Re: [PATCH v5] hfs: update sanity check of the root record

[Tetsuo Handa]

On 2026/03/31 6:45, Viacheslav Dubeyko wrote:
> I've already reviewed this patch. And I am not agree with this suggestion.
> 
> We prepare the key with HFSPLUS_ROOT_CNID [1]:
> 
> err = hfsplus_cat_build_key(sb, fd.search_key, HFSPLUS_ROOT_CNID, &str);

What we are talking about is not hfsplus but hfs.
I can't catch why you are talking about hfsplus function.

> 
> The hfs_brec_read() executes the search of the record [2]:
> 
> 	res = hfs_brec_find(fd);
> 	if (res)
> 		return res;
> 
> The hfs_brec_find() should found the record for requested key. And if the found
> thread record contains not correct CNID, then we can check the found thread
> record and return error as the result of the search.

hfs_brec_read() indeed calls hfs_brec_find(). But I can't interpret how to extract
CNID as of returning from hfs_brec_find().

  int hfs_brec_read(struct hfs_find_data *fd, void *rec, u32 rec_len)
  {
  	int res;
  
  	res = hfs_brec_find(fd);
  	if (res)
  		return res;
  	if (fd->entrylength > rec_len)
  		return -EINVAL;
  	hfs_bnode_read(fd->bnode, rec, fd->entryoffset, fd->entrylength);
  	return 0;
  }

Since hfs_brec_read() doesn't know which type of struct (one of "struct hfs_cat_file",
"struct hfs_cat_dir" or "struct hfs_cat_thread") does the caller of hfs_brec_read()
want to read, I don't think hfs_brec_read() can tell whether the CNID is correct.

I am waiting for your response on
https://lkml.kernel.org/r/9f66743b-70e0-4886-884e-5203f5c02ed8@xxxxxxxxxxxxxxxxxxx
where the caller of hfs_brec_read() can tell whether the CNID is correct. But such
change is a matter of preference.

You can respond with your patch which will be much faster.