From patchwork Mon Jan 15 09:51:19 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= X-Patchwork-Id: 13519435 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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C0AD5C3DA79 for ; Mon, 15 Jan 2024 09:51:46 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rPJd0-0006Ds-JC; Mon, 15 Jan 2024 04:51:34 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rPJcx-00069C-Kd for qemu-devel@nongnu.org; Mon, 15 Jan 2024 04:51:31 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rPJcw-0002qx-06 for qemu-devel@nongnu.org; Mon, 15 Jan 2024 04:51:31 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1705312288; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=DvwmNHCQyt34NpybuLwlaeryZi7wm7zvb0vdyD5HB74=; b=FoARwMRqZY27B5qFdZSqL38I7ch9bdQ8qRq0IUhyiIDLRZ3DuTl5Z5ZRXqmwZIS+0Ldv0N 0O+kcz2ADTN62fDVriwp4lNdGjHyoeEyu6QdQH41PwfKGUg1ticZz80+cd6oC5uDSM7DhX 0StjSyPrKH+OtZwBOvO2lDw9i5vC2tc= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-599-uIPGQWqGMHCiuI-ekJBkJw-1; Mon, 15 Jan 2024 04:51:21 -0500 X-MC-Unique: uIPGQWqGMHCiuI-ekJBkJw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2C73E8371C8; Mon, 15 Jan 2024 09:51:21 +0000 (UTC) Received: from toolbox.redhat.com (unknown [10.42.28.53]) by smtp.corp.redhat.com (Postfix) with ESMTP id CF7BD1C060B2; Mon, 15 Jan 2024 09:51:19 +0000 (UTC) From: =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= To: qemu-devel@nongnu.org Cc: Fiona Ebner , Markus Frank , Gerd Hoffmann , =?utf-8?q?Marc-Andr=C3=A9_Lureau?= , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= Subject: [PATCH] ui: reject extended clipboard message if not activated Date: Mon, 15 Jan 2024 09:51:19 +0000 Message-ID: <20240115095119.654271-1-berrange@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -48 X-Spam_score: -4.9 X-Spam_bar: ---- X-Spam_report: (-4.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-2.758, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 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-bounces+qemu-devel=archiver.kernel.org@nongnu.org The extended clipboard message protocol requires that the client activate the extension by requesting a psuedo encoding. If this is not done, then any extended clipboard messages from the client should be considered invalid and the client dropped. Signed-off-by: Daniel P. Berrangé Reviewed-by: Marc-André Lureau --- The need for fix was identified as part of investigation for CVE-2023-6683. This does NOT, however, fix that CVE as it only addresses one of the problem codepaths that can trigger that CVE. ui/vnc.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/ui/vnc.c b/ui/vnc.c index 4f23a0fa79..3b2c71e653 100644 --- a/ui/vnc.c +++ b/ui/vnc.c @@ -2445,6 +2445,11 @@ static int protocol_client_msg(VncState *vs, uint8_t *data, size_t len) } if (read_s32(data, 4) < 0) { + if (!vnc_has_feature(vs, VNC_FEATURE_CLIPBOARD_EXT)) { + error_report("vnc: extended clipboard message while disabled"); + vnc_client_error(vs); + break; + } if (dlen < 4) { error_report("vnc: malformed payload (header less than 4 bytes)" " in extended clipboard pseudo-encoding.");