWcHruOL/hjgJ37QiKOTQsh3hf/uMWrffFY2xMEortZU5pgXjowsKge7+f6zIqCw QNGg== X-Gm-Message-State: APjAAAVJIySdemTjjYgZbskQui5VhnK5n/VJK0wv4oYqfo9xLTO9O3sa Y8/bbQ3b/+ji/rRXcp8hWUsDmj5xGQHn3svv3bMEkA== 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 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: 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: 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);