pallet-identity: Be more paranoid ;) (#12170)

* pallet-identity: Be more paranoid ;)

Check that a registrar is providing judgement for the correct identity.

* Fixes

* Fix alliance

* 🤦

* Fixes

* ...

substrate/frame/identity/src/lib.rs

@@ -79,7 +79,7 @@ mod types;
 pub mod weights;
 
 use frame_support::traits::{BalanceStatus, Currency, OnUnbalanced, ReservableCurrency};
-use sp_runtime::traits::{AppendZerosInput, Saturating, StaticLookup, Zero};
+use sp_runtime::traits::{AppendZerosInput, Hash, Saturating, StaticLookup, Zero};
 use sp_std::prelude::*;
 pub use weights::WeightInfo;
 
@@ -236,6 +236,8 @@ pub mod pallet {
 		NotSub,
 		/// Sub-account isn't owned by sender.
 		NotOwned,
+		/// The provided judgement was for a different identity.
+		JudgementForDifferentIdentity,
 	}
 
 	#[pallet::event]
@@ -746,6 +748,7 @@ pub mod pallet {
 		/// - `target`: the account whose identity the judgement is upon. This must be an account
 		///   with a registered identity.
 		/// - `judgement`: the judgement of the registrar of index `reg_index` about `target`.
+		/// - `identity`: The hash of the [`IdentityInfo`] for that the judgement is provided.
 		///
 		/// Emits `JudgementGiven` if successful.
 		///
@@ -765,6 +768,7 @@ pub mod pallet {
 			#[pallet::compact] reg_index: RegistrarIndex,
 			target: AccountIdLookupOf<T>,
 			judgement: Judgement<BalanceOf<T>>,
+			identity: T::Hash,
 		) -> DispatchResultWithPostInfo {
 			let sender = ensure_signed(origin)?;
 			let target = T::Lookup::lookup(target)?;
@@ -772,10 +776,14 @@ pub mod pallet {
 			<Registrars<T>>::get()
 				.get(reg_index as usize)
 				.and_then(Option::as_ref)
-				.and_then(|r| if r.account == sender { Some(r) } else { None })
+				.filter(|r| r.account == sender)
 				.ok_or(Error::<T>::InvalidIndex)?;
 			let mut id = <IdentityOf<T>>::get(&target).ok_or(Error::<T>::InvalidTarget)?;
 
+			if T::Hashing::hash_of(&id.info) != identity {
+				return Err(Error::<T>::JudgementForDifferentIdentity.into())
+			}
+
 			let item = (reg_index, judgement);
 			match id.judgements.binary_search_by_key(&reg_index, |x| x.0) {
 				Ok(position) => {