Auth method 3 (#54)

* Add changes from prior work

* Remove import of ops

* Cleanup and format

* Rename functions to match opcode naming

* Re-order lib.sw

* Fix types to use ContractId

* Refactor and cleanup

* Reorder lib.sw

* Clean up comments and types

* FIx lib deps ordering

* cleanup

* congig:update gitignore

* Commit stashed changes with get_coin_owner WIP

* Fix:cleanup merge conflict resolution mistake

* Clean up a bit and use Result.

* General cleanup.

* Improve comment.

* Fix a bunch of type errors.

* Add missed assert.

* Fix order to make compile.

* Refactor.

* fix

* Fix build errors.

* Update offsets for 255 max inputs.

* Remove warnings.

* Improve error name.

* Fix some asm.

* Fix more asm

* space

* Fix comment

* Fix offsets.

* Refactor to use new tx module.

* test: add auth test project

* test: register auth tests

* test: add tests to mod.rs

* test: add auth testing abi & contract

* test: add auth caller contract & script

* test: fix enum variant name

* test: fix import of result

* test: refactor types to workaround MissingData error from SDK

* test: fix number of args passed

* test: ignore script test

* style: forc fmt

* style: cargo fmt

* test: work on script test

* Remove redundant assert.

* Clean up tests, not working yet.

* Fix test for some reason.

* Fix test.

Co-authored-by: Nick Furfaro <nfurfaro33@gmail.com>

Author: adlerjohn

src/assert.sw

@@ -0,0 +1,12 @@
+library assert;
+
+use ::panic::panic;
+
+/// Assert that a value is true
+pub fn assert(a: bool) {
+    if !a {
+        panic(0);
+    } else {
+        ()
+    }
+}

src/chain.sw

@@ -27,12 +27,3 @@ pub fn log_u8(val: u8) {
         log r1 zero zero zero;
     }
 }
-
-/// Assert that a value is true
-pub fn assert(a: bool) {
-    if !a {
-        panic(0);
-    } else {
-        ()
-    }
-}

src/chain/auth.sw

@@ -1,41 +1,98 @@
 library auth;
-//! Functionality for determining who is calling an ABI method
+//! Functionality for determining who is calling a contract.
 
 use ::address::Address;
+use ::assert::assert;
+use ::b512::B512;
 use ::contract_id::ContractId;
+use ::option::*;
 use ::result::Result;
+use ::tx::*;
 
 pub enum AuthError {
-    ContextError: (),
+    InputsNotAllOwnedBySameAddress: (),
 }
 
 pub enum Sender {
     Address: Address,
-    Id: ContractId,
+    ContractId: ContractId,
 }
 
-/// Returns `true` if the caller is external (ie: a script or predicate).
-// ref: https://github.com/FuelLabs/fuel-specs/blob/master/specs/vm/opcodes.md#gm-get-metadata
+/// Returns `true` if the caller is external (i.e. a script).
+/// Otherwise, returns `false`.
+/// ref: https://github.com/FuelLabs/fuel-specs/blob/master/specs/vm/opcodes.md#gm-get-metadata
 pub fn caller_is_external() -> bool {
     asm(r1) {
         gm r1 i1;
         r1: bool
     }
 }
 
-/// Get the `Sender` (ie: `Address`| ContractId) from which a call was made.
-/// Returns a Result::Ok(Sender) or Result::Error.
-// NOTE: Currently only returns Result::Ok variant if the parent context is Internal.
+/// If caller is internal, returns the contract ID of the caller.
+/// Otherwise, undefined behavior.
+pub fn caller_contract_id() -> ContractId {
+    ~ContractId::from(asm(r1) {
+        gm r1 i2;
+        r1: b256
+    })
+}
+
+/// Get the `Sender` (i.e. `Address` or `ContractId`) from which a call was made.
+/// Returns a `Result::Ok(Sender)`, or `Result::Err(AuthError)` if a sender cannot be determined.
 pub fn msg_sender() -> Result<Sender, AuthError> {
     if caller_is_external() {
-        // TODO: Add call to get_coins_owner() here when implemented,
-        Result::Err(AuthError::ContextError)
+        let sender_res = get_coins_owner();
+        if let Result::Ok(sender) = sender_res {
+            Result::Ok(sender)
+        } else {
+            sender_res
+        }
     } else {
-        // Get caller's contract ID
-        let id = ~ContractId::from(asm(r1) {
-            gm r1 i2;
-            r1: b256
-        });
-        Result::Ok(Sender::Id(id))
+        // Get caller's `ContractId`.
+        Result::Ok(Sender::ContractId(caller_contract_id()))
+    }
+}
+
+/// Get the owner of the inputs (of type `InputCoin`) to a TransactionScript,
+/// if they all share the same owner.
+fn get_coins_owner() -> Result<Sender, AuthError> {
+    let target_input_type = 0u8;
+    let inputs_count = tx_inputs_count();
+
+    let mut candidate = Option::None::<Address>();
+    let mut i = 0u64;
+
+    while i < inputs_count {
+        let input_pointer = tx_input_pointer(i);
+        let input_type = tx_input_type(input_pointer);
+        if input_type != target_input_type {
+            // type != InputCoin
+            // Continue looping.
+            i = i + 1;
+        } else {
+            // type == InputCoin
+            let input_owner = Option::Some(tx_input_coin_owner(input_pointer));
+            if candidate.is_none() {
+                // This is the first input seen of the correct type.
+                candidate = input_owner;
+                i = i + 1;
+            } else {
+                // Compare current coin owner to candidate.
+                // `candidate` and `input_owner` must be `Option::Some` at this point,
+                // so can unwrap safely.
+                if input_owner.unwrap() == candidate.unwrap() {
+                    // Owners are a match, continue looping.
+                    i = i + 1;
+                } else {
+                    // Owners don't match. Return Err.
+                    i = inputs_count;
+                    return Result::Err(AuthError::InputsNotAllOwnedBySameAddress);
+                };
+            };
+        };
     }
+
+    // `candidate` must be `Option::Some` at this point, so can unwrap safely.
+    // Note: `inputs_count` is guaranteed to be at least 1 for any valid tx.
+    Result::Ok(Sender::Address(candidate.unwrap()))
 }

src/lib.sw

@@ -1,6 +1,7 @@
 library std;
 
 dep panic;
+dep assert;
 dep option;
 dep result;
 dep constants;

tests/test_artifacts/auth_caller_contract/.gitignore

@@ -0,0 +1,2 @@
+out
+target

tests/test_artifacts/auth_caller_contract/Forc.toml

@@ -0,0 +1,9 @@
+[project]
+authors = ["Fuel Labs <contact@fuel.sh>"]
+entry = "main.sw"
+license = "Apache-2.0"
+name = "auth_caller_contract"
+
+[dependencies]
+std = { path = "../../../" }
+auth_testing_abi = { path = "../auth_testing_abi"}

tests/test_artifacts/auth_caller_contract/src/main.sw

@@ -0,0 +1,20 @@
+contract;
+
+use auth_testing_abi::*;
+use std::contract_id::ContractId;
+use std::chain::auth::*;
+use std::constants::ZERO;
+use std::result::*;
+
+abi AuthCaller {
+    fn call_auth_contract(auth_id: ContractId, expected_id: ContractId) -> bool;
+}
+
+impl AuthCaller for Contract {
+    // TODO: improve this to return the ContractId itself.
+    // This is a workaround for the MissingData("cannot parse custom type with no components") error
+    fn call_auth_contract(auth_id: ContractId, expected_id: ContractId) -> bool {
+        let auth_contract = abi(AuthTesting, ~ContractId::into(auth_id));
+        auth_contract.returns_msg_sender(expected_id)
+    }
+}

tests/test_artifacts/auth_caller_script/.gitignore

@@ -0,0 +1,2 @@
+out
+target

tests/test_artifacts/auth_caller_script/Forc.toml

@@ -0,0 +1,9 @@
+[project]
+authors = ["Fuel Labs <contact@fuel.sh>"]
+entry = "main.sw"
+license = "Apache-2.0"
+name = "auth_caller_script"
+
+[dependencies]
+std = { path = "../../../" }
+auth_testing_abi = { path = "../auth_testing_abi"}

tests/test_artifacts/auth_caller_script/src/main.sw

@@ -0,0 +1,18 @@
+script;
+
+use auth_testing_abi::AuthTesting;
+use std::contract_id::ContractId;
+use std::chain::auth::*;
+use std::result::*;
+
+fn main() -> u64 {
+    // TODO: ContractId for auth_testing_contract should ideally be passed to script as an arg when possible.
+    let auth_contract = abi(AuthTesting, 0x377fd69456e97da7456331c18a859c9eb3ce741268c299eaea0167c0eff678ad);
+    let auth_caller_contract = ~ContractId::from(0x2fc63a758319acb31e34cbc2853b5ae4068b81dacb674db15b0b6d8d7dac074a);
+    let value = auth_contract.returns_msg_sender(auth_caller_contract);
+    if !value {
+        0
+    } else {
+        1
+    }
+}