From patchwork Mon Jan 24 18:41:52 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 536388 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 BC736C433F5 for ; Mon, 24 Jan 2022 18:59:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344759AbiAXS7K (ORCPT ); Mon, 24 Jan 2022 13:59:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44664 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343815AbiAXS46 (ORCPT ); Mon, 24 Jan 2022 13:56:58 -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 0EE71C061753; Mon, 24 Jan 2022 10:55:01 -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 C0A63B8121A; Mon, 24 Jan 2022 18:54:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D2F0CC340EA; Mon, 24 Jan 2022 18:54:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643050498; bh=qJAm7nxkvWLXikpp65EDpvm73EhmGBm8p+/E1dgdSS0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=A8tuTd34f10vxkcqfyyi2ZAAE120up6vp5uHkxRKar3KI/636c/AZqU5U6lN2JvvM ViCytgWTSXu+1VMORszkKJmm/S2mFQqboJGR3b0VJ11SzxGa6ziEGUbGHMtREhmBMm 9iIdyYUczqV9ve9IHocxYp3NKXKnF8+QgS89eaDc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Michael Kuron , Mauro Carvalho Chehab Subject: [PATCH 4.9 022/157] media: dib0700: fix undefined behavior in tuner shutdown Date: Mon, 24 Jan 2022 19:41:52 +0100 Message-Id: <20220124183933.500112255@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124183932.787526760@linuxfoundation.org> References: <20220124183932.787526760@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Michael Kuron commit f7b77ebe6d2f49c7747b2d619586d1aa33f9ea91 upstream. This fixes a problem where closing the tuner would leave it in a state where it would not tune to any channel when reopened. This problem was discovered as part of https://github.com/hselasky/webcamd/issues/16. Since adap->id is 0 or 1, this bit-shift overflows, which is undefined behavior. The driver still worked in practice as the overflow would in most environments result in 0, which rendered the line a no-op. When running the driver as part of webcamd however, the overflow could lead to 0xff due to optimizations by the compiler, which would, in the end, improperly shut down the tuner. The bug is a regression introduced in the commit referenced below. The present patch causes identical behavior to before that commit for adap->id equal to 0 or 1. The driver does not contain support for dib0700 devices with more adapters, assuming such even exist. Tests have been performed with the Xbox One Digital TV Tuner on amd64. Not all dib0700 devices are expected to be affected by the regression; this code path is only taken by those with incorrect endpoint numbers. Link: https://lore.kernel.org/linux-media/1d2fc36d94ced6f67c7cc21dcc469d5e5bdd8201.1632689033.git.mchehab+huawei@kernel.org Cc: stable@vger.kernel.org Fixes: 7757ddda6f4f ("[media] DiB0700: add function to change I2C-speed") Signed-off-by: Michael Kuron Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Greg Kroah-Hartman --- drivers/media/usb/dvb-usb/dib0700_core.c | 2 -- 1 file changed, 2 deletions(-) --- a/drivers/media/usb/dvb-usb/dib0700_core.c +++ b/drivers/media/usb/dvb-usb/dib0700_core.c @@ -610,8 +610,6 @@ int dib0700_streaming_ctrl(struct dvb_us deb_info("the endpoint number (%i) is not correct, use the adapter id instead", adap->fe_adap[0].stream.props.endpoint); if (onoff) st->channel_state |= 1 << (adap->id); - else - st->channel_state |= 1 << ~(adap->id); } else { if (onoff) st->channel_state |= 1 << (adap->fe_adap[0].stream.props.endpoint-2);