From 46a02b7b4a7d379c80018734fe47acad1846bdb0 Mon Sep 17 00:00:00 2001
From: "mergify[bot]" <37929162+mergify[bot]@users.noreply.github.com>
Date: Tue, 1 Mar 2022 17:12:47 +0000
Subject: [PATCH] Allow sub-rent-exempt-minimum transfers to `1nc1nerator`
 (backport #23382) (#23404)

* Allow sub-rent-exempt-minimum transfers to `1nc1nerator` (#23382)

* Add failing test

* Allow small burns to incinerator

* Use check_id method

(cherry picked from commit 19448ba078379846213fd3d5691feefb2b2f4810)

# Conflicts:
#	runtime/src/account_rent_state.rs

* Fix conflicts

Co-authored-by: Tyera Eulberg <tyera@solana.com>
---
 runtime/src/account_rent_state.rs |  4 +++-
 runtime/src/bank.rs               | 22 ++++++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/runtime/src/account_rent_state.rs b/runtime/src/account_rent_state.rs
index 9763902755..16aec996b7 100644
--- a/runtime/src/account_rent_state.rs
+++ b/runtime/src/account_rent_state.rs
@@ -56,7 +56,9 @@ pub(crate) fn check_rent_state(
 ) -> Result<()> {
     if let Some((pre_rent_state, post_rent_state)) = pre_rent_state.zip(post_rent_state) {
         submit_rent_state_metrics(pre_rent_state, post_rent_state);
-        if !post_rent_state.transition_allowed_from(pre_rent_state) {
+        if !solana_sdk::incinerator::check_id(address)
+            && !post_rent_state.transition_allowed_from(pre_rent_state)
+        {
             debug!("Account {:?} not rent exempt, state {:?}", address, account);
             return Err(TransactionError::InvalidRentPayingAccount);
         }
diff --git a/runtime/src/bank.rs b/runtime/src/bank.rs
index 38494d401b..572edefbe2 100644
--- a/runtime/src/bank.rs
+++ b/runtime/src/bank.rs
@@ -17030,6 +17030,28 @@ pub(crate) mod tests {
         ));
     }
 
+    // Ensure System transfers of any size can be made to the incinerator
+    #[test]
+    fn test_rent_state_incinerator() {
+        let GenesisConfigInfo {
+            mut genesis_config,
+            mint_keypair,
+            ..
+        } = create_genesis_config_with_leader(sol_to_lamports(100.), &Pubkey::new_unique(), 42);
+        genesis_config.rent = Rent::default();
+        let rent_exempt_minimum = genesis_config.rent.minimum_balance(0);
+
+        // Activate features, including require_rent_exempt_accounts
+        activate_all_features(&mut genesis_config);
+
+        let bank = Bank::new_for_tests(&genesis_config);
+
+        for amount in [rent_exempt_minimum - 1, rent_exempt_minimum] {
+            bank.transfer(amount, &mint_keypair, &solana_sdk::incinerator::id())
+                .unwrap();
+        }
+    }
+
     #[test]
     fn test_rent_state_list_len() {
         let GenesisConfigInfo {