Some improvements on economic security

substrate/client/tests/dex.rs

@@ -11,7 +11,7 @@ use serai_client::{
     SeraiAddress, PublicKey,
   },
   in_instructions::primitives::{
-    InInstruction, InInstructionWithBalance, Batch, IN_INSTRUCTION_EXECUTOR, OutAddress,
+    InInstruction, InInstructionWithBalance, Batch, ADD_LIQUIDITY_ACCOUNT, SWAP_ACCOUNT, OutAddress,
   },
   dex::DexEvent,
   Serai,
@@ -270,7 +270,7 @@ serai_test!(
     assert_eq!(
       events,
       vec![DexEvent::LiquidityAdded {
-        who: IN_INSTRUCTION_EXECUTOR,
+        who: ADD_LIQUIDITY_ACCOUNT,
         mint_to: pair.public().into(),
         pool_id: Coin::Bitcoin,
         coin_amount: 10_000_000_000_000, // half of sent amount
@@ -357,8 +357,8 @@ serai_test!(
       assert_eq!(
         events,
         vec![DexEvent::SwapExecuted {
-          who: IN_INSTRUCTION_EXECUTOR,
-          send_to: IN_INSTRUCTION_EXECUTOR,
+          who: SWAP_ACCOUNT,
+          send_to: SWAP_ACCOUNT,
           path,
           amount_in: 20_000_000_000_000,
           amount_out: 11066655622377
@@ -396,7 +396,7 @@ serai_test!(
       assert_eq!(
         events,
         vec![DexEvent::SwapExecuted {
-          who: IN_INSTRUCTION_EXECUTOR,
+          who: SWAP_ACCOUNT,
           send_to: out_address.as_native().unwrap(),
           path,
           amount_in: 20_000_000_000_000,
@@ -434,7 +434,7 @@ serai_test!(
       assert_eq!(
         events,
         vec![DexEvent::SwapExecuted {
-          who: IN_INSTRUCTION_EXECUTOR,
+          who: SWAP_ACCOUNT,
           send_to: out_address.as_native().unwrap(),
           path,
           amount_in: 10_000_000_000_000,

substrate/coins/pallet/Cargo.toml

@@ -33,6 +33,7 @@ pallet-transaction-payment = { git = "https://github.com/serai-dex/substrate", d
 
 serai-primitives = { path = "../../primitives", default-features = false, features = ["serde"] }
 coins-primitives = { package = "serai-coins-primitives", path = "../primitives", default-features = false }
+in-ins-primitives = { package = "serai-in-instructions-primitives", path = "../../in-instructions/primitives", default-features = false }
 
 [features]
 std = [
@@ -47,6 +48,7 @@ std = [
 
   "serai-primitives/std",
   "coins-primitives/std",
+  "in-ins-primitives/std",
 ]
 
 runtime-benchmarks = [

substrate/coins/pallet/src/lib.rs

@@ -3,11 +3,11 @@
 use serai_primitives::{Coin, SubstrateAmount, Balance};
 
 pub trait AllowMint {
-  fn is_allowed(balance: &Balance) -> bool;
+  fn is_allowed(balance: &Balance, for_swap: bool) -> bool;
 }
 
 impl AllowMint for () {
-  fn is_allowed(_: &Balance) -> bool {
+  fn is_allowed(_: &Balance, _: bool) -> bool {
     true
   }
 }
@@ -33,6 +33,8 @@ pub mod pallet {
   pub use coins_primitives as primitives;
   use primitives::*;
 
+  use in_ins_primitives::SWAP_ACCOUNT;
+
   type LiquidityTokensInstance = crate::Instance1;
 
   #[pallet::config]
@@ -159,7 +161,7 @@ pub mod pallet {
     ///
     /// Errors if any amount overflows.
     pub fn mint(to: Public, balance: Balance) -> Result<(), Error<T, I>> {
-      if !T::AllowMint::is_allowed(&balance) {
+      if !T::AllowMint::is_allowed(&balance, to == SWAP_ACCOUNT.into()) {
         Err(Error::<T, I>::MintNotAllowed)?;
       }
 

substrate/dex/pallet/src/lib.rs

@@ -151,6 +151,7 @@ pub mod pallet {
   /// Map from `PoolId` to `()`. This establishes whether a pool has been officially
   /// created rather than people sending tokens directly to a pool's public account.
   #[pallet::storage]
+  #[pallet::getter(fn pools)]
   pub type Pools<T: Config> = StorageMap<_, Blake2_128Concat, PoolId, (), OptionQuery>;
 
   #[pallet::storage]

substrate/in-instructions/pallet/src/lib.rs

@@ -52,6 +52,10 @@ pub mod pallet {
   pub enum Error<T> {
     /// Coin and OutAddress types don't match.
     InvalidAddressForCoin,
+    /// SRI minting is not allowed.
+    CantMintSRI,
+    /// There is too much coin that is not in the pool.
+    TooMuchCoinOutOfPool,
   }
 
   #[pallet::pallet]
@@ -85,6 +89,34 @@ pub mod pallet {
     fn execute(instruction: InInstructionWithBalance) -> Result<(), DispatchError> {
       match instruction.instruction {
         InInstruction::Transfer(address) => {
+          let coin = instruction.balance.coin;
+          if coin == Coin::Serai {
+            Err(Error::<T>::CantMintSRI)?;
+          }
+
+          // check how much in-pool vs out-of-pool if we have a pool and has certain amount of
+          // liquidty available.
+          let pool_id = Dex::<T>::get_pool_id(coin, Coin::Serai).unwrap();
+          if Dex::<T>::pools(pool_id).is_some() {
+            let pool_account = Dex::<T>::get_pool_account(pool_id);
+            let in_pool_sri = Coins::<T>::balance(pool_account, Coin::Serai).0;
+
+            // TODO: should be a const where?
+            if in_pool_sri >= 10_000 * 10_u64.pow(8) {
+              let in_pool = Coins::<T>::balance(pool_account, coin).0;
+
+              // get out-of-pool
+              let total = Coins::<T>::supply(coin);
+              let out_of_pool = total - in_pool;
+              let new_out_of_pool = out_of_pool.saturating_add(instruction.balance.amount.0);
+
+              // only allow if out-of-pool is less than 20% of pool value
+              if new_out_of_pool > in_pool / 5 {
+                Err(Error::<T>::TooMuchCoinOutOfPool)?;
+              }
+            }
+          }
+
           Coins::<T>::mint(address.into(), instruction.balance)?;
         }
         InInstruction::Dex(call) => {
@@ -93,11 +125,11 @@ pub mod pallet {
           // called directly from Serai with a native transaction.
           match call {
             DexCall::SwapAndAddLiquidity(address) => {
-              let origin = RawOrigin::Signed(IN_INSTRUCTION_EXECUTOR.into());
+              let origin = RawOrigin::Signed(ADD_LIQUIDITY_ACCOUNT.into());
               let coin = instruction.balance.coin;
 
               // mint the given coin on the account
-              Coins::<T>::mint(IN_INSTRUCTION_EXECUTOR.into(), instruction.balance)?;
+              Coins::<T>::mint(ADD_LIQUIDITY_ACCOUNT.into(), instruction.balance)?;
 
               // swap half of it for SRI
               let half = instruction.balance.amount.0 / 2;
@@ -107,11 +139,11 @@ pub mod pallet {
                 path,
                 half,
                 1, // minimum out, so we accept whatever we get.
-                IN_INSTRUCTION_EXECUTOR.into(),
+                ADD_LIQUIDITY_ACCOUNT.into(),
               )?;
 
               // get how much we got for our swap
-              let sri_amount = Coins::<T>::balance(IN_INSTRUCTION_EXECUTOR.into(), Coin::Serai).0;
+              let sri_amount = Coins::<T>::balance(ADD_LIQUIDITY_ACCOUNT.into(), Coin::Serai).0;
 
               // add liquidity
               Dex::<T>::add_liquidity(
@@ -127,18 +159,18 @@ pub mod pallet {
               // TODO: minimums are set to 1 above to guarantee successful adding liq call.
               // Ideally we either get this info from user or send the leftovers back to user.
               // Let's send the leftovers back to user for now.
-              let coin_balance = Coins::<T>::balance(IN_INSTRUCTION_EXECUTOR.into(), coin);
-              let sri_balance = Coins::<T>::balance(IN_INSTRUCTION_EXECUTOR.into(), Coin::Serai);
+              let coin_balance = Coins::<T>::balance(ADD_LIQUIDITY_ACCOUNT.into(), coin);
+              let sri_balance = Coins::<T>::balance(ADD_LIQUIDITY_ACCOUNT.into(), Coin::Serai);
               if coin_balance != Amount(0) {
                 Coins::<T>::transfer_internal(
-                  IN_INSTRUCTION_EXECUTOR.into(),
+                  ADD_LIQUIDITY_ACCOUNT.into(),
                   address.into(),
                   Balance { coin, amount: coin_balance },
                 )?;
               }
               if sri_balance != Amount(0) {
                 Coins::<T>::transfer_internal(
-                  IN_INSTRUCTION_EXECUTOR.into(),
+                  ADD_LIQUIDITY_ACCOUNT.into(),
                   address.into(),
                   Balance { coin: Coin::Serai, amount: sri_balance },
                 )?;
@@ -154,7 +186,7 @@ pub mod pallet {
               }
 
               // mint the given coin on our account
-              Coins::<T>::mint(IN_INSTRUCTION_EXECUTOR.into(), instruction.balance)?;
+              Coins::<T>::mint(SWAP_ACCOUNT.into(), instruction.balance)?;
 
               // get the path
               let mut path = vec![instruction.balance.coin, Coin::Serai];
@@ -166,13 +198,13 @@ pub mod pallet {
               // if the address is internal, we can directly swap to it. if not, we swap to
               // ourselves and burn the coins to send them back on the external chain.
               let send_to = if send_to_external {
-                IN_INSTRUCTION_EXECUTOR
+                SWAP_ACCOUNT
               } else {
                 out_address.clone().as_native().unwrap()
               };
 
               // do the swap
-              let origin = RawOrigin::Signed(IN_INSTRUCTION_EXECUTOR.into());
+              let origin = RawOrigin::Signed(SWAP_ACCOUNT.into());
               Dex::<T>::swap_exact_tokens_for_tokens(
                 origin.clone().into(),
                 BoundedVec::try_from(path).unwrap(),
@@ -185,8 +217,7 @@ pub mod pallet {
               // if it is requested to an external address.
               if send_to_external {
                 // see how much we got
-                let coin_balance =
-                  Coins::<T>::balance(IN_INSTRUCTION_EXECUTOR.into(), out_balance.coin);
+                let coin_balance = Coins::<T>::balance(SWAP_ACCOUNT.into(), out_balance.coin);
                 let instruction = OutInstructionWithBalance {
                   instruction: OutInstruction {
                     address: out_address.as_external().unwrap(),

substrate/in-instructions/primitives/src/lib.rs

@@ -27,8 +27,11 @@ pub use shorthand::*;
 
 pub const MAX_BATCH_SIZE: usize = 25_000; // ~25kb
 
-// This is the account which will be the origin for any dispatched `InInstruction`s.
-pub const IN_INSTRUCTION_EXECUTOR: SeraiAddress = system_address(b"InInstructions-executor");
+// This is the account which will be the origin for add liquidity instructions.
+pub const ADD_LIQUIDITY_ACCOUNT: SeraiAddress = system_address(b"add-liquidty-account");
+
+// This is the account which will be the origin for swap intructions.
+pub const SWAP_ACCOUNT: SeraiAddress = system_address(b"swap-account");
 
 #[derive(Clone, PartialEq, Eq, Debug, Encode, Decode, MaxEncodedLen, TypeInfo)]
 #[cfg_attr(feature = "std", derive(Zeroize))]

substrate/validator-sets/pallet/src/lib.rs

@@ -1031,14 +1031,20 @@ pub mod pallet {
   }
 
   impl<T: Config> AllowMint for Pallet<T> {
-    fn is_allowed(balance: &Balance) -> bool {
+    fn is_allowed(balance: &Balance, for_swap: bool) -> bool {
       // get the required stake
       let current_required = Self::required_stake_for_network(balance.coin.network());
       let new_required = current_required + Self::required_stake(balance);
 
       // get the total stake for the network & compare.
-      let staked = Self::total_allocated_stake(balance.coin.network()).unwrap_or(Amount(0));
-      staked.0 >= new_required
+      let mut staked = Self::total_allocated_stake(balance.coin.network()).unwrap_or(Amount(0)).0;
+
+      // we leave 5% buffer on our stake for swap mints.
+      if !for_swap {
+        staked -= staked / 20; // TODO: this should be a const but where?
+      }
+
+      staked >= new_required
     }
   }