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 X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 26448C35249 for ; Wed, 5 Feb 2020 07:22:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EDA752082E for ; Wed, 5 Feb 2020 07:22:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725497AbgBEHWb (ORCPT ); Wed, 5 Feb 2020 02:22:31 -0500 Received: from seldsegrel01.sonyericsson.com ([37.139.156.29]:17277 "EHLO SELDSEGREL01.sonyericsson.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725468AbgBEHWb (ORCPT ); Wed, 5 Feb 2020 02:22:31 -0500 X-Greylist: delayed 601 seconds by postgrey-1.27 at vger.kernel.org; Wed, 05 Feb 2020 02:22:30 EST Subject: Re: [PATCH 5.4 17/78] HID: Fix slab-out-of-bounds read in hid_field_extract (Broken!) To: Greg Kroah-Hartman , , Alan Stern , Jiri Kosina CC: , References: <20200114094352.428808181@linuxfoundation.org> <20200114094356.028051662@linuxfoundation.org> From: peter enderborg Message-ID: <27ba705a-6734-9a92-a60c-23e27c9bce6d@sony.com> Date: Wed, 5 Feb 2020 08:12:27 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20200114094356.028051662@linuxfoundation.org> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Language: en-GB X-SEG-SpamProfiler-Analysis: v=2.3 cv=V88DLtvi c=1 sm=1 tr=0 a=T5MYTZSj1jWyQccoVcawfw==:117 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=IkcTkHD0fZMA:10 a=l697ptgUJYAA:10 a=hSkVLCK3AAAA:8 a=VwQbUJbxAAAA:8 a=ag1SF4gXAAAA:8 a=mkI5n4lM7TqXLe6ThCMA:9 a=QEXdDO2ut3YA:10 a=cQPPKAXgyycSBL8etih5:22 a=AjGcO6oz07-iQ99wixmX:22 a=Yupwre4RP9_Eg_Bd0iYG:22 X-SEG-SpamProfiler-Score: 0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On 1/14/20 11:00 AM, Greg Kroah-Hartman wrote: > From: Alan Stern > > commit 8ec321e96e056de84022c032ffea253431a83c3c upstream. > > The syzbot fuzzer found a slab-out-of-bounds bug in the HID report > handler. The bug was caused by a report descriptor which included a > field with size 12 bits and count 4899, for a total size of 7349 > bytes. > > The usbhid driver uses at most a single-page 4-KB buffer for reports. > In the test there wasn't any problem about overflowing the buffer, > since only one byte was received from the device. Rather, the bug > occurred when the HID core tried to extract the data from the report > fields, which caused it to try reading data beyond the end of the > allocated buffer. > > This patch fixes the problem by rejecting any report whose total > length exceeds the HID_MAX_BUFFER_SIZE limit (minus one byte to allow > for a possible report index). In theory a device could have a report > longer than that, but if there was such a thing we wouldn't handle it > correctly anyway. > > Reported-and-tested-by: syzbot+09ef48aa58261464b621@syzkaller.appspotmail.com > Signed-off-by: Alan Stern > CC: > Signed-off-by: Jiri Kosina > Signed-off-by: Greg Kroah-Hartman > > --- > drivers/hid/hid-core.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > --- a/drivers/hid/hid-core.c > +++ b/drivers/hid/hid-core.c > @@ -288,6 +288,12 @@ static int hid_add_field(struct hid_pars > offset = report->size; > report->size += parser->global.report_size * parser->global.report_count; > > + /* Total size check: Allow for possible report index byte */ > + if (report->size > (HID_MAX_BUFFER_SIZE - 1) << 3) { > + hid_err(parser->device, "report is too long\n"); > + return -1; > + } > + > if (!parser->local.usage_index) /* Ignore padding fields */ > return 0; > > > > This patch breaks Elgato StreamDeck.