DRAFT: redesign - track cumulative borrows using a u64 counter instead of a bool flag

Anchor.toml

@@ -10,4 +10,4 @@ cluster = "localnet"
 wallet = "~/.config/solana/id.json"
 
 [scripts]
-test = "mocha -t 1000000 tests/"
+test = "yarn mocha -t 1000000 tests/"

app/api.js

@@ -153,14 +153,13 @@ function borrow(user, mint, amount) {
     // we could also have a client approval, and this would be my ideal design
     // but requiring a third instruction drastically reduces avail bytes for transaction proper
     // the new tx format might make this viable by cutting address repetition tho
-    let repayIxn = adobe.instruction.repay(new anchor.BN(amount), {
+    let repayIxn = adobe.instruction.repay({
         accounts: {
             user: user.publicKey,
             state: stateKey,
             pool: poolKey,
             poolToken: poolTokenKey,
             userToken: userTokenKey,
-            instructions: SYSVAR_INSTRUCTIONS_PUBKEY,
             tokenProgram: TOKEN_PROGRAM_ID,
     }});
 

package.json

@@ -1,7 +1,7 @@
 {
     "type": "module",
     "dependencies": {
-        "@project-serum/anchor": "^0.17.0",
+        "@project-serum/anchor": "0.18.0",
         "@solana/spl-token": "^0.1.8"
     },
     "devDependencies": {

programs/adobe/src/lib.rs

@@ -1,14 +1,14 @@
-use core::convert::TryInto;
 use anchor_lang::prelude::*;
-use anchor_lang::Discriminator;
-use anchor_spl::token::{self, Mint, TokenAccount, MintTo, Burn, Transfer, Token};
 use anchor_lang::solana_program as solana;
+use anchor_lang::Discriminator;
+use anchor_spl::token::{self, Burn, Mint, MintTo, Token, TokenAccount, Transfer};
+use core::convert::TryInto;
 
 declare_id!("VzRKfyFWHZtYWbQWfcnCGBrTg3tqqRV2weUqvrvVhuo");
 
-const TOKEN_NAMESPACE: &[u8]   = b"TOKEN";
+const TOKEN_NAMESPACE: &[u8] = b"TOKEN";
 const VOUCHER_NAMESPACE: &[u8] = b"VOUCHER";
-const REPAY_OPCODE: u64        = 0xea674352d0eadba6;
+const REPAY_OPCODE: u64 = 0xea674352d0eadba6;
 
 #[program]
 #[deny(unused_must_use)]
@@ -32,7 +32,7 @@ pub mod adobe {
         msg!("adobe add_pool");
 
         ctx.accounts.pool.bump = pool_bump;
-        ctx.accounts.pool.borrowing = false;
+        ctx.accounts.pool.borrowing = 0;
         ctx.accounts.pool.token_mint = ctx.accounts.token_mint.key();
         ctx.accounts.pool.pool_token = ctx.accounts.pool_token.key();
         ctx.accounts.pool.voucher_mint = ctx.accounts.voucher_mint.key();
@@ -45,10 +45,7 @@ pub mod adobe {
     pub fn deposit(ctx: Context<Deposit>, amount: u64) -> ProgramResult {
         msg!("adobe deposit");
 
-        let state_seed: &[&[&[u8]]] = &[&[
-            &State::discriminator()[..],
-            &[ctx.accounts.state.bump],
-        ]];
+        let state_seed: &[&[&[u8]]] = &[&[&State::discriminator()[..], &[ctx.accounts.state.bump]]];
 
         let transfer_ctx = CpiContext::new_with_signer(
             ctx.accounts.token_program.to_account_info(),
@@ -82,10 +79,7 @@ pub mod adobe {
     pub fn withdraw(ctx: Context<Withdraw>, amount: u64) -> ProgramResult {
         msg!("adobe withdraw");
 
-        let state_seed: &[&[&[u8]]] = &[&[
-            &State::discriminator()[..],
-            &[ctx.accounts.state.bump],
-        ]];
+        let state_seed: &[&[&[u8]]] = &[&[&State::discriminator()[..], &[ctx.accounts.state.bump]]];
 
         let burn_ctx = CpiContext::new_with_signer(
             ctx.accounts.token_program.to_account_info(),
@@ -119,47 +113,39 @@ pub mod adobe {
     pub fn borrow(ctx: Context<Borrow>, amount: u64) -> ProgramResult {
         msg!("adobe borrow");
 
-        if ctx.accounts.pool.borrowing {
-            return Err(AdobeError::Borrowing.into());
-        }
-
         let ixns = ctx.accounts.instructions.to_account_info();
 
-        // make sure this isnt a cpi call
-        let current_index = solana::sysvar::instructions::load_current_index_checked(&ixns)? as usize;
-        let current_ixn = solana::sysvar::instructions::load_instruction_at_checked(current_index, &ixns)?;
-        if current_ixn.program_id != *ctx.program_id {
-            return Err(AdobeError::CpiBorrow.into());
-        }
+        let current_index =
+            solana::sysvar::instructions::load_current_index_checked(&ixns)? as usize;
 
         // loop through instructions, looking for an equivalent repay to this borrow
         let mut i = current_index + 1;
         loop {
             // get the next instruction, die if theres no more
             if let Ok(ixn) = solana::sysvar::instructions::load_instruction_at_checked(i, &ixns) {
-                // check if we have a toplevel repay toward the same pool
-                // if so, confirm the amount, otherwise next instruction
+                // check if we have a toplevel repay toward the same pool,
+                // otherwise next instruction
                 if ixn.program_id == *ctx.program_id
-                && u64::from_be_bytes(ixn.data[..8].try_into().unwrap()) == REPAY_OPCODE
-                && ixn.accounts[2].pubkey == ctx.accounts.pool.key() {
-                    if u64::from_le_bytes(ixn.data[8..16].try_into().unwrap()) == amount {
-                        break;
-                    } else {
-                        return Err(AdobeError::IncorrectRepay.into());
-                    }
+                    && u64::from_be_bytes(ixn.data[..8].try_into().unwrap()) == REPAY_OPCODE
+                    && ixn.accounts[2].pubkey == ctx.accounts.pool.key()
+                {
+                    break;
                 } else {
                     i += 1;
                 }
-            }
-            else {
+            } else {
                 return Err(AdobeError::NoRepay.into());
             }
         }
 
-        let state_seed: &[&[&[u8]]] = &[&[
-            &State::discriminator()[..],
-            &[ctx.accounts.state.bump],
-        ]];
+        ctx.accounts.pool.borrowing = ctx
+            .accounts
+            .pool
+            .borrowing
+            .checked_add(amount)
+            .ok_or(AdobeError::ExcessiveBorrow)?;
+
+        let state_seed: &[&[&[u8]]] = &[&[&State::discriminator()[..], &[ctx.accounts.state.bump]]];
 
         let transfer_ctx = CpiContext::new_with_signer(
             ctx.accounts.token_program.to_account_info(),
@@ -172,29 +158,16 @@ pub mod adobe {
         );
 
         token::transfer(transfer_ctx, amount)?;
-        ctx.accounts.pool.borrowing = true;
 
         Ok(())
     }
 
     // REPAY
     // receives tokens
-    pub fn repay(ctx: Context<Repay>, amount: u64) -> ProgramResult {
+    pub fn repay(ctx: Context<Repay>) -> ProgramResult {
         msg!("adobe repay");
 
-        let ixns = ctx.accounts.instructions.to_account_info();
-
-        // make sure this isnt a cpi call
-        let current_index = solana::sysvar::instructions::load_current_index_checked(&ixns)? as usize;
-        let current_ixn = solana::sysvar::instructions::load_instruction_at_checked(current_index, &ixns)?;
-        if current_ixn.program_id != *ctx.program_id {
-            return Err(AdobeError::CpiRepay.into());
-        }
-
-        let state_seed: &[&[&[u8]]] = &[&[
-            &State::discriminator()[..],
-            &[ctx.accounts.state.bump],
-        ]];
+        let state_seed: &[&[&[u8]]] = &[&[&State::discriminator()[..], &[ctx.accounts.state.bump]]];
 
         let transfer_ctx = CpiContext::new_with_signer(
             ctx.accounts.token_program.to_account_info(),
@@ -206,8 +179,8 @@ pub mod adobe {
             state_seed,
         );
 
-        token::transfer(transfer_ctx, amount)?;
-        ctx.accounts.pool.borrowing = false;
+        token::transfer(transfer_ctx, ctx.accounts.pool.borrowing)?;
+        ctx.accounts.pool.borrowing = 0;
 
         Ok(())
     }
@@ -331,8 +304,6 @@ pub struct Repay<'info> {
     pub pool_token: Account<'info, TokenAccount>,
     #[account(mut, constraint =  user_token.mint == pool.token_mint)]
     pub user_token: Account<'info, TokenAccount>,
-    #[account(address = solana::sysvar::instructions::ID)]
-    pub instructions: UncheckedAccount<'info>,
     pub token_program: Program<'info, Token>,
 }
 
@@ -347,7 +318,7 @@ pub struct State {
 #[derive(Default)]
 pub struct Pool {
     bump: u8,
-    borrowing: bool,
+    borrowing: u64,
     token_mint: Pubkey,
     pool_token: Pubkey,
     voucher_mint: Pubkey,
@@ -356,13 +327,7 @@ pub struct Pool {
 #[error]
 pub enum AdobeError {
     #[msg("borrow requires an equivalent repay")]
-    NoRepay,
-    #[msg("repay exists but in the wrong amount")]
-    IncorrectRepay,
-    #[msg("cannot call borrow via cpi")]
-    CpiBorrow,
-    #[msg("cannot call repay via cpi")]
-    CpiRepay,
-    #[msg("a borrow is already in progress")]
-    Borrowing,
+    NoRepay, // 0x12c
+    #[msg("excessive borrow amount")]
+    ExcessiveBorrow, // 0x12d
 }

programs/evil/src/lib.rs

@@ -1,5 +1,5 @@
+use adobe::cpi::accounts::{Borrow, Repay};
 use anchor_lang::prelude::*;
-use adobe::cpi::accounts::{ Borrow, Repay};
 
 declare_id!("5zAQ1XhjuHcQtUXJSTjbmyDagmKVHDMi5iADv5PfYEUK");
 
@@ -25,10 +25,10 @@ pub mod evil {
         Ok(())
     }
 
-    pub fn repay_proxy(ctx: Context<Adobe>, amount: u64) -> ProgramResult {
+    pub fn repay_proxy(ctx: Context<Adobe>) -> ProgramResult {
         msg!("evil repay_proxy");
 
-        adobe::cpi::repay(ctx.accounts.into_repay_context(), amount)?;
+        adobe::cpi::repay(ctx.accounts.into_repay_context())?;
 
         Ok(())
     }
@@ -72,7 +72,6 @@ impl<'info> Adobe<'info> {
                 pool: self.pool.clone(),
                 pool_token: self.pool_token.clone(),
                 user_token: self.user_token.clone(),
-                instructions: self.instructions.clone(),
                 token_program: self.token_program.clone(),
             },
         )

tests/adobe.js

@@ -1,13 +1,12 @@
 import assert from "assert";
 import anchor from "@project-serum/anchor";
 import spl from "@solana/spl-token";
-import { findAddr, findAssocAddr, discriminator, airdrop } from "../app/util.js";
+import { findAddr, discriminator, airdrop } from "../app/util.js";
 import * as api from "../app/api.js";
 
 const LAMPORTS_PER_SOL = anchor.web3.LAMPORTS_PER_SOL;
 const SYSVAR_INSTRUCTIONS_PUBKEY = anchor.web3.SYSVAR_INSTRUCTIONS_PUBKEY;
 const TOKEN_PROGRAM_ID = spl.TOKEN_PROGRAM_ID;
-const ASSOCIATED_TOKEN_PROGRAM_ID = spl.ASSOCIATED_TOKEN_PROGRAM_ID;
 
 const TXN_OPTS = {commitment: "processed", preflightCommitment: "processed", skipPreflight: true};
 const TOKEN_DECIMALS = 6;
@@ -127,17 +126,6 @@ describe("adobe flash loan program", () => {
         balAfter = await poolBalance(tokenMint);
         assert.equal(balAfter, balBefore, "program token balance unchanged");
 
-        // dont fully repay
-        [borrowIxn] = api.borrow(wallet, tokenMint, amount + 1);
-        txn = new anchor.web3.Transaction;
-        txn.add(borrowIxn);
-        txn.add(repayIxn);
-
-        balBefore = await poolBalance(tokenMint);
-        await assert.rejects(provider.send(txn), "borrow more than repay fails");
-        balAfter = await poolBalance(tokenMint);
-        assert.equal(balAfter, balBefore, "program token balance unchanged");
-
         // borrow too much
         [borrowIxn, repayIxn] = api.borrow(wallet, tokenMint, amount * 10);
         txn = new anchor.web3.Transaction;
@@ -150,18 +138,18 @@ describe("adobe flash loan program", () => {
         assert.equal(balAfter, balBefore, "program token balance unchanged");
 
         // double borrow (raw instruction)
+        [borrowIxn, repayIxn] = api.borrow(wallet, tokenMint, amount / 10);
         txn = new anchor.web3.Transaction;
         txn.add(borrowIxn);
         txn.add(borrowIxn);
         txn.add(repayIxn);
 
         balBefore = await poolBalance(tokenMint);
-        await assert.rejects(provider.send(txn), "multiple borrow fails");
+        await provider.send(txn);
         balAfter = await poolBalance(tokenMint);
         assert.equal(balAfter, balBefore, "program token balance unchanged");
 
-        // dounle borrow (direct cpi)
-        [borrowIxn, repayIxn] = api.borrow(wallet, tokenMint, amount / 10);
+        // double borrow (direct cpi)
         let evilIxn = evil.instruction.borrowProxy(new anchor.BN(amount / 10), {
             accounts: {
                 user: wallet.publicKey,
@@ -181,7 +169,7 @@ describe("adobe flash loan program", () => {
         txn.add(repayIxn);
 
         balBefore = await poolBalance(tokenMint);
-        await assert.rejects(provider.send(txn), "borrow and cpi fails");
+        await provider.send(txn);
         balAfter = await poolBalance(tokenMint);
         assert.equal(balAfter, balBefore, "program token balance unchanged");
 
@@ -191,7 +179,7 @@ describe("adobe flash loan program", () => {
         txn.add(repayIxn);
 
         balBefore = await poolBalance(tokenMint);
-        await assert.rejects(provider.send(txn), "cpi and borrow fails");
+        await provider.send(txn);
         balAfter = await poolBalance(tokenMint);
         assert.equal(balAfter, balBefore, "program token balance unchanged");
 
@@ -201,11 +189,11 @@ describe("adobe flash loan program", () => {
         txn.add(repayIxn);
 
         balBefore = await poolBalance(tokenMint);
-        await assert.rejects(provider.send(txn), "cpi and cpi fails");
+        await provider.send(txn);
         balAfter = await poolBalance(tokenMint);
         assert.equal(balAfter, balBefore, "program token balance unchanged");
 
-        // dounle borrow (batched cpi)
+        // double borrow (batched cpi)
         evilIxn = evil.instruction.borrowDouble(new anchor.BN(amount / 10), {
             accounts: {
                 user: wallet.publicKey,
@@ -224,7 +212,7 @@ describe("adobe flash loan program", () => {
         txn.add(repayIxn);
 
         balBefore = await poolBalance(tokenMint);
-        await assert.rejects(provider.send(txn), "cpi double borrow fails");
+        await provider.send(txn);
         balAfter = await poolBalance(tokenMint);
         assert.equal(balAfter, balBefore, "program token balance unchanged");
 
@@ -261,7 +249,7 @@ describe("adobe flash loan program", () => {
                 adobeProgram: adobe.programId,
             },
         });
-        let evilRepay = evil.instruction.repayProxy(new anchor.BN(1), {
+        let evilRepay = evil.instruction.repayProxy({
             accounts: {
                 user: wallet.publicKey,
                 state: stateKey,
@@ -281,7 +269,7 @@ describe("adobe flash loan program", () => {
         txn.add(repayIxn);
 
         balBefore = await poolBalance(tokenMint);
-        await assert.rejects(provider.send(txn), "cpi dummy repay fails");
+        await provider.send(txn);
         balAfter = await poolBalance(tokenMint);
         assert.equal(balAfter, balBefore, "program token balance unchanged");
     });

yarn.lock

@@ -9,10 +9,10 @@
   dependencies:
     regenerator-runtime "^0.13.4"
 
-"@project-serum/anchor@^0.17.0":
-  version "0.17.0"
-  resolved "https://registry.yarnpkg.com/@project-serum/anchor/-/anchor-0.17.0.tgz#99a2cc59cae2939c1db1197950b7b606319ea7a8"
-  integrity sha512-vctZHZD5rUP1WXUUaJFdKl+1u0dE+O2+jejmYcb0InAZiwXdGAW8mX47U902voT94PdCr0aNHuyOQ8I75nfinw==
+"@project-serum/anchor@0.18.0":
+  version "0.18.0"
+  resolved "https://registry.yarnpkg.com/@project-serum/anchor/-/anchor-0.18.0.tgz#867144282e59482230f797f73ee9f5634f846061"
+  integrity sha512-WTm+UB93MoxyCbjnHIibv/uUEoO/5gL4GEtE/aMioLF8Z4i0vCMPnvAN0xpk9VBu3t7ld2DcCE/L+6Z7dwU++w==
   dependencies:
     "@project-serum/borsh" "^0.2.2"
     "@solana/web3.js" "^1.17.0"