Re: [PATCH v2] ksmb: discard write access to the directory open

[Ralph Boehme <slow@samba.org>]

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On 7/5/24 2:33 PM, Namjae Jeon wrote:
> 2024년 7월 5일 (금) 오후 8:54, Ralph Boehme <slow@samba.org>님이 작성:
>>
>> On 7/5/24 5:27 AM, Hobin Woo wrote:
>>> may_open() does not allow a directory to be opened with the write access.
>>> However, some writing flags set by client result in adding write access
>>> on server, making ksmbd incompatible with FUSE file system. Simply, let's
>>> discard the write access when opening a directory.
>>
>> afair this should cause a failure like EACCESS or EISDIR and just be
>> ignored. What does a Windows server return in this case, or Samba for
>> that matter as it (hopefully) will behave like Windows.
>  From what I've checked the packet dump, Samba doesn't return any
> errors in the same case.
> Samba seems to open it with O_RDONLY if it is directory, So there is
> no problem, is it right?

Hm, it seems my memory is playing tricks on me. Samba indeed forces 
O_RDONLY for directories in the servers and ignores the client requested 
access mask. Interestingly we don't seem to have any test for this case, 
at least I couldn't find any with a quick search. Quickly putting 
together a torture test shows Windows behaves the same. MS-FSA doesn't 
mention any such check should be done for directories as well. Getinfo 
on such a handle even returns the original unmodified client access 
mask, including the write access.

Sorry for the noise! :)

-slow

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