driver/bug: suspected missing null check in hisi_lpc.c

driver/bug: suspected missing null check in hisi_lpc.c

[YE Chengfeng]

Hi,

https://github.com/torvalds/linux/blob/master/drivers/bus/hisi_lpc.c#L483

Our experimental static analysis tool detects a null-ptr-reference problem. It could be false positive, we report this to you just in case.

Null check is missing for the return pointer of ACPI_COMPANION at line 483 and line 504. It seems that there could be potential null-ptr-dereference problem at line 488 and line 509. Could you spare some time to have a look at it?

Thanks so much,
Chengfeng

回复: driver/bug: suspected missing null check in hisi_lpc.c

[YE Chengfeng]

It is driver/bus, sorry for the typo.

-----邮件原件-----
发件人: YE Chengfeng 
发送时间: 2021年10月25日 23:22
收件人: linux-kernel@vger.kernel.org; john.garry@huawei.com
主题: driver/bug: suspected missing null check in hisi_lpc.c

Hi,

https://github.com/torvalds/linux/blob/master/drivers/bus/hisi_lpc.c#L483

Our experimental static analysis tool detects a null-ptr-reference problem. It could be false positive, we report this to you just in case.

Null check is missing for the return pointer of ACPI_COMPANION at line 483 and line 504. It seems that there could be potential null-ptr-dereference problem at line 488 and line 509. Could you spare some time to have a look at it?

Thanks so much,
Chengfeng

Re: 回复: driver/bug: suspected missing null check in hisi_lpc.c

[John Garry]

On 25/10/2021 16:31, YE Chengfeng wrote:
> It is driver/bus, sorry for the typo.
> 
> -----邮件原件-----
> 发件人: YE Chengfeng
> 发送时间: 2021年10月25日 23:22
> 收件人: linux-kernel@vger.kernel.org; john.garry@huawei.com
> 主题: driver/bug: suspected missing null check in hisi_lpc.c
> 
> Hi,
> 
> https://github.com/torvalds/linux/blob/master/drivers/bus/hisi_lpc.c#L483
> 
> Our experimental static analysis tool detects a null-ptr-reference problem. It could be false positive, we report this to you just in case.
> 
> Null check is missing for the return pointer of ACPI_COMPANION at line 483 and line 504. It seems that there could be potential null-ptr-dereference problem at line 488 and line 509. Could you spare some time to have a look at it?
> 
> Thanks so much,
> Chengfeng
> 

I don't think that we should have a problem as ACPI_COMPANION() should 
just not return NULL for us. But I can't give you a better reason than 
that without fully examining the ACPI code, which I'm not keen on...

Thanks,
John

回复: 回复: driver/bug: suspected missing null check in hisi_lpc.c

[YE Chengfeng]

Thanks for your reply.

You are right. I found that null-check is already performed in the caller of this two function. Sorry for the bothering.

Best Regards,
Chengfeng 

-----邮件原件-----
发件人: John Garry <john.garry@huawei.com> 
发送时间: 2021年10月26日 18:33
收件人: YE Chengfeng <cyeaa@connect.ust.hk>; linux-kernel@vger.kernel.org
主题: Re: 回复: driver/bug: suspected missing null check in hisi_lpc.c

On 25/10/2021 16:31, YE Chengfeng wrote:
> It is driver/bus, sorry for the typo.
> 
> -----邮件原件-----
> 发件人: YE Chengfeng
> 发送时间: 2021年10月25日 23:22
> 收件人: linux-kernel@vger.kernel.org; john.garry@huawei.com
> 主题: driver/bug: suspected missing null check in hisi_lpc.c
> 
> Hi,
> 
> https://apc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgith
> ub.com%2Ftorvalds%2Flinux%2Fblob%2Fmaster%2Fdrivers%2Fbus%2Fhisi_lpc.c
> %23L483&amp;data=04%7C01%7Ccyeaa%40connect.ust.hk%7Cc26f0b4a52504737c2
> 7508d9986bf5ae%7C6c1d415239d044ca88d9b8d6ddca0708%7C1%7C0%7C6377084117
> 14447677%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiL
> CJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=lkx93QoK%2FN1ilG0u5il5l
> hVjUiAbVY6RX%2FuJh%2BBHmuI%3D&amp;reserved=0
> 
> Our experimental static analysis tool detects a null-ptr-reference problem. It could be false positive, we report this to you just in case.
> 
> Null check is missing for the return pointer of ACPI_COMPANION at line 483 and line 504. It seems that there could be potential null-ptr-dereference problem at line 488 and line 509. Could you spare some time to have a look at it?
> 
> Thanks so much,
> Chengfeng
> 

I don't think that we should have a problem as ACPI_COMPANION() should just not return NULL for us. But I can't give you a better reason than that without fully examining the ACPI code, which I'm not keen on...

Thanks,
John