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 E332BC38A2D for ; Mon, 24 Oct 2022 16:46:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234905AbiJXQqb (ORCPT ); Mon, 24 Oct 2022 12:46:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37328 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234860AbiJXQpR (ORCPT ); Mon, 24 Oct 2022 12:45:17 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CC5C71213F7; Mon, 24 Oct 2022 08:30:52 -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 ams.source.kernel.org (Postfix) with ESMTPS id 980EBB818F3; Mon, 24 Oct 2022 12:39:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0319CC433D6; Mon, 24 Oct 2022 12:39:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666615172; bh=jGz9UnPEkKK77ys6ki/ZwBM6QS832DXZwbCU8wf7c4w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hRYCzTOnOeh0+ypvNFLsC1TcY4LNIZJoTtrzT9thfFsIoElEe0+R9LPrHA5+aUzXW 6olpIzdhXk6zNDJA2gJzK/BaqGfVSqLW5Bce4BdNrvVhqVGQzF74n2AHklOftCPxuZ j17Xa4qHpkMUtHmmWlkha4wiQ8/qrFwHTOA0FoPM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chuck Lever , Jeff Layton , Sasha Levin Subject: [PATCH 5.15 149/530] NFSD: Protect against send buffer overflow in NFSv2 READDIR Date: Mon, 24 Oct 2022 13:28:13 +0200 Message-Id: <20221024113051.808603543@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024113044.976326639@linuxfoundation.org> References: <20221024113044.976326639@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: linux-kernel@vger.kernel.org From: Chuck Lever [ Upstream commit 00b4492686e0497fdb924a9d4c8f6f99377e176c ] Restore the previous limit on the @count argument to prevent a buffer overflow attack. Fixes: 53b1119a6e50 ("NFSD: Fix READDIR buffer overflow") Signed-off-by: Chuck Lever Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin --- fs/nfsd/nfsproc.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c index 081cca405983..b009da1dcbb5 100644 --- a/fs/nfsd/nfsproc.c +++ b/fs/nfsd/nfsproc.c @@ -557,12 +557,11 @@ static void nfsd_init_dirlist_pages(struct svc_rqst *rqstp, struct xdr_buf *buf = &resp->dirlist; struct xdr_stream *xdr = &resp->xdr; - count = clamp(count, (u32)(XDR_UNIT * 2), svc_max_payload(rqstp)); - memset(buf, 0, sizeof(*buf)); /* Reserve room for the NULL ptr & eof flag (-2 words) */ - buf->buflen = count - XDR_UNIT * 2; + buf->buflen = clamp(count, (u32)(XDR_UNIT * 2), (u32)PAGE_SIZE); + buf->buflen -= XDR_UNIT * 2; buf->pages = rqstp->rq_next_page; rqstp->rq_next_page++; -- 2.35.1