lightning-commando-rune – Command to Authorize Remote Peer Access

SYNOPSIS

commando-rune [rune] [restrictions]

DESCRIPTION

The commando-rune RPC command creates a base64 string called a rune which can be used to access commands on this node. Each rune contains a unique id (a number starting at 0), and can have restrictions inside it. Nobody can remove restrictions from a rune: if you try, the rune will be rejected. There is no limit on how many runes you can issue: the node doesn’t store them, but simply decodes and checks them as they are received.

If rune is supplied, the restrictions are simple appended to that rune (it doesn’t need to be a rune belonging to this node). If no rune is supplied, a new one is constructed, with a new unique id.

restrictions can be the string “readonly” (creates a rune which allows most get and list commands, and the summary command), or an array of restrictions, or a single resriction.

Each restriction is a set of one or more alternatives, such as “method is listpeers”, or “method is listpeers OR time is before 2023”. Alternatives use a simple language to examine the command which is being run:

  • time: the current UNIX time, e.g. “time<1656759180”.
  • id: the node_id of the peer, e.g. “id=024b9a1fa8e006f1e3937f65f66c408e6da8e1ca728ea43222a7381df1cc449605”.
  • method: the command being run, e.g. “method=withdraw”.
  • rate: the rate limit, per minute, e.g. “rate=60”.
  • pnum: the number of parameters. e.g. “pnum<2”.
  • pnameX: the parameter named X. e.g. “pnamedestination=1RustyRX2oai4EYYDpQGWvEL62BBGqN9T”.
  • parrN: the N’th parameter. e.g. “parr0=1RustyRX2oai4EYYDpQGWvEL62BBGqN9T”.

RESTRICTION FORMAT

Restrictions are one or more alternatives, separated by |. Each alternative is name operator value. The valid names are shown above. If a value contains |, & or \\, it must be preceeded by a \\.

  • =: passes if equal ie. identical. e.g. method=withdraw
  • /: not equals, e.g. method/withdraw
  • ^: starts with, e.g. id^024b9a1fa8e006f1e3937f
  • $: ends with, e.g. id$381df1cc449605.
  • ~: contains, e.g. id~006f1e3937f65f66c40.
  • <: is a decimal integer, and is less than. e.g. time<1656759180
  • >: is a decimal integer, and is greater than. e.g. time>1656759180
  • {: preceeds in alphabetical order (or matches but is shorter), e.g. id{02ff.
  • }: follows in alphabetical order (or matches but is longer), e.g. id}02ff.
  • #: a comment, ignored, e.g. dumb example#.
  • !: only passes if the name does not exist. e.g. pnamedestination!. Every other operator except # fails if name does not exist!

EXAMPLES

This creates a fresh rune which can do anything:

$ lightning-cli commando-rune
{
   "rune": "KUhZzNlECC7pYsz3QVbF1TqjIUYi3oyESTI7n60hLMs9MA==",
   "unique_id": "0"
}

We can add restrictions to that rune, like so:

$ lightning-cli commando-rune rune=KUhZzNlECC7pYsz3QVbF1TqjIUYi3oyESTI7n60hLMs9MA== restrictions=readonly
{
   "rune": "NbL7KkXcPQsVseJ9TdJNjJK2KsPjnt_q4cE_wvc873I9MCZtZXRob2RebGlzdHxtZXRob2ReZ2V0fG1ldGhvZD1zdW1tYXJ5Jm1ldGhvZC9saXN0ZGF0YXN0b3Jl",
   "unique_id": "0"
}

The “readonly” restriction is a short-cut for two restrictions:

  1. method^list|method^get|method=summary: You may call list, get or summary.
  2. method/listdatastore: But not listdatastore: that contains sensitive stuff!

We can do the same manually, like so:

$ lightning-cli commando-rune rune=KUhZzNlECC7pYsz3QVbF1TqjIUYi3oyESTI7n60hLMs9MA== restrictions='["method^list|method^get|method=summary","method/listdatastore"]'
{
   "rune": "NbL7KkXcPQsVseJ9TdJNjJK2KsPjnt_q4cE_wvc873I9MCZtZXRob2RebGlzdHxtZXRob2ReZ2V0fG1ldGhvZD1zdW1tYXJ5Jm1ldGhvZC9saXN0ZGF0YXN0b3Jl",
   "unique_id": "0"
}

Let’s create a rune which lets a specific peer (024b9a1fa8e006f1e3937f65f66c408e6da8e1ca728ea43222a7381df1cc449605) run “listpeers” on themselves:

$ lightning-cli commando-rune restrictions='["id=024b9a1fa8e006f1e3937f65f66c408e6da8e1ca728ea43222a7381df1cc449605","method=listpeers","pnum=1","pnameid=024b9a1fa8e006f1e3937f65f66c408e6da8e1ca728ea43222a7381df1cc449605|parr0=024b9a1fa8e006f1e3937f65f66c408e6da8e1ca728ea43222a7381df1cc449605"]'
{
   "rune": "FE8GHiGVvxcFqCQcClVRRiNE_XEeLYQzyG2jmqto4jM9MiZpZD0wMjRiOWExZmE4ZTAwNmYxZTM5MzdmNjVmNjZjNDA4ZTZkYThlMWNhNzI4ZWE0MzIyMmE3MzgxZGYxY2M0NDk2MDUmbWV0aG9kPWxpc3RwZWVycyZwbnVtPTEmcG5hbWVpZD0wMjRiOWExZmE4ZTAwNmYxZTM5MzdmNjVmNjZjNDA4ZTZkYThlMWNhNzI4ZWE0MzIyMmE3MzgxZGYxY2M0NDk2MDV8cGFycjA9MDI0YjlhMWZhOGUwMDZmMWUzOTM3ZjY1ZjY2YzQwOGU2ZGE4ZTFjYTcyOGVhNDMyMjJhNzM4MWRmMWNjNDQ5NjA1",
   "unique_id": "2"
}

This allows listpeers with 1 argument (pnum=1), which is either by name (pnameid), or position (parr0). We could shorten this in several ways: either allowing only positional or named parameters, or by testing the start of the parameters only. Here’s an example which only checks the first 9 bytes of the listpeers parameter:

$ lightning-cli commando-rune restrictions='["id=024b9a1fa8e006f1e3937f65f66c408e6da8e1ca728ea43222a7381df1cc449605","method=listpeers","pnum=1","pnameid^024b9a1fa8e006f1e393|parr0^024b9a1fa8e006f1e393"]'
 {
   "rune": "fTQnfL05coEbiBO8SS0cvQwCcPLxE9c02pZCC6HRVEY9MyZpZD0wMjRiOWExZmE4ZTAwNmYxZTM5MzdmNjVmNjZjNDA4ZTZkYThlMWNhNzI4ZWE0MzIyMmE3MzgxZGYxY2M0NDk2MDUmbWV0aG9kPWxpc3RwZWVycyZwbnVtPTEmcG5hbWVpZF4wMjRiOWExZmE4ZTAwNmYxZTM5M3xwYXJyMF4wMjRiOWExZmE4ZTAwNmYxZTM5Mw==",
   "unique_id": "3"
}

Before we give this to our peer, let’s add two more restrictions: that it only be usable for 24 hours from now (time<), and that it can only be used twice a minute (rate=2). date +%s can give us the current time in seconds:

$ lightning-cli commando-rune rune=fTQnfL05coEbiBO8SS0cvQwCcPLxE9c02pZCC6HRVEY9MyZpZD0wMjRiOWExZmE4ZTAwNmYxZTM5MzdmNjVmNjZjNDA4ZTZkYThlMWNhNzI4ZWE0MzIyMmE3MzgxZGYxY2M0NDk2MDUmbWV0aG9kPWxpc3RwZWVycyZwbnVtPTEmcG5hbWVpZF4wMjRiOWExZmE4ZTAwNmYxZTM5M3xwYXJyMF4wMjRiOWExZmE4ZTAwNmYxZTM5Mw== restrictions='["time<'$(($(date +%s) + 24*60*60))'","rate=2"]'
{
   "rune": "tU-RLjMiDpY2U0o3W1oFowar36RFGpWloPbW9-RuZdo9MyZpZD0wMjRiOWExZmE4ZTAwNmYxZTM5MzdmNjVmNjZjNDA4ZTZkYThlMWNhNzI4ZWE0MzIyMmE3MzgxZGYxY2M0NDk2MDUmbWV0aG9kPWxpc3RwZWVycyZwbnVtPTEmcG5hbWVpZF4wMjRiOWExZmE4ZTAwNmYxZTM5M3xwYXJyMF4wMjRiOWExZmE4ZTAwNmYxZTM5MyZ0aW1lPDE2NTY5MjA1MzgmcmF0ZT0y",
   "unique_id": "3"
}

You can also use lightning-decode(7) to examine runes you have been given:

$ .lightning-cli decode tU-RLjMiDpY2U0o3W1oFowar36RFGpWloPbW9-RuZdo9MyZpZD0wMjRiOWExZmE4ZTAwNmYxZTM5MzdmNjVmNjZjNDA4ZTZkYThlMWNhNzI4ZWE0MzIyMmE3MzgxZGYxY2M0NDk2MDUmbWV0aG9kPWxpc3RwZWVycyZwbnVtPTEmcG5hbWVpZF4wMjRiOWExZmE4ZTAwNmYxZTM5M3xwYXJyMF4wMjRiOWExZmE4ZTAwNmYxZTM5MyZ0aW1lPDE2NTY5MjA1MzgmcmF0ZT0y
{
   "type": "rune",
   "unique_id": "3",
   "string": "b54f912e33220e9636534a375b5a05a306abdfa4451a95a5a0f6d6f7e46e65da:=3&id=024b9a1fa8e006f1e3937f65f66c408e6da8e1ca728ea43222a7381df1cc449605&method=listpeers&pnum=1&pnameid^024b9a1fa8e006f1e393|parr0^024b9a1fa8e006f1e393&time<1656920538&rate=2",
   "restrictions": [
      {
         "alternatives": [
            "id=024b9a1fa8e006f1e3937f65f66c408e6da8e1ca728ea43222a7381df1cc449605"
         ],
         "summary": "id (of commanding peer) equal to '024b9a1fa8e006f1e3937f65f66c408e6da8e1ca728ea43222a7381df1cc449605'"
      },
      {
         "alternatives": [
            "method=listpeers"
         ],
         "summary": "method (of command) equal to 'listpeers'"
      },
      {
         "alternatives": [
            "pnum=1"
         ],
         "summary": "pnum (number of command parameters) equal to 1"
      },
      {
         "alternatives": [
            "pnameid^024b9a1fa8e006f1e393",
            "parr0^024b9a1fa8e006f1e393"
         ],
         "summary": "pnameid (object parameter 'id') starts with '024b9a1fa8e006f1e393' OR parr0 (array parameter #0) starts with '024b9a1fa8e006f1e393'"
      },
      {
         "alternatives": [
            "time<1656920538"
         ],
         "summary": "time (in seconds since 1970) less than 1656920538 (approximately 19 hours 18 minutes from now)"
      },
      {
         "alternatives": [
            "rate=2"
         ],
         "summary": "rate (max per minute) equal to 2"
      }
   ],
   "valid": true
}

SHARING RUNES

Because anyone can add a restriction to a rune, you can always turn a normal rune into a read-only rune, or restrict access for 30 minutes from the time you give it to someone. Adding restrictions before sharing runes is best practice.

If a rune has a ratelimit, any derived rune will have the same id, and thus will compete for that ratelimit. You might want to consider adding a tighter ratelimit to a rune before sharing it, so you will keep the remainder. For example, if you rune has a limit of 60 times per minute, adding a limit of 5 times per minute and handing that rune out means you can still use your original rune 55 times per minute.

RETURN VALUE

On success, an object is returned, containing:

  • rune (string): the resulting rune
  • unique_id (string): the id of this rune: this is set at creation and cannot be changed (even as restrictions are added)

The following warnings may also be returned:

  • warning_unrestricted_rune: A warning shown when runes are created with powers that could drain your node

AUTHOR

Rusty Russell <rusty@rustcorp.com.au> wrote the original Python commando.py plugin, the in-tree commando plugin, and this manual page.

Christian Decker came up with the name “commando”, which almost excuses his previous adoption of the name “Eltoo”.

SEE ALSO

lightning-commando(7), lightning-decode(7)