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 X-Spam-Level: X-Spam-Status: No, score=-11.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5773C43457 for ; Mon, 19 Oct 2020 22:04:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A80822453 for ; Mon, 19 Oct 2020 22:04:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fieldses.org header.i=@fieldses.org header.b="G1OgnST/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387804AbgJSWEl (ORCPT ); Mon, 19 Oct 2020 18:04:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56598 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387789AbgJSWEl (ORCPT ); Mon, 19 Oct 2020 18:04:41 -0400 Received: from fieldses.org (fieldses.org [IPv6:2600:3c00:e000:2f7::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D5809C0613CE; Mon, 19 Oct 2020 15:04:40 -0700 (PDT) Received: by fieldses.org (Postfix, from userid 2815) id D2023ABC; Mon, 19 Oct 2020 18:04:39 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org D2023ABC DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1603145079; bh=pHT45ccTuok+op00pL2TV3tQJKjTMnhWNMf1KA4PwoU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=G1OgnST/gN2QkFK5f+2holxaHhBR6QuKfzIhisMVa7tAz3OfpkgU8JVkFDoLpXxZw y9+o7IYVilw+iuqGnAkz5ERfab+Qd8BaKfyWzX0qTKBYvGPatc6d1MwforBM9rELe4 gnDKlL8CExdro9VlcbbLUrHl7fA/fh0maiSNc7NY= Date: Mon, 19 Oct 2020 18:04:39 -0400 From: "J. Bruce Fields" To: Martijn de Gouw Cc: Trond Myklebust , Anna Schumaker , Chuck Lever , "David S. Miller" , Jakub Kicinski , Arnd Bergmann , NeilBrown , Alexey Dobriyan , Roberto Bergantinos Corpas , "open list:NFS, SUNRPC, AND LOCKD CLIENTS" , "open list:NETWORKING [GENERAL]" , open list Subject: Re: [PATCH] SUNRPC: fix copying of multiple pages in gss_read_proxy_verf() Message-ID: <20201019220439.GC6692@fieldses.org> References: <20201019114229.52973-1-martijn.de.gouw@prodrive-technologies.com> <20201019152301.GC32403@fieldses.org> <834dc52b-34fc-fee5-0274-fdc8932040e6@prodrive-technologies.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <834dc52b-34fc-fee5-0274-fdc8932040e6@prodrive-technologies.com> User-Agent: Mutt/1.5.21 (2010-09-15) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Oct 19, 2020 at 03:46:39PM +0000, Martijn de Gouw wrote: > Hi > > On 19-10-2020 17:23, J. Bruce Fields wrote: > > On Mon, Oct 19, 2020 at 01:42:27PM +0200, Martijn de Gouw wrote: > >> When the passed token is longer than 4032 bytes, the remaining part > >> of the token must be copied from the rqstp->rq_arg.pages. But the > >> copy must make sure it happens in a consecutive way. > > > > Thanks. Apologies, but I don't immediately see where the copy is > > non-consecutive. What exactly is the bug in the existing code? > > In the first memcpy 'length' bytes are copied from argv->iobase, but > since the header is in front, this never fills the whole first page of > in_token->pages. > > The memcpy in the loop copies the following bytes, but starts writing at > the next page of in_token->pages. This leaves the last bytes of page 0 > unwritten. > > Next to that, the remaining data is in page 0 of rqstp->rq_arg.pages, > not page 1. Got it, thanks. Looks like the culprit might be a patch from a year ago from Chuck, 5866efa8cbfb "SUNRPC: Fix svcauth_gss_proxy_init()"? At least, that's the last major patch to touch this code. --b. > > Regards, Martijn > > > > > --b. > > > >> > >> Signed-off-by: Martijn de Gouw > >> --- > >> net/sunrpc/auth_gss/svcauth_gss.c | 27 +++++++++++++++++---------- > >> 1 file changed, 17 insertions(+), 10 deletions(-) > >> > >> diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c > >> index 258b04372f85..bd4678db9d76 100644 > >> --- a/net/sunrpc/auth_gss/svcauth_gss.c > >> +++ b/net/sunrpc/auth_gss/svcauth_gss.c > >> @@ -1147,9 +1147,9 @@ static int gss_read_proxy_verf(struct svc_rqst *rqstp, > >> struct gssp_in_token *in_token) > >> { > >> struct kvec *argv = &rqstp->rq_arg.head[0]; > >> - unsigned int page_base, length; > >> - int pages, i, res; > >> - size_t inlen; > >> + unsigned int length, pgto_offs, pgfrom_offs; > >> + int pages, i, res, pgto, pgfrom; > >> + size_t inlen, to_offs, from_offs; > >> > >> res = gss_read_common_verf(gc, argv, authp, in_handle); > >> if (res) > >> @@ -1177,17 +1177,24 @@ static int gss_read_proxy_verf(struct svc_rqst *rqstp, > >> memcpy(page_address(in_token->pages[0]), argv->iov_base, length); > >> inlen -= length; > >> > >> - i = 1; > >> - page_base = rqstp->rq_arg.page_base; > >> + to_offs = length; > >> + from_offs = rqstp->rq_arg.page_base; > >> while (inlen) { > >> - length = min_t(unsigned int, inlen, PAGE_SIZE); > >> - memcpy(page_address(in_token->pages[i]), > >> - page_address(rqstp->rq_arg.pages[i]) + page_base, > >> + pgto = to_offs >> PAGE_SHIFT; > >> + pgfrom = from_offs >> PAGE_SHIFT; > >> + pgto_offs = to_offs & ~PAGE_MASK; > >> + pgfrom_offs = from_offs & ~PAGE_MASK; > >> + > >> + length = min_t(unsigned int, inlen, > >> + min_t(unsigned int, PAGE_SIZE - pgto_offs, > >> + PAGE_SIZE - pgfrom_offs)); > >> + memcpy(page_address(in_token->pages[pgto]) + pgto_offs, > >> + page_address(rqstp->rq_arg.pages[pgfrom]) + pgfrom_offs, > >> length); > >> > >> + to_offs += length; > >> + from_offs += length; > >> inlen -= length; > >> - page_base = 0; > >> - i++; > >> } > >> return 0; > >> } > >> -- > >> 2.20.1 > > -- > Martijn de Gouw > Designer > Prodrive Technologies > Mobile: +31 63 17 76 161 > Phone: +31 40 26 76 200