From nobody Fri Dec 19 19:07:34 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 1E936C433FE for ; Sat, 22 Oct 2022 07:53:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232036AbiJVHxo (ORCPT ); Sat, 22 Oct 2022 03:53:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38542 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231893AbiJVHv1 (ORCPT ); Sat, 22 Oct 2022 03:51:27 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F3F362C2AF3; Sat, 22 Oct 2022 00:46:26 -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 B8D7460B6B; Sat, 22 Oct 2022 07:43:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A0DE4C433D6; Sat, 22 Oct 2022 07:43:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666424622; bh=vvroSdVnhpOzWpAlb2Ota3DJevOUQESG8b8NQmA2ZKA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZzoUd26cmmDtzdt4T7fljJZ9Axaag8op/CxXm4TLV3rrkG8JwKpa85FrFOxd6Llj+ 94vbKNXmPfGYiaJmsavaaeaIofQg07Jw3Al0hfareDFz02CwEOKFBUa0UiWWVn8Akx VhKOBYYTTqQGVoRXBszD1CASuhGrjiK9pyiyTQgY= 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 5.19 197/717] NFSD: Protect against send buffer overflow in NFSv2 READDIR Date: Sat, 22 Oct 2022 09:21:16 +0200 Message-Id: <20221022072450.362303294@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221022072415.034382448@linuxfoundation.org> References: <20221022072415.034382448@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 16cde315f454..f65eba938a57 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 =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