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 B08C3C44527 for ; Mon, 20 Jul 2026 10:39:32 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wllOo-0003mr-3q; Mon, 20 Jul 2026 06:39:02 -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 1wllOf-0003kl-E9 for qemu-devel@nongnu.org; Mon, 20 Jul 2026 06:38:53 -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 1wllOc-0008H3-Mm for qemu-devel@nongnu.org; Mon, 20 Jul 2026 06:38:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1784543930; 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=hmMOrL1qy0em1clNfQjUh4hOg8rqOth/0bemYGgGW1Y=; b=AEK866STj6F9FMfIALLrtyT49ulFN4ULkt3sslFWj8A8ni+xAi6KtMKt+slruWG4zqoRNX VUqb7UYbIVyrAu+NjTlzMOddHNa+zxJroQnZy8X4dNa+LNswUV2wu1s472VK8pcvnL6blI f0gfwtJ0L7qvXAiD7sMVIHURJTbOvNs= Received: from mx-prod-mc-03.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-219-wkUA_KIbPvyOda2kUdcJyQ-1; Mon, 20 Jul 2026 06:38:48 -0400 X-MC-Unique: wkUA_KIbPvyOda2kUdcJyQ-1 X-Mimecast-MFC-AGG-ID: wkUA_KIbPvyOda2kUdcJyQ_1784543927 Received: from mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.95]) (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-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9D4F81944E45 for ; Mon, 20 Jul 2026 10:38:47 +0000 (UTC) Received: from thuth-p1g4.redhat.com (unknown [10.44.34.82]) by mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 513611588; Mon, 20 Jul 2026 10:38:46 +0000 (UTC) From: Thomas Huth To: qemu-devel@nongnu.org, Stefan Hajnoczi Cc: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Subject: [PULL 5/7] usbredir: fix infinite loop and SIGFPE with zero max_packet_size Date: Mon, 20 Jul 2026 12:38:31 +0200 Message-ID: <20260720103833.364506-6-thuth@redhat.com> In-Reply-To: <20260720103833.364506-1-thuth@redhat.com> References: <20260720103833.364506-1-thuth@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.6 on 10.30.177.95 Received-SPF: permerror client-ip=170.10.129.124; envelope-from=thuth@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=-0.01, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, T_SPF_PERMERROR=0.01 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: Marc-André Lureau A malicious usbredir peer can send an ep_info message resetting max_packet_size to 0 after bulk receiving has started. This causes: - infinite loop in usbredir_buffered_bulk_packet() where the splitting loop increments by max_packet_size (0) - SIGFPE in usbredir_buffered_bulk_in_complete_ftdi() from modulo by 0 - SIGFPE in usbredir_handle_buffered_bulk_in_data() from division by 0 when computing bytes_per_transfer Fix by stopping and disabling bulk receiving in usbredir_ep_info() when max_packet_size is set to 0. Add post-load check, and assert() for the invariant. Fixes: CVE-2026-63319 Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/3995 Reported-by: Tristan @TristanInSec Signed-off-by: Marc-André Lureau Reviewed-by: Thomas Huth Message-ID: <20260716141107.3597076-1-marcandre.lureau@redhat.com> Signed-off-by: Thomas Huth --- hw/usb/redirect.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/hw/usb/redirect.c b/hw/usb/redirect.c index 284bcbdb34d..dfd9e8bb50c 100644 --- a/hw/usb/redirect.c +++ b/hw/usb/redirect.c @@ -690,6 +690,7 @@ static void usbredir_buffered_bulk_in_complete_ftdi(USBRedirDevice *dev, struct buf_packet *bulkp; int count; + assert(maxp != 0); while ((bulkp = QTAILQ_FIRST(&dev->endpoint[EP2I(ep)].bufpq)) && p->actual_length < p->iov.size && p->status == USB_RET_SUCCESS) { if (bulkp->len < 2) { @@ -739,6 +740,7 @@ static void usbredir_handle_buffered_bulk_in_data(USBRedirDevice *dev, .stream_id = 0, .no_transfers = 5, }; + assert(dev->endpoint[EP2I(ep)].max_packet_size != 0); /* Round bytes_per_transfer up to a multiple of max_packet_size */ bpt = 512 + dev->endpoint[EP2I(ep)].max_packet_size - 1; bpt /= dev->endpoint[EP2I(ep)].max_packet_size; @@ -793,6 +795,7 @@ static void usbredir_handle_bulk_data(USBRedirDevice *dev, USBPacket *p, } if (dev->endpoint[EP2I(ep)].bulk_receiving_enabled) { + assert(maxp != 0); if (size != 0 && (size % maxp) == 0) { usbredir_handle_buffered_bulk_in_data(dev, p, ep); return; @@ -1796,6 +1799,17 @@ static void usbredir_ep_info(void *priv, if (usbredirparser_peer_has_cap(dev->parser, usb_redir_cap_ep_info_max_packet_size)) { dev->endpoint[i].max_packet_size = ep_info->max_packet_size[i]; + if (ep_info->max_packet_size[i] == 0 && + dev->endpoint[i].bulk_receiving_enabled) { + USBPacket *p = dev->endpoint[i].pending_async_packet; + usbredir_stop_bulk_receiving(dev, I2EP(i)); + dev->endpoint[i].bulk_receiving_enabled = 0; + if (p != NULL) { + dev->endpoint[i].pending_async_packet = NULL; + p->status = USB_RET_IOERROR; + usb_packet_complete(&dev->dev, p); + } + } } #if USBREDIR_VERSION >= 0x000700 if (usbredirparser_peer_has_cap(dev->parser, @@ -2156,6 +2170,7 @@ static void usbredir_buffered_bulk_packet(void *priv, uint64_t id, } /* Data must be in maxp chunks for buffered_bulk_add_*_data_to_packet */ + assert(dev->endpoint[EP2I(ep)].max_packet_size != 0); len = dev->endpoint[EP2I(ep)].max_packet_size; status = usb_redir_success; free_on_destroy = NULL; @@ -2239,6 +2254,15 @@ static int usbredir_post_load(void *priv, int version_id) usbredir_setup_usb_eps(dev); usbredir_check_bulk_receiving(dev); + for (int i = 0; i < MAX_ENDPOINTS; i++) { + if (dev->endpoint[i].bulk_receiving_started && + dev->endpoint[i].max_packet_size == 0) { + error_report("usbredir: endpoint %d has bulk receiving started " + "with zero max_packet_size", i); + return -EINVAL; + } + } + return 0; } -- 2.55.0