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Check for overflow in rent partition calculation (#13569)

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Co-authored-by: Carl Lin <carl@solana.com>
This commit is contained in:
carllin
2020-11-19 04:17:00 -08:00
committed by GitHub
parent 1cd70edec0
commit 110acd20dc
1 changed files with 34 additions and 0 deletions
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34
runtime/src/bank.rs
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@ -3046,6 +3046,8 @@ impl Bank {
let partition_width = (PREFIX_MAX - partition_count + 1) / partition_count + 1; let partition_width = (PREFIX_MAX - partition_count + 1) / partition_count + 1;
let mut start_key_prefix = if start_index == 0 && end_index == 0 { let mut start_key_prefix = if start_index == 0 && end_index == 0 {
0 0
} else if start_index + 1 == partition_count {
PREFIX_MAX
} else { } else {
(start_index + 1) * partition_width (start_index + 1) * partition_width
}; };
@ -5646,6 +5648,38 @@ pub(crate) mod tests {
0xff, 0xff, 0xff, 0xff, 0xff, 0xff 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
]) ])
); );
fn should_cause_overflow(partition_count: u64) -> bool {
// Check `partition_width = (u64::max_value() + 1) / partition_count` is exact and
// does not have a remainder.
// This way, `partition_width * partition_count == (u64::max_value() + 1)`,
// so the test actually tests for overflow
(u64::max_value() - partition_count + 1) % partition_count == 0
}
let max_exact = 64;
// Make sure `max_exact` divides evenly when calculating `calculate_partition_width`
assert!(should_cause_overflow(max_exact));
// Make sure `max_unexact` doesn't divide evenly when calculating `calculate_partition_width`
let max_unexact = 10;
assert!(!should_cause_overflow(max_unexact));
for max in &[max_exact, max_unexact] {
let range = Bank::pubkey_range_from_partition((max - 1, max - 1, *max));
assert_eq!(
range,
Pubkey::new_from_array([
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff
])
..=Pubkey::new_from_array([
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
])
);
}
} }
fn map_to_test_bad_range() -> AccountMap<Pubkey, i8> { fn map_to_test_bad_range() -> AccountMap<Pubkey, i8> {