smb3: Replace smb2pdu 1-element arrays with flex-arrays

smb3: Replace smb2pdu 1-element arrays with flex-arrays

Origin: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit?id=06aa6eff7b243891c631b40852a0c453e274955d

commit eb3e28c1e89b4984308777231887e41aa8a0151f upstream.

The kernel is globally removing the ambiguous 0-length and 1-element
arrays in favor of flexible arrays, so that we can gain both compile-time
and run-time array bounds checking[1].

Replace the trailing 1-element array with a flexible array in the
following structures:

        struct smb2_err_rsp
        struct smb2_tree_connect_req
        struct smb2_negotiate_rsp
        struct smb2_sess_setup_req
        struct smb2_sess_setup_rsp
        struct smb2_read_req
        struct smb2_read_rsp
        struct smb2_write_req
        struct smb2_write_rsp
        struct smb2_query_directory_req
        struct smb2_query_directory_rsp
        struct smb2_set_info_req
        struct smb2_change_notify_rsp
        struct smb2_create_rsp
        struct smb2_query_info_req
        struct smb2_query_info_rsp

Replace the trailing 1-element array with a flexible array, but leave
the existing structure padding:

        struct smb2_file_all_info
        struct smb2_lock_req

Adjust all related size calculations to match the changes to sizeof().

No machine code output or .data section differences are produced after
these changes.

[1] For lots of details, see both:
    https://docs.kernel.org/process/deprecated.html#zero-length-and-one-element-arrays
    https://people.kernel.org/kees/bounded-flexible-arrays-in-c

Cc: Steve French <sfrench@samba.org>
Cc: Paulo Alcantara <pc@cjr.nz>
Cc: Ronnie Sahlberg <lsahlber@redhat.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Vasiliy Kovalev <kovalev@altlinux.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name smb3-Replace-smb2pdu-1-element-arrays-with-flex-arra.patch