Re: Regression Bug: use-after-free Write in udf_close_lvid

[Kun Hu]

> 2025年1月6日 22:19，Kun Hu <huk23@xxxxxxxxxxxxxx> 写道：
> 
> 
>> 
>> The syzlang reproducer seems to be missing (the link points to C code). As
>> a result one has to decipher what's actually happening from the C code
>> which is a bit tedious... Please fix that.
> 
> Sorry for incorrect link, 
> 
> Syzlang Reproducer: https://drive.google.com/file/d/1vshdFSRaGY3N4wyFscZdjKZsMU5j0z6H/view?usp=sharing
> 
>> 
>>> Similar Bug: https://lkml.org/lkml/2022/5/24/336
>> 
>> I have checked your reproducer and as far as I can tell it will modify
>> block device under a mounted filesystem (trying to use the same loop device
>> for xfs and udf). Such action is effectively equivalent to corrupting
>> memory. Please make sure CONFIG_BLK_DEV_WRITE_MOUNTED is disabled in all
>> your kernel configs used for fuzzing to avoid these invalid reproducers.
>> Thanks!
>> 
> 
> OK. I'll retest and get back to you on the results of those issues you mentioned
> 
> —
> thanks，
> Kun Hu
> 


This crash has not been reproduced after disable CONFIG_BLK_DEV_WRITE_MOUNTED.

——
Thanks,
Kun Hu