From: Rustam Subkhankulov <subkhankulov@ispras.ru>
To: Tzung-Bi Shih <tzungbi@kernel.org>
Cc: Benson Leung <bleung@chromium.org>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
chrome-platform@lists.linux.dev, linux-kernel@vger.kernel.org,
Alexey Khoroshilov <khoroshilov@ispras.ru>,
ldv-project@linuxtesting.org
Subject: Re: [PATCH] platform/chrome: fix double-free in chromeos_laptop_prepare()
Date: Sat, 20 Aug 2022 20:05:13 +0300 [thread overview]
Message-ID: <7d4dd8009a777a7d32f4872dc0285878dbbb91b8.camel@ispras.ru> (raw)
In-Reply-To: <YvnS7IKr/9VhffHX@google.com>
On Mon, 2022-08-15 at 05:00 +0000, Tzung-Bi Shih wrote:
> Alternatively, I would prefer to fix the double-free by setting
> `i2c_peripherals` to NULL after [1].
Since 'cros_laptop->num_i2c_peripherals' is assigned with nonzero value
(otherwise the code on 'err_out' is not executed), setting
'i2c_peripherals' to NULL after [1] will cause dereferencing of
NULL pointer in chromeos_laptop_destroy() at [2].
[1]:
https://elixir.bootlin.com/linux/v5.19/source/drivers/platform/chrome/chromeos_laptop.c#L787
[2]:
https://elixir.bootlin.com/linux/v5.19/source/drivers/platform/chrome/chromeos_laptop.c#L860
> After a quick glance, I found an invalid memory access at [2] if
> `i2c_peripherals` is NULL (see [3]).
After applying the patch, there will be no invalid memory access at [2]
if 'i2c_peripherals' is NULL, because in this situation
'cros_laptop->num_i2c_peripherals' is zero and there is no single
iteration of the loop.
> Or was the double-free issue
> discovered by
> some static analysis?
Yes, it was discovered by SVACE static analysis tool.
next prev parent reply other threads:[~2022-08-20 15:05 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-13 22:08 Rustam Subkhankulov
2022-08-15 5:00 ` Tzung-Bi Shih
2022-08-20 17:05 ` Rustam Subkhankulov [this message]
2022-08-21 4:51 ` Dmitry Torokhov
2022-08-22 6:40 ` Tzung-Bi Shih
2022-08-22 7:00 ` patchwork-bot+chrome-platform
2022-08-24 2:20 ` patchwork-bot+chrome-platform
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