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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 225CAC433F5 for ; Mon, 24 Jan 2022 19:12:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345308AbiAXTL6 (ORCPT ); Mon, 24 Jan 2022 14:11:58 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:60190 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344119AbiAXTDs (ORCPT ); Mon, 24 Jan 2022 14:03:48 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 160C3B8121F; Mon, 24 Jan 2022 19:03:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 37B45C340E5; Mon, 24 Jan 2022 19:03:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643051025; bh=7Jxp6D6htDCCccYyU2JW7clNMIT81xHBMJgawc9qhac=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wl7eGZzFa3+txvPB5u9IIuX4lUyp6royOSONPSbjxr2HIEc0LgNGz7xScYoHKX/hN XCzTFlXjRCsSmPN87Jq+xTypBL92hEAI7ylwNetIq1yJY5rL/LczQbkFsMY/rCC65b ikwzVyAQ0cMMJGcNPSkFZichAeO7B9W5NGJl+0tE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alan Stern , syzbot+3ae6a2b06f131ab9849f@syzkaller.appspotmail.com Subject: [PATCH 4.14 003/186] USB: Fix "slab-out-of-bounds Write" bug in usb_hcd_poll_rh_status Date: Mon, 24 Jan 2022 19:41:18 +0100 Message-Id: <20220124183937.218520473@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124183937.101330125@linuxfoundation.org> References: <20220124183937.101330125@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Alan Stern commit 1d7d4c07932e04355d6e6528d44a2f2c9e354346 upstream. When the USB core code for getting root-hub status reports was originally written, it was assumed that the hub driver would be its only caller. But this isn't true now; user programs can use usbfs to communicate with root hubs and get status reports. When they do this, they may use a transfer_buffer that is smaller than the data returned by the HCD, which will lead to a buffer overflow error when usb_hcd_poll_rh_status() tries to store the status data. This was discovered by syzbot: BUG: KASAN: slab-out-of-bounds in memcpy include/linux/fortify-string.h:225 [inline] BUG: KASAN: slab-out-of-bounds in usb_hcd_poll_rh_status+0x5f4/0x780 drivers/usb/core/hcd.c:776 Write of size 2 at addr ffff88801da403c0 by task syz-executor133/4062 This patch fixes the bug by reducing the amount of status data if it won't fit in the transfer_buffer. If some data gets discarded then the URB's completion status is set to -EOVERFLOW rather than 0, to let the user know what happened. Reported-and-tested-by: syzbot+3ae6a2b06f131ab9849f@syzkaller.appspotmail.com Signed-off-by: Alan Stern Cc: Link: https://lore.kernel.org/r/Yc+3UIQJ2STbxNua@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hcd.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) --- a/drivers/usb/core/hcd.c +++ b/drivers/usb/core/hcd.c @@ -761,6 +761,7 @@ void usb_hcd_poll_rh_status(struct usb_h { struct urb *urb; int length; + int status; unsigned long flags; char buffer[6]; /* Any root hubs with > 31 ports? */ @@ -778,11 +779,17 @@ void usb_hcd_poll_rh_status(struct usb_h if (urb) { clear_bit(HCD_FLAG_POLL_PENDING, &hcd->flags); hcd->status_urb = NULL; + if (urb->transfer_buffer_length >= length) { + status = 0; + } else { + status = -EOVERFLOW; + length = urb->transfer_buffer_length; + } urb->actual_length = length; memcpy(urb->transfer_buffer, buffer, length); usb_hcd_unlink_urb_from_ep(hcd, urb); - usb_hcd_giveback_urb(hcd, urb, 0); + usb_hcd_giveback_urb(hcd, urb, status); } else { length = 0; set_bit(HCD_FLAG_POLL_PENDING, &hcd->flags);