From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=198.175.65.14 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793283114; b=RnPVmyBGj2TxNNpC29+9wx3jHmXHnSarnW27Tt8lFw733tOvsmjw3ogboH/A/epWRDI8 bUdhUeo3nJlkwMRJXHLYCMTsJMTrFt2q+w2g2ad9PFs2Gxyt5s7BtB37FS6pxK0YhSGk8 3KQwYAWK4sBptwDmSF97dDdF7IjnxFrMrhk+OTEbIY8MZtRLZ7s8QsljSZT6pW/l4ytnh 5NmNtYiMWTYbdUixDbGT25gdFWK67yQhmxdcWvWDGhmsE/Ua7aoAgCLECq9X0U9J1fGQV u/wk1ASD9kcFqPq2hU2Tm7TCjdwu7BfqR0lTkLzpAXpNBXG8CFLWh+/N06oFBgvrxQQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793283114; 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=OzKnLRYb2RHjO5vpLJyGvVckIFjS3eGZhvq3T7EZubc=; b=Tu08MJ7C8iqE/R6bFOqel7SDzPa70BbTXKx4GXKwaxpu7K3LOGXL15o5C0JQJqpkSDnx AxSpVtg7aZLrwyUVjP9hg34PUNrven1O9MwrSiFEFz1p/QAZYa2CaxtPRHFEK5VYWqKaV D/dINz8UHSUQbRp8fSsSdSKIjEmOKbdRI2/8bl9WIphBhadsh2TbKyhdZkfGtTSEHidiB BnFRfiioyfQm5qkXbR/oFhC1jKMFrslcOV5mqjIGGznVhEjgHQdmoXCweA+1/oL4YReRT NpxpHZ9ofmilS4xdIdMr5pkNGoL2F9XRkCJcQAKnGA6GaFOyRoh67RygxyY+zNFBAww== 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=fDYnTqh3; arc=none smtp.remote-ip=198.175.65.14 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.14]) (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 67432606A31C; Thu, 29 Oct 2026 14:11:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 67432606A31C 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=fDYnTqh3 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1793283113; x=1824819113; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=IGMKDb/7ZPZl5Y96TrIzG3Ewn1xwYH/zIgJht6qrTJ0=; b=fDYnTqh3F8xuKC47a9Tz6thYrEq018NyAv7hFiix94oZbCqJgAWDuKL7 ESr1XE7oSmrO78RoPkADJLWNEorogILaM0xF8LYeTgEuIKREW6+SLZ6RP zSRxplTAte8x1Tg8JdfHCuKvFxAe5jgmOWdZg30rSrONaDMRZgrKxJk+h gtDNv2d9q4cqvFzE2Ow2KrUaQMwVFrAWPX+rTcUBQjyBqQAjVZLg2NPJ6 sjtoW9ltK5g+33kuPZM9f/5aocGISGNnsfB7jHNn28wwpjcdrlvlUlyMX ZNlHQtmsyvX1Hvry75YATOg8IdslyLf/U0eTQ5NPXZYHVfjhqZO8ggEeH A==; X-CSE-ConnectionGUID: ERafY8wWT/aYNReuhvW4CA== X-CSE-MsgGUID: +n46ajfjRsyynT1owP65Ag== X-IronPort-AV: E=McAfee;i="6800,10657,11949"; a="1903513" X-IronPort-AV: E=Sophos;i="6.27,184,1787036400"; d="scan'208";a="1903513" Received: from fmviesa006.fm.intel.com ([10.60.135.146]) by orvoesa106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Oct 2026 07:11:52 -0700 X-CSE-ConnectionGUID: uyNBvJHcSg+cXeZLEedqOg== X-CSE-MsgGUID: 6UbarMXGSZOTtgWO97tlQw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,184,1787036400"; d="scan'208";a="5524691" Received: from ncintean-mobl1.ger.corp.intel.com (HELO localhost) ([10.245.245.129]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Oct 2026 07:11:49 -0700 Date: Thu, 29 Oct 2026 16:11:47 +0200 From: Andy Shevchenko To: Tristan Madani Cc: Marius Cristea , Jonathan Cameron , David Lechner , Nuno =?iso-8859-1?Q?S=E1?= , Andy Shevchenko , linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, Tristan Madani Subject: Re: [PATCH v3] iio: adc: pac1934: validate ACPI _DSM return type and bounds Message-ID: References: <20261029001447.1114691-1-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: <20261029001447.1114691-1-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 12:14:47AM +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 device *dev = &client->dev; > unsigned short bi_dir_mask; > int idx, i; > + unsigned int count; > guid_t guid; Preserve reversed xmas tree order. > + count = min(rez->package.count & ~1u, > + (unsigned int)(PAC1934_MAX_NUM_CHANNELS * 2)); No, you are not supposed to cast parameters for min(). It should work for int as small positive predefined number. ... Ditto for the other case of min(). -- With Best Regards, Andy Shevchenko