Re: [Caml-list] Safe marshall?

["Gerd Stolpmann" <info@gerd-stolpmann.de>]

Gerd Stolpmann said:
>
> Oliver Bandel said:
>> On Thu, Feb 17, 2005 at 03:14:30PM -0800, Eric Stokes wrote:
>>> I have to agree with Gerd, if at all possible use a protocol compiler
>>> such as XDR, or ASN.1, even signing might not be secure if your
>>
>> Yes, XDR seems to be a good idea.
>>
>>
>>> attacker can get ahold of the keys you are using. I can attest to the
>>> robustness of Gerd's XDR implementation, I have used it in several
>>> projects.
>>
>> Well.. is there already an XDR-binding for OCaml?
>
> Yes, as already pointed out, it is part of my SunRPC implementation:
> http://ocaml-programming.de/programming/rpc.html. It is not a binding,
> however, but a pure O'Caml implementation.
>
> It is quite easy and obvious how to use the XDR part alone without the
> rest of RPC. For example, to define a record with an integer
> and a string of maximum 20 characters:
>
> open Xdr
> open Rtypes
> let my_type_term   X_struct [ "my_int", X_int;

Oops, obviously somebody has stolen my "=". It is of course
let my_type_term = X_struct (etc.).

>             "my_string", (X_string (uint4_of_int 20)) ]
> let my_type = validate_xdt_type_term my_type_term
>
> Now, to encode a value:
>
> let my_val   XV_struct [ "my_int", (XV_int (int4_of_int 42));
>              "my_string", (XV_string "Sample") ]
> let my_val_as_wire_string   pack_xdr_value_as_string my_val my_type []
>
> my_val_as_wire_string can now be sent over the network. For
> decoding, use:
>
> let my_val_again   unpack_xdr_value my_val_as_wire_string my_type []
>
> If the string is illegal (e.g. my_string is longer than
> 20 characters), exceptions will be thrown.
>
> One can also use ocamlrpcgen to generate parts of the above
> code, including automatic conversion between XDR and the
> corresponding O'Caml types (e.g. an XDR struct is converted
> to an O'Caml record type). For complex protocols, the overhead
> of learning ocamlrpcgen is worth the effort.
>
> One should also consider using RPC directly rather than to invent
> a new networking layer.
>
> Gerd
>
>> Where to find it?!
>>
>> Ciao,
>>   Oliver
>>
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>
>
> ------------------------------------------------------------
> Gerd Stolpmann * Viktoriastr. 45 * 64293 Darmstadt * Germany
> gerd@gerd-stolpmann.de          http://www.gerd-stolpmann.de
> ------------------------------------------------------------
>
>
>
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------------------------------------------------------------
Gerd Stolpmann * Viktoriastr. 45 * 64293 Darmstadt * Germany
gerd@gerd-stolpmann.de          http://www.gerd-stolpmann.de
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