From patchwork Mon Nov 15 03:43:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Liam Beguin X-Patchwork-Id: 12618643 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D97FAC433FE for ; Mon, 15 Nov 2021 03:44:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BFDC460555 for ; Mon, 15 Nov 2021 03:44:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236971AbhKODq7 (ORCPT ); Sun, 14 Nov 2021 22:46:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50812 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236995AbhKODqs (ORCPT ); Sun, 14 Nov 2021 22:46:48 -0500 Received: from mail-qk1-x729.google.com (mail-qk1-x729.google.com [IPv6:2607:f8b0:4864:20::729]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BD510C061208; Sun, 14 Nov 2021 19:43:49 -0800 (PST) Received: by mail-qk1-x729.google.com with SMTP id q64so4623664qkd.5; Sun, 14 Nov 2021 19:43:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Jw54IKpjaf2lkn1AccMjzP5THrJX1wdOQq5FTCzCg5c=; b=DjLRDmDVbl1ZyXfxqXLk1sdMNlIAw/tQVyXtqgCGXuAKMPNc4nEPFvThwMufa8lLo8 qvw4v2b66A4cDzPnMM5L8jKgwt8JixhJGrd2K3pNktNZo4axDrN88DodndrSpeSsPpUa 9YDH6Th83X0FdrwVZdQa/bRD1wxHPXZcXbuoBme1Mp73SfDoDWZCGw4fELV0GSLlPjVM +ypz+eb5fPoVEjZNh3I/TnmdAdu8NFfzSiqAK/nZIqdLs5ZlN/eUcq7sBndG3H0usBr+ Rx5EDYhyIxZIZWayZocsEphIKMEU+cQbSDHIVg5F3C08K/KJj/lzN8zhEt1THYiNpr71 S6HA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Jw54IKpjaf2lkn1AccMjzP5THrJX1wdOQq5FTCzCg5c=; b=6b/cFSupnqZF+0A4NDrwbbLTztH3DIb/vyFgg+kNGDEl1+qe4h7fV4lbwHUUGGXaBk Q9MNjV/laMZs8P5L8lWdKlrRs44bGMjtxz3w8ZCf4/Xsl56++CrOfFOp3LaNVwfmP8tQ gs2RkU2Nf067PzQVc77bGx5yPISwNcExdXJWlkXzeuPcToWumfd6R4tf9B2fzMaM5xfK x5YN4xsAzK4jPbAOuOfDe0GSiSjpm6AzWGNK05Vg3vx8eQPOQ5bmLKTmjcksiZLGpBMj ir0w91qCoensHTNcPUUmPhE8B4x6cAomglFCE6cIku9E/dATy8MFpI1JAQHEjP+wOIPF Ttqw== X-Gm-Message-State: AOAM533c+8PRlNceqLOwjAsCreAmz3AQu2nylwXWtT3k/0gIUstIa51k KjC/jOlOwyKJH+BsH3hyOH8= X-Google-Smtp-Source: ABdhPJxL/aQ5f6EoQ5PThbTF+n8FB/+yxi8RKinApwa1x4nntEkDDH6FvPHU7hQOwMcq2q8zlFgHWQ== X-Received: by 2002:a05:620a:3191:: with SMTP id bi17mr22879088qkb.266.1636947828961; Sun, 14 Nov 2021 19:43:48 -0800 (PST) Received: from shaak.. (198-48-202-89.cpe.pppoe.ca. [198.48.202.89]) by smtp.gmail.com with ESMTPSA id h5sm206519qkn.62.2021.11.14.19.43.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 14 Nov 2021 19:43:48 -0800 (PST) From: Liam Beguin To: liambeguin@gmail.com, peda@axentia.se, jic23@kernel.org, lars@metafoo.de Cc: linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, robh+dt@kernel.org Subject: [PATCH v9 08/14] iio: afe: rescale: reduce risk of integer overflow Date: Sun, 14 Nov 2021 22:43:28 -0500 Message-Id: <20211115034334.1713050-9-liambeguin@gmail.com> X-Mailer: git-send-email 2.32.0.452.g940fe202adcb In-Reply-To: <20211115034334.1713050-1-liambeguin@gmail.com> References: <20211115034334.1713050-1-liambeguin@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org From: Liam Beguin Reduce the risk of integer overflow by doing the scale calculation on a 64-bit integer. Since the rescaling is only performed on *val, reuse the IIO_VAL_FRACTIONAL_LOG2 case. Signed-off-by: Liam Beguin --- drivers/iio/afe/iio-rescale.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c index 394f8b16b29c..17036130d364 100644 --- a/drivers/iio/afe/iio-rescale.c +++ b/drivers/iio/afe/iio-rescale.c @@ -27,16 +27,13 @@ int rescale_process_scale(struct rescale *rescale, int scale_type, u32 neg; switch (scale_type) { - case IIO_VAL_FRACTIONAL: - *val *= rescale->numerator; - *val2 *= rescale->denominator; - return scale_type; case IIO_VAL_INT: *val *= rescale->numerator; if (rescale->denominator == 1) return scale_type; *val2 = rescale->denominator; return IIO_VAL_FRACTIONAL; + case IIO_VAL_FRACTIONAL: case IIO_VAL_FRACTIONAL_LOG2: tmp = (s64)*val * 1000000000LL; tmp = div_s64(tmp, rescale->denominator);