Re: [syzbot] [hfs?] WARNING in hfs_write_inode

[Michael Schmitz <schmitzmic@gmail.com>]

Hi Linus,

Am 06.01.2023 um 12:46 schrieb Michael Schmitz:
> Hi Linus,
>
> Am 06.01.2023 um 10:53 schrieb Linus Torvalds:
>> On Thu, Jan 5, 2023 at 1:35 PM Michael Schmitz <schmitzmic@gmail.com>
>> wrote:
>>>
>>> Looking at Linus' patch, I wonder whether the missing fd.entrylength
>>> size test in the HFS_IS_RSRC(inode) case was due to the fact that a
>>> file's resource fork may be empty?
>>
>> But if that is the case, then the subsequent hfs_bnode_read would
>> return garbage, no? And then writing it back after the update would be
>> even worse.
>>
>> So adding that
>>
>> +               if (fd.entrylength < sizeof(struct hfs_cat_file))
>> +                       goto out;
>>
>> would seem to be the right thing anyway. No?
>
> Yes, it would seem to be the right thing (in order to avoid further
> corrupting HFS data structures). Returning -EIO might cause a regression
> though.

A brief test on a HFS filesystem image (copy of my yaboot bootstrap 
partition) did not show any regression, so your patch appears to be just 
fine as-is.

Cheers,

	Michael