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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2E22C76196 for ; Tue, 28 Mar 2023 14:56:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233581AbjC1O4t (ORCPT ); Tue, 28 Mar 2023 10:56:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60180 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233584AbjC1O4s (ORCPT ); Tue, 28 Mar 2023 10:56:48 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D8E2E06E for ; Tue, 28 Mar 2023 07:56:45 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0B5C46184A for ; Tue, 28 Mar 2023 14:56:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 21EC6C433D2; Tue, 28 Mar 2023 14:56:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1680015404; bh=DmaVV7jGxjG0d4G2n1lFi9tL5s5lJwLPa1YCvsO5V90=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jE8Xy81Ge7Fajt9LPlpsFDzLYnMagUoGh3kDiUlLDCKgp8Pp12CnfR6B1Qca/A41s /X6/7m98KGfPw8jyvDXN+7CVMRZscJx/Pb3ypEKWlH1OLvk7ln8Vmu1qV/17+Ed5e4 y871D+oWVPL2HE2qG83qeF6E51R/dKvk0jSYsR68= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Al Viro , Dario Lesca , David Critch , Jeff Layton , Chuck Lever , Sasha Levin Subject: [PATCH 6.1 036/224] nfsd: dont replace page in rq_pages if its a continuation of last page Date: Tue, 28 Mar 2023 16:40:32 +0200 Message-Id: <20230328142618.841062246@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230328142617.205414124@linuxfoundation.org> References: <20230328142617.205414124@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jeff Layton [ Upstream commit 27c934dd8832dd40fd34776f916dc201e18b319b ] The splice read calls nfsd_splice_actor to put the pages containing file data into the svc_rqst->rq_pages array. It's possible however to get a splice result that only has a partial page at the end, if (e.g.) the filesystem hands back a short read that doesn't cover the whole page. nfsd_splice_actor will plop the partial page into its rq_pages array and return. Then later, when nfsd_splice_actor is called again, the remainder of the page may end up being filled out. At this point, nfsd_splice_actor will put the page into the array _again_ corrupting the reply. If this is done enough times, rq_next_page will overrun the array and corrupt the trailing fields -- the rq_respages and rq_next_page pointers themselves. If we've already added the page to the array in the last pass, don't add it to the array a second time when dealing with a splice continuation. This was originally handled properly in nfsd_splice_actor, but commit 91e23b1c3982 ("NFSD: Clean up nfsd_splice_actor()") removed the check for it. Fixes: 91e23b1c3982 ("NFSD: Clean up nfsd_splice_actor()") Cc: Al Viro Reported-by: Dario Lesca Tested-by: David Critch Link: https://bugzilla.redhat.com/show_bug.cgi?id=2150630 Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin --- fs/nfsd/vfs.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 59f9a8cee012a..dc3ba13546dd6 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -874,8 +874,15 @@ nfsd_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf, struct page *last_page; last_page = page + (offset + sd->len - 1) / PAGE_SIZE; - for (page += offset / PAGE_SIZE; page <= last_page; page++) + for (page += offset / PAGE_SIZE; page <= last_page; page++) { + /* + * Skip page replacement when extending the contents + * of the current page. + */ + if (page == *(rqstp->rq_next_page - 1)) + continue; svc_rqst_replace_page(rqstp, page); + } if (rqstp->rq_res.page_len == 0) // first call rqstp->rq_res.page_base = offset % PAGE_SIZE; rqstp->rq_res.page_len += sd->len; -- 2.39.2