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 95CC4C433F5 for ; Mon, 24 Jan 2022 20:08:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1378706AbiAXUI0 (ORCPT ); Mon, 24 Jan 2022 15:08:26 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:45018 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353262AbiAXUCA (ORCPT ); Mon, 24 Jan 2022 15:02:00 -0500 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 ams.source.kernel.org (Postfix) with ESMTPS id 8D8DDB8121A; Mon, 24 Jan 2022 20:01:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B4C16C340E5; Mon, 24 Jan 2022 20:01:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643054515; bh=gHJkcpYKXR/RhQBBuV2zUOoAWjs3ei98HPq/WqtjGlw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RxT/LwrzdMcvb0o/8WoYEAXRBUqgPOFYa+5uwSceg+rs5HS9nW99qCESBdE67sZjk GvK4C8AMAMwDE42ErMtWmf0CGewd5/G0z1GqsabbXXCsABXqQhbglhduFF3uIFSl7Y sKD2LhJRim/X90RpjM2f8cYJ9V925zCBBWWE98Sk= 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 5.10 414/563] i2c: i801: Dont silently correct invalid transfer size Date: Mon, 24 Jan 2022 19:42:59 +0100 Message-Id: <20220124184038.762166278@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124184024.407936072@linuxfoundation.org> References: <20220124184024.407936072@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: 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