Scripting

A simple script could look like this:

descr = "example.com"

function verify(user, password)
    session = http_mksession()

    -- get csrf token
    req = http_request(session, 'GET', 'https://example.com/login', {})
    resp = http_send(req)
    if last_err() then return end

    -- parse token from html
    html = resp['text']
    csrf = html_select(html, 'input[name="csrf"]')
    token = csrf["attrs"]["value"]

    -- send login
    req = http_request(session, 'POST', 'https://example.com/login', {
        form={
            user=user,
            password=password,
            csrf=token
        }
    })
    resp = http_send(req)
    if last_err() then return end

    -- search response for successful login
    html = resp['text']
    return html:find('Login successful') ~= nil
end

Please see the reference and [examples](/scripts) for all available functions. Keep in mind that you can use print(x) and badtouch oneshot to debug your script.

base64_decode

Decode a base64 string.

base64_decode("ww==")

base64_encode

Encode a binary array with base64.

base64_encode("\x00\xff")

clear_err

Clear all recorded errors to prevent a requeue.

if last_err() then
    clear_err()
    return false
else
    return true
end

execve

Execute an external program. Returns the exit code.

execve("myprog", {"arg1", "arg2", "--arg", "3"})

hex

Hex encode a list of bytes.

hex("\x6F\x68\x61\x69\x0A\x00")

hmac_md5

Calculate an hmac with md5. Returns a binary array.

hmac_md5("secret", "my authenticated message")

hmac_sha1

Calculate an hmac with sha1. Returns a binary array.

hmac_sha1("secret", "my authenticated message")

hmac_sha2_256

Calculate an hmac with sha2_256. Returns a binary array.

hmac_sha2_256("secret", "my authenticated message")

hmac_sha2_512

Calculate an hmac with sha2_512. Returns a binary array.

hmac_sha2_512("secret", "my authenticated message")

hmac_sha3_256

Calculate an hmac with sha3_256. Returns a binary array.

hmac_sha3_256("secret", "my authenticated message")

hmac_sha3_512

Calculate an hmac with sha3_512. Returns a binary array.

hmac_sha3_512("secret", "my authenticated message")

html_select

Parses an html document and returns the first element that matches the css selector. The return value is a table with text being the inner text and attrs being a table of the elements attributes.

csrf = html_select(html, 'input[name="csrf"]')
token = csrf["attrs"]["value"]

html_select_list

Same as html_select but returns all matches instead of the first one.

html_select_list(html, 'input[name="csrf"]')

http_basic_auth

Sends a GET request with basic auth. Returns true if no WWW-Authenticate header is set and the status code is not 401.

http_basic_auth("https://httpbin.org/basic-auth/foo/buzz", user, password)

http_mksession

Create a session object. This is similar to requests.Session in python-requests and keeps track of cookies.

session = http_mksession()

http_request

Prepares an http request. The first argument is the session reference and cookies from that session are copied into the request. After the request has been sent, the cookies from the response are copied back into the session.

The next arguments are the method, the url and additional options. Please note that you still need to specify an empty table {} even if no options are set. The following options are available:

  • query - a map of query parameters that should be set on the url
  • headers - a map of headers that should be set
  • basic_auth - configure the basic auth header with {"user, "password"}
  • user_agent - overwrite the default user agent with a string
  • json - the request body that should be json encoded
  • form - the request body that should be form encoded
  • body - the raw request body as string
req = http_request(session, 'POST', 'https://httpbin.org/post', {
    json={
        user=user,
        password=password,
    }
})
resp = http_send(req)
if last_err() then return end
if resp["status"] ~= 200 then return "invalid status code" end

http_send

Send the request that has been built with http_request. Returns a table with the following keys:

  • status - the http status code
  • headers - a table of headers
  • text - the response body as string
req = http_request(session, 'POST', 'https://httpbin.org/post', {
    json={
        user=user,
        password=password,
    }
})
resp = http_send(req)
if last_err() then return end
if resp["status"] ~= 200 then return "invalid status code" end

json_decode

Decode a lua value from a json string.

json_decode("{\"data\":{\"password\":\"fizz\",\"user\":\"bar\"},\"list\":[1,3,3,7]}")

json_encode

Encode a lua value to a json string. Note that empty tables are encoded to an empty object {} instead of an empty list [].

x = json_encode({
    hello="world",
    almost_one=0.9999,
    list={1,3,3,7},
    data={
        user=user,
        password=password,
        empty=nil
    }
})

last_err

Returns nil if no error has been recorded, returns a string otherwise.

if last_err() then return end

ldap_bind

Connect to an ldap server and try to authenticate with the given user.

ldap_bind("ldaps://ldap.example.com/",
    "cn=\"" .. ldap_escape(user) .. "\",ou=users,dc=example,dc=com", password)

ldap_escape

Escape an attribute value in a relative distinguished name.

ldap_escape(user)

ldap_search_bind

Connect to an ldap server, log into a search user, search for the target user and then try to authenticate with the first DN that was returned by the search.

ldap_search_bind("ldaps://ldap.example.com/",
    -- the user we use to find the correct DN
    "cn=search_user,ou=users,dc=example,dc=com", "searchpw",
    -- base DN we search in
    "dc=example,dc=com",
    -- the user we test
    user, password)

md5

Hash a byte array with md5 and return the results as bytes.

hex(md5("\x00\xff"))

mysql_connect

Connect to a mysql database and try to authenticate with the provided credentials. Returns a mysql connection on success.

sock = mysql_connect("127.0.0.1", 3306, user, password)

mysql_query

Run a query on a mysql connection. The 3rd parameter is for prepared statements.

rows = mysql_query(sock, 'SELECT VERSION(), :foo as foo', {
    foo='magic'
})

print

Prints the value of a variable. Please note that this bypasses the regular writer and may interfer with the progress bar. Only use this for debugging.

print({
    data={
        user=user,
        password=password
    }
})

rand

Returns a random u32 with a minimum and maximum constraint. The return value can be greater or equal to the minimum boundary, and always lower than the maximum boundary. This function has not been reviewed for cryptographic security.

rand(0, 256)

randombytes

Generate the specified number of random bytes.

randombytes(16)

sha1

Hash a byte array with sha1 and return the results as bytes.

hex(sha1("\x00\xff"))

sha2_256

Hash a byte array with sha2_256 and return the results as bytes.

hex(sha2_256("\x00\xff"))

sha2_512

Hash a byte array with sha2_512 and return the results as bytes.

hex(sha2_512("\x00\xff"))

sha3_256

Hash a byte array with sha3_256 and return the results as bytes.

hex(sha3_256("\x00\xff"))

sha3_512

Hash a byte array with sha3_512 and return the results as bytes.

hex(sha3_512("\x00\xff"))

sleep

Pauses the thread for the specified number of seconds. This is mostly used to debug concurrency.

sleep(3)

sock_connect

Create a tcp connection.

sock = sock_connect("127.0.0.1", 1337)

sock_send

Send data to the socket.

sock_send(sock, "hello world")

sock_recv

Receive up to 4096 bytes from the socket.

x = sock_recv(sock)

sock_sendline

Send a string to the socket. A newline is automatically appended to the string.

sock_sendline(sock, line)

sock_recvline

Receive a line from the socket. The line includes the newline.

x = sock_recvline(sock)

sock_recvall

Receive all data from the socket until EOF.

x = sock_recvall(sock)

sock_recvline_contains

Receive lines from the server until a line contains the needle, then return this line.

x = sock_recvline_contains(sock, needle)

sock_recvline_regex

Receive lines from the server until a line matches the regex, then return this line.

x = sock_recvline_regex(sock, "^250 ")

sock_recvn

Receive exactly n bytes from the socket.

x = sock_recvn(sock, 4)

sock_recvuntil

Receive until the needle is found, then return all data including the needle.

x = sock_recvuntil(sock, needle)

sock_sendafter

Receive until the needle is found, then write data to the socket.

sock_sendafter(sock, needle, data)

sock_newline

Overwrite the default n newline.

sock_newline(sock, "\r\n")

Wrapping python scripts

The badtouch runtime is still very bare bones, so you might have to shell out to your regular python script occasionally. Your wrapper may look like this:

descr = "example.com"

function verify(user, password)
    ret = execve("./docs/test.py", {user, password})
    if last_err() then return end

    if ret == 2 then
        return "script signaled an exception"
    end

    return ret == 0
end

Your python script may look like this:

import sys

try:
    if sys.argv[1] == "foo" and sys.argv[2] == "bar":
        # correct credentials
        sys.exit(0)
    else:
        # incorrect credentials
        sys.exit(1)
except:
    # signal an exception
    # this requeues the attempt instead of discarding it
    sys.exit(2)