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=-17.4 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,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 02AFCC432BE for ; Thu, 29 Jul 2021 09:45:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D51AE60FD7 for ; Thu, 29 Jul 2021 09:45:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235459AbhG2Jp0 (ORCPT ); Thu, 29 Jul 2021 05:45:26 -0400 Received: from lb1-smtp-cloud8.xs4all.net ([194.109.24.21]:40891 "EHLO lb1-smtp-cloud8.xs4all.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235019AbhG2JpZ (ORCPT ); Thu, 29 Jul 2021 05:45:25 -0400 Received: from cust-b5b5937f ([IPv6:fc0c:c16d:66b8:757f:c639:739b:9d66:799d]) by smtp-cloud8.xs4all.net with ESMTPA id 92bPmQVBPXTlc92bQmWAb2; Thu, 29 Jul 2021 11:45:20 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=xs4all.nl; s=s2; t=1627551920; bh=vbIVqTDTAteecuz2DMVo/JVX+W1bA/dNCU66Lx7X4hQ=; h=Subject:To:From:Message-ID:Date:MIME-Version:Content-Type:From: Subject; b=oj7yqS63iQ8xIlHb6YQBYHE+KFC1OPqMIO2uSUXeJnhSiaLA/P/YGmhVRKK6GymIC dc3sL5xLB4XZnbqtxKr0eTGP1BB3WxT4/vo3NBDcs5n1QmSROu01fWVyGYmD1ZW4vp PkRCNhJfbAzF6kx40MWnun3TsUs5inX5A20u4WtMkzapxYN2wDgBtI8i8DzOBtIPco o02aSaxcEiq4UhrxDZsD+/rhgppOl2BCbQjUqY0c8KKQgBbIlgiRa8Ar2noTrWd3vh AylIMKNeKc2UKWvZ32/4ZhPiqoIu8AW4cWu4t7ChONrqom6YclnVMDNJusmzYIeEUM sZuKF0Auop+GA== Subject: Re: [PATCH v2] media: em28xx: add missing em28xx_close_extension To: Pavel Skripkin , mchehab@kernel.org Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+a6969ef522a36d3344c9@syzkaller.appspotmail.com References: <7df1705e-b2c7-ddfc-9cc5-582fb1a304e5@xs4all.nl> <20210721194307.12155-1-paskripkin@gmail.com> From: Hans Verkuil Message-ID: <3b1de658-ebf0-e45f-49ef-953e3467e7d4@xs4all.nl> Date: Thu, 29 Jul 2021 11:45:19 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210721194307.12155-1-paskripkin@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-CMAE-Envelope: MS4xfKd8PN8J7/4z6Rk4e1ePDXyaG+++PODV2c39F/Q4Syb0lmmnIUmzTpFFugx8QSYNQp207C6WweJSGQkN4lW+pAqnONjyq97UP66u/ADAINzi4C7M4CUD 07Io7n/EwXDJBBinsVPr05P29+ZaJLTjeAcm2uk60o6QJhA8Rdm+fDcZMKCjyA5M/DZgMh4I3vvPWwpPdBS6vI97twj8mdaq6L3/2cHpxa8FycfAkJWTglPe ZYozeKYYKgn3o5Mw8dwn4+xhbpaDW/0YcwQ7x8ReBk5DAvaaSxxHcEK9+48PgG6Vmn3FBYOW8IMVcvyW1RfAmj1K4y+gyFPyX6aPtSssmyeSwmzbiwGaDooE 6I5+vCiJ4QeeLVj+t/0BkTQEG1EnttHDQnrVO95zCSsYsRlpFSxvUNtbJ7zsFWwqG55Pf+GovQ0pBwrVb55mH2T2ztwMjlmqMCQ2VlhUdkkae7stWducgEOx 4bX7hHCAvWKNYvd8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 21/07/2021 21:43, Pavel Skripkin wrote: > If em28xx dev has ->dev_next pointer, we need to delete dev_next list node > from em28xx_extension_devlist on disconnect to avoid UAF bugs and > corrupted list bugs, since driver frees this pointer on disconnect. > > Fixes: 1a23f81b7dc3 ("V4L/DVB (9979): em28xx: move usb probe code to a proper place") > Reported-and-tested-by: syzbot+a6969ef522a36d3344c9@syzkaller.appspotmail.com > Signed-off-by: Pavel Skripkin > --- > > Changes in v2: > Previous patch was completely broken. I've done some debugging > again and found true root case of the reported bug. > > --- > drivers/media/usb/em28xx/em28xx-cards.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c > index c1e0dccb7408..d56b040e1bd7 100644 > --- a/drivers/media/usb/em28xx/em28xx-cards.c > +++ b/drivers/media/usb/em28xx/em28xx-cards.c > @@ -4139,8 +4139,10 @@ static void em28xx_usb_disconnect(struct usb_interface *intf) > > em28xx_close_extension(dev); > > - if (dev->dev_next) > + if (dev->dev_next) { > em28xx_release_resources(dev->dev_next); > + em28xx_close_extension(dev->dev_next); Wouldn't it be better to swap these two? That order is also used for em28xx_close_extension(dev) and em28xx_release_resources(dev). You do need to store dev->dev_next in a temp variable, though. Regards, Hans > + } > em28xx_release_resources(dev); > > if (dev->dev_next) { >