From nobody Fri Oct 17 10:11:57 2025 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 99E96C4332F for ; Wed, 19 Oct 2022 08:52:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231792AbiJSIww (ORCPT ); Wed, 19 Oct 2022 04:52:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41520 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231782AbiJSIwO (ORCPT ); Wed, 19 Oct 2022 04:52:14 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F1455926B; Wed, 19 Oct 2022 01:50:01 -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 95F2E61831; Wed, 19 Oct 2022 08:48:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A91D2C433D6; Wed, 19 Oct 2022 08:48:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666169297; bh=gxtBNvdGmC3q4uYGpTMNCsXLCpfFaT+/XRIRyBojW4w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FcPhd3Df0+h627L1mFlGr0TJv+lz12asEPSOUR9srBuzvKh+2nGGNBeWFqy6DVES4 bPpv84gxnWpGTGvutURdte2DziZ9qB3Li11OpfZpeE1OvAZDUlg7jEaBe/G18Ow9lo OpRQaVU+adlbGTtIA7S44mdtFGfccHbwbkOHxGR0= 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 6.0 224/862] NFSD: Protect against send buffer overflow in NFSv2 READDIR Date: Wed, 19 Oct 2022 10:25:11 +0200 Message-Id: <20221019083259.940007979@linuxfoundation.org> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221019083249.951566199@linuxfoundation.org> References: <20221019083249.951566199@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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 fcbf7e4083af..4b19cc727ea5 100644 --- a/fs/nfsd/nfsproc.c +++ b/fs/nfsd/nfsproc.c @@ -568,12 +568,11 @@ static void nfsd_init_dirlist_pages(struct svc_rqst *= rqstp, struct xdr_buf *buf =3D &resp->dirlist; struct xdr_stream *xdr =3D &resp->xdr; =20 - count =3D clamp(count, (u32)(XDR_UNIT * 2), svc_max_payload(rqstp)); - memset(buf, 0, sizeof(*buf)); =20 /* Reserve room for the NULL ptr & eof flag (-2 words) */ - buf->buflen =3D count - XDR_UNIT * 2; + buf->buflen =3D clamp(count, (u32)(XDR_UNIT * 2), (u32)PAGE_SIZE); + buf->buflen -=3D XDR_UNIT * 2; buf->pages =3D rqstp->rq_next_page; rqstp->rq_next_page++; =20 --=20 2.35.1