Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754957AbaFXSCU (ORCPT ); Tue, 24 Jun 2014 14:02:20 -0400 Received: from kanga.kvack.org ([205.233.56.17]:35070 "EHLO kanga.kvack.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752650AbaFXSCR (ORCPT ); Tue, 24 Jun 2014 14:02:17 -0400 Date: Tue, 24 Jun 2014 14:02:17 -0400 From: Benjamin LaHaise To: Linus Torvalds , security@kernel.org Cc: linux-aio@kvack.org, linux-kernel@vger.kernel.org, Mateusz Guzik , Petr Matousek , Kent Overstreet , Jeff Moyer , stable@vger.kernel.org Subject: [PATCH 2/2] aio: fix kernel memory disclosure in io_getevents() introduced in v3.10 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A kernel memory disclosure was introduced in aio_read_events_ring() in v3.10 by commit a31ad380bed817aa25f8830ad23e1a0480fef797. The changes made to aio_read_events_ring() failed to correctly limit the index into ctx->ring_pages[], allowing an attacked to cause the subsequent kmap() of an arbitrary page with a copy_to_user() to copy the contents into userspace. This vulnerability has been assigned CVE-2014-0206. Thanks to Mateusz and Petr for disclosing this issue. This patch applies to v3.12+. A separate backport is needed for 3.10/3.11. Signed-off-by: Benjamin LaHaise Cc: Mateusz Guzik Cc: Petr Matousek Cc: Kent Overstreet Cc: Jeff Moyer Cc: stable@vger.kernel.org --- fs/aio.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/aio.c b/fs/aio.c index 6a9c7e4..955947e 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -1063,6 +1063,9 @@ static long aio_read_events_ring(struct kioctx *ctx, if (head == tail) goto out; + head %= ctx->nr_events; + tail %= ctx->nr_events; + while (ret < nr) { long avail; struct io_event *ev; -- 1.8.2.1 -- "Thought is the essence of where you are now." -- 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/