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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D670FC433EF for ; Mon, 4 Oct 2021 13:16:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C08466323A for ; Mon, 4 Oct 2021 13:16:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236112AbhJDNRq (ORCPT ); Mon, 4 Oct 2021 09:17:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:53200 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236118AbhJDNPs (ORCPT ); Mon, 4 Oct 2021 09:15:48 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7E56461BA3; Mon, 4 Oct 2021 13:06:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1633352778; bh=6XxndlJ+hbnPD+TaMAe645ki6TjPjn91KhRQqbaYJ/U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=w3pmL1uR3JfrpbiOlz2KCQ/xSDEEso8tv45vaxvnZkEaOGOw4cuzEwU+7z+NumUwC ++qdbFk8rVsVdwsXxzVQZtr41rZI/eWkcX+gJ0p9tzGVIw6vBlMNuP7KhAJ4uycYjW mWVba/OOH5aZP7NN5p4x2nMuvpfYG02LjOlAb41Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nadezda Lutovinova , Guenter Roeck Subject: [PATCH 5.4 06/56] hwmon: (w83793) Fix NULL pointer dereference by removing unnecessary structure field Date: Mon, 4 Oct 2021 14:52:26 +0200 Message-Id: <20211004125030.214035100@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211004125030.002116402@linuxfoundation.org> References: <20211004125030.002116402@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: Nadezda Lutovinova commit dd4d747ef05addab887dc8ff0d6ab9860bbcd783 upstream. If driver read tmp value sufficient for (tmp & 0x08) && (!(tmp & 0x80)) && ((tmp & 0x7) == ((tmp >> 4) & 0x7)) from device then Null pointer dereference occurs. (It is possible if tmp = 0b0xyz1xyz, where same literals mean same numbers) Also lm75[] does not serve a purpose anymore after switching to devm_i2c_new_dummy_device() in w83791d_detect_subclients(). The patch fixes possible NULL pointer dereference by removing lm75[]. Found by Linux Driver Verification project (linuxtesting.org). Cc: stable@vger.kernel.org Signed-off-by: Nadezda Lutovinova Link: https://lore.kernel.org/r/20210921155153.28098-3-lutovinova@ispras.ru [groeck: Dropped unnecessary continuation lines, fixed multi-line alignments] Signed-off-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman --- drivers/hwmon/w83793.c | 26 +++++++++++--------------- 1 file changed, 11 insertions(+), 15 deletions(-) --- a/drivers/hwmon/w83793.c +++ b/drivers/hwmon/w83793.c @@ -202,7 +202,6 @@ static inline s8 TEMP_TO_REG(long val, s } struct w83793_data { - struct i2c_client *lm75[2]; struct device *hwmon_dev; struct mutex update_lock; char valid; /* !=0 if following fields are valid */ @@ -1566,7 +1565,6 @@ w83793_detect_subclients(struct i2c_clie int address = client->addr; u8 tmp; struct i2c_adapter *adapter = client->adapter; - struct w83793_data *data = i2c_get_clientdata(client); id = i2c_adapter_id(adapter); if (force_subclients[0] == id && force_subclients[1] == address) { @@ -1586,21 +1584,19 @@ w83793_detect_subclients(struct i2c_clie } tmp = w83793_read_value(client, W83793_REG_I2C_SUBADDR); - if (!(tmp & 0x08)) - data->lm75[0] = devm_i2c_new_dummy_device(&client->dev, adapter, - 0x48 + (tmp & 0x7)); - if (!(tmp & 0x80)) { - if (!IS_ERR(data->lm75[0]) - && ((tmp & 0x7) == ((tmp >> 4) & 0x7))) { - dev_err(&client->dev, - "duplicate addresses 0x%x, " - "use force_subclients\n", data->lm75[0]->addr); - return -ENODEV; - } - data->lm75[1] = devm_i2c_new_dummy_device(&client->dev, adapter, - 0x48 + ((tmp >> 4) & 0x7)); + + if (!(tmp & 0x88) && (tmp & 0x7) == ((tmp >> 4) & 0x7)) { + dev_err(&client->dev, + "duplicate addresses 0x%x, use force_subclient\n", 0x48 + (tmp & 0x7)); + return -ENODEV; } + if (!(tmp & 0x08)) + devm_i2c_new_dummy_device(&client->dev, adapter, 0x48 + (tmp & 0x7)); + + if (!(tmp & 0x80)) + devm_i2c_new_dummy_device(&client->dev, adapter, 0x48 + ((tmp >> 4) & 0x7)); + return 0; }