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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 14522C388F7 for ; Mon, 9 Nov 2020 13:35:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B46112065D for ; Mon, 9 Nov 2020 13:35:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604928920; bh=ZLeOPp5R7YSkfvBZOBDb/LOc6Tl0ZFDGmKBNdeIOBdI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uUtnCI0ITLZTtd/lSlrIV0eDzoVSQ8yBtKCQE9wbOy+PoAzgahU30W67CNE1sBC5o x7ULCeDv2w0G9ehSLWunpUo5MY+C+eBSLKzD5nX5OhAgZhIMAPCw83uGwoOubfczQm 6QT1hQoSP3OnHGwu7j+YGAig0E+MvFMg/0eokf/o= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732353AbgKINfT (ORCPT ); Mon, 9 Nov 2020 08:35:19 -0500 Received: from mail.kernel.org ([198.145.29.99]:58280 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729906AbgKINF0 (ORCPT ); Mon, 9 Nov 2020 08:05:26 -0500 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 0017420663; Mon, 9 Nov 2020 13:05:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604927125; bh=ZLeOPp5R7YSkfvBZOBDb/LOc6Tl0ZFDGmKBNdeIOBdI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=T0spUrOcuPdGqcywbSUr/w8e3fg2+/Bx512uFPnZn+1ehWAe5z7tmudWoyDQk8G5p ooAxRLQ0BDWmnsAwcxZ0OxkkoA7GZKqSeDaFYypg1Fskqi/0WZSTHF4BmGvaLGqrNC w51Rphjhb8G3wNC3pHjujBMqSYB1P/ixj1gzfjVI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Stefano Garzarella , "Michael S. Tsirkin" Subject: [PATCH 4.9 078/117] vringh: fix __vringh_iov() when riov and wiov are different Date: Mon, 9 Nov 2020 13:55:04 +0100 Message-Id: <20201109125029.389389164@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201109125025.630721781@linuxfoundation.org> References: <20201109125025.630721781@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Stefano Garzarella commit 5745bcfbbf89b158416075374254d3c013488f21 upstream. If riov and wiov are both defined and they point to different objects, only riov is initialized. If the wiov is not initialized by the caller, the function fails returning -EINVAL and printing "Readable desc 0x... after writable" error message. This issue happens when descriptors have both readable and writable buffers (eg. virtio-blk devices has virtio_blk_outhdr in the readable buffer and status as last byte of writable buffer) and we call __vringh_iov() to get both type of buffers in two different iovecs. Let's replace the 'else if' clause with 'if' to initialize both riov and wiov if they are not NULL. As checkpatch pointed out, we also avoid crashing the kernel when riov and wiov are both NULL, replacing BUG() with WARN_ON() and returning -EINVAL. Fixes: f87d0fbb5798 ("vringh: host-side implementation of virtio rings.") Cc: stable@vger.kernel.org Signed-off-by: Stefano Garzarella Link: https://lore.kernel.org/r/20201008204256.162292-1-sgarzare@redhat.com Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman --- drivers/vhost/vringh.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) --- a/drivers/vhost/vringh.c +++ b/drivers/vhost/vringh.c @@ -272,13 +272,14 @@ __vringh_iov(struct vringh *vrh, u16 i, desc_max = vrh->vring.num; up_next = -1; + /* You must want something! */ + if (WARN_ON(!riov && !wiov)) + return -EINVAL; + if (riov) riov->i = riov->used = 0; - else if (wiov) + if (wiov) wiov->i = wiov->used = 0; - else - /* You must want something! */ - BUG(); for (;;) { void *addr;