From patchwork Wed Apr 1 18:56:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Trond Myklebust X-Patchwork-Id: 11469455 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8CE7F17EF for ; Wed, 1 Apr 2020 18:59:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6C78020784 for ; Wed, 1 Apr 2020 18:59:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585767543; bh=377he6UN6s3hghZdwMeYOuNO0ogsCGWOC/L/PVnnRqg=; h=From:To:Subject:Date:In-Reply-To:References:List-ID:From; b=Rn74JQ/znoiTsetOkTqNJsbNWzQ7baz36tsYO3iLjGI3ppyO7bImQ+R8oEo3UH2R6 5ovn9QWYfalStajIl1V+MouH9Go1hvZDpPBcrkPJgxQnCu3V8zvBpm3X2oQYb+3kS5 QhvmOjL3OnefRB9QU3yEv25Tu5vqk5bNVVs9HzEc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726785AbgDAS7C (ORCPT ); Wed, 1 Apr 2020 14:59:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:36666 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732148AbgDAS7C (ORCPT ); Wed, 1 Apr 2020 14:59:02 -0400 Received: from localhost.localdomain (c-68-36-133-222.hsd1.mi.comcast.net [68.36.133.222]) (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 B2BC820784 for ; Wed, 1 Apr 2020 18:59:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585767541; bh=377he6UN6s3hghZdwMeYOuNO0ogsCGWOC/L/PVnnRqg=; h=From:To:Subject:Date:In-Reply-To:References:From; b=z6J4PJg0OuBMpIm+Dd8f2QnOts2xqciDG5upmXiEy3UoX/Wc9VGJ4FO4hdkd1A7PQ AdG6tuTCMth2K8/8EGEj1u21TM5tB2WDIOR4sApZ8nLssKE3csnaNBBM+xKnZWWguK tth3QodQLmFaTVD5dYjsjf+AxtNXeT78mCpuUYbE= From: trondmy@kernel.org To: linux-nfs@vger.kernel.org Subject: [PATCH 03/10] NFS: Fix use-after-free issues in nfs_pageio_add_request() Date: Wed, 1 Apr 2020 14:56:45 -0400 Message-Id: <20200401185652.1904777-4-trondmy@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200401185652.1904777-3-trondmy@kernel.org> References: <20200401185652.1904777-1-trondmy@kernel.org> <20200401185652.1904777-2-trondmy@kernel.org> <20200401185652.1904777-3-trondmy@kernel.org> MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org From: Trond Myklebust We need to ensure that we create the mirror requests before calling nfs_pageio_add_request_mirror() on the request we are adding. Otherwise, we can end up with a use-after-free if the call to nfs_pageio_add_request_mirror() triggers I/O. Fixes: c917cfaf9bbe ("NFS: Fix up NFS I/O subrequest creation") Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust --- fs/nfs/pagelist.c | 48 +++++++++++++++++++++++------------------------ 1 file changed, 24 insertions(+), 24 deletions(-) diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index 0e3f0f241d83..99eb839c5778 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -1191,38 +1191,38 @@ int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc, if (desc->pg_error < 0) goto out_failed; - for (midx = 0; midx < desc->pg_mirror_count; midx++) { - if (midx) { - nfs_page_group_lock(req); - - /* find the last request */ - for (lastreq = req->wb_head; - lastreq->wb_this_page != req->wb_head; - lastreq = lastreq->wb_this_page) - ; - - dupreq = nfs_create_subreq(req, lastreq, - pgbase, offset, bytes); - - nfs_page_group_unlock(req); - if (IS_ERR(dupreq)) { - desc->pg_error = PTR_ERR(dupreq); - goto out_failed; - } - } else - dupreq = req; + /* Create the mirror instances first, and fire them off */ + for (midx = 1; midx < desc->pg_mirror_count; midx++) { + nfs_page_group_lock(req); + + /* find the last request */ + for (lastreq = req->wb_head; + lastreq->wb_this_page != req->wb_head; + lastreq = lastreq->wb_this_page) + ; + + dupreq = nfs_create_subreq(req, lastreq, + pgbase, offset, bytes); + + nfs_page_group_unlock(req); + if (IS_ERR(dupreq)) { + desc->pg_error = PTR_ERR(dupreq); + goto out_failed; + } - if (nfs_pgio_has_mirroring(desc)) - desc->pg_mirror_idx = midx; + desc->pg_mirror_idx = midx; if (!nfs_pageio_add_request_mirror(desc, dupreq)) goto out_cleanup_subreq; } + desc->pg_mirror_idx = 0; + if (!nfs_pageio_add_request_mirror(desc, req)) + goto out_failed; + return 1; out_cleanup_subreq: - if (req != dupreq) - nfs_pageio_cleanup_request(desc, dupreq); + nfs_pageio_cleanup_request(desc, dupreq); out_failed: nfs_pageio_error_cleanup(desc); return 0;