The semantics of paths in VFS modules

Richard Sharpe realrichardsharpe at gmail.com
Sun Apr 3 19:42:08 UTC 2016


On Sun, Apr 3, 2016 at 12:05 PM, Uri Simchoni <uri at samba.org> wrote:
> On 04/02/2016 11:17 PM, Richard Sharpe wrote:
>> On Sat, Apr 2, 2016 at 12:54 PM, Uri Simchoni <uri at samba.org> wrote:
>>> Hi,
>>>
>>> I would like to document the meaning of path names in the wiki
>>> (add it to the vfs module writing page), and thought I'd first submit it
>>> to the list to get comments.
>>
>> In general I like it.
>>
>> There are some special cases, I think, such as if you allow wide
>> links, then Samba cannot use paths relative to the root of the share.
>>
>> Maybe it falls under what you have already written.
> Thanks for reading and commenting.
>
> I haven't covered this one, and should probably write something about
> wide links (I intend to cover more semantics of individual functions and
> this can fall under realpath). However, it appears to me that even if
> wide links are allowed, smbd would not, as a result, hand paths which
> are not relative to the share's root to VFS modules.
>
> I mean, if we have "foo" --> /etc/shadow, then the SMB operations are on
> foo, and so are the resulting VFS operations. There's realpath_fn which
> would *return* /etc/shadow, but smbd would use the return val only for
> comparison and not pass it on to other VFS modules.
>
> Please correct me if I'm wrong.

Hmmm, I don't know. I will have to look, and perhaps Samba simply
passes the original name to SMB_VFS_OPEN, in which case there is not a
problem.

We have seen some absolute names, I believe, but maybe only on initial
connection to the share.

-- 
Regards,
Richard Sharpe
(何以解憂?唯有杜康。--曹操)



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