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=-6.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 2302BC004C9 for ; Tue, 7 May 2019 10:50:36 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EC9012054F for ; Tue, 7 May 2019 10:50:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EC9012054F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:44389 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hNxgB-00078m-8w for qemu-devel@archiver.kernel.org; Tue, 07 May 2019 06:50:35 -0400 Received: from eggs.gnu.org ([209.51.188.92]:32960) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hNxf0-0006fv-EJ for qemu-devel@nongnu.org; Tue, 07 May 2019 06:49:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hNxez-0006fU-Au for qemu-devel@nongnu.org; Tue, 07 May 2019 06:49:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37214) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hNxez-0006f2-4p for qemu-devel@nongnu.org; Tue, 07 May 2019 06:49:21 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6B6A988305; Tue, 7 May 2019 10:49:20 +0000 (UTC) Received: from [10.40.204.24] (ovpn-204-24.brq.redhat.com [10.40.204.24]) by smtp.corp.redhat.com (Postfix) with ESMTP id A32525B099; Tue, 7 May 2019 10:49:19 +0000 (UTC) To: Richard Henderson , qemu-devel@nongnu.org References: <20190506173353.32206-1-richard.henderson@linaro.org> <20190506173353.32206-10-richard.henderson@linaro.org> From: Laurent Vivier Message-ID: Date: Tue, 7 May 2019 12:49:18 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20190506173353.32206-10-richard.henderson@linaro.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Tue, 07 May 2019 10:49:20 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v4 09/24] ui/vnc: Use gcrypto_random_bytes for start_auth_vnc X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 06/05/2019 19:33, Richard Henderson wrote: > Use a better interface for random numbers than rand(). > Fail gracefully if for some reason we cannot use the crypto system. >=20 > Reviewed-by: Philippe Mathieu-Daud=C3=A9 > Reviewed-by: Gerd Hoffmann > Reviewed-by: Daniel P. Berrang=C3=A9 > Signed-off-by: Richard Henderson > --- > v2: Use qcrypto_random_bytes, not qemu_getrandom, as there is > no need for deterministic results for this interface. > v3: Fail gracefully in the event qcrypto_random_bytes fails. > --- > ui/vnc.c | 22 +++++++++++----------- > 1 file changed, 11 insertions(+), 11 deletions(-) >=20 > diff --git a/ui/vnc.c b/ui/vnc.c > index 785edf3af1..d83f4a6ff9 100644 > --- a/ui/vnc.c > +++ b/ui/vnc.c > @@ -43,6 +43,7 @@ > #include "crypto/hash.h" > #include "crypto/tlscredsanon.h" > #include "crypto/tlscredsx509.h" > +#include "crypto/random.h" > #include "qom/object_interfaces.h" > #include "qemu/cutils.h" > #include "io/dns-resolver.h" > @@ -2547,16 +2548,6 @@ static void authentication_failed(VncState *vs) > vnc_client_error(vs); > } > =20 > -static void make_challenge(VncState *vs) > -{ > - int i; > - > - srand(time(NULL)+getpid()+getpid()*987654+rand()); > - > - for (i =3D 0 ; i < sizeof(vs->challenge) ; i++) > - vs->challenge[i] =3D (int) (256.0*rand()/(RAND_MAX+1.0)); > -} > - > static int protocol_client_auth_vnc(VncState *vs, uint8_t *data, size= _t len) > { > unsigned char response[VNC_AUTH_CHALLENGE_SIZE]; > @@ -2628,7 +2619,16 @@ reject: > =20 > void start_auth_vnc(VncState *vs) > { > - make_challenge(vs); > + Error *err =3D NULL; > + > + if (qcrypto_random_bytes(vs->challenge, sizeof(vs->challenge), &er= r)) { > + trace_vnc_auth_fail(vs, vs->auth, "cannot get random bytes", > + error_get_pretty(err)); > + error_free(err); > + authentication_failed(vs); > + return; > + } > + This part is weird for me: if auth fails we send "vnc_write_u32(vs, 1)"=20 but if it succeeds we send the challenge. There is no success value to=20 send (like "vnc_write_u32(vs, 0)") ? > /* Send client a 'random' challenge */ > vnc_write(vs, vs->challenge, sizeof(vs->challenge)); > vnc_flush(vs); >=20