From patchwork Tue Jul 6 01:06:20 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: 12359671 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 C7B20C07E99 for ; Tue, 6 Jul 2021 01:06:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A52216196C for ; Tue, 6 Jul 2021 01:06:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229722AbhGFBJD (ORCPT ); Mon, 5 Jul 2021 21:09:03 -0400 Received: from mail-wr1-f54.google.com ([209.85.221.54]:41788 "EHLO mail-wr1-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229753AbhGFBJD (ORCPT ); Mon, 5 Jul 2021 21:09:03 -0400 Received: by mail-wr1-f54.google.com with SMTP id u8so23956518wrq.8 for ; Mon, 05 Jul 2021 18:06:25 -0700 (PDT) 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=AAt2/9fsX8msYKcUtaCFzrmkaM3hAZjJLNAanXNK3v4=; b=EF/JzakONreT6F/dLDtZ3HebP/QNk2f/eRSnJNMitA2O+O65Q9Pkyc7jKjQbBuCylh yn/m29WhooKPITyrQtXBucjiJaG67RcrNsjFrq6jejwFKsWC0gi9UXqSf4vH35OHaYnO 24xzrlN7eMw9OeDn18FKQPH3vH8JvzXLvXsyqOvoYg3k3EKUThBqG+rMEFK51Pr+iMXC 1ic8t5rKzmTHwh14a6bExS2hiTRavVgvXkpxHOg9lib7+uawn9AJd/olOmdViZxkUTl/ 9/QJzV5csKjdUSD7y5XH+FOajDK239UOV42B0z+lv5myzFKLVmDSFWEU46aEEEH/wmLc X7OA== X-Gm-Message-State: AOAM532MmGl44H9ZPmtnTVyWjt3DtptOppAuH9zhBV5B56K74SFJc6zR xuA4zJOPlbjQY8o8ZNfiysQ= X-Google-Smtp-Source: ABdhPJyB5uRbyrgCQ8HHumPxTdwQWDi30dLZloF8VoL7Hk1WgvKffYPggolbnLfCigN9HsE0raocqw== X-Received: by 2002:a5d:508b:: with SMTP id a11mr18100207wrt.280.1625533584782; Mon, 05 Jul 2021 18:06:24 -0700 (PDT) Received: from workstation.lan ([95.155.85.46]) by smtp.gmail.com with ESMTPSA id m12sm13379418wms.24.2021.07.05.18.06.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Jul 2021 18:06:24 -0700 (PDT) From: =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= To: Bjorn Helgaas Cc: Lorenzo Pieralisi , Kishon Vijay Abraham I , linux-pci@vger.kernel.org Subject: [PATCH v2 2/4] PCI/sysfs: Check CAP_SYS_ADMIN before parsing user input Date: Tue, 6 Jul 2021 01:06:20 +0000 Message-Id: <20210706010622.3058968-2-kw@linux.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210706010622.3058968-1-kw@linux.com> References: <20210706010622.3058968-1-kw@linux.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Check if the "CAP_SYS_ADMIN" capability flag is set before parsing user input as it makes more sense to first check whether the current user actually has the right permissions before accepting any input from such user. This will also make order in which enable_store() and msi_bus_store() perform the "CAP_SYS_ADMIN" capability check consistent with other PCI-related sysfs objects that first verify whether user has this capability set. Signed-off-by: Krzysztof Wilczyński --- drivers/pci/pci-sysfs.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 0f98c4843764..bc4c141e4c1c 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -275,13 +275,13 @@ static ssize_t enable_store(struct device *dev, struct device_attribute *attr, struct pci_dev *pdev = to_pci_dev(dev); ssize_t result = 0; - if (kstrtobool(buf, &enable) < 0) - return -EINVAL; - /* this can crash the machine when done on the "wrong" device */ if (!capable(CAP_SYS_ADMIN)) return -EPERM; + if (kstrtobool(buf, &enable) < 0) + return -EINVAL; + device_lock(dev); if (dev->driver) result = -EBUSY; @@ -377,12 +377,12 @@ static ssize_t msi_bus_store(struct device *dev, struct device_attribute *attr, struct pci_dev *pdev = to_pci_dev(dev); struct pci_bus *subordinate = pdev->subordinate; - if (kstrtobool(buf, &enable) < 0) - return -EINVAL; - if (!capable(CAP_SYS_ADMIN)) return -EPERM; + if (kstrtobool(buf, &enable) < 0) + return -EINVAL; + /* * "no_msi" and "bus_flags" only affect what happens when a driver * requests MSI or MSI-X. They don't affect any drivers that have