From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx.gpxsee.org (mx.gpxsee.org [37.205.14.76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F0E6E207A00; Wed, 16 Oct 2024 12:07:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=37.205.14.76 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729080473; cv=none; b=NE0twuW55y5AVaA/kJ3We5kipNmk+DaDSmTo0wXMurtZqnLjglsOPRaFY7jVF1044Ka7rAoHzuDuazZIEa/yP24AAVy7NIgmH9dbrJgcsGpxt2xtMPDoA5pqsRA7m9EMYy1CK8fLuk7mN/T7j1+BZaSUq15xdIOWM0XxYDFNDK4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729080473; c=relaxed/simple; bh=Cd/nJwokvfsxNybbuDAbUxVhvuqfcKV+Gv2tM2d77nw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=iiktNw54Vt9a+k0UiOjXhEvlwV19LdGy4znrYn+4P+z+9mr0TLlyRvM9e/2f5u+043qs+3pzPKSOnhZYD9ZNka6N/kxPwdGXvbkLVMRcj64qV/VZNU++8C3wiHcU/8sQIE9VxQo0GlIziEkF0KqIpUYifkM4VtDny+E0xbPNjoc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gpxsee.org; spf=pass smtp.mailfrom=gpxsee.org; arc=none smtp.client-ip=37.205.14.76 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gpxsee.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gpxsee.org Received: from [192.168.4.15] (unknown [62.77.71.229]) by mx.gpxsee.org (Postfix) with ESMTPSA id 4BABE2BE05; Wed, 16 Oct 2024 13:59:19 +0200 (CEST) Message-ID: Date: Wed, 16 Oct 2024 13:59:18 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 05/13] media: mgb4: protect driver against spectre To: Mauro Carvalho Chehab Cc: Hans Verkuil , Martin Tuma , linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, stable@vger.kernel.org References: <4675c8e726c7d55bbecf9f4772370daa8b46ccd3.1729074076.git.mchehab+huawei@kernel.org> Content-Language: en-US From: =?UTF-8?Q?Martin_T=C5=AFma?= In-Reply-To: <4675c8e726c7d55bbecf9f4772370daa8b46ccd3.1729074076.git.mchehab+huawei@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 16. 10. 24 12:22 odp., Mauro Carvalho Chehab wrote: > Frequency range is set from sysfs via frequency_range_store(), > being vulnerable to spectre, as reported by smatch: > > drivers/media/pci/mgb4/mgb4_cmt.c:231 mgb4_cmt_set_vin_freq_range() warn: potential spectre issue 'cmt_vals_in' [r] > drivers/media/pci/mgb4/mgb4_cmt.c:238 mgb4_cmt_set_vin_freq_range() warn: possible spectre second half. 'reg_set' > > Fix it. > > Fixes: 0ab13674a9bd ("media: pci: mgb4: Added Digiteq Automotive MGB4 driver") > Cc: stable@vger.kernel.org > Signed-off-by: Mauro Carvalho Chehab > --- > drivers/media/pci/mgb4/mgb4_cmt.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/media/pci/mgb4/mgb4_cmt.c b/drivers/media/pci/mgb4/mgb4_cmt.c > index 70dc78ef193c..a25b68403bc6 100644 > --- a/drivers/media/pci/mgb4/mgb4_cmt.c > +++ b/drivers/media/pci/mgb4/mgb4_cmt.c > @@ -227,6 +227,8 @@ void mgb4_cmt_set_vin_freq_range(struct mgb4_vin_dev *vindev, > u32 config; > size_t i; > > + freq_range = array_index_nospec(freq_range, ARRAY_SIZE(cmt_vals_in)); > + > addr = cmt_addrs_in[vindev->config->id]; > reg_set = cmt_vals_in[freq_range]; > I still do not fully understand the exact vulnerability here, but the patch should definitely not do any harm, so I'm ok with it even if it's real purpose would only be to silence the smatch warning :-) Reviewed-by: Martin Tůma