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 16EBFC433FE for ; Tue, 25 Jan 2022 00:24:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352643AbiAYAYW (ORCPT ); Mon, 24 Jan 2022 19:24:22 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60946 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1578510AbiAXWDD (ORCPT ); Mon, 24 Jan 2022 17:03:03 -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 D6978C0C093F; Mon, 24 Jan 2022 12:41:18 -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 727E161008; Mon, 24 Jan 2022 20:41:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 531E6C340E5; Mon, 24 Jan 2022 20:41:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643056877; bh=3cmUl0Kng61V5pxa0ERWvC6ByxCde87qlfadGwheNM8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wEQ6S8YQNfy0Pisb2KfukdubQa8Z7lQhl+wGCaJpKFm/gcK1lLmRlBTDfRDGm0wO5 92kYLZrLJcbv0g2uehF55MOcZNNPNRkDYUEJXzkN82T5QCK1DJTt5zqSFzqe836b5/ 4Sfe7IyijmOishsZowA6mxfBzHBVTuWzIDxNJ5ao= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Heiner Kallweit , Jean Delvare , Wolfram Sang , Sasha Levin Subject: [PATCH 5.15 629/846] i2c: i801: Dont silently correct invalid transfer size Date: Mon, 24 Jan 2022 19:42:26 +0100 Message-Id: <20220124184122.734921413@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124184100.867127425@linuxfoundation.org> References: <20220124184100.867127425@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 1f929e6c30bea..98e39a17fb830 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -763,6 +763,11 @@ static int i801_block_transaction(struct i801_priv *priv, union i2c_smbus_data * 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 */ @@ -776,16 +781,6 @@ static int i801_block_transaction(struct i801_priv *priv, union i2c_smbus_data * } } - 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