From patchwork Wed Dec 2 15:40:02 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Seth Forshee X-Patchwork-Id: 7748101 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id E6523BEEE1 for ; Wed, 2 Dec 2015 15:52:02 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id EE0B3204E7 for ; Wed, 2 Dec 2015 15:52:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 03ED620511 for ; Wed, 2 Dec 2015 15:52:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932765AbbLBPvY (ORCPT ); Wed, 2 Dec 2015 10:51:24 -0500 Received: from mail-io0-f172.google.com ([209.85.223.172]:35076 "EHLO mail-io0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758683AbbLBPmF (ORCPT ); Wed, 2 Dec 2015 10:42:05 -0500 Received: by ioc74 with SMTP id 74so49319840ioc.2 for ; Wed, 02 Dec 2015 07:42:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=y+FUp222mT7SmSct54tR0p/5Or4CNldUBAVqU8U2UPM=; b=0QoQnaw+SsHOz0IBjewmfRmu98tPSEGB6Uu6w+16PPuSNfMuSSN4jDxbnTBuL0o03K DS9rkWex6aq95ZH0Nfg20NHLpCJI6mMZWYJXwgAdhHKPiZ7qNEDAmZAMlUJWdt0mpI6H oc1LdF2dLwbr5Thk2YAZGvVcieQUy8Gf/PFqCZ8T9NfQvX+bvYigPfVUVZN5aSqI3rm4 t++pvwr2aL4k2dVMAwHQNBM3XT5KUHqPl9TwNvcpOnp0gVjUCDlqZCQ0C9rI6ttVrG9D 9XktRWoXm+1P9+m8fZMcWI1f2ggOpa22fLDrV92BZMKgOH6rOYp62EWpp+Fh0DuUPpgf 9r7Q== 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=y+FUp222mT7SmSct54tR0p/5Or4CNldUBAVqU8U2UPM=; b=GZp1wFbvXNrRzexQVfoppuGEQTrhQsziwssEhTAHHKjdVUQe0l1y/8lKYqaySe3U9a Q6RWn/+zFnNpN+TGAYdOZksVJ3K/yWwobuOkHbUhQV1xl2zXll2KXOGC2dQjsX480aOs O0RmqvlrvukXLPu2DS/dWxyK4ICBMKrtspzf4HJPOjVoHq/WB+yXryvvas4u2sYFHqFy IahJWxd+ixAVi+Ag9VX6K3NXSi0YG7fO2VvioDHzF/i6Z1zCZJl7uCy7s5BbAl8FWO5c 7Ytvl1dyZMKsOFFDK8MbfKGs2xgGWSetrB1uYEE9A185SyuFXfHwm4qI2mamG/1tfxfN G2MA== X-Gm-Message-State: ALoCoQnoZPyJXcH6ZlA316VrQdnr1nADwkUzfA9MUN5Ykhg8i/orntxlo61lqPOSRiZaNSLVmPqx X-Received: by 10.107.33.203 with SMTP id h194mr3863086ioh.108.1449070924781; Wed, 02 Dec 2015 07:42:04 -0800 (PST) Received: from localhost (199-87-125-144.dyn.kc.surewest.net. [199.87.125.144]) by smtp.gmail.com with ESMTPSA id j10sm1332857igx.13.2015.12.02.07.42.04 (version=TLS1_2 cipher=AES128-SHA bits=128/128); Wed, 02 Dec 2015 07:42:04 -0800 (PST) From: Seth Forshee To: "Eric W. Biederman" , Alexander Viro Cc: Serge Hallyn , Richard Weinberger , Austin S Hemmelgarn , Miklos Szeredi , linux-bcache@vger.kernel.org, dm-devel@redhat.com, linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-fsdevel@vger.kernel.org, fuse-devel@lists.sourceforge.net, linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov, Seth Forshee Subject: [PATCH 02/19] block_dev: Check permissions towards block device inode when mounting Date: Wed, 2 Dec 2015 09:40:02 -0600 Message-Id: <1449070821-73820-3-git-send-email-seth.forshee@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1449070821-73820-1-git-send-email-seth.forshee@canonical.com> References: <1449070821-73820-1-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=-6.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID,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 Acked-by: Serge Hallyn --- 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 3ebbde85d898..4fdb6ab59816 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1424,9 +1424,14 @@ 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;