directory with a symlink pointing to non-existing file

[Jeremy Allison]

On Thu, Oct 21, 2021 at 10:23:04AM -0700, Jeremy Allison via samba-technical wrote:
>On Thu, Oct 21, 2021 at 10:05:47AM -0700, Jeremy Allison via samba-technical wrote:
>>On Thu, Oct 21, 2021 at 06:35:35PM +0200, Pavel Filipensky via samba-technical wrote:
>>>Hi,
>>>
>>>if on local linux file system there is a directory with only one file - a
>>>symlink pointing to a non-existing file then:
>>>- from SMB point of view the directory is *empty*, such symlink is not shown
>>>- but SMB does allow to delete such *empty* directory, it gives
>>>NT_STATUS_DIRECTORY_NOT_EMPTY
>>>
>>>This is seen with samba 4.10 and 4.13. Could there be a difference with the
>>>latest samba?
>>>
>>>setting those smb.conf params has no effect:
>>>
>>>allow insecure wide links = yes
>>>unix extensions = no
>>>follow symlinks = yes
>>>wide links = yes
>>
>>Can you try setting the share parameter:
>>
>>delete veto files = yes
>>
>>I think this will allow a dangling symlink
>>to be removed when a directory is deleted
>>(at least in 4.15.0).
>
>Ah, just checked - it doesn't work due
>to the check in can_delete_directory_fsp()
>due to this code:
>
>1930                 if (S_ISLNK(smb_dname_full->st.st_ex_mode)) {
>1931                         TALLOC_FREE(talloced);
>1932                         TALLOC_FREE(fullname);
>1933                         TALLOC_FREE(smb_dname_full);
>1934                         DBG_DEBUG("got name %s - can't delete\n", dname);
>1935                         status = NT_STATUS_DIRECTORY_NOT_EMPTY;
>1936                         break;
>1937                 }
>
>if dname had matches a veto file parameter then
>it would allow deletion, but not if it's a non
>vetoed pathname.

Done lots more investigation on this, and it looks like
recursive directory deletion with veto files is broken in 4.15.0.

I'll log a bug and fix..