From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1ADC4C433F5 for ; Mon, 17 Jan 2022 17:07:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242697AbiAQRHL (ORCPT ); Mon, 17 Jan 2022 12:07:11 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45108 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242128AbiAQRFL (ORCPT ); Mon, 17 Jan 2022 12:05:11 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BEE29C06136E; Mon, 17 Jan 2022 09:03:44 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 5E69361225; Mon, 17 Jan 2022 17:03:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF67BC36AED; Mon, 17 Jan 2022 17:03:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1642439023; bh=gHJkcpYKXR/RhQBBuV2zUOoAWjs3ei98HPq/WqtjGlw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pKSzQsXbDmND+HDfrdvVzRDZe6wu5iaZ2uXs2lCYYN4ccNTeaef9QZXPksUaIx9Vt kcC+UwAjSSJkPGbS/V9UYPKF7bvega+REtkzlPB39VQRu25D8KnoSfQEhBKxYS6Zyn 0iFP9wIJFXEzlEyY/uQkKYSJ1osA54wCKra1H/zfYOJ8rMfYh22xe7thqJ/hcGHUGq 575RNT48xW+s40eo/AKgysWHE8dCkrKGFzQmbkDfq17kvYfa7jQc/Y7Dfz1FDTGTgY k+pvyehmKArmCThzG9aF1ZNSe2Cdx/1NbvaNetHxyQvnQL1NFKuJhX1i89gcXYxcg0 yx4KHoSXgm29Q== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Heiner Kallweit , Jean Delvare , Wolfram Sang , Sasha Levin , jdelvare@suse.com, linux-i2c@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 08/34] i2c: i801: Don't silently correct invalid transfer size Date: Mon, 17 Jan 2022 12:02:58 -0500 Message-Id: <20220117170326.1471712-8-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220117170326.1471712-1-sashal@kernel.org> References: <20220117170326.1471712-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Heiner Kallweit [ Upstream commit effa453168a7eeb8a562ff4edc1dbf9067360a61 ] If an invalid block size is provided, reject it instead of silently changing it to a supported value. Especially critical I see the case of a write transfer with block length 0. In this case we have no guarantee that the byte we would write is valid. When silently reducing a read to 32 bytes then we don't return an error and the caller may falsely assume that we returned the full requested data. If this change should break any (broken) caller, then I think we should fix the caller. Signed-off-by: Heiner Kallweit Reviewed-by: Jean Delvare Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-i801.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index eab6fd6b890eb..5618c1ff34dc3 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -797,6 +797,11 @@ static int i801_block_transaction(struct i801_priv *priv, int result = 0; unsigned char hostc; + if (read_write == I2C_SMBUS_READ && command == I2C_SMBUS_BLOCK_DATA) + data->block[0] = I2C_SMBUS_BLOCK_MAX; + else if (data->block[0] < 1 || data->block[0] > I2C_SMBUS_BLOCK_MAX) + return -EPROTO; + if (command == I2C_SMBUS_I2C_BLOCK_DATA) { if (read_write == I2C_SMBUS_WRITE) { /* set I2C_EN bit in configuration register */ @@ -810,16 +815,6 @@ static int i801_block_transaction(struct i801_priv *priv, } } - if (read_write == I2C_SMBUS_WRITE - || command == I2C_SMBUS_I2C_BLOCK_DATA) { - if (data->block[0] < 1) - data->block[0] = 1; - if (data->block[0] > I2C_SMBUS_BLOCK_MAX) - data->block[0] = I2C_SMBUS_BLOCK_MAX; - } else { - data->block[0] = 32; /* max for SMBus block reads */ - } - /* Experience has shown that the block buffer can only be used for SMBus (not I2C) block transactions, even though the datasheet doesn't mention this limitation. */ -- 2.34.1