From patchwork Tue Oct 13 17:04:15 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Seth Forshee X-Patchwork-Id: 7387051 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id E92639F1B9 for ; Tue, 13 Oct 2015 17:08:13 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 1211A20780 for ; Tue, 13 Oct 2015 17:08:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EE4702077D for ; Tue, 13 Oct 2015 17:08:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753183AbbJMRHw (ORCPT ); Tue, 13 Oct 2015 13:07:52 -0400 Received: from mail-io0-f172.google.com ([209.85.223.172]:36784 "EHLO mail-io0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753207AbbJMRF0 (ORCPT ); Tue, 13 Oct 2015 13:05:26 -0400 Received: by ioii196 with SMTP id i196so27954108ioi.3 for ; Tue, 13 Oct 2015 10:05:26 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=82307GhF4DfEulDFlEN5o0F3tZyKr/GCBK6KOIrNfu0=; b=futeNFXRZn56Nx3G/t+xVk7yxGAwVvJnvMOJob/B3Os+SFivukF1qvfpKb9CnqSy9d LYEpVRAwdkCHM32dRmDwydFM+rVbKtBU0LJoSjrtyipNmXElCn3Og+VlNMU8gJAET0cY 3D8Ir32OhJn7keluJyJEg2Ym/w8M9fskxiN/kRAlg+Zh+m2oAuD/lyBZmt4F2UKD9ueO NO8wdq+YVYJNzzu82gHLO+JJ4AtY7jRUiuHTaixxx+kZWdBvzQ9p4lRDwrh7l7+Tqr2h NwP0k2vg6a4bwxAKJCNEha45pboBYBO/F4B3OeHu6KYbaYXXYxP2UzMFJ5OJ4R2fIZys N5Eg== X-Gm-Message-State: ALoCoQlMZ5/qrHdkWgG/yeNHS11YLddAQj9LDXJMiyN1RXZjw0fTRJho4l3nVw97BEdD/6gV10P3 X-Received: by 10.107.167.204 with SMTP id q195mr42257792ioe.119.1444755925923; Tue, 13 Oct 2015 10:05:25 -0700 (PDT) Received: from localhost (199-87-125-144.dyn.kc.surewest.net. [199.87.125.144]) by smtp.gmail.com with ESMTPSA id q11sm1899322ioe.19.2015.10.13.10.05.25 (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Tue, 13 Oct 2015 10:05:25 -0700 (PDT) From: Seth Forshee To: "Eric W. Biederman" , Alexander Viro Cc: Serge Hallyn , Andy Lutomirski , linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-bcache@vger.kernel.org, dm-devel@redhat.com, linux-raid@vger.kernel.org, Seth Forshee Subject: [PATCH v2 2/7] block_dev: Check permissions towards block device inode when mounting Date: Tue, 13 Oct 2015 12:04:15 -0500 Message-Id: <1444755861-54997-3-git-send-email-seth.forshee@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1444755861-54997-1-git-send-email-seth.forshee@canonical.com> References: <1444755861-54997-1-git-send-email-seth.forshee@canonical.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Unprivileged users should not be able to mount block devices when they lack sufficient privileges towards the block device inode. Update blkdev_get_by_path() to validate that the user has the required access to the inode at the specified path. The check will be skipped for CAP_SYS_ADMIN, so privileged mounts will continue working as before. Signed-off-by: Seth Forshee --- fs/block_dev.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/block_dev.c b/fs/block_dev.c index f1f0aa7214a3..54d94cd64577 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1394,9 +1394,14 @@ struct block_device *blkdev_get_by_path(const char *path, fmode_t mode, void *holder) { struct block_device *bdev; + int perm = 0; int err; - bdev = lookup_bdev(path, 0); + if (mode & FMODE_READ) + perm |= MAY_READ; + if (mode & FMODE_WRITE) + perm |= MAY_WRITE; + bdev = lookup_bdev(path, perm); if (IS_ERR(bdev)) return bdev;