From patchwork Sat Feb 20 06:28:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= X-Patchwork-Id: 12096733 X-Patchwork-Delegate: bhelgaas@google.com 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=-21.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 3AA21C433DB for ; Sat, 20 Feb 2021 06:29:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC70960238 for ; Sat, 20 Feb 2021 06:29:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229734AbhBTG3Z (ORCPT ); Sat, 20 Feb 2021 01:29:25 -0500 Received: from mail-wm1-f47.google.com ([209.85.128.47]:35556 "EHLO mail-wm1-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229483AbhBTG3U (ORCPT ); Sat, 20 Feb 2021 01:29:20 -0500 Received: by mail-wm1-f47.google.com with SMTP id n10so9580942wmq.0 for ; Fri, 19 Feb 2021 22:29:04 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=0JzuFOhjTPAxCOUJqxrebftEnNwtKMwJNNdlwliQLAw=; b=UgxIcNIZh/X2JNFwcocI6SOY9Cc0qgFxFUoBhlBwkv94rrTf9A5CLlZPEToi6t5Tmq pdUTZfDH39jNjx1WqFX6cxDXCpQHay/8h8Ml7628tN2eEFGBCDKKbNWAuU3dYteLpkrf YqfHgyIBzpzFOID+0Vnhg8FbzNWpaxyTpRXlkS0g2GaxepvrqwQtShs6nRe39yeR/WjJ ZveoWsCS7sGQQ88ygzw5b7CmYVy9SIHL/vlRcg5WO3BbEi3/ynj9iEqYxG5rsl5th84U YVXStr9QLO9aja6j80c0AsVzGF1R+fD9GYgV/68Pdp5vSIx8RZsu1xK/2ZL9tpR1UDwj 8JfQ== X-Gm-Message-State: AOAM530TMdY6s0AsfrnmLNsXacmDy8FSw1v8pInxzC7v2c4NshzZWAyR LoblvQSm+Vp1/zbyabEeSgk= X-Google-Smtp-Source: ABdhPJw+uUyXrQ8LINBtu02Gq0g2VnjEAwORryqjgVZ9pfTUk11xTR+iQl3RwowQQWF2l1anPBVM3g== X-Received: by 2002:a7b:cf32:: with SMTP id m18mr11236261wmg.53.1613802518720; Fri, 19 Feb 2021 22:28:38 -0800 (PST) Received: from workstation.lan ([95.155.85.46]) by smtp.gmail.com with ESMTPSA id y62sm18161262wmy.9.2021.02.19.22.28.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 19 Feb 2021 22:28:38 -0800 (PST) From: =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= To: Kurt Schwemmer Cc: Logan Gunthorpe , Bjorn Helgaas , "Gustavo A . R . Silva" , linux-pci@vger.kernel.org Subject: [PATCH] PCI/switchtec: Fix Spectre v1 vulnerability Date: Sat, 20 Feb 2021 06:28:37 +0000 Message-Id: <20210220062837.1683159-1-kw@linux.com> X-Mailer: git-send-email 2.30.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org The "partition" member of the struct switchtec_ioctl_pff_port can be indirectly controlled from user-space through an IOCTL that the device driver provides enabling conversion between a PCI Function Framework (PFF) number and Switchtec logical port ID and partition number, thus allowing for command-line tooling [1] interact with the device from user-space. This can lead to potential exploitation of the Spectre variant 1 [2] vulnerability since the value of the partition is then used directly as an index to mmio_part_cfg_all of the struct switchtec_dev to retrieve configuration from Switchtec for a specific partition number. Fix this by sanitizing the value coming from user-space through the available IOCTL before it's then used as an index to mmio_part_cfg_all. This issue was detected with the help of Smatch: drivers/pci/switch/switchtec.c:1118 ioctl_port_to_pff() warn: potential spectre issue 'stdev->mmio_part_cfg_all' [r] (local cap) Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [3]. Related commit 46feb6b495f7 ("switchtec: Fix Spectre v1 vulnerability"). 1. https://github.com/Microsemi/switchtec-user/blob/master/lib/platform/linux.c 2. https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/spectre.html 3. https://lore.kernel.org/lkml/CAPcyv4gLKYiCtXsKFX2FY+rW93aRtQt9zB8hU1hMsj770m8gxQ@mail.gmail.com/ Signed-off-by: Krzysztof Wilczyński Reviewed-by: Logan Gunthorpe --- drivers/pci/switch/switchtec.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c index ba52459928f7..bb6957101fc0 100644 --- a/drivers/pci/switch/switchtec.c +++ b/drivers/pci/switch/switchtec.c @@ -1112,12 +1112,15 @@ static int ioctl_port_to_pff(struct switchtec_dev *stdev, if (copy_from_user(&p, up, sizeof(p))) return -EFAULT; - if (p.partition == SWITCHTEC_IOCTL_EVENT_LOCAL_PART_IDX) + if (p.partition == SWITCHTEC_IOCTL_EVENT_LOCAL_PART_IDX) { pcfg = stdev->mmio_part_cfg; - else if (p.partition < stdev->partition_count) + } else if (p.partition < stdev->partition_count) { + p.partition = array_index_nospec(p.partition, + stdev->partition_count); pcfg = &stdev->mmio_part_cfg_all[p.partition]; - else + } else { return -EINVAL; + } switch (p.port) { case 0: