From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934964Ab1KJD2c (ORCPT ); Wed, 9 Nov 2011 22:28:32 -0500 Received: from cantor2.suse.de ([195.135.220.15]:42512 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934093Ab1KJD20 (ORCPT ); Wed, 9 Nov 2011 22:28:26 -0500 X-Mailbox-Line: From gregkh@clark.kroah.org Wed Nov 9 13:27:13 2011 Message-Id: <20111109212713.387658464@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Wed, 09 Nov 2011 13:27:29 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Richard Weinberger Subject: [127/262] um: fix ubd cow size In-Reply-To: <20111109212847.GA20838@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Richard Weinberger commit 8535639810e578960233ad39def3ac2157b0c3ec upstream. ubd_file_size() cannot use ubd_dev->cow.file because at this time ubd_dev->cow.file is not initialized. Therefore, ubd_file_size() will always report a wrong disk size when COW files are used. Reading from /dev/ubd* would crash the kernel. We have to read the correct disk size from the COW file's backing file. Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman --- arch/um/drivers/ubd_kern.c | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) --- a/arch/um/drivers/ubd_kern.c +++ b/arch/um/drivers/ubd_kern.c @@ -513,8 +513,37 @@ __uml_exitcall(kill_io_thread); static inline int ubd_file_size(struct ubd *ubd_dev, __u64 *size_out) { char *file; + int fd; + int err; - file = ubd_dev->cow.file ? ubd_dev->cow.file : ubd_dev->file; + __u32 version; + __u32 align; + char *backing_file; + time_t mtime; + unsigned long long size; + int sector_size; + int bitmap_offset; + + if (ubd_dev->file && ubd_dev->cow.file) { + file = ubd_dev->cow.file; + + goto out; + } + + fd = os_open_file(ubd_dev->file, global_openflags, 0); + if (fd < 0) + return fd; + + err = read_cow_header(file_reader, &fd, &version, &backing_file, \ + &mtime, &size, §or_size, &align, &bitmap_offset); + os_close_file(fd); + + if(err == -EINVAL) + file = ubd_dev->file; + else + file = backing_file; + +out: return os_file_size(file, size_out); }