Unique Usernames in Identity Pallet (paritytech#2651)

This PR allows _username authorities_ to issue unique usernames that
correspond with an account. It also provides two-way lookup, that is
from `AccountId` to a single, "primary" `Username` (alongside
`Registration`) and multiple unique `Username`s to an `AccountId`.

Key features:

- Username Authorities added (and removed) via privileged origin.
- Authorities have a `suffix` and an `allocation`. They can grant up to
`allocation` usernames. Their `suffix` will be appended to the usernames
that they issue. A suffix may be up to 7 characters long.
- Users can ask an authority to grant them a username. This will take
the form `myusername.suffix`. The entire name (including suffix) must be
less than or equal to 32 alphanumeric characters.
- Users can approve a username for themselves in one of two ways (that
is, authorities cannot grant them arbitrarily):
- Pre-sign the entire username (including suffix) with a secret key that
corresponds to their `AccountId` (for keyed accounts, obviously); or
- Accept the username after it has been granted by an authority (it will
be queued until accepted) (for non-keyed accounts like pure proxies or
multisigs).
- The system does not require any funds or deposits. Users without an
identity will be given a default one (presumably all fields set to
`None`). If they update this info, they will need to place the normal
storage deposit.
- If a user does not have any username, their first one will be set as
`Primary`, and their `AccountId` will map to that one. If they get
subsequent usernames, they can choose which one to be their primary via
`set_primary_username`.
- There are some state cleanup functions to remove expired usernames
that have not been accepted and dangling usernames whose owners have
called `clear_identity`.

TODO:

- [x] Add migration to runtimes
- [x] Probably do off-chain migration into People Chain genesis
- [x] Address a few TODO questions in code (please review)

---------

Co-authored-by: Liam Aharon <liam.aharon@hotmail.com>
Co-authored-by: Gonçalo Pestana <g6pestana@gmail.com>
Co-authored-by: Oliver Tale-Yazdi <oliver.tale-yazdi@parity.io>
Co-authored-by: Dónal Murray <donal.murray@parity.io>

substrate/bin/node/runtime/src/impls.rs

@@ -64,7 +64,7 @@ impl IdentityVerifier<AccountId> for AllianceIdentityVerifier {
 	fn has_good_judgement(who: &AccountId) -> bool {
 		use pallet_identity::Judgement;
 		crate::Identity::identity(who)
-			.map(|registration| registration.judgements)
+			.map(|(registration, _)| registration.judgements)
 			.map_or(false, |judgements| {
 				judgements
 					.iter()

substrate/bin/node/runtime/src/lib.rs

@@ -1500,6 +1500,12 @@ impl pallet_identity::Config for Runtime {
 	type Slashed = Treasury;
 	type ForceOrigin = EnsureRootOrHalfCouncil;
 	type RegistrarOrigin = EnsureRootOrHalfCouncil;
+	type OffchainSignature = Signature;
+	type SigningPublicKey = <Signature as traits::Verify>::Signer;
+	type UsernameAuthorityOrigin = EnsureRoot<Self::AccountId>;
+	type PendingUsernameExpiration = ConstU32<{ 7 * DAYS }>;
+	type MaxSuffixLength = ConstU32<7>;
+	type MaxUsernameLength = ConstU32<32>;
 	type WeightInfo = pallet_identity::weights::SubstrateWeight<Runtime>;
 }
 
@@ -2208,13 +2214,17 @@ pub type Executive = frame_executive::Executive<
 	Migrations,
 >;
 
+// We don't have a limit in the Relay Chain.
+const IDENTITY_MIGRATION_KEY_LIMIT: u64 = u64::MAX;
+
 // All migrations executed on runtime upgrade as a nested tuple of types implementing
 // `OnRuntimeUpgrade`. Note: These are examples and do not need to be run directly
 // after the genesis block.
 type Migrations = (
 	pallet_nomination_pools::migration::versioned::V6ToV7<Runtime>,
 	pallet_alliance::migration::Migration<Runtime>,
 	pallet_contracts::Migration<Runtime>,
+	pallet_identity::migration::versioned::V0ToV1<Runtime, IDENTITY_MIGRATION_KEY_LIMIT>,
 );
 
 type EventRecord = frame_system::EventRecord<

substrate/frame/alliance/src/mock.rs

@@ -19,7 +19,10 @@
 
 pub use sp_core::H256;
 use sp_runtime::traits::Hash;
-pub use sp_runtime::{traits::BlakeTwo256, BuildStorage};
+pub use sp_runtime::{
+	traits::{BlakeTwo256, IdentifyAccount, IdentityLookup, Lazy, Verify},
+	BuildStorage, MultiSignature,
+};
 use sp_std::convert::{TryFrom, TryInto};
 
 pub use frame_support::{
@@ -101,6 +104,7 @@ parameter_types! {
 	pub const MaxSubAccounts: u32 = 2;
 	pub const MaxAdditionalFields: u32 = 2;
 	pub const MaxRegistrars: u32 = 20;
+	pub const PendingUsernameExpiration: u64 = 100;
 }
 ord_parameter_types! {
 	pub const One: u64 = 1;
@@ -124,9 +128,34 @@ impl pallet_identity::Config for Test {
 	type Slashed = ();
 	type RegistrarOrigin = EnsureOneOrRoot;
 	type ForceOrigin = EnsureTwoOrRoot;
+	type OffchainSignature = AccountU64;
+	type SigningPublicKey = AccountU64;
+	type UsernameAuthorityOrigin = EnsureOneOrRoot;
+	type PendingUsernameExpiration = PendingUsernameExpiration;
+	type MaxSuffixLength = ConstU32<7>;
+	type MaxUsernameLength = ConstU32<32>;
 	type WeightInfo = ();
 }
 
+#[derive(Clone, Debug, Encode, Decode, PartialEq, Eq, TypeInfo)]
+pub struct AccountU64(u64);
+impl IdentifyAccount for AccountU64 {
+	type AccountId = u64;
+	fn into_account(self) -> u64 {
+		0u64
+	}
+}
+impl Verify for AccountU64 {
+	type Signer = AccountU64;
+	fn verify<L: Lazy<[u8]>>(
+		&self,
+		_msg: L,
+		_signer: &<Self::Signer as IdentifyAccount>::AccountId,
+	) -> bool {
+		false
+	}
+}
+
 pub struct AllianceIdentityVerifier;
 impl IdentityVerifier<AccountId> for AllianceIdentityVerifier {
 	fn has_required_identities(who: &AccountId) -> bool {
@@ -135,7 +164,7 @@ impl IdentityVerifier<AccountId> for AllianceIdentityVerifier {
 
 	fn has_good_judgement(who: &AccountId) -> bool {
 		if let Some(judgements) =
-			Identity::identity(who).map(|registration| registration.judgements)
+			Identity::identity(who).map(|(registration, _)| registration.judgements)
 		{
 			judgements
 				.iter()

substrate/frame/identity/Cargo.toml

@@ -18,6 +18,7 @@ targets = ["x86_64-unknown-linux-gnu"]
 [dependencies]
 codec = { package = "parity-scale-codec", version = "3.6.1", default-features = false, features = ["derive", "max-encoded-len"] }
 enumflags2 = { version = "0.7.7" }
+log = { version = "0.4.17", default-features = false }
 scale-info = { version = "2.10.0", default-features = false, features = ["derive"] }
 frame-benchmarking = { path = "../benchmarking", default-features = false, optional = true }
 frame-support = { path = "../support", default-features = false }
@@ -29,6 +30,7 @@ sp-std = { path = "../../primitives/std", default-features = false }
 [dev-dependencies]
 pallet-balances = { path = "../balances" }
 sp-core = { path = "../../primitives/core" }
+sp-keystore = { path = "../../primitives/keystore" }
 
 [features]
 default = ["std"]
@@ -39,10 +41,12 @@ std = [
 	"frame-benchmarking?/std",
 	"frame-support/std",
 	"frame-system/std",
+	"log/std",
 	"pallet-balances/std",
 	"scale-info/std",
 	"sp-core/std",
 	"sp-io/std",
+	"sp-keystore/std",
 	"sp-runtime/std",
 	"sp-std/std",
 ]

substrate/frame/identity/src/benchmarking.rs

@@ -22,22 +22,43 @@
 use super::*;
 
 use crate::Pallet as Identity;
+use codec::Encode;
 use frame_benchmarking::{
 	account, impl_benchmark_test_suite, v2::*, whitelisted_caller, BenchmarkError,
 };
 use frame_support::{
-	ensure,
-	traits::{EnsureOrigin, Get},
+	assert_ok, ensure,
+	traits::{EnsureOrigin, Get, OnFinalize, OnInitialize},
 };
 use frame_system::RawOrigin;
-use sp_runtime::traits::Bounded;
+use sp_io::crypto::{sr25519_generate, sr25519_sign};
+use sp_runtime::{
+	traits::{Bounded, IdentifyAccount, One},
+	MultiSignature, MultiSigner,
+};
 
 const SEED: u32 = 0;
 
+fn assert_has_event<T: Config>(generic_event: <T as Config>::RuntimeEvent) {
+	frame_system::Pallet::<T>::assert_has_event(generic_event.into());
+}
+
 fn assert_last_event<T: Config>(generic_event: <T as Config>::RuntimeEvent) {
 	frame_system::Pallet::<T>::assert_last_event(generic_event.into());
 }
 
+fn run_to_block<T: Config>(n: frame_system::pallet_prelude::BlockNumberFor<T>) {
+	while frame_system::Pallet::<T>::block_number() < n {
+		crate::Pallet::<T>::on_finalize(frame_system::Pallet::<T>::block_number());
+		frame_system::Pallet::<T>::on_finalize(frame_system::Pallet::<T>::block_number());
+		frame_system::Pallet::<T>::set_block_number(
+			frame_system::Pallet::<T>::block_number() + One::one(),
+		);
+		frame_system::Pallet::<T>::on_initialize(frame_system::Pallet::<T>::block_number());
+		crate::Pallet::<T>::on_initialize(frame_system::Pallet::<T>::block_number());
+	}
+}
+
 // Adds `r` registrars to the Identity Pallet. These registrars will have set fees and fields.
 fn add_registrars<T: Config>(r: u32) -> Result<(), &'static str> {
 	for i in 0..r {
@@ -95,7 +116,28 @@ fn add_sub_accounts<T: Config>(
 	Ok(subs)
 }
 
-#[benchmarks]
+fn bench_suffix() -> Vec<u8> {
+	b"bench".to_vec()
+}
+
+fn bench_username() -> Vec<u8> {
+	// len = 24
+	b"veryfastbenchmarkmachine".to_vec()
+}
+
+fn bounded_username<T: Config>(username: Vec<u8>, suffix: Vec<u8>) -> Username<T> {
+	let mut full_username = Vec::with_capacity(username.len() + suffix.len() + 1);
+	full_username.extend(username);
+	full_username.extend(b".");
+	full_username.extend(suffix);
+	Username::<T>::try_from(full_username).expect("test usernames should fit within bounds")
+}
+
+#[benchmarks(
+	where
+		<T as frame_system::Config>::AccountId: From<sp_runtime::AccountId32>,
+		T::OffchainSignature: From<MultiSignature>,
+)]
 mod benchmarks {
 	use super::*;
 
@@ -523,5 +565,166 @@ mod benchmarks {
 		Ok(())
 	}
 
+	#[benchmark]
+	fn add_username_authority() -> Result<(), BenchmarkError> {
+		let origin =
+			T::UsernameAuthorityOrigin::try_successful_origin().expect("can generate origin");
+
+		let authority: T::AccountId = account("authority", 0, SEED);
+		let authority_lookup = T::Lookup::unlookup(authority.clone());
+		let suffix = bench_suffix();
+		let allocation = 10;
+
+		#[extrinsic_call]
+		_(origin as T::RuntimeOrigin, authority_lookup, suffix, allocation);
+
+		assert_last_event::<T>(Event::<T>::AuthorityAdded { authority }.into());
+		Ok(())
+	}
+
+	#[benchmark]
+	fn remove_username_authority() -> Result<(), BenchmarkError> {
+		let origin =
+			T::UsernameAuthorityOrigin::try_successful_origin().expect("can generate origin");
+
+		let authority: T::AccountId = account("authority", 0, SEED);
+		let authority_lookup = T::Lookup::unlookup(authority.clone());
+		let suffix = bench_suffix();
+		let allocation = 10;
+
+		assert_ok!(Identity::<T>::add_username_authority(
+			origin.clone(),
+			authority_lookup.clone(),
+			suffix,
+			allocation
+		));
+
+		#[extrinsic_call]
+		_(origin as T::RuntimeOrigin, authority_lookup);
+
+		assert_last_event::<T>(Event::<T>::AuthorityRemoved { authority }.into());
+		Ok(())
+	}
+
+	#[benchmark]
+	fn set_username_for() -> Result<(), BenchmarkError> {
+		// Set up a username authority.
+		let auth_origin =
+			T::UsernameAuthorityOrigin::try_successful_origin().expect("can generate origin");
+		let authority: T::AccountId = account("authority", 0, SEED);
+		let authority_lookup = T::Lookup::unlookup(authority.clone());
+		let suffix = bench_suffix();
+		let allocation = 10;
+
+		Identity::<T>::add_username_authority(
+			auth_origin,
+			authority_lookup,
+			suffix.clone(),
+			allocation,
+		)?;
+
+		let username = bench_username();
+		let bounded_username = bounded_username::<T>(username.clone(), suffix.clone());
+		let encoded_username = Encode::encode(&bounded_username.to_vec());
+
+		let public = sr25519_generate(0.into(), None);
+		let who_account: T::AccountId = MultiSigner::Sr25519(public).into_account().into();
+		let who_lookup = T::Lookup::unlookup(who_account.clone());
+
+		let signature =
+			MultiSignature::Sr25519(sr25519_sign(0.into(), &public, &encoded_username).unwrap());
+
+		// Verify signature here to avoid surprise errors at runtime
+		assert!(signature.verify(&encoded_username[..], &public.into()));
+
+		#[extrinsic_call]
+		_(RawOrigin::Signed(authority.clone()), who_lookup, username, Some(signature.into()));
+
+		assert_has_event::<T>(
+			Event::<T>::UsernameSet {
+				who: who_account.clone(),
+				username: bounded_username.clone(),
+			}
+			.into(),
+		);
+		assert_has_event::<T>(
+			Event::<T>::PrimaryUsernameSet { who: who_account, username: bounded_username }.into(),
+		);
+		Ok(())
+	}
+
+	#[benchmark]
+	fn accept_username() -> Result<(), BenchmarkError> {
+		let caller: T::AccountId = whitelisted_caller();
+		let username = bounded_username::<T>(bench_username(), bench_suffix());
+
+		Identity::<T>::queue_acceptance(&caller, username.clone());
+
+		#[extrinsic_call]
+		_(RawOrigin::Signed(caller.clone()), username.clone());
+
+		assert_last_event::<T>(Event::<T>::UsernameSet { who: caller, username }.into());
+		Ok(())
+	}
+
+	#[benchmark]
+	fn remove_expired_approval() -> Result<(), BenchmarkError> {
+		let caller: T::AccountId = whitelisted_caller();
+		let username = bounded_username::<T>(bench_username(), bench_suffix());
+		Identity::<T>::queue_acceptance(&caller, username.clone());
+
+		let expected_exiration =
+			frame_system::Pallet::<T>::block_number() + T::PendingUsernameExpiration::get();
+
+		run_to_block::<T>(expected_exiration + One::one());
+
+		#[extrinsic_call]
+		_(RawOrigin::Signed(caller.clone()), username);
+
+		assert_last_event::<T>(Event::<T>::PreapprovalExpired { whose: caller }.into());
+		Ok(())
+	}
+
+	#[benchmark]
+	fn set_primary_username() -> Result<(), BenchmarkError> {
+		let caller: T::AccountId = whitelisted_caller();
+		let first_username = bounded_username::<T>(bench_username(), bench_suffix());
+		let second_username = bounded_username::<T>(b"slowbenchmark".to_vec(), bench_suffix());
+
+		// First one will be set as primary. Second will not be.
+		Identity::<T>::insert_username(&caller, first_username);
+		Identity::<T>::insert_username(&caller, second_username.clone());
+
+		#[extrinsic_call]
+		_(RawOrigin::Signed(caller.clone()), second_username.clone());
+
+		assert_last_event::<T>(
+			Event::<T>::PrimaryUsernameSet { who: caller, username: second_username }.into(),
+		);
+		Ok(())
+	}
+
+	#[benchmark]
+	fn remove_dangling_username() -> Result<(), BenchmarkError> {
+		let caller: T::AccountId = whitelisted_caller();
+		let first_username = bounded_username::<T>(bench_username(), bench_suffix());
+		let second_username = bounded_username::<T>(b"slowbenchmark".to_vec(), bench_suffix());
+
+		// First one will be set as primary. Second will not be.
+		Identity::<T>::insert_username(&caller, first_username);
+		Identity::<T>::insert_username(&caller, second_username.clone());
+
+		// User calls `clear_identity`, leaving their second username as "dangling"
+		Identity::<T>::clear_identity(RawOrigin::Signed(caller.clone()).into())?;
+
+		#[extrinsic_call]
+		_(RawOrigin::Signed(caller.clone()), second_username.clone());
+
+		assert_last_event::<T>(
+			Event::<T>::DanglingUsernameRemoved { who: caller, username: second_username }.into(),
+		);
+		Ok(())
+	}
+
 	impl_benchmark_test_suite!(Identity, crate::tests::new_test_ext(), crate::tests::Test);
 }