From patchwork Wed Dec 30 16:20:44 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alan Stern X-Patchwork-Id: 355438 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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_SANE_1 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 86EDAC433DB for ; Wed, 30 Dec 2020 16:21:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4B0E220780 for ; Wed, 30 Dec 2020 16:21:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726524AbgL3QVZ (ORCPT ); Wed, 30 Dec 2020 11:21:25 -0500 Received: from netrider.rowland.org ([192.131.102.5]:55779 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1726290AbgL3QVZ (ORCPT ); Wed, 30 Dec 2020 11:21:25 -0500 Received: (qmail 728335 invoked by uid 1000); 30 Dec 2020 11:20:44 -0500 Date: Wed, 30 Dec 2020 11:20:44 -0500 From: Alan Stern To: Greg KH , Felipe Balbi Cc: gustavoars@kernel.org, USB mailing list , syzkaller-bugs@googlegroups.com Subject: [PATCH] USB: Gadget: dummy-hcd: Fix shift-out-of-bounds bug Message-ID: <20201230162044.GA727759@rowland.harvard.edu> References: <20201229164314.GB694118@rowland.harvard.edu> <0000000000009f3cf405b79d5267@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <0000000000009f3cf405b79d5267@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org The dummy-hcd driver was written under the assumption that all the parameters in URBs sent to its root hub would be valid. With URBs sent from userspace via usbfs, that assumption can be violated. In particular, the driver doesn't fully check the port-feature values stored in the wValue entry of Clear-Port-Feature and Set-Port-Feature requests. Values that are too large can cause the driver to perform an invalid left shift of more than 32 bits. Ironically, two of those left shifts are unnecessary, because they implement Set-Port-Feature requests that hubs are not required to support, according to section 11.24.2.13 of the USB-2.0 spec. This patch adds the appropriate checks for the port feature selector values and removes the unnecessary feature settings. It also rejects requests to set the TEST feature or to set or clear the INDICATOR and C_OVERCURRENT features, as none of these are relevant to dummy-hcd's root-hub emulation. Reported-and-tested-by: syzbot+5925509f78293baa7331@syzkaller.appspotmail.com Signed-off-by: Alan Stern CC: --- [as1951] drivers/usb/gadget/udc/dummy_hcd.c | 35 +++++++++++++++++++++++------------ 1 file changed, 23 insertions(+), 12 deletions(-) Index: usb-devel/drivers/usb/gadget/udc/dummy_hcd.c =================================================================== --- usb-devel.orig/drivers/usb/gadget/udc/dummy_hcd.c +++ usb-devel/drivers/usb/gadget/udc/dummy_hcd.c @@ -2114,9 +2114,21 @@ static int dummy_hub_control( dum_hcd->port_status &= ~USB_PORT_STAT_POWER; set_link_state(dum_hcd); break; - default: + case USB_PORT_FEAT_ENABLE: + case USB_PORT_FEAT_C_ENABLE: + case USB_PORT_FEAT_C_SUSPEND: + /* Not allowed for USB-3 */ + if (hcd->speed == HCD_USB3) + goto error; + fallthrough; + case USB_PORT_FEAT_C_CONNECTION: + case USB_PORT_FEAT_C_RESET: dum_hcd->port_status &= ~(1 << wValue); set_link_state(dum_hcd); + break; + default: + /* Disallow INDICATOR and C_OVER_CURRENT */ + goto error; } break; case GetHubDescriptor: @@ -2277,18 +2289,17 @@ static int dummy_hub_control( */ dum_hcd->re_timeout = jiffies + msecs_to_jiffies(50); fallthrough; + case USB_PORT_FEAT_C_CONNECTION: + case USB_PORT_FEAT_C_RESET: + case USB_PORT_FEAT_C_ENABLE: + case USB_PORT_FEAT_C_SUSPEND: + /* Not allowed for USB-3, and ignored for USB-2 */ + if (hcd->speed == HCD_USB3) + goto error; + break; default: - if (hcd->speed == HCD_USB3) { - if ((dum_hcd->port_status & - USB_SS_PORT_STAT_POWER) != 0) { - dum_hcd->port_status |= (1 << wValue); - } - } else - if ((dum_hcd->port_status & - USB_PORT_STAT_POWER) != 0) { - dum_hcd->port_status |= (1 << wValue); - } - set_link_state(dum_hcd); + /* Disallow TEST, INDICATOR, and C_OVER_CURRENT */ + goto error; } break; case GetPortErrorCount: