From: Guenter Roeck <linux@roeck-us.net>
To: Nadezda Lutovinova <lutovinova@ispras.ru>
Cc: Marc Hulsman <m.hulsman@tudelft.nl>,
Rudolf Marek <r.marek@assembler.cz>,
Jean Delvare <jdelvare@suse.com>,
linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org,
ldv-project@linuxtesting.org
Subject: Re: [PATCH v2 2/3] hwmon: (w83792d) Fix NULL pointer dereference by removing unnecessary structure field
Date: Sat, 2 Oct 2021 05:12:34 -0700 [thread overview]
Message-ID: <20211002121234.GA2188531@roeck-us.net> (raw)
In-Reply-To: <20210921155153.28098-2-lutovinova@ispras.ru>
On Tue, Sep 21, 2021 at 06:51:52PM +0300, Nadezda Lutovinova wrote:
> If driver read val value sufficient for
> (val & 0x08) && (!(val & 0x80)) && ((val & 0x7) == ((val >> 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).
>
> Signed-off-by: Nadezda Lutovinova <lutovinova@ispras.ru>
Applied, after fixing multi-line alignments
> ---
> v2:
> - split one file per patch
> - remove lm75[] instead of adding checking
> ---
> drivers/hwmon/w83792d.c | 31 ++++++++++++++-----------------
> 1 file changed, 14 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/hwmon/w83792d.c b/drivers/hwmon/w83792d.c
> index abd5c3a722b9..8a72be4ad74f 100644
> --- a/drivers/hwmon/w83792d.c
> +++ b/drivers/hwmon/w83792d.c
> @@ -264,9 +264,6 @@ struct w83792d_data {
> char valid; /* !=0 if following fields are valid */
> unsigned long last_updated; /* In jiffies */
>
> - /* array of 2 pointers to subclients */
> - struct i2c_client *lm75[2];
> -
> u8 in[9]; /* Register value */
> u8 in_max[9]; /* Register value */
> u8 in_min[9]; /* Register value */
> @@ -927,7 +924,6 @@ w83792d_detect_subclients(struct i2c_client *new_client)
> int address = new_client->addr;
> u8 val;
> struct i2c_adapter *adapter = new_client->adapter;
> - struct w83792d_data *data = i2c_get_clientdata(new_client);
>
> id = i2c_adapter_id(adapter);
> if (force_subclients[0] == id && force_subclients[1] == address) {
> @@ -946,20 +942,21 @@ w83792d_detect_subclients(struct i2c_client *new_client)
> }
>
> val = w83792d_read_value(new_client, W83792D_REG_I2C_SUBADDR);
> +
> + if (!(val & 0x88) && (val & 0x7) == ((val >> 4) & 0x7)) {
> + dev_err(&new_client->dev,
> + "duplicate addresses 0x%x, use force_subclient\n",
> + 0x48 + (val & 0x7));
> + return -ENODEV;
> + }
> +
> if (!(val & 0x08))
> - data->lm75[0] = devm_i2c_new_dummy_device(&new_client->dev, adapter,
> - 0x48 + (val & 0x7));
> - if (!(val & 0x80)) {
> - if (!IS_ERR(data->lm75[0]) &&
> - ((val & 0x7) == ((val >> 4) & 0x7))) {
> - dev_err(&new_client->dev,
> - "duplicate addresses 0x%x, use force_subclient\n",
> - data->lm75[0]->addr);
> - return -ENODEV;
> - }
> - data->lm75[1] = devm_i2c_new_dummy_device(&new_client->dev, adapter,
> - 0x48 + ((val >> 4) & 0x7));
> - }
> + devm_i2c_new_dummy_device(&new_client->dev, adapter,
> + 0x48 + (val & 0x7));
> +
> + if (!(val & 0x80))
> + devm_i2c_new_dummy_device(&new_client->dev, adapter,
> + 0x48 + ((val >> 4) & 0x7));
>
> return 0;
> }
next prev parent reply other threads:[~2021-10-02 12:12 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-11 16:15 hwmon: Error handling in w83793.c, w83791d.c, w83792d.c Nadezda Lutovinova
2021-08-11 16:15 ` [PATCH] hwmon: Correct the error " Nadezda Lutovinova
2021-08-11 18:18 ` Guenter Roeck
2021-09-21 15:51 ` [PATCH v2 1/3] hwmon: (w83791d) Fix NULL pointer dereference by removing unnecessary structure field Nadezda Lutovinova
2021-10-02 12:07 ` Guenter Roeck
2021-09-21 15:51 ` [PATCH v2 2/3] hwmon: (w83792d) " Nadezda Lutovinova
2021-10-02 12:12 ` Guenter Roeck [this message]
2021-09-21 15:51 ` [PATCH v2 3/3] hwmon: (w83793) " Nadezda Lutovinova
2021-10-02 12:15 ` Guenter Roeck
2021-08-11 17:51 ` hwmon: Error handling in w83793.c, w83791d.c, w83792d.c Guenter Roeck
2021-08-11 18:19 ` Guenter Roeck
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20211002121234.GA2188531@roeck-us.net \
--to=linux@roeck-us.net \
--cc=jdelvare@suse.com \
--cc=ldv-project@linuxtesting.org \
--cc=linux-hwmon@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=lutovinova@ispras.ru \
--cc=m.hulsman@tudelft.nl \
--cc=r.marek@assembler.cz \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).