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 83026C4332F for ; Mon, 24 Jan 2022 19:12:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346871AbiAXTMx (ORCPT ); Mon, 24 Jan 2022 14:12:53 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:35354 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346740AbiAXTJ1 (ORCPT ); Mon, 24 Jan 2022 14:09:27 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 69B1D60917; Mon, 24 Jan 2022 19:09:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2FE0EC340E5; Mon, 24 Jan 2022 19:09:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643051365; bh=yNneMOoQvQQmJG7O7bWEOtcq/cm7Q7vMIAyMICcbcwk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GUL0Rb1HHBhFrYHWRlwEjnDu1/H5qD+jxgSTDiBJbjBQhFbLqsnYvKedfvK93TpZR pr6uu9oO/hScMJYg6fE3WiTpT6aa2W4EaTHhl/QMg0vz90pZIj8bKi7nsLc6rC6SQM xGHfj8lDEzMfeyM3aj42dB+MvjxAjwZBgcxU8lsU= 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 4.14 137/186] i2c: i801: Dont silently correct invalid transfer size Date: Mon, 24 Jan 2022 19:43:32 +0100 Message-Id: <20220124183941.512341856@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124183937.101330125@linuxfoundation.org> References: <20220124183937.101330125@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 7b1654b0fb6db..c817e3d4b52b8 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -769,6 +769,11 @@ 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 */ @@ -782,16 +787,6 @@ 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