Support authorized invocation with different accounts (#321)

* Add sign functions for contract invoke function op's

* Documentation update

* Add minor changes

* Add requested changes

---------

Co-authored-by: Edwin Steven Guayacan <EdwinGuayacan@users.noreply.github.com>

docs/examples/soroban/invoke_contract_functions.md

@@ -1,4 +1,5 @@
 # Invoke Contract Function
+
 > **Warning**
 > Please note that Soroban is still under development, so breaking changes may occur.
 
@@ -9,6 +10,9 @@ There are three ways to perform a contract function invocation:
 
 ### Without Contract Authorization
 
+> **Note**
+> Used to invoke functions that don't require any authorization.
+
 ```elixir
 alias Stellar.TxBuild.{
   Account,
@@ -66,6 +70,9 @@ source_account
 
 ### With Authorization
 
+> **Note**
+> Used when the tx submitter and the invoker are the same.
+
 ```elixir
 alias Stellar.TxBuild.{
   InvokeHostFunction,
@@ -133,19 +140,18 @@ source_account
 |> Stellar.TxBuild.envelope()
 ```
 
-### With Stellar Account Authorization (WIP: Preview 10 support)
+### With Stellar Account Authorization
+
+> **Note**
+> Used when the tx submitter is different from the invoker.
 
 ```elixir
 alias StellarBase.XDR.{SorobanResources, SorobanTransactionData, UInt32}
 
 alias Stellar.TxBuild.{
-  ContractAuth,
-  AddressWithNonce,
-  AuthorizedInvocation,
   BaseFee,
   InvokeHostFunction,
   HostFunction,
-  HostFunctionArgs,
   SCVal,
   SCAddress,
   SequenceNumber,
@@ -155,59 +161,42 @@ alias Stellar.TxBuild.{
 alias Stellar.Horizon.Accounts
 alias Stellar.KeyPair
 
-contract_id = "8367a1324fdbb56d41e6a6cea2364e389e9f4e17d3ebea810d7bdeca663c2cd5"
-function_name = "inc"
+contract_address =
+  "CAMGSYINVVL6WP3Q5WPNL7FS4GZP37TWV7MKIRQF5QMYLK3N2SW4P3RC"
+  |> SCAddress.new()
+  |> (&SCVal.new(address: &1)).()
+function_name = SCVal.new(symbol: "inc")
 
 ## invoker
-{public_key, secret_key} =
+{invoker_public_key, invoker_secret_key} =
   KeyPair.from_secret_seed("SCAVFA3PI3MJLTQNMXOUNBSEUOSY66YMG3T2KCQKLQBENNVLVKNPV3EK")
 
 ## submitter
-keypair2 =
-  {public_key_2, _secret_key_2} =
+submitter_keypair =
+  {submitter_public_key, _submitter_secret_key} =
   KeyPair.from_secret_seed("SDRD4CSRGPWUIPRDS5O3CJBNJME5XVGWNI677MZDD4OD2ZL2R6K5IQ24")
 
-address_type = SCAddress.new(public_key)
+address_type = SCAddress.new(invoker_public_key)
 address = SCVal.new(address: address_type)
-args = [address, SCVal.new(u128: %{hi: 0, lo: 2})]
-
-function_args =
-  HostFunctionArgs.new(
-    type: :invoke,
-    contract_id: contract_id,
-    function_name: function_name,
-    args: args
-  )
-
-auth_invocation =
-  AuthorizedInvocation.new(
-    contract_id: contract_id,
-    function_name: function_name,
-    args: args,
-    sub_invocations: []
-  )
-
-# Nonce increment by 1 each successfully contract call
-address_with_nonce = AddressWithNonce.new(address: address_type, nonce: 0)
-
-contract_auth =
-  ContractAuth.new(
-    address_with_nonce: address_with_nonce,
-    authorized_invocation: auth_invocation
-  )
-  |> ContractAuth.sign(secret_key)
-
-function = HostFunction.new(args: function_args, auth: [contract_auth])
-
-invoke_host_function_op =
-  InvokeHostFunction.new(functions: [function], source_account: public_key_2)
-
-source_account = Stellar.TxBuild.Account.new(public_key_2)
-{:ok, seq_num} = Accounts.fetch_next_sequence_number(public_key)
+
+args =
+  SCVec.new([
+    contract_address,
+    function_name,
+    address,
+    SCVal.new(u128: %{hi: 0, lo: 2})
+  ])
+
+host_function = HostFunction.new(invoke_contract: args)
+
+invoke_host_function_op = InvokeHostFunction.new(host_function: host_function)
+
+source_account = Stellar.TxBuild.Account.new(submitter_public_key)
+{:ok, seq_num} = Accounts.fetch_next_sequence_number(submitter_public_key)
 sequence_number = SequenceNumber.new(seq_num)
-signature = Stellar.TxBuild.Signature.new(keypair2)
+signature = Stellar.TxBuild.Signature.new(submitter_keypair)
 
-# Use this XDR to simulate the transaction and get the soroban_data and min_resource_fee
+# Use this XDR to simulate the transaction and get the soroban_data, the invoke_host_function auth and the min_resource_fee
 source_account
 |> Stellar.TxBuild.new(sequence_number: sequence_number)
 |> Stellar.TxBuild.add_operation(invoke_host_function_op)
@@ -218,19 +207,27 @@ source_account
    resources: %SorobanResources{instructions: %UInt32{datum: datum}} = resources
  } = soroban_data,
  ""} =
-  "AAAAAwAAAAAAAAAAyU545WHCcUig2re/I2xMg5FaqNroaTV+AXQbahq8ftYAAAAGg2ehMk/btW1B5qbOojZOOJ6fThfT6+qBDXveymY8LNUAAAAUAAAAB0YZgeyJouAsCYZs6da/3e+lEoTyazuT0hzldmfbT2xPAAAAAgAAAAaDZ6EyT9u1bUHmps6iNk44np9OF9Pr6oENe97KZjws1QAAABAAAAABAAAAAgAAAA8AAAAHQ291bnRlcgAAAAATAAAAAAAAAADJTnjlYcJxSKDat78jbEyDkVqo2uhpNX4BdBtqGrx+1gAAAAaDZ6EyT9u1bUHmps6iNk44np9OF9Pr6oENe97KZjws1QAAABUAAAAAAAAAAMlOeOVhwnFIoNq3vyNsTIORWqja6Gk1fgF0G2oavH7WABQR1AAAFLAAAAGoAAACZAAAAAAAAAB4AAAAAA=="
+  "AAAAAAAAAAIAAAAAAAAAAMlOeOVhwnFIoNq3vyNsTIORWqja6Gk1fgF0G2oavH7WAAAAB5g18rNSrgYpg/O7tgIlBv42+QqjpEFv6gEqW+oDFUZbAAAAAAAAAAIAAAAGAAAAAAAAAADJTnjlYcJxSKDat78jbEyDkVqo2uhpNX4BdBtqGrx+1gAAABU69WqNb/7SRQAAAAAAAAAAAAAABgAAAAEYaWENrVfrP3DtntX8suGy/f52r9ikRgXsGYWrbdStxwAAABQAAAABAAAAAAA4FMMAABWQAAABmAAAA/AAAAAAAAAAxQ=="
 |> Base.decode64!()
 |> SorobanTransactionData.decode_xdr!()
 
+# Use the Soroban RPC `getLatestLedger` endpoint to obtain this number.
+# This number needs to be in the same ledger when submitting the transaction, otherwise the function invocation will fail.
+latest_ledger = 164_265
+
+auth_xdr = "AAAAAQAAAAAAAAAAyU545WHCcUig2re/I2xMg5FaqNroaTV+AXQbahq8ftY69WqNb/7SRQAAAAAAAAAAAAAAAAAAAAEYaWENrVfrP3DtntX8suGy/f52r9ikRgXsGYWrbdStxwAAAANpbmMAAAAAAgAAABIAAAAAAAAAAMlOeOVhwnFIoNq3vyNsTIORWqja6Gk1fgF0G2oavH7WAAAACQAAAAAAAAAAAAAAAAAAAAIAAAAA"
+
+auth = SorobanAuthorizationEntry.sign_xdr(auth_xdr, invoker_secret_key, latest_ledger)
+invoke_host_function_op = InvokeHostFunction.set_auth(invoke_host_function_op, [auth])
+
 # Needed calculations since simulate_transaction returns soroban_data
 # with wrong calculated instructions value because there are two signers
 new_instructions = UInt32.new(datum + round(datum * 0.25))
 new_resources = %{resources | instructions: new_instructions}
 soroban_data = %{soroban_data | resources: new_resources}
 
-# Arbitrary additional fee(10_000)
-min_resource_fee = 97_397 + 10_000
-fee = BaseFee.new(min_resource_fee + 100)
+# `round(min_resource_fee*0.1)` is needed since the cost of the transaction will increase because there are two signers.
+fee = BaseFee.new(min_resource_fee + round(min_resource_fee*0.1) +100)
 
 # Use the XDR generated here to send it to the futurenet
 source_account

lib/tx_build/soroban_authorization_entry.ex

@@ -3,17 +3,36 @@ defmodule Stellar.TxBuild.SorobanAuthorizationEntry do
   `SorobanAuthorizationEntry` struct definition.
   """
 
+  alias StellarBase.XDR.HashIDPreimage, as: HashIDPreimageXDR
+
+  alias StellarBase.XDR.HashIDPreimageSorobanAuthorization,
+    as: HashIDPreimageSorobanAuthorizationXDR
+
+  alias StellarBase.XDR.SCVec, as: SCVecXDR
+  alias StellarBase.XDR.SorobanAddressCredentials, as: SorobanAddressCredentialsXDR
+  alias StellarBase.XDR.SorobanAuthorizedInvocation, as: SorobanAuthorizedInvocationXDR
+  alias StellarBase.XDR.{EnvelopeType, Hash, Int64, SorobanAuthorizationEntry, UInt32}
+  alias Stellar.{KeyPair, Network}
+
   alias Stellar.TxBuild.{
+    HashIDPreimage,
+    HashIDPreimageSorobanAuthorization,
+    SCMapEntry,
+    SCVal,
+    SCVec,
+    SorobanAddressCredentials,
     SorobanCredentials,
     SorobanAuthorizedInvocation
   }
 
-  alias StellarBase.XDR.SorobanAuthorizationEntry
-
   @behaviour Stellar.TxBuild.XDR
 
   @type error :: {:error, atom()}
   @type validation :: {:ok, any()} | error()
+  @type base_64 :: String.t()
+  @type secret_key :: String.t()
+  @type sign_authorization :: String.t()
+  @type latest_ledger :: non_neg_integer()
   @type credentials :: SorobanCredentials.t()
   @type root_invocation :: SorobanAuthorizedInvocation.t()
 
@@ -56,6 +75,119 @@ defmodule Stellar.TxBuild.SorobanAuthorizationEntry do
 
   def to_xdr(_struct), do: {:error, :invalid_struct}
 
+  @spec sign(credentials :: t(), secret_key :: secret_key()) :: t() | error()
+  def sign(
+        %__MODULE__{
+          credentials: %SorobanCredentials{
+            value:
+              %SorobanAddressCredentials{
+                nonce: nonce,
+                signature_expiration_ledger: signature_expiration_ledger,
+                signature_args: signature_args
+              } = soroban_address_credentials
+          },
+          root_invocation: root_invocation
+        } = credentials,
+        secret_key
+      )
+      when is_binary(secret_key) do
+    {public_key, _secret_key} = KeyPair.from_secret_seed(secret_key)
+    raw_public_key = KeyPair.raw_public_key(public_key)
+    network_id = network_id_xdr()
+
+    signature =
+      [
+        network_id: network_id,
+        nonce: nonce,
+        signature_expiration_ledger: signature_expiration_ledger + 3,
+        invocation: root_invocation
+      ]
+      |> HashIDPreimageSorobanAuthorization.new()
+      |> (&HashIDPreimage.new(soroban_auth: &1)).()
+      |> HashIDPreimage.to_xdr()
+      |> HashIDPreimageXDR.encode_xdr!()
+      |> hash()
+      |> KeyPair.sign(secret_key)
+
+    public_key_map_entry =
+      SCMapEntry.new(
+        SCVal.new(symbol: "public_key"),
+        SCVal.new(bytes: raw_public_key)
+      )
+
+    signature_map_entry =
+      SCMapEntry.new(
+        SCVal.new(symbol: "signature"),
+        SCVal.new(bytes: signature)
+      )
+
+    signature_sc_val = SCVal.new(map: [public_key_map_entry, signature_map_entry])
+
+    soroban_address_credentials = %{
+      soroban_address_credentials
+      | signature_args: SCVec.append_sc_val(signature_args, signature_sc_val)
+    }
+
+    %{credentials | credentials: soroban_address_credentials}
+  end
+
+  def sign(_args, _secret_key), do: {:error, :invalid_sign_args}
+
+  @spec sign_xdr(
+          base_64 :: base_64(),
+          secret_key :: secret_key(),
+          latest_ledger :: latest_ledger()
+        ) :: sign_authorization() | error()
+  def sign_xdr(base_64, secret_key, latest_ledger)
+      when is_binary(base_64) and is_binary(secret_key) and is_integer(latest_ledger) do
+    {%SorobanAuthorizationEntry{
+       credentials:
+         %{
+           value:
+             %SorobanAddressCredentialsXDR{
+               nonce: nonce
+             } = soroban_address_credentials
+         } = credentials,
+       root_invocation: root_invocation
+     } = soroban_auth,
+     ""} =
+      base_64
+      |> Base.decode64!()
+      |> SorobanAuthorizationEntry.decode_xdr!()
+
+    signature_expiration_ledger = UInt32.new(latest_ledger + 3)
+
+    signature_args =
+      nonce
+      |> build_signature_args_from_xdr(
+        signature_expiration_ledger,
+        root_invocation,
+        secret_key
+      )
+      |> SCVal.to_xdr()
+      |> (&SCVecXDR.new([&1])).()
+
+    soroban_address_credentials = %{
+      soroban_address_credentials
+      | signature_args: signature_args,
+        signature_expiration_ledger: signature_expiration_ledger
+    }
+
+    credentials = %{credentials | value: soroban_address_credentials}
+
+    %{soroban_auth | credentials: credentials}
+    |> SorobanAuthorizationEntry.encode_xdr!()
+    |> Base.encode64()
+  end
+
+  def sign_xdr(_base_64, _secret_key, _latest_ledger), do: {:error, :invalid_sign_args}
+
+  @spec network_id_xdr :: binary()
+  defp network_id_xdr, do: hash(Network.passphrase())
+
+  @spec hash(data :: binary()) :: binary()
+  defp hash(data), do: :crypto.hash(:sha256, data)
+
   @spec validate_credentials(credentials :: credentials()) :: validation()
   defp validate_credentials(%SorobanCredentials{} = credentials), do: {:ok, credentials}
   defp validate_credentials(_credentials), do: {:error, :invalid_credentials}
@@ -65,4 +197,48 @@ defmodule Stellar.TxBuild.SorobanAuthorizationEntry do
     do: {:ok, root_invocation}
 
   defp validate_root_invocation(_root_invocation), do: {:error, :invalid_root_invocation}
+
+  @spec build_signature_args_from_xdr(
+          nonce :: Int64.t(),
+          signature_expiration_ledger :: UInt32.t(),
+          root_invocation :: SorobanAuthorizedInvocationXDR.t(),
+          secret_key :: secret_key()
+        ) :: SCVal.t() | error()
+  defp build_signature_args_from_xdr(
+         nonce,
+         signature_expiration_ledger,
+         root_invocation,
+         secret_key
+       ) do
+    {public_key, _secret_key} = KeyPair.from_secret_seed(secret_key)
+    raw_public_key = KeyPair.raw_public_key(public_key)
+    envelope_type = EnvelopeType.new(:ENVELOPE_TYPE_SOROBAN_AUTHORIZATION)
+
+    signature =
+      network_id_xdr()
+      |> Hash.new()
+      |> HashIDPreimageSorobanAuthorizationXDR.new(
+        nonce,
+        signature_expiration_ledger,
+        root_invocation
+      )
+      |> HashIDPreimageXDR.new(envelope_type)
+      |> HashIDPreimageXDR.encode_xdr!()
+      |> hash()
+      |> KeyPair.sign(secret_key)
+
+    public_key_map_entry =
+      SCMapEntry.new(
+        SCVal.new(symbol: "public_key"),
+        SCVal.new(bytes: raw_public_key)
+      )
+
+    signature_map_entry =
+      SCMapEntry.new(
+        SCVal.new(symbol: "signature"),
+        SCVal.new(bytes: signature)
+      )
+
+    SCVal.new(map: [public_key_map_entry, signature_map_entry])
+  end
 end