From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Benjamin LaHaise , Kent Overstreet , Mateusz Guzik , Petr Matousek Subject: [PATCH 3.15 111/139] aio: fix aio request leak when events are reaped by userspace Date: Sat, 28 Jun 2014 10:47:52 -0700 Message-Id: <20140628174610.481727437@linuxfoundation.org> In-Reply-To: <20140628174605.352098823@linuxfoundation.org> References: <20140628174605.352098823@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Benjamin LaHaise commit f8567a3845ac05bb28f3c1b478ef752762bd39ef upstream. The aio cleanups and optimizations by kmo that were merged into the 3.10 tree added a regression for userspace event reaping. Specifically, the reference counts are not decremented if the event is reaped in userspace, leading to the application being unable to submit further aio requests. This patch applies to 3.12+. A separate backport is required for 3.10/3.11. This issue was uncovered as part of CVE-2014-0206. Signed-off-by: Benjamin LaHaise Cc: Kent Overstreet Cc: Mateusz Guzik Cc: Petr Matousek Signed-off-by: Greg Kroah-Hartman --- fs/aio.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/fs/aio.c +++ b/fs/aio.c @@ -1021,6 +1021,7 @@ void aio_complete(struct kiocb *iocb, lo /* everything turned out well, dispose of the aiocb. */ kiocb_free(iocb); + put_reqs_available(ctx, 1); /* * We have to order our ring_info tail store above and test @@ -1100,8 +1101,6 @@ static long aio_read_events_ring(struct flush_dcache_page(ctx->ring_pages[0]); pr_debug("%li h%u t%u\n", ret, head, tail); - - put_reqs_available(ctx, ret); out: mutex_unlock(&ctx->ring_lock);