Messages in this thread | | | Subject | Re: [PATCH] platform/chrome: fix double-free in chromeos_laptop_prepare() | From | Rustam Subkhankulov <> | Date | Sat, 20 Aug 2022 20:05:13 +0300 |
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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.
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