Confined: a safe resource bound immutable interpreter

• source: https://github.com/jul/confined
• ticketing: https://github.com/jul/confined/issues

Use

The purpose of this interpreter is to confine the user in a predictable way so that you don't have to fear to give your user the possibility to execute arbitrary code on your servers.

The language is mapping its input/internal stack to immutable data structures so that remote it is safe to pass it

Usage

Language

Sandbox for the language with console exists as a standalone script. At the end of the session your code can be replayed like this:

like:

(p3) jul@plumeau:~/src/confined$ confineds -j '{ "name":"jul", "tva":19.56}' session.2022-05-03-19:01:05.confined

results:

**************** CODE *********************


$name "ien": CAT
$tva >NUM 100: DIV 40: MUL
$tva >NUM 100: DIV
"tva": TAG
DUP
20:prix
MUL


**************** STACK ********************

******************************************
|   3 | "julien":
|   2 | 7.824:
|   1 | 0.1956:tva
|   0 | 3.912:prix
******************************************

Templating

Standalone

Templating usage be used like python -mconfined

For usage:

python confined -mconfined -h

As code

Can also be used programmatically

Example:

print templatize(dict(
    price=1,
    q=3,
    vat=19.6,
    name="super carcajou", country="FR"
),'''
<:
"hello":world
:> ici <:
    $name
:> has
<:
    $price >NUM
    $q >NUM MUL
    $vat >NUM 100:_per_cent_to_per_one DIV
    1:_having_price_AND_vat ADD MUL >STR
    " ":_separator
    CAT
    "comment in string and drop":_or_in_tag
    DROP
    "€":_cur "$":_cur
    $country
    "FR":_cocorico
    1:_nb_of_lines_for_looking_match
    MATCH
    IFT
    CAT :>
may I have a dict please? <:
    $price >NUM
    $q
    "a string":with_a_name
    "ignored":_because_tag_starts_with_
    1231231231231231:a_long_int
    "a new name":_with_space
    TAG
    EDICT
:>  ....
<: "fin": :>
end''')

Gives:

hello ici super carcajou has
18.31 €
may I have a dict please? {
    "q": "3",
    "price": "1",
    "with_a_name": "a string",
    "a new name": "1231231231231231"
}  ....
fin
end

Changelog

• 0.1.16 requirements for prompt_toolkit added, fixed tokenization errors
• 0.1.15 confineds now save and restore your code at the end of session
• 0.1.14 proud enough of confineds the console to interact with stack
• 0.1.13 now put confined error in stack.
• 0.1.12 putting errors in the stack. Having fun adding function to remember how it works.
• 0.1.11 improved error handling (light), bug fixed in templating
• 0.1.10 python3 (overdue)
• 0.1.9 after too many failure, embedding check_arg in this
• 0.1.4 forgot howto declare requirements
• 0.1.2 going to fast, mis clicked a button in pypi
• 0.1.1 initial release
• 0.1.0 initial release oops forgot __name__ == main

Roadmap before 1.0.0

• ensuring that stack is controled in size
• handle Decimal nitroglycerine correctly so that users CAN multiply safely
• Having a cheatsheet for the language
• create a loads/dumps to be able to serialize code from a user for remote execution
• limiting the size of the input scripts
• using only iterator to be able to do nth repeated operation without copying everything in memory
• handle versions compatibility for remote execution
• handle the precisions and formating of Decimal
• enough tests to feel secure

Bigger roadmap

Affter reading this https://compudanzas.net/uxn_tutorial.html I want to make a virtual machine that is fun to work with for a kid. I want to add the possibility to extend the language both in python to create interfaces/drivers and in the language itslef (like in tcl).