Re: [PATCH v3] ksmbd: fill in FileSysIdentifier in FS_POSIX_INFORMATION

[Namjae Jeon]

On Mon, Aug 24, 2026 at 11:40 PM Aleksandr Khromov <haa@xxxxxxxxx> wrote:
>
> smb2_get_info_filesystem() reports 56 bytes for FS_POSIX_INFORMATION,
> that is the whole of FILE_SYSTEM_POSIX_INFO, but never assigns
> FileSysIdentifier.  Those eight bytes go to the client as they are found
> in the response buffer.
>
> The buffer is zeroed on allocation, so a standalone request leaks
> nothing.  A compound request can leak: the offset of the next response
> is advanced by the length pinned for the previous one, so a reply that
> was written into the buffer and then dropped in favour of the short
> error response of smb2_set_err_rsp() stays there, and the next reply is
> laid over it with only the header cleared.
>
> Report the file system id statfs() returned, which is what the field is
> for.  FileSysIdentifier is __le64 and f_fsid is a pair of ints, so
> assemble the value first, val[0] as the low half, and convert it on the
> way out.
>
> Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Aleksandr Khromov <haa@xxxxxxxxx>
Applied it to #ksmbd-for-next.
Thanks!