enforce proper range for rent burn_percent (#7217)

* enforce proper range for burn_percent

clap-utils/src/input_validators.rs

@@ -97,3 +97,24 @@ pub fn is_port(port: String) -> Result<(), String> {
         .map(|_| ())
         .map_err(|e| format!("{:?}", e))
 }
+
+pub fn is_valid_percentage(percentage: String) -> Result<(), String> {
+    percentage
+        .parse::<u8>()
+        .map_err(|e| {
+            format!(
+                "Unable to parse input percentage, provided: {}, err: {:?}",
+                percentage, e
+            )
+        })
+        .and_then(|v| {
+            if v > 100 {
+                Err(format!(
+                    "Percentage must be in range of 0 to 100, provided: {}",
+                    v
+                ))
+            } else {
+                Ok(())
+            }
+        })
+}

genesis/src/main.rs

@@ -8,6 +8,7 @@ mod unlocks;
 use crate::genesis_accounts::add_genesis_accounts;
 use clap::{crate_description, crate_name, value_t, value_t_or_exit, App, Arg, ArgMatches};
 use solana_clap_utils::input_parsers::pubkey_of;
+use solana_clap_utils::input_validators::is_valid_percentage;
 use solana_genesis::Base64Account;
 use solana_ledger::{blocktree::create_new_ledger, poh::compute_hashes_per_tick};
 use solana_sdk::{
@@ -249,7 +250,8 @@ fn main() -> Result<(), Box<dyn error::Error>> {
                 .value_name("NUMBER")
                 .takes_value(true)
                 .default_value(default_rent_burn_percentage)
-                .help("amount of rent to burn, as a fraction of std::u8::MAX."),
+                .help("percentage of collected rent to burn")
+                .validator(is_valid_percentage),
         )
         .arg(
             Arg::with_name("target_signatures_per_slot")

programs/stake/src/stake_state.rs

@@ -1394,7 +1394,7 @@ mod tests {
                 &Rent {
                     lamports_per_byte_year: 42,
                     ..Rent::default()
-                }
+                },
             ),
             Err(InstructionError::InsufficientFunds)
         );

runtime/src/bank.rs

@@ -1706,6 +1706,7 @@ mod tests {
             &dummy_leader_pubkey,
             dummy_leader_lamports,
         );
+
         genesis_config.rent = Rent {
             lamports_per_byte_year: 5,
             exemption_threshold: 1.2,

sdk/src/rent.rs

@@ -23,8 +23,8 @@ pub const DEFAULT_LAMPORTS_PER_BYTE_YEAR: u64 = 0; //1_000_000_000 / 100 * 365 /
 /// default amount of time (in years) the balance has to include rent for
 pub const DEFAULT_EXEMPTION_THRESHOLD: f64 = 2.0;
 
-/// default amount of rent to burn, as a fraction of std::u8::MAX
-pub const DEFAULT_BURN_PERCENT: u8 = ((50usize * std::u8::MAX as usize) / 100usize) as u8;
+/// default percentage of rent to burn (Valid values are 0 to 100)
+pub const DEFAULT_BURN_PERCENT: u8 = 100;
 
 /// account storage overhead for calculation of base rent
 pub const ACCOUNT_STORAGE_OVERHEAD: u64 = 128;