Re: question about CVE-2022-3169

["linan (AK)" <linan122@huawei.com>]

在 2022/11/11 9:37, Chaitanya Kulkarni 写道:
> Lian,
> 
> On 11/10/22 02:23, linan (AK) wrote:
>> Hi,
>> 1e866afd4bcd("nvme: ensure subsystem reset is single threaded")
>> fixed CVE-2022-3169.
>>
>> IIUC, ERROR path I got in this CVE:
>>              CPU1                                CPU2
>> nvme_dev_ioctl                            nvme_dev_ioctl
>>     nvme_reset_ctrl_sync                      nvme_reset_subsystem
>>         reset_work
>>           nvme_reset_work
>>             nvme_setup_io_queues
>>               nvme_remap_bar(dev, size)
>>                 if (size <= dev->bar_mapped_size)
>>                   return 0;
>>                 iounmap
>>                                                 reg_write32   //error
>>                 ioremap
>>
>> In nvme_remap_bar(), the premise of ioremap is "size >
>> dev->bar_mapped_size".
>>     size = NVME_REG_DBS + ((nr_io_queues + 1) * 8 * dev->db_stride);
>>       1)nr_io_queue = dev->nr_allocated_queues - 1, Onece set to
>> "nvme_max_io_queues(dev) + 1" during probe time, it could not change.
>>       2)db_stride is doorbell stride, it didn't change during my test
>> Therefore, I cant find a way to make iounmap happen.
>>
>> Could you tell me how you trigger the ERROR?
>>
>> Thanks,
>> Nan.
>>
> 
> Do you have a script to reproduce this ?
> 
> -ck
> 

I can't reproduce it. "cause the driver to unbind from the device at the 
same time as sending a subsystem reset", you can have a try like Keith said.