From mboxrd@z Thu Jan 1 00:00:00 1970 From: 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> References: <1449070821-73820-1-git-send-email-seth.forshee@canonical.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1449070821-73820-1-git-send-email-seth.forshee@canonical.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-mtd" Errors-To: linux-mtd-bounces+gldm-linux-mtd-36=gmane.org@lists.infradead.org To: "Eric W. Biederman" , Alexander Viro Cc: Serge Hallyn , Seth Forshee , dm-devel@redhat.com, Miklos Szeredi , Richard Weinberger , linux-security-module@vger.kernel.org, linux-bcache@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 List-Id: linux-raid.ids 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 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; -- 1.9.1 ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/