Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755699Ab0LHAky (ORCPT ); Tue, 7 Dec 2010 19:40:54 -0500 Received: from kroah.org ([198.145.64.141]:54760 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754940Ab0LHAe1 (ORCPT ); Tue, 7 Dec 2010 19:34:27 -0500 X-Mailbox-Line: From gregkh@clark.site Tue Dec 7 16:06:40 2010 Message-Id: <20101208000640.912118071@clark.site> User-Agent: quilt/0.48-11.2 Date: Tue, 07 Dec 2010 16:04:13 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Jens Axboe Subject: [14/44] bio: take care not overflow page count when mapping/copying user data In-Reply-To: <20101208003205.GA4286@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1888 Lines: 64 2.6.27-stable review patch. If anyone has any objections, please let us know. ------------------ From: Jens Axboe commit cb4644cac4a2797afc847e6c92736664d4b0ea34 upstream. If the iovec is being set up in a way that causes uaddr + PAGE_SIZE to overflow, we could end up attempting to map a huge number of pages. Check for this invalid input type. Reported-by: Dan Rosenberg Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- fs/bio.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) --- a/fs/bio.c +++ b/fs/bio.c @@ -593,6 +593,12 @@ struct bio *bio_copy_user_iov(struct req end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT; start = uaddr >> PAGE_SHIFT; + /* + * Overflow, abort + */ + if (end < start) + return ERR_PTR(-EINVAL); + nr_pages += end - start; len += iov[i].iov_len; } @@ -691,6 +697,12 @@ static struct bio *__bio_map_user_iov(st unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; unsigned long start = uaddr >> PAGE_SHIFT; + /* + * Overflow, abort + */ + if (end < start) + return ERR_PTR(-EINVAL); + nr_pages += end - start; /* * buffer must be aligned to at least hardsector size for now @@ -718,7 +730,7 @@ static struct bio *__bio_map_user_iov(st unsigned long start = uaddr >> PAGE_SHIFT; const int local_nr_pages = end - start; const int page_limit = cur_page + local_nr_pages; - + ret = get_user_pages_fast(uaddr, local_nr_pages, write_to_vm, &pages[cur_page]); if (ret < local_nr_pages) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/