Track account writable deescalation (#14626)

programs/bpf/rust/invoke/src/lib.rs

@@ -29,6 +29,7 @@ const TEST_INSTRUCTION_META_TOO_LARGE: u8 = 10;
 const TEST_RETURN_ERROR: u8 = 11;
 const TEST_PRIVILEGE_DEESCALATION_ESCALATION_SIGNER: u8 = 12;
 const TEST_PRIVILEGE_DEESCALATION_ESCALATION_WRITABLE: u8 = 13;
+const TEST_WRITE_DEESCALATION: u8 = 14;
 
 // const MINT_INDEX: usize = 0;
 const ARGUMENT_INDEX: usize = 1;
@@ -331,6 +332,28 @@ fn process_instruction(
                     assert_eq!(data[i as usize], i);
                 }
             }
+
+            msg!("Verify data write before cpi call with deescalated writable");
+            {
+                {
+                    let mut data = accounts[ARGUMENT_INDEX].try_borrow_mut_data()?;
+                    for i in 0..100 {
+                        data[i as usize] = 42;
+                    }
+                }
+
+                let invoked_instruction = create_instruction(
+                    *accounts[INVOKED_PROGRAM_INDEX].key,
+                    &[(accounts[ARGUMENT_INDEX].key, false, false)],
+                    vec![VERIFY_PRIVILEGE_DEESCALATION],
+                );
+                invoke(&invoked_instruction, accounts)?;
+
+                let data = accounts[ARGUMENT_INDEX].try_borrow_data()?;
+                for i in 0..100 {
+                    assert_eq!(data[i as usize], 42);
+                }
+            }
         }
         TEST_PRIVILEGE_ESCALATION_SIGNER => {
             msg!("Test privilege escalation signer");
@@ -534,6 +557,15 @@ fn process_instruction(
             );
             invoke(&invoked_instruction, accounts)?;
         }
+        TEST_WRITE_DEESCALATION => {
+            msg!("Test writable deescalation");
+            let instruction = create_instruction(
+                *accounts[INVOKED_PROGRAM_INDEX].key,
+                &[(accounts[INVOKED_ARGUMENT_INDEX].key, false, false)],
+                vec![WRITE_ACCOUNT, 10],
+            );
+            let _ = invoke(&instruction, accounts);
+        }
         _ => panic!(),
     }