From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933230Ab1DNRql (ORCPT ); Thu, 14 Apr 2011 13:46:41 -0400 Received: from mail.windriver.com ([147.11.1.11]:38222 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933155Ab1DNRqe (ORCPT ); Thu, 14 Apr 2011 13:46:34 -0400 From: Paul Gortmaker To: stable@kernel.org, linux-kernel@vger.kernel.org Cc: stable-review@kernel.org, Jens Axboe , Paul Gortmaker Subject: [34-longterm 066/209] bio: take care not overflow page count when mapping/copying user data Date: Thu, 14 Apr 2011 13:41:36 -0400 Message-Id: <1302803039-9400-67-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.7.4.4 In-Reply-To: <1302803039-9400-1-git-send-email-paul.gortmaker@windriver.com> References: <1302803039-9400-1-git-send-email-paul.gortmaker@windriver.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jens Axboe ===================================================================== | This is a commit scheduled for the next v2.6.34 longterm release. | | If you see a problem with using this for longterm, please comment.| ===================================================================== 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: Paul Gortmaker --- fs/bio.c | 14 +++++++++++++- 1 files changed, 13 insertions(+), 1 deletions(-) diff --git a/fs/bio.c b/fs/bio.c index 75ea4c3..b3e0174 100644 --- a/fs/bio.c +++ b/fs/bio.c @@ -834,6 +834,12 @@ struct bio *bio_copy_user_iov(struct request_queue *q, 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; } @@ -961,6 +967,12 @@ static struct bio *__bio_map_user_iov(struct request_queue *q, 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 @@ -988,7 +1000,7 @@ static struct bio *__bio_map_user_iov(struct request_queue *q, 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) { -- 1.7.4.4