From patchwork Tue Mar 26 18:27:26 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Garrett X-Patchwork-Id: 10871941 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 51C8B17E6 for ; Tue, 26 Mar 2019 18:28:24 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3E12028DEE for ; Tue, 26 Mar 2019 18:28:24 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3221128DD7; Tue, 26 Mar 2019 18:28:24 +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 B214E28DEE for ; Tue, 26 Mar 2019 18:28:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732693AbfCZS2V (ORCPT ); Tue, 26 Mar 2019 14:28:21 -0400 Received: from mail-ua1-f74.google.com ([209.85.222.74]:43200 "EHLO mail-ua1-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732682AbfCZS2V (ORCPT ); Tue, 26 Mar 2019 14:28:21 -0400 Received: by mail-ua1-f74.google.com with SMTP id o12so1682012uaj.10 for ; Tue, 26 Mar 2019 11:28:21 -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=Yz7oOrcDdKUM0oYpsGth5oCv8+Sc+iqvbZ8HKnhPKCnBF9rUHCL9szQCMAPU1PE8KZ V5oNz+OBCLawb6XGwCVNO/3W7ZIGW6CJqa38iNh+smM0l3Mf3WI096uUxVztD+vMlcy8 withllnQOAKuH6gF0+c6jcTe8VCipjbIFvdZQ3SG7qlyXzoR+Tduukj9v5gmr817WjTN 9qDDUFYKJxhZTZ6Uwfhk7qeYMwY0kNDGpr/Xub4PUqKY1bIS3otzcyj76HMmWPO1Cupi V7GyBI5YYjxdJUAmUSXaa8vzKtz1GNVChjlfHcl09ljj04vfopWnPSjdHPO8UC5ktyD4 6Vaw== 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=jDJtUIctmzbIOZ3ngktNmDOegFA0Mo8JjmBIbPxwSJuT9kgbvt97GG7FY6fXTFsvqK uzIRXk7DJXpkv/i33CwpgGkBNVSiPT9577qnocit1yE/P4Um3KjhB1IqihMtc6Q0DyLE 26V7eHZQLfAXcTdtXNgYoNf12Z1seHv0XpL3Tk2+jdYq9Fle30FZ69IXyFsoyb8gcFVw yr7oK7+oGKPgJ7VBe5E3ROXgqDCqEFswLoYRMi3US7JZJE90Z5MWSQCoupknEdIQEBp0 8G/siQ60M6qcFVEAJyfyr3gdjh/OEtJqwOZTf79U3SqZ2lU6I+Gp4Q6ywJ59wGg7a+Sx d6zQ== X-Gm-Message-State: APjAAAXxhbJfbC2gvdMvr+BOlGssEpIR91sXWE/X00Y/mqEDCo7bUE9Q x+hyQ9MvQ1AQco5IFZYGLKRimemgTC/LkcKy9bjrlg== X-Google-Smtp-Source: APXvYqxJT/ULfLCwvV7wSB2GAtE6Vz8ph2N7xnq6Ot24PIma7JsvCCcrM8TBMNJZ/wPOc6HUu0fWwieS5ffY5o8z3DZmWA== X-Received: by 2002:a1f:a4d:: with SMTP id 74mr14878315vkk.13.1553624900606; Tue, 26 Mar 2019 11:28:20 -0700 (PDT) Date: Tue, 26 Mar 2019 11:27:26 -0700 In-Reply-To: <20190326182742.16950-1-matthewgarrett@google.com> Message-Id: <20190326182742.16950-11-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190326182742.16950-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.21.0.392.gf8f6787159e-goog Subject: [PATCH V31 10/25] 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);