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 0E2A0C433EF for ; Fri, 7 Jan 2022 10:06:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346644AbiAGKGz (ORCPT ); Fri, 7 Jan 2022 05:06:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41096 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346613AbiAGKGz (ORCPT ); Fri, 7 Jan 2022 05:06:55 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D7AB9C061245; Fri, 7 Jan 2022 02:06:54 -0800 (PST) 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 7AB27B81F80; Fri, 7 Jan 2022 10:06:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9557DC36AE0; Fri, 7 Jan 2022 10:06:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1641550012; bh=dbXWvgtCasKfVtJH5uVkp9Vf74ZRziPbM2Ato3R4ZzQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Rdb7rAYA19kw0YA20UnHia29Qi3HST9LHf/be6joqDkXIGYziDOqKqjyUjqLB5znR eITl3R3+EP8sc7+u70BvNetujaFUCGTk5DUkh9zpRDFBs2tK/AuYpqykAEGVXb0jkx j4ptn29mCvzkTr6fbZ3S+r/em4CL5JqCoZSRIWW8= Date: Fri, 7 Jan 2022 11:06:49 +0100 From: Greg KH To: Pavel Skripkin Cc: davem@davemloft.net, kuba@kernel.org, tanghui20@huawei.com, andrew@lunn.ch, oneukum@suse.com, arnd@arndb.de, linux-usb@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+003c0a286b9af5412510@syzkaller.appspotmail.com Subject: Re: [PATCH] net: mcs7830: handle usb read errors properly Message-ID: References: <20220106225716.7425-1-paskripkin@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220106225716.7425-1-paskripkin@gmail.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Jan 07, 2022 at 01:57:16AM +0300, Pavel Skripkin wrote: > Syzbot reported uninit value in mcs7830_bind(). The problem was in > missing validation check for bytes read via usbnet_read_cmd(). > > usbnet_read_cmd() internally calls usb_control_msg(), that returns > number of bytes read. Code should validate that requested number of bytes > was actually read. > > So, this patch adds missing size validation check inside > mcs7830_get_reg() to prevent uninit value bugs > > CC: Arnd Bergmann > Reported-and-tested-by: syzbot+003c0a286b9af5412510@syzkaller.appspotmail.com > Fixes: 2a36d7083438 ("USB: driver for mcs7830 (aka DeLOCK) USB ethernet adapter") > Signed-off-by: Pavel Skripkin > --- > > @Arnd, I am not sure about mcs7830_get_rev() function. > > Is get_reg(22, 2) == 1 valid read? If so, I think, we should call > usbnet_read_cmd() directly here, since other callers care only about > negative error values. > > Thanks > > > --- > drivers/net/usb/mcs7830.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/usb/mcs7830.c b/drivers/net/usb/mcs7830.c > index 326cc4e749d8..fdda0616704e 100644 > --- a/drivers/net/usb/mcs7830.c > +++ b/drivers/net/usb/mcs7830.c > @@ -108,8 +108,16 @@ static const char driver_name[] = "MOSCHIP usb-ethernet driver"; > > static int mcs7830_get_reg(struct usbnet *dev, u16 index, u16 size, void *data) > { > - return usbnet_read_cmd(dev, MCS7830_RD_BREQ, MCS7830_RD_BMREQ, > - 0x0000, index, data, size); > + int ret; > + > + ret = usbnet_read_cmd(dev, MCS7830_RD_BREQ, MCS7830_RD_BMREQ, > + 0x0000, index, data, size); > + if (ret < 0) > + return ret; > + else if (ret < size) > + return -ENODATA; We have a usb core function that handles these "short reads are an error" issue. Perhaps usbnet_read_cmd() should be converted to use it instead? thanks, greg k-h