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=-8.3 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=no 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 82AECC3A5A8 for ; Wed, 4 Sep 2019 16:47:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 572202087E for ; Wed, 4 Sep 2019 16:47:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="iIiZLF14" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732325AbfIDQro (ORCPT ); Wed, 4 Sep 2019 12:47:44 -0400 Received: from mail-io1-f45.google.com ([209.85.166.45]:43722 "EHLO mail-io1-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732324AbfIDQrn (ORCPT ); Wed, 4 Sep 2019 12:47:43 -0400 Received: by mail-io1-f45.google.com with SMTP id u185so41855292iod.10 for ; Wed, 04 Sep 2019 09:47:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=sFnr7zgJe+61oG4oqxymDnM4izKIkBVQkyb90hB3S+I=; b=iIiZLF14sOBStDzF/zd5qvQJo3HPHJzWwvCAMo/xC62V6+aBfDX2kCYoBGGFUL3io9 mWteVTYIKwVmcppcgjI1Gz1JAjVVCiH8X54EIkWjj6U27wYnJiIYrUt3pXw9gVP7wPn/ 4tuIZY8AfhSpnphPjvx4Hgk9KszlkdMQOFMlLTO2Ebh9fCM+JJRVD6JJgeiTgVNJqYQa JR8hQpqmlmA+DIrPW9H61r1U6ESB3m1BaWvc1rcuGx7tUZlmPqVnJO9VdyK1rpiMSxuY FVQxbLlmDI5xjHezuh8ZT8KOGWtLHQUqteGreVrFv/CpWVoh3ir59di5coFcOFJIy+Zh AfkQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=sFnr7zgJe+61oG4oqxymDnM4izKIkBVQkyb90hB3S+I=; b=cX9UXqCHTaCaUHOvtdwVffCASZkc3OSld7Swvx14s9CELHBxw8RSnByy1S8trDspl+ TNWTeByhm5emJzw0w7INXzfrUoBqn+knrDEbyMwjf62twjkj1UsGM5mWkFRHA4LqDjbS mbgX+YFWS+m4Ea+yu2hfF+2cR/hKzFcbnfTUVmXfma21u+CjwxrtYfDBO4K7VMPLKBNu 0zIjdQEVjeL7XN8T4ZHNYT7nmWfWk5pLVecWyDGogHPVHFG9ADBg9uFfG5Dj8dONzniu c0s21P9GCxc0TDcFPE2j7bwPWXN4L87Bb+2rO+7DVss011/09GBrAO6IMiD0nwUlYxN8 mRTw== X-Gm-Message-State: APjAAAVnxd1je4giQSevTt/zvBvlDT0EI0mtBXpRSEdYJOxO+9mzIb2e B269aThlFZScPqR1a190MwiGiPG+3kJe+BTHuZFV4A== X-Google-Smtp-Source: APXvYqxSl27LcKurdt2fQvWY+lSxjaoKv1CHvidnAFxG8QO4wPpbzVxnVi7kqXp7e40rk4a0QrrOJkCYYK+1aHl5iSo= X-Received: by 2002:a02:6a17:: with SMTP id l23mr5941298jac.102.1567615662334; Wed, 04 Sep 2019 09:47:42 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Matthew Garrett Date: Wed, 4 Sep 2019 09:47:30 -0700 Message-ID: Subject: Re: Should PCI "new_id" support be disabled when kernel is locked down? To: Ian Abbott Cc: LSM List , linux-pci@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On Wed, Sep 4, 2019 at 9:12 AM Ian Abbott wrote: > > Hello, > > The "new_id" PCI driver sysfs attribute can be used to make an arbitrary > PCI driver match an arbitrary PCI vendor/device ID. That could easily > crash the kernel or at least make it do weird things if used > inappropriately. Is this scenario in scope for the "lockdown" security > module? Crashing the kernel isn't really a concern - the issue is more whether it's possible to get a driver to perform a sufficient number of writes to a device that it can in turn cause the device to overwrite the kernel in a controlled manner. This seems theoretically possible, but I think I'm inclined to leave it as is unless someone demonstrates that it's more than theoretical.