From patchwork Tue Nov 17 16:39:05 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Seth Forshee X-Patchwork-Id: 7639401 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 47A62BF90C for ; Tue, 17 Nov 2015 16:44:36 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 7B5092044B for ; Tue, 17 Nov 2015 16:44:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9D2B020416 for ; Tue, 17 Nov 2015 16:44:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932110AbbKQQmv (ORCPT ); Tue, 17 Nov 2015 11:42:51 -0500 Received: from mail-ig0-f179.google.com ([209.85.213.179]:34601 "EHLO mail-ig0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754461AbbKQQkF (ORCPT ); Tue, 17 Nov 2015 11:40:05 -0500 Received: by igvg19 with SMTP id g19so99526507igv.1 for ; Tue, 17 Nov 2015 08:40:05 -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=82307GhF4DfEulDFlEN5o0F3tZyKr/GCBK6KOIrNfu0=; b=zVM6u1pq2AXxM/14EVK4XFXSc/qsLT3rCXKsJfbR1XJiohq6LHd/2JIopsnQi+RZZz zvgyc5KnKVwwHn0H1kRdwRtwvwFq4768+d8iz5VCXnrLnVt1NmPyj8k/9roYKBOjXqNj K6SX33tk4QVoIcs5291R6GFukAZVjjc9PMePvngomshMazzuYBiXhrJOCnBblx+aihtC aoV7JWFXY39XdFGJBquWjwDPSf7CDlqtTYLPKHoSYpKmWdTxYm+947r+LG30GYoQ5p8n EJU2Ci4J+vJQgv/TRnpP4noSAMsPvOVHGeyFZS4MaEoGdAcWQDBhPZKtlNAxxWcCnw8b 0y8w== 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=bAVnnNpiXgflpPBLtZG2CFqlWWlYrWfJo6PF2vcZrUMKEhug/XfJnGLhk1NzuqBixp tDvUNysaMYwXZaOZgmFtEPujztVNLCQCFwRwmahc/lAe0SZyqQYYAiL9W7vWxphSCcTr sgkCCE96pKE0UvfF2fQVVD74ZS9ZuVBQiKMgStKFRduF08T1EB5UeKO/yPj3qigfW2wf Sqjg0mk0l97HTk0MZw5MFUwhiT37Mn35JN0amCo8z50qfeO4uSj58FycnsXYzuqPlOGp OZv06pt2Gt+s8oo5cGxK9PBfBaP7v6YG+WEWEorXzKesD0PUSJfFeZo2CYzQiz6/jvIs vIxg== X-Gm-Message-State: ALoCoQnHC7lBms9NwscRNFsnYNf4Ybv/PjNKnk1p0uDAMwNKIzvid0X+Isgi2o6OW9GqTDHjAy4x X-Received: by 10.50.78.194 with SMTP id d2mr2742488igx.72.1447778404956; Tue, 17 Nov 2015 08:40:04 -0800 (PST) Received: from localhost (199-87-125-144.dyn.kc.surewest.net. [199.87.125.144]) by smtp.gmail.com with ESMTPSA id 81sm13239047iot.17.2015.11.17.08.40.04 (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Tue, 17 Nov 2015 08:40:04 -0800 (PST) From: Seth Forshee To: "Eric W. Biederman" , Alexander Viro Cc: Serge Hallyn , Andy Lutomirski , linux-kernel@vger.kernel.org, linux-bcache@vger.kernel.org, dm-devel@redhat.com, linux-raid@vger.kernel.org, linux-mtd@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov, Seth Forshee Subject: [PATCH v3 2/7] block_dev: Check permissions towards block device inode when mounting Date: Tue, 17 Nov 2015 10:39:05 -0600 Message-Id: <1447778351-118699-3-git-send-email-seth.forshee@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1447778351-118699-1-git-send-email-seth.forshee@canonical.com> References: <1447778351-118699-1-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=-7.4 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD,T_DKIM_INVALID,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;