From patchwork Wed Sep 15 23:01:25 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: 12497713 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=-16.7 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 77106C433F5 for ; Wed, 15 Sep 2021 23:01:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53BD660234 for ; Wed, 15 Sep 2021 23:01:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232740AbhIOXCu (ORCPT ); Wed, 15 Sep 2021 19:02:50 -0400 Received: from mail-lf1-f53.google.com ([209.85.167.53]:35416 "EHLO mail-lf1-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231922AbhIOXCu (ORCPT ); Wed, 15 Sep 2021 19:02:50 -0400 Received: by mail-lf1-f53.google.com with SMTP id m3so8870059lfu.2 for ; Wed, 15 Sep 2021 16:01:30 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=CEaTlQvNZpRF49/gdrsx+pw4YoE0fPAtiHHb2K0ZQps=; b=t/OvYzvEWgUlyOylROv1OlNj/KTKwKQS1pIe6Oo1gGDM5xWRSzz2iIBvB5qj3rkjB2 SrDnd64jmDZYdti4rb0PM6TqQTieYP1fhdZ+DXUm/df2rfCaEXLi70APQ9cXRCj7gSa6 H3L4/+uCqCRtG2942mHIQzkZaW6BsJhNNfgZQIEXjKUXTJwqCuCjsrhKS+SSSlYdTXZG kwojXqOagBJANrGdDWmABo5Yy6zF9sW8OiarirS80dTs8CNvUPSoAsBYQMarlMAY2MKN kDZm/FOFzFkTgC3c1Q8mltQUACEUY01Khlj49M2agvdsT93MMoZ2GZSAfhZaCw5Gn5Jy PCdQ== X-Gm-Message-State: AOAM5300HoOkZLmQlr2Mb3vbe4xDwoNREo6TivDiI6naay0nGK//Bh/s wLzfVZ5eYi029sxMAHmQSrVhOcbtoC4= X-Google-Smtp-Source: ABdhPJxlmpXlzlgfoQcXm+pgGKTknCtXHe8w8UaMsiACFebo1gaTl3sOgmSpaozdz89RjLJvIernwg== X-Received: by 2002:a05:651c:510:: with SMTP id o16mr2158708ljp.257.1631746889685; Wed, 15 Sep 2021 16:01:29 -0700 (PDT) Received: from workstation.lan ([95.155.85.46]) by smtp.gmail.com with ESMTPSA id d15sm107386lfn.220.2021.09.15.16.01.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Sep 2021 16:01:29 -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 v3 1/3] PCI/sysfs: Check CAP_SYS_ADMIN before parsing user input Date: Wed, 15 Sep 2021 23:01:25 +0000 Message-Id: <20210915230127.2495723-1-kw@linux.com> X-Mailer: git-send-email 2.33.0 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 | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 7fb5cd17cc98..6832e161be1c 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -273,15 +273,16 @@ static ssize_t enable_store(struct device *dev, struct device_attribute *attr, { struct pci_dev *pdev = to_pci_dev(dev); unsigned long val; - ssize_t result = kstrtoul(buf, 0, &val); - - if (result < 0) - return result; + ssize_t result; /* this can crash the machine when done on the "wrong" device */ if (!capable(CAP_SYS_ADMIN)) return -EPERM; + result = kstrtoul(buf, 0, &val); + if (result < 0) + return result; + device_lock(dev); if (dev->driver) result = -EBUSY; @@ -378,12 +379,12 @@ static ssize_t msi_bus_store(struct device *dev, struct device_attribute *attr, struct pci_bus *subordinate = pdev->subordinate; unsigned long val; - if (kstrtoul(buf, 0, &val) < 0) - return -EINVAL; - if (!capable(CAP_SYS_ADMIN)) return -EPERM; + if (kstrtoul(buf, 0, &val) < 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