From patchwork Tue Apr 26 19:36:18 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Seth Forshee X-Patchwork-Id: 615123 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2001:1868:205::9]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3qvYLH1LNFz9t4h for ; Wed, 27 Apr 2016 05:38:47 +1000 (AEST) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=canonical-com.20150623.gappssmtp.com header.i=@canonical-com.20150623.gappssmtp.com header.b=B8HIVwhr; dkim-atps=neutral Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1av8nY-0002GP-Nl; Tue, 26 Apr 2016 19:37:28 +0000 Received: from mail-io0-x22c.google.com ([2607:f8b0:4001:c06::22c]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1av8nK-0001wN-6X for linux-mtd@lists.infradead.org; Tue, 26 Apr 2016 19:37:14 +0000 Received: by mail-io0-x22c.google.com with SMTP id u185so30176130iod.3 for ; Tue, 26 Apr 2016 12:36:53 -0700 (PDT) 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=UHwmomD63z/RGnd7NeaL27R4JrM01/jEm5xMtjenPws=; b=B8HIVwhrPuXoz7l43B03uyqFwMN2nLBg8/1QDFqGG3QIg4eUlQTV9ZRQvGDsDe3TnL VOk9VYybs16BdJM9Uq0kC5NI7GPm71crin8wuRXAAVv1F2Nfy5OyRlTRM4f85wCYTbz/ 9+B86FvjoyJxb2iruRM02GdFQvkLvh9kv9mNf9IV3CqUpKDF84M2su8fbSOhqpecEXWI sA1spUWDYlfsRPObT/M9qGq2h/43/63pegJCbO41GCzfbBpAKZyssdilNi4r9gccxHSE VGOv9vu4xRJHAwHR0B5Ux9TKdkRZAY6yQkCp0sinZnIg5zrxEl8tMCYaXcp8FzZE9MvA Mr1w== 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=UHwmomD63z/RGnd7NeaL27R4JrM01/jEm5xMtjenPws=; b=VrkJnqkuabfiU2X/ZXsti20jjKBWw+NbnfxAO33mekQ0FYfxh6uhb+b83VBZRRP+Td 8n9CGngBbpj3JqC3MDaPPvtcfBVvXs46wWOLTJS0XdXauc6sn1SKFLxx7JDOYwEEpjYL pk1+uwavBvkRJg7sG4lPl2h7YuwOWVNxe9WpVB5SEOyhubZywuwPo4oPJTSIAtZ2gAVN fQ7Yk6jiDbIt2QnjQWT6mJv63ZPZbalIjAyX9xSszXY9Sg7EDyLmXfUyIWLOeBv1ipeR Wri5tjfBQyTyCB98Me3MLfXG3p64DnmlxANeQlMN+MWFicgk/GuztaRiOcQXH0HnPRZC y+4A== X-Gm-Message-State: AOPr4FU2G029WiXDad+9m18UGTUILHNuRrg1wm//5y1GlWd/NORWEIEamwW4tokpGZxmAyLl X-Received: by 10.107.43.88 with SMTP id r85mr6312680ior.140.1461699413063; Tue, 26 Apr 2016 12:36:53 -0700 (PDT) Received: from localhost ([2605:a601:aab:f920:39a1:5bcf:aa:5b00]) by smtp.gmail.com with ESMTPSA id 78sm2370431iof.22.2016.04.26.12.36.52 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 26 Apr 2016 12:36:52 -0700 (PDT) From: Seth Forshee To: "Eric W. Biederman" , Alexander Viro Subject: [PATCH v4 05/21] block_dev: Check permissions towards block device inode when mounting Date: Tue, 26 Apr 2016 14:36:18 -0500 Message-Id: <1461699396-33000-6-git-send-email-seth.forshee@canonical.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1461699396-33000-1-git-send-email-seth.forshee@canonical.com> References: <1461699396-33000-1-git-send-email-seth.forshee@canonical.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160426_123714_293932_9571D933 X-CRM114-Status: UNSURE ( 9.87 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -2.6 (--) X-Spam-Report: SpamAssassin version 3.4.0 on bombadil.infradead.org summary: Content analysis details: (-2.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [2607:f8b0:4001:c06:0:0:0:22c listed in] [list.dnswl.org] -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-bcache@vger.kernel.org, Serge Hallyn , Seth Forshee , dm-devel@redhat.com, Miklos Szeredi , Richard Weinberger , linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, fuse-devel@lists.sourceforge.net, Austin S Hemmelgarn , linux-mtd@lists.infradead.org, selinux@tycho.nsa.gov, linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org, Pavel Tikhomirov MIME-Version: 1.0 Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org 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 e9b937845bdb..2007040afb7b 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1429,9 +1429,14 @@ 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;