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=-2.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 CC097C4338F for ; Wed, 18 Aug 2021 16:27:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AA584610CB for ; Wed, 18 Aug 2021 16:27:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229876AbhHRQ2d (ORCPT ); Wed, 18 Aug 2021 12:28:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229780AbhHRQ2c (ORCPT ); Wed, 18 Aug 2021 12:28:32 -0400 Received: from mail-ej1-x634.google.com (mail-ej1-x634.google.com [IPv6:2a00:1450:4864:20::634]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 88963C061764 for ; Wed, 18 Aug 2021 09:27:57 -0700 (PDT) Received: by mail-ej1-x634.google.com with SMTP id z20so6230137ejf.5 for ; Wed, 18 Aug 2021 09:27:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Z80Zd/gcSBuEJU8VgaNn2TIZQx1th4KMYyB+YUjxLJM=; b=g+vKtasUY9Dirx+14jGWh0PBxXL2sGGo0B0rJE9sFE12R9ahdv5ah2kr0dAUh9Yqru ybQZkZbpR8J3pErzEt+rAcsYM3z68tQ0cw9Y+h5X7f0fbm3mp89vwGPbsaEyEeDUNTdk pri8mEJwk13OUhocFrK/KmnX12qzVE2D/P+j0HXPZLDPZ1qhzuYOV2tA4EhJStsumXsS MIwGNnGw9ansDmJS9te5Wc53ioONRHntp6m3ouwsy8JwaHYOVHCsQBPJ12q+Bpyb0i9d YhTTVUakd+eXINdLjX8fRiHzRfarm9UIMdNvoGC4Z1IP7Wi6prsiFZpGqztND6Z9Xrh3 XN1A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Z80Zd/gcSBuEJU8VgaNn2TIZQx1th4KMYyB+YUjxLJM=; b=nSK88RzzwvN/c7yVXlI4yvJVSwbqWwO9W/A22UCasODh+jyVMSuPy/V2Gl24+AP23n 9/QLA192/2gJiFithXRh/LMsHFLpwf73PugDjwsH+F3kijcJNo7f+o607U2jfICD2+GZ LZUgdRxhu4wj1WgSt413YxZUuM3Q0Dn9G40DiaBihDHkU1Vq1Kyaa2D0507zCeDBid2i CyFt40C6/oU6ybbWq9TNXOYpZ57tv/3DmJpb3A2S/j0+6SCi3T3Eu+O3FtVDSZW2DqDs 6VIvdc7NEA0RP5hH5cTmcSgo3XrSdrfdghfrAErBo5/UzcN9IhWZWSDO9PVBAwT48CsP hNkw== X-Gm-Message-State: AOAM533yJdO4rDYnphncOXb62DLITM2yKuRWtpsl1DCI0A8C39ZVhzVJ K/XE32GObmTsn7x/MTbtMC+6D+tWQ9ZvNfAu3z0= X-Google-Smtp-Source: ABdhPJxDlWCvk8qXCibpmlWj3SE5a1Va8VhuQlGNg7oG905cCZMuUVN/53D2pd5DMCcTQHUpXojs9GIQdO/IndnBGoo= X-Received: by 2002:a17:906:c2ca:: with SMTP id ch10mr10609779ejb.203.1629304076115; Wed, 18 Aug 2021 09:27:56 -0700 (PDT) MIME-Version: 1.0 References: <20210818041021.1210797-1-lsahlber@redhat.com> <815daf08-7569-59ce-0318-dfe2b16e1d96@talpey.com> In-Reply-To: <815daf08-7569-59ce-0318-dfe2b16e1d96@talpey.com> From: ronnie sahlberg Date: Thu, 19 Aug 2021 02:27:44 +1000 Message-ID: Subject: Re: Disable key exchange if ARC4 is not available To: Tom Talpey Cc: Ronnie Sahlberg , linux-cifs , Steve French Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org On Wed, Aug 18, 2021 at 11:18 PM Tom Talpey wrote: > > On 8/18/2021 12:10 AM, Ronnie Sahlberg wrote: > > Steve, > > > > We depend on ARC4 for generating the encrypted session key in key exchange. > > This patch disables the key exchange/encrypted session key for ntlmssp > > IF the kernel does not have any ARC4 support. > > > > This allows to build the cifs module even if ARC4 has been removed > > though with a weaker type of NTLMSSP support. > > It's a good goal but it seems wrong to downgrade the security > so silently. Wouldn't it be a better approach to select ARC4, > and thereby force the build to succeed or fail? Alternatively, > change the #ifndef ARC4 to a positive option named (for example) > DOWNGRADED_NTLMSSP or something equally foreboding? > > Tom.