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=-11.6 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,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 4A411C433E0 for ; Fri, 24 Jul 2020 20:28:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 15A5D206F6 for ; Fri, 24 Jul 2020 20:28:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fieldses.org header.i=@fieldses.org header.b="TI0/HcHq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726553AbgGXU23 (ORCPT ); Fri, 24 Jul 2020 16:28:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47106 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726397AbgGXU23 (ORCPT ); Fri, 24 Jul 2020 16:28:29 -0400 Received: from fieldses.org (fieldses.org [IPv6:2600:3c00:e000:2f7::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 65427C0619D3 for ; Fri, 24 Jul 2020 13:28:29 -0700 (PDT) Received: by fieldses.org (Postfix, from userid 2815) id 28EC11C79; Fri, 24 Jul 2020 16:28:27 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org 28EC11C79 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1595622507; bh=1uanzv4u/6A0uIHTkBrKiSc/04s4Y+mAgOdMqyClhs4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=TI0/HcHqIFumukUaC1JwvdPyk8sqqkJhFTxpkDXXdLxAXP9t7JwMwwKB8jo4WgVfI WgVFxqaQufInl9pqWK/6deGZCTeQKJmtxF7OZ1uPie/WmrOOoq+bcmQTlYbBqka8Bl VRGlgXazATBVpP/d6Nkwb+toggjC8A+qUZlcChKQ= Date: Fri, 24 Jul 2020 16:28:27 -0400 From: "J. Bruce Fields" To: Chuck Lever Cc: linux-nfs@vger.kernel.org Subject: Re: [PATCH v2] SUNRPC: Fix ("SUNRPC: Add "@len" parameter to gss_unwrap()") Message-ID: <20200724202827.GA9244@fieldses.org> References: <159561664051.1673.12679579228291628238.stgit@klimt.1015granger.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <159561664051.1673.12679579228291628238.stgit@klimt.1015granger.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Fri, Jul 24, 2020 at 02:55:07PM -0400, Chuck Lever wrote: > Braino when converting "buf->len -=" to "buf->len = len -". > > The result is under-estimation of the ralign and rslack values. On > krb5p mounts, this has caused READDIR to fail with EIO, and KASAN > splats when decoding READLINK replies. > > As a result of fixing this oversight, the gss_unwrap method now > returns a buf->len that can be shorter than priv_len for small > RPC messages. The additional adjustment done in unwrap_priv_data() > can underflow buf->len. This causes the nfsd_request_too_large > check to fail during some NFSv3 operations. > > Reported-by: Marian Rainer-Harbach > Reported-by: Pierre Sauter > BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1886277 > Fixes: 31c9590ae468 ("SUNRPC: Add "@len" parameter to gss_unwrap()") > Signed-off-by: Chuck Lever > --- > net/sunrpc/auth_gss/gss_krb5_wrap.c | 2 +- > net/sunrpc/auth_gss/svcauth_gss.c | 1 - > 2 files changed, 1 insertion(+), 2 deletions(-) > > Hi Bruce- > > I can take this in v5.9 if you agree it's a righteous fix. Righteous! Well, seems like a reasonable step, anyway. I just wish I had a more complete understanding. Anyway, Reviewed-by: J. Bruce Fields --b. > Changes since RFC: > - series squashed into a single patch > - "pad" is still calculated in unwrap_priv_data for later use > > diff --git a/net/sunrpc/auth_gss/gss_krb5_wrap.c b/net/sunrpc/auth_gss/gss_krb5_wrap.c > index cf0fd170ac18..90b8329fef82 100644 > --- a/net/sunrpc/auth_gss/gss_krb5_wrap.c > +++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c > @@ -584,7 +584,7 @@ gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, int len, > buf->head[0].iov_len); > memmove(ptr, ptr + GSS_KRB5_TOK_HDR_LEN + headskip, movelen); > buf->head[0].iov_len -= GSS_KRB5_TOK_HDR_LEN + headskip; > - buf->len = len - GSS_KRB5_TOK_HDR_LEN + headskip; > + buf->len = len - (GSS_KRB5_TOK_HDR_LEN + headskip); > > /* Trim off the trailing "extra count" and checksum blob */ > xdr_buf_trim(buf, ec + GSS_KRB5_TOK_HDR_LEN + tailskip); > diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c > index 7d83f54aaaa6..258b04372f85 100644 > --- a/net/sunrpc/auth_gss/svcauth_gss.c > +++ b/net/sunrpc/auth_gss/svcauth_gss.c > @@ -990,7 +990,6 @@ unwrap_priv_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct gs > > maj_stat = gss_unwrap(ctx, 0, priv_len, buf); > pad = priv_len - buf->len; > - buf->len -= pad; > /* The upper layers assume the buffer is aligned on 4-byte boundaries. > * In the krb5p case, at least, the data ends up offset, so we need to > * move it around. */ >