From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (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 428FC1F4C8E for ; Mon, 29 Jun 2026 14:03:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782741836; cv=none; b=nm/x5MFyq230PwqQQqNqOPOgDW0D0aaFfsJhaFzAS13IoGKm8DHid2uFohk5MXaH3vTP7h81zs7kfDiAU7EMfGk/LG6ZbnrnEwM1dgLKgOexf/24E+UrlTDd5eg/0qEt+OwyOS8MTvWhWWeRRBrsI2Cdrhl1ilK2hkMTVSAFdjc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782741836; c=relaxed/simple; bh=eUQy5dIVkGOPF7LgCqRM5et4TAg7d4dNO2DfxVAJKVQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fALpAaP0Lx/5SFBxWaAhcPK/TPnNrh0ixHaaua1Vc4xbvdcrOEfLTRhXnw9HIaikq4xhpBdq3c0dqo9sqWYdvPkOAr62hP1tOFiMocqwuxubBPIkpcP5gqo066cQJJN6g2RGzcH2rQYmlz6Zz26gGNi3eXAv/4Ejr7aGKsDpFNY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=XForSyUP; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="XForSyUP" Received: from killaraus.ideasonboard.com (2001-14ba-70f3-e800--a06.rev.dnainternet.fi [IPv6:2001:14ba:70f3:e800::a06]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id A25608D4; Mon, 29 Jun 2026 16:03:10 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1782741790; bh=eUQy5dIVkGOPF7LgCqRM5et4TAg7d4dNO2DfxVAJKVQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XForSyUPGMN7+8DNu55RkCE0JcWjnalqc6ia/H3Tj9L9tP3q521MY5v5fpA54S8VK D/bYPSuJYJfqYwEhr7yDfhFFPUXzgH4NHXFNc6gxvZ7h/LuRQOMy/VKV1msLY7RW/t x5ix2CPC88K4MngLOLziMYXWqHh3ZTub4/ROruKU= Date: Mon, 29 Jun 2026 17:03:52 +0300 From: Laurent Pinchart To: Hans Verkuil Cc: Linux Media Mailing List Subject: Re: [PATCH] media: cec: extron-da-hd-4k-plus: add sanity check Message-ID: <20260629140352.GA3102371@killaraus.ideasonboard.com> References: <362ab4a1-6591-4715-ad1e-956a65ec322c@kernel.org> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <362ab4a1-6591-4715-ad1e-956a65ec322c@kernel.org> Hi Hans, Thank you for the patch. On Thu, Jun 18, 2026 at 01:03:19PM +0200, Hans Verkuil wrote: > Add check to prevent overflowing msg.msg[] in case the incoming data > is malformed. > > Signed-off-by: Hans Verkuil > --- > diff --git a/drivers/media/cec/usb/extron-da-hd-4k-plus/extron-da-hd-4k-plus.c b/drivers/media/cec/usb/extron-da-hd-4k-plus/extron-da-hd-4k-plus.c > index 3381d86096a1..3c6ce6f3d93e 100644 > --- a/drivers/media/cec/usb/extron-da-hd-4k-plus/extron-da-hd-4k-plus.c > +++ b/drivers/media/cec/usb/extron-da-hd-4k-plus/extron-da-hd-4k-plus.c > @@ -657,7 +657,8 @@ static void extron_process_received(struct extron_port *port, const char *data) > if (!port || port->disconnected) > return; > > - if (len < 5 || (len - 2) % 3 || data[len - 2] != '*') > + if (len < 5 || ((len - 2) / 3 > sizeof(msg.msg)) || I think you should use ARRAY_SIZE > + (len - 2) % 3 || data[len - 2] != '*') This seems correct, but I think the code would be easier to read and maintain if you wrote int len; /* The last two bytes are ignored because ... */ len = strlen(data) - 2; /* * Ensure the data has at least one message, at most the number * of messages that fit in msg.msg, and no extra bytes. */ if (len < 3 || len / 3 > ARRAY_SIZE(msg.msg) || len % 3) goto malformed; if (data[len] != '*') goto malformed; > goto malformed; > > while (*data != '*') { > -- Regards, Laurent Pinchart