access_mask needed for rename

[Jeremy Allison]

On Wed, Nov 02, 2016 at 11:29:33AM -0700, Kenny Dinh wrote:
> Hi all,
> 
> In the *can_rename* function in *source3/smbd/reply.c*, we check for of an
> existing open handle's access_mask to have either DELETE_ACCESS or
> FILE_WRITE_ATTRIBUTES to decide if the rename operation is allowed.  This
> means that if the file was opened with only FILE_WRITE_ATTRIBUTES without
> DELETE_ACCESS, the rename would be allowed to go through.  This failed the
> smbtorture *smb2.rename.simple_no_delete *test.
> The strict rule (which is what MS does) is to allow rename request to go
> through only if DELETE_ACCESS is specified.
> 
> Was there any reason to relax to rule, (and deviate from the behavior on MS
> server), to allow the rename to go through even when the file handle was
> opened with only the FILE_WRITE_ATTRIBUTES access_mask?

There's a long history to this I recall.

Can you try all possible rename tests with your change (remove
the FILE_WRITE_ATTRIBUTES). Might be some issue with SMB1-only
tests.

This also may correspond to older code that didn't have a
file handle.

I do remember trying to remove this several years ago
and not being able to.

The core fileserver code might be in better shape to attempt
this now.

Jeremy.

> Below is the function, and the line in question is 2685.
> 
> 2654 static NTSTATUS can_rename(connection_struct *conn, files_struct *fsp,
> 2655                         uint16_t dirtype)
> 2656 {
> 2657         if (!CAN_WRITE(conn)) {
> 2658                 return NT_STATUS_MEDIA_WRITE_PROTECTED;
> 2659         }
> 2660
> 2661         if ((dirtype & (FILE_ATTRIBUTE_HIDDEN |
> FILE_ATTRIBUTE_SYSTEM)) !=
> 2662                         (FILE_ATTRIBUTE_HIDDEN |
> FILE_ATTRIBUTE_SYSTEM)) {
> 2663                 /* Only bother to read the DOS attribute if we might
> deny the
> 2664                    rename on the grounds of attribute missmatch. */
> 2665                 uint32_t fmode = dos_mode(conn, fsp->fsp_name);
> 2666                 if ((fmode & ~dirtype) & (FILE_ATTRIBUTE_HIDDEN |
> FILE_ATTRIBUTE_SYSTEM)) {
> 2667                         return NT_STATUS_NO_SUCH_FILE;
> 2668                 }
> 2669         }
> 2670
> 2671         if (S_ISDIR(fsp->fsp_name->st.st_ex_mode)) {
> 2672                 if (fsp->posix_flags &
> (FSP_POSIX_FLAGS_OPEN|FSP_POSIX_FLAGS_RENAME)) {
> 2673                         return NT_STATUS_OK;
> 2674                 }
> 2675
> 2676                 /* If no pathnames are open below this
> 2677                    directory, allow the rename. */
> 2678
> 2679                 if (file_find_subpath(fsp)) {
> 2680                         return NT_STATUS_ACCESS_DENIED;
> 2681                 }
> 2682                 return NT_STATUS_OK;
> 2683         }
> 2684
> *2685         if (fsp->access_mask & (DELETE_ACCESS|FILE_WRITE_ATTRIBUTES))
> {*
> *2686                 return NT_STATUS_OK;*
> *2687         }*
> 2688
> 2689         return NT_STATUS_ACCESS_DENIED;
> 2690 }