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 Received: from lists1p.gnu.org (lists1p.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 E77E1C79F87 for ; Fri, 4 Sep 2026 11:00:58 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1x2ReB-0004Wj-6k; Fri, 04 Sep 2026 06:59:51 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1x2ReA-0004WW-EL for qemu-devel@nongnu.org; Fri, 04 Sep 2026 06:59:50 -0400 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 1x2Re9-0007bj-1q for qemu-devel@nongnu.org; Fri, 04 Sep 2026 06:59:50 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1788519588; 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: in-reply-to:in-reply-to:references:references; bh=24q1MZ0ugZdhngBNFVmvW75PJPqXcwOs83tFjUN7CUc=; b=fM4+tBYWjLIhDqHaGxkgbpolkV/47LZUDKL3sfik8imJ07chcfZ+ayr5R2NnTb5H4Sr/l7 3gOC5skZLM5RhzPf+zjDEQ1nluScL6zuwop2S1mKWo4ujRyRTHvVkKKe6Upb2y7QqYUbAT 1vkJzaNIxKlgcGbc4w3sGq0MKOKYQSs= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-563-xjwH6UXXOaugC4KFNYdQGw-1; Fri, 04 Sep 2026 06:59:47 -0400 X-MC-Unique: xjwH6UXXOaugC4KFNYdQGw-1 X-Mimecast-MFC-AGG-ID: xjwH6UXXOaugC4KFNYdQGw_1788519586 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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 mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id CAE8519540DB; Fri, 4 Sep 2026 10:59:45 +0000 (UTC) Received: from berrange.csb (headnet03.pony-001.prod.iad2.dc.redhat.com [10.2.32.114]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id A301418005BD; Fri, 4 Sep 2026 10:59:43 +0000 (UTC) From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= To: qemu-devel@nongnu.org Cc: =?UTF-8?q?Alex=20Benn=C3=A9e?= , Pierrick Bouvier , devel@lists.libvirt.org, =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Paolo Bonzini , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , qemu-stable@nongnu.org, "Denis V. Lunev" Subject: [PULL 05/13] io/channel-websock: send an HTTP 400 when the greeting has no space Date: Fri, 4 Sep 2026 11:59:21 +0100 Message-ID: <20260904105929.3450663-6-berrange@redhat.com> In-Reply-To: <20260904105929.3450663-1-berrange@redhat.com> References: <20260904105929.3450663-1-berrange@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 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: 12 X-Spam_score: 1.2 X-Spam_bar: + X-Spam_report: (1.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_H2=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development 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 From: Denis V. Lunev qio_channel_websock_extract_headers() returns 0 without queueing a response when the request line contains no space, unlike every sibling check which jumps to bad_request. encoutput stays empty, yet qio_channel_websock_handshake_read() still reports success and the caller arms a G_IO_OUT watch to flush nothing. Flushing that empty buffer is where QEMU crashes. Any client can trigger it before authentication on a VNC websocket port: printf 'stats\r\nx\r\n\r\n' | nc $host $port Fixes: 07e95cd529af ("io: fully parse & validate HTTP headers for websocket protocol handshake") Fixes: f69a8bde2935 ("io: send proper HTTP response for websocket errors") Fixes: CVE-2026-84788 Cc: qemu-stable@nongnu.org Cc: Daniel P. Berrangé Cc: Marc-André Lureau Reviewed-by: Daniel P. Berrangé Reviewed-by: Marc-André Lureau Signed-off-by: Denis V. Lunev Signed-off-by: Daniel P. Berrangé --- io/channel-websock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/io/channel-websock.c b/io/channel-websock.c index 1929abf56a..66c91ed2a2 100644 --- a/io/channel-websock.c +++ b/io/channel-websock.c @@ -230,7 +230,7 @@ qio_channel_websock_extract_headers(QIOChannelWebsock *ioc, tmp = strchr(buffer, ' '); if (!tmp) { error_setg(errp, "Missing HTTP path delimiter"); - return 0; + goto bad_request; } *tmp = '\0'; -- 2.55.0