From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34EF1C43441 for ; Mon, 19 Nov 2018 16:55:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F300121104 for ; Mon, 19 Nov 2018 16:55:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="WkmsV3MW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F300121104 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391117AbeKTDUH (ORCPT ); Mon, 19 Nov 2018 22:20:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:59360 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390603AbeKTDUG (ORCPT ); Mon, 19 Nov 2018 22:20:06 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 84D7F206BA; Mon, 19 Nov 2018 16:55:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1542646552; bh=E6aPQV8v4bgHxu+qayvaR6b+2t4DKafqYDvyWnO8PIk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WkmsV3MWvvaBSuX1YaSSCj181jfsvh4q6oxjF3Ydlqg3o7UG2pKr9+p2UvgA8xzyA EcwvM7xv1kcpgxTkDqTb5oBYM+ODXMUNtIDF+ol9Xyh4QZ6EXmX8uAWxNi9rRKlbLi IIrff9v6wEGo6JKI1Wul4iq0mM4h8mgKGG5QoYxo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lukas Czerner , Zorro Lang , Miklos Szeredi Subject: [PATCH 4.9 72/83] fuse: fix use-after-free in fuse_direct_IO() Date: Mon, 19 Nov 2018 17:29:38 +0100 Message-Id: <20181119162626.093978363@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181119162612.046511542@linuxfoundation.org> References: <20181119162612.046511542@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lukas Czerner commit ebacb81273599555a7a19f7754a1451206a5fc4f upstream. In async IO blocking case the additional reference to the io is taken for it to survive fuse_aio_complete(). In non blocking case this additional reference is not needed, however we still reference io to figure out whether to wait for completion or not. This is wrong and will lead to use-after-free. Fix it by storing blocking information in separate variable. This was spotted by KASAN when running generic/208 fstest. Signed-off-by: Lukas Czerner Reported-by: Zorro Lang Signed-off-by: Miklos Szeredi Fixes: 744742d692e3 ("fuse: Add reference counting for fuse_io_priv") Cc: # v4.6 Signed-off-by: Greg Kroah-Hartman --- fs/fuse/file.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -2900,10 +2900,12 @@ fuse_direct_IO(struct kiocb *iocb, struc } if (io->async) { + bool blocking = io->blocking; + fuse_aio_complete(io, ret < 0 ? ret : 0, -1); /* we have a non-extending, async request, so return */ - if (!io->blocking) + if (!blocking) return -EIOCBQUEUED; wait_for_completion(&wait);