From 8f7c05c7cf63d214df18aeb356ec5de29051391e Mon Sep 17 00:00:00 2001
From: ara <226676426+ara-stock@users.noreply.github.com>
Date: Sat, 10 Oct 2026 12:27:56 +0900
Subject: [PATCH] program: Return an error instead of panicking on Reallocate
 overflow

Reallocate added the record header size to the requested data length
with checked_add(...).unwrap(), so a data_length close to u64::MAX made
the program panic instead of returning InvalidArgument.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 program/src/processor.rs    |  2 +-
 program/tests/functional.rs | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/program/src/processor.rs b/program/src/processor.rs
index 477013f..f435403 100644
--- a/program/src/processor.rs
+++ b/program/src/processor.rs
@@ -161,7 +161,7 @@ pub fn process_instruction(
                 .checked_add(
                     usize::try_from(data_length).map_err(|_| ProgramError::InvalidArgument)?,
                 )
-                .unwrap();
+                .ok_or(ProgramError::InvalidArgument)?;
 
             // reallocate
             if data_info.data_len() >= needed_account_length {
diff --git a/program/tests/functional.rs b/program/tests/functional.rs
index 6454e4b..0fa0338 100644
--- a/program/tests/functional.rs
+++ b/program/tests/functional.rs
@@ -730,3 +730,38 @@ fn reallocate_fail_unsigned() {
         ],
     );
 }
+
+#[test]
+fn reallocate_fail_data_length_overflow() {
+    let mollusk = Mollusk::new(&id(), "spl_record");
+    let payer = Address::new_unique();
+    let authority = Address::new_unique();
+    let account = Address::new_unique();
+    let data = &[111u8; 8];
+    let mut ixs = initialize_instructions(&payer, &authority, &account, data).to_vec();
+    ixs.push(instruction::reallocate(&account, &authority, u64::MAX));
+    let checks = [
+        [Check::success()],
+        [Check::success()],
+        [Check::success()],
+        [Check::err(ProgramError::InvalidArgument)],
+    ];
+    mollusk.process_and_validate_instruction_chain(
+        ixs.iter()
+            .zip(checks.iter().map(|c| c.as_ref()))
+            .collect::<Vec<_>>()
+            .as_slice(),
+        &[
+            (
+                payer,
+                Account {
+                    lamports: 1_000_000_000,
+                    ..Default::default()
+                },
+            ),
+            (authority, Account::default()),
+            (account, Account::default()),
+            mollusk_svm::program::keyed_account_for_system_program(),
+        ],
+    );
+}