From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=192.198.163.7 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793353646; b=HlwdLBxIo/EpPX2MjN8e2JK9+Mq/rTOvyVFoiv9giWrNElGs8mMffzVD+WtCI5GEL6m2 RWoA/8FY5QsNyKL1fEBw2qfUu9657Sn4aebey+9yNgHPuFAJ3WqTTJLi7HhYoLoRXPgPf HIP4NBS3AYypMEgCr2jPBdaZ3WwT848nHPf4x7N2C2Zh+ZHOkjyf1iEP4uxuKRbTsgkmO TbREfdav9kzPncd9lgHOD+Z320IuFblVodbFxodX2/G14i/L7r5JVViwhud9SMtK9Ezou GhBAjDnP0PQilFMijjXZjslPouYTn8Zg2kUcZdZZ4CRuPWFvb0hwp41QNtS4JoJ0rJw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793353646; h=DMARC-Filter:DKIM-Signature:X-CSE-ConnectionGUID:X-CSE-MsgGUID: X-IronPort-AV:X-IronPort-AV:Received:X-CSE-ConnectionGUID: X-CSE-MsgGUID:X-ExtLoop1:X-IronPort-AV:Received:Date:From:To:Cc: Subject:Message-ID:References:MIME-Version:Content-Type: Content-Disposition:In-Reply-To:Organization; bh=QaZJzYnrmgn/3/+MnWVhC1pUB6YQ4dkPpe2aqBqfGes=; b=azpemxHAb2E/cjcpHWX8p29QxBUsSs352L9Qa8VZ9W7SvBNxC4Icq7xQrGEOqn24OFEl 3pD6wFv5nXgQqd5q9vWDnb9g0bwzQBZhA4aSQlOcn6kxNTE03EIZ5T/WBNtKGMVgSMnQ2 bJgkPBkjjAJlcrohNFHJXnVVhSRqtSvwRdVI7pppVXTzZ5XB6t9zbHrg7XTLUxTGVzil7 7DJ1hHBWts39gZzD9xa6GkTXqPs1L8OPKQLer5LHK1wkV2SnRte1/DBTmsq6nExOXMuoz wviKYEWwkfoa/t0t6MxTDYS0w/wi7QGjplFJMyKvF9hKYnizI6WwrEU+Meae6coxzWg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=RYK8qgmF; arc=none smtp.remote-ip=192.198.163.7 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.7]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B3C94606A31C; Fri, 30 Oct 2026 09:47:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org B3C94606A31C Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=RYK8qgmF DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1793353644; x=1824889644; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=cWBxoB6m9qlpzRPldiJg4DoVUNnWvIe79hiZSg3Ps1E=; b=RYK8qgmFnWsXl/OstC1O+MrmBKc6wCBCFdBcoZbXRvBt0W1D04/v/9GJ 1Tpt7fOgWRbYYqLq3Fk20/POHgLcGe5Zboo6v7B22zCjHcOGNfuZhP0Fr 5j8das1ThucUAR+5E1LhC0YB7XasUWzYpNBtVc1AC+eFFp42u7cRmmeA5 3p+bKAKs8elqMVP0bMMu9svz7710TY2deLA/zSbm0NW4XLWmUQeHi+bKm EYAZAtajNOb+VFphsJjv+WXz1cwbRC7zdj4iwOSp4L1IknFYnnBIR/7Gn Y2ad6CkDBhTYJd/aFGFnizsk5CHD5ZlPy7mY7U95SKYaHBbPZWk1mIeGX g==; X-CSE-ConnectionGUID: COEFM0R5Td6TRZIXAYEIPw== X-CSE-MsgGUID: b7BjjgCASD6zUiK3sVgbfA== X-IronPort-AV: E=McAfee;i="6800,10657,11950"; a="1996164" X-IronPort-AV: E=Sophos;i="6.27,186,1787036400"; d="scan'208";a="1996164" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by fmvoesa101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Oct 2026 02:47:11 -0700 X-CSE-ConnectionGUID: Co0TvGOiQ9CACnqcrqQWtA== X-CSE-MsgGUID: eY5aRmYBQ9qhKHVYjMhA7Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,186,1787036400"; d="scan'208";a="5520571" Received: from ettammin-mobl3.ger.corp.intel.com (HELO localhost) ([10.245.245.247]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Oct 2026 02:47:09 -0700 Date: Fri, 30 Oct 2026 11:47:06 +0200 From: Andy Shevchenko To: Tristan Madani Cc: Marius Cristea , Jonathan Cameron , David Lechner , Nuno Sa , Andy Shevchenko , linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, Tristan Madani Subject: Re: [PATCH v4] iio: adc: pac1934: validate ACPI _DSM return type and bounds Message-ID: References: <20261029165602.3265518-1-tristmd@gmail.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261029165602.3265518-1-tristmd@gmail.com> Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo On Thu, Oct 29, 2026 at 04:56:02PM +0000, Tristan Madani wrote: > pac1934_acpi_parse_channel_config() calls acpi_evaluate_dsm() four > times to read channel configuration but does not validate the returned > object type or array bounds: > > 1. No check that the returned object is ACPI_TYPE_PACKAGE. If > firmware returns a different type, accessing rez->package.count > and rez->package.elements on a non-package object produces > unpredictable values. > > 2. The loop bounds use rez->package.count directly without capping > to PAC1934_MAX_NUM_CHANNELS (4). A package with more elements > than expected causes writes past the fixed-size labels[], > shunts[], and active_channels[] arrays. > > 3. The bipolar and sample rate DSM calls access elements[0] without > verifying package.count >= 1. > > Use acpi_evaluate_dsm_typed() with ACPI_TYPE_PACKAGE to validate the > return type at evaluation time. Cap loop iterations to > PAC1934_MAX_NUM_CHANNELS, and verify package count >= 1 before > accessing elements[0]. ... > static int pac1934_acpi_parse_channel_config(struct i2c_client *client, > struct pac1934_chip_info *info) > { > - acpi_handle handle; > - union acpi_object *rez; > struct device *dev = &client->dev; > unsigned short bi_dir_mask; > - int idx, i; > + union acpi_object *rez; > + acpi_handle handle; > + unsigned int count; > guid_t guid; > + int idx, i; No need to touch lines that are unrelated to your change. Just make sure that your change tries to keep reversed xmas tree order as much as possible. ... > - for (i = 0; i < rez->package.count; i += 2) { > + count = min(rez->package.count & ~1u, PAC1934_MAX_NUM_CHANNELS * 2); What is the purpose of 'u' suffix? In case if you want to keep that 32-bit value this might be even wrong (I haven't checked the promotion rules for the values with suffix, though). > + for (i = 0; i < count; i += 2) { -- With Best Regards, Andy Shevchenko