2019-08-31 18:19:25

by Guenter Roeck

[permalink] [raw]
Subject: Re: [PATCH] Fix a double free bug in rsi_91x_deinit

On Mon, Aug 19, 2019 at 06:02:29PM -0400, Hui Peng wrote:
> `dev` (struct rsi_91x_usbdev *) field of adapter
> (struct rsi_91x_usbdev *) is allocated and initialized in
> `rsi_init_usb_interface`. If any error is detected in information
> read from the device side, `rsi_init_usb_interface` will be
> freed. However, in the higher level error handling code in
> `rsi_probe`, if error is detected, `rsi_91x_deinit` is called
> again, in which `dev` will be freed again, resulting double free.
>
> This patch fixes the double free by removing the free operation on
> `dev` in `rsi_init_usb_interface`, because `rsi_91x_deinit` is also
> used in `rsi_disconnect`, in that code path, the `dev` field is not
> (and thus needs to be) freed.
>
> This bug was found in v4.19, but is also present in the latest version
> of kernel.
>
> Reported-by: Hui Peng <[email protected]>
> Reported-by: Mathias Payer <[email protected]>
> Signed-off-by: Hui Peng <[email protected]>

FWIW:

Reviewed-by: Guenter Roeck <[email protected]>

This patch is listed as fix for CVE-2019-15504, which has a CVSS 2.0 score
of 10.0 (high) and CVSS 3.0 score of 9.8 (critical).

Are there any plans to apply this patch to the upstream kernel anytime
soon ? If not, are there reasons to believe that the problem is not as
severe as its CVSS score may indicate ?

Thanks,
Guenter

> ---
> drivers/net/wireless/rsi/rsi_91x_usb.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/drivers/net/wireless/rsi/rsi_91x_usb.c b/drivers/net/wireless/rsi/rsi_91x_usb.c
> index c0a163e40402..ac917227f708 100644
> --- a/drivers/net/wireless/rsi/rsi_91x_usb.c
> +++ b/drivers/net/wireless/rsi/rsi_91x_usb.c
> @@ -640,7 +640,6 @@ static int rsi_init_usb_interface(struct rsi_hw *adapter,
> kfree(rsi_dev->tx_buffer);
>
> fail_eps:
> - kfree(rsi_dev);
>
> return status;
> }
> --
> 2.22.1
>


2019-08-31 18:34:13

by Hui Peng

[permalink] [raw]
Subject: Re: [PATCH] Fix a double free bug in rsi_91x_deinit

On 8/31/19 2:18 PM, Guenter Roeck wrote:
> On Mon, Aug 19, 2019 at 06:02:29PM -0400, Hui Peng wrote:
>> `dev` (struct rsi_91x_usbdev *) field of adapter
>> (struct rsi_91x_usbdev *) is allocated and initialized in
>> `rsi_init_usb_interface`. If any error is detected in information
>> read from the device side, `rsi_init_usb_interface` will be
>> freed. However, in the higher level error handling code in
>> `rsi_probe`, if error is detected, `rsi_91x_deinit` is called
>> again, in which `dev` will be freed again, resulting double free.
>>
>> This patch fixes the double free by removing the free operation on
>> `dev` in `rsi_init_usb_interface`, because `rsi_91x_deinit` is also
>> used in `rsi_disconnect`, in that code path, the `dev` field is not
>> (and thus needs to be) freed.
>>
>> This bug was found in v4.19, but is also present in the latest version
>> of kernel.
>>
>> Reported-by: Hui Peng <[email protected]>
>> Reported-by: Mathias Payer <[email protected]>
>> Signed-off-by: Hui Peng <[email protected]>
> FWIW:
>
> Reviewed-by: Guenter Roeck <[email protected]>
>
> This patch is listed as fix for CVE-2019-15504, which has a CVSS 2.0 score
> of 10.0 (high) and CVSS 3.0 score of 9.8 (critical).
>
> Are there any plans to apply this patch to the upstream kernel anytime
> soon ? If not, are there reasons to believe that the problem is not as
> severe as its CVSS score may indicate ?
This patch is also still under review.
> Thanks,
> Guenter
>
>> ---
>> drivers/net/wireless/rsi/rsi_91x_usb.c | 1 -
>> 1 file changed, 1 deletion(-)
>>
>> diff --git a/drivers/net/wireless/rsi/rsi_91x_usb.c b/drivers/net/wireless/rsi/rsi_91x_usb.c
>> index c0a163e40402..ac917227f708 100644
>> --- a/drivers/net/wireless/rsi/rsi_91x_usb.c
>> +++ b/drivers/net/wireless/rsi/rsi_91x_usb.c
>> @@ -640,7 +640,6 @@ static int rsi_init_usb_interface(struct rsi_hw *adapter,
>> kfree(rsi_dev->tx_buffer);
>>
>> fail_eps:
>> - kfree(rsi_dev);
>>
>> return status;
>> }
>> --
>> 2.22.1
>>