From nobody Fri Oct 17 10:31:36 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 8D288C4332F for ; Wed, 19 Oct 2022 08:56:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231902AbiJSI4r (ORCPT ); Wed, 19 Oct 2022 04:56:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60556 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231907AbiJSI4Q (ORCPT ); Wed, 19 Oct 2022 04:56:16 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C475E9C2E0; Wed, 19 Oct 2022 01:52:21 -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 51F6D61840; Wed, 19 Oct 2022 08:48:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6B3C0C433C1; Wed, 19 Oct 2022 08:48:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666169291; bh=UCOXvJhWORPwHaVSbJcOe6oEVxI7zAC7T2lMUEbvagY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0bC7j9+XpRTM6b58F0QrhaFRqTYVozzReqca64QCH8pPs0GESVC2gxFgTIwBuRlXt Mpukn0JLDraf5ZE0OHB0xJm3I3Y1Knx4UwTQMfmZlJOFknIzWmKs0vIqSgIEAa2PJ5 jXpM9ciIu+Nt6VE7/bhSMNqsnWZMjDE90fAiuQnA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jeff Layton , Chuck Lever , Sasha Levin Subject: [PATCH 6.0 222/862] SUNRPC: Fix svcxdr_init_decodes end-of-buffer calculation Date: Wed, 19 Oct 2022 10:25:09 +0200 Message-Id: <20221019083259.849441093@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 90bfc37b5ab91c1a6165e3e5cfc49bf04571b762 ] Ensure that stream-based argument decoding can't go past the actual end of the receive buffer. xdr_init_decode's calculation of the value of xdr->end over-estimates the end of the buffer because the Linux kernel RPC server code does not remove the size of the RPC header from rqstp->rq_arg before calling the upper layer's dispatcher. The server-side still uses the svc_getnl() macros to decode the RPC call header. These macros reduce the length of the head iov but do not update the total length of the message in the buffer (buf->len). A proper fix for this would be to replace the use of svc_getnl() and friends in the RPC header decoder, but that would be a large and invasive change that would be difficult to backport. Fixes: 5191955d6fc6 ("SUNRPC: Prepare for xdr_stream-style decoding on the = server-side") Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin --- include/linux/sunrpc/svc.h | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h index daecb009c05b..5a830b66f059 100644 --- a/include/linux/sunrpc/svc.h +++ b/include/linux/sunrpc/svc.h @@ -544,16 +544,27 @@ static inline void svc_reserve_auth(struct svc_rqst *= rqstp, int space) } =20 /** - * svcxdr_init_decode - Prepare an xdr_stream for svc Call decoding + * svcxdr_init_decode - Prepare an xdr_stream for Call decoding * @rqstp: controlling server RPC transaction context * + * This function currently assumes the RPC header in rq_arg has + * already been decoded. Upon return, xdr->p points to the + * location of the upper layer header. */ static inline void svcxdr_init_decode(struct svc_rqst *rqstp) { struct xdr_stream *xdr =3D &rqstp->rq_arg_stream; - struct kvec *argv =3D rqstp->rq_arg.head; + struct xdr_buf *buf =3D &rqstp->rq_arg; + struct kvec *argv =3D buf->head; =20 - xdr_init_decode(xdr, &rqstp->rq_arg, argv->iov_base, NULL); + /* + * svc_getnl() and friends do not keep the xdr_buf's ::len + * field up to date. Refresh that field before initializing + * the argument decoding stream. + */ + buf->len =3D buf->head->iov_len + buf->page_len + buf->tail->iov_len; + + xdr_init_decode(xdr, buf, argv->iov_base, NULL); xdr_set_scratch_page(xdr, rqstp->rq_scratch_page); } =20 --=20 2.35.1