Code Review: Smart Contract VM 02/13/19

Cargo.toml

@@ -20,6 +20,7 @@ serde_json = "1.0"
 rust-crypto = "0.2" 
 sha2 = "0.8.0"
 dirs = "1.0.4"
+regex = "1"
 
 [dependencies.secp256k1]
 version = "0.11.5"

src/address/c32.rs

@@ -16,3 +16,320 @@
  You should have received a copy of the GNU General Public License
  along with Blockstack. If not, see <http://www.gnu.org/licenses/>.
 */
+use super::Error;
+use crypto::sha2::Sha256;
+use crypto::digest::Digest;
+
+const C32_CHARACTERS: &str = "0123456789ABCDEFGHJKMNPQRSTVWXYZ";
+
+fn c32_encode(input_bytes: &[u8]) -> String {
+    let c32_chars: &[u8] = C32_CHARACTERS.as_bytes();
+
+    let mut result = vec![];
+    let mut carry = 0;
+    let mut carry_bits = 0;
+
+    for current_value in input_bytes.iter().rev() {
+        let low_bits_to_take = 5 - carry_bits;
+        let low_bits = current_value & ((1<<low_bits_to_take) - 1);
+        let c32_value = (low_bits << carry_bits) + carry;
+        result.push(c32_chars[c32_value as usize]);
+        carry_bits = (8 + carry_bits) - 5;
+        carry = current_value >> (8 - carry_bits);
+
+        if carry_bits >= 5 {
+            let c32_value = carry & ((1<<5) - 1);
+            result.push(c32_chars[c32_value as usize]);
+            carry_bits = carry_bits - 5;
+            carry = carry >> 5;
+        }
+    }
+
+    if carry_bits > 0 {
+        result.push(c32_chars[carry as usize]);
+    }
+
+    // remove leading zeros from c32 encoding
+
+    while let Some(v) = result.pop() {
+        if v != c32_chars[0] {
+            result.push(v);
+            break;
+        }
+    }
+
+    // add leading zeros from input.
+
+    for current_value in input_bytes.iter() {
+        if *current_value == 0 {
+            result.push(c32_chars[0]);
+        } else {
+            break;
+        }
+    }
+
+    let result: Vec<u8> = result.drain(..).rev().collect();
+    String::from_utf8(result).unwrap()
+}
+
+fn c32_decode(input_str: &str) -> Result<Vec<u8>, Error> {
+    let mut result = vec![];
+    let mut carry: u16 = 0;
+    let mut carry_bits = 0; // can be up to 5
+
+    let iter_c32_digits = input_str.chars().rev()
+        .map(|x| { C32_CHARACTERS.find(x) });
+
+    for current_result in iter_c32_digits {
+        let current_5bit = current_result.ok_or(Error::InvalidCrockford32)?;
+        carry += (current_5bit as u16) << carry_bits;
+        carry_bits += 5;
+
+        if carry_bits >= 8 {
+            result.push((carry & ((1<<8) - 1)) as u8);
+            carry_bits -= 8;
+            carry = carry >> 8;
+        }
+    }
+
+    if carry_bits > 0 {
+        result.push(carry as u8);
+    }
+
+    // remove leading zeros from Vec<u8> encoding
+    while let Some(v) = result.pop() {
+        if v != 0 {
+            result.push(v);
+            break;
+        }
+    }
+
+    // add leading zeros from input.
+    for current_value in input_str.chars() {
+        if current_value == '0' {
+            result.push(0);
+        } else {
+            break;
+        }
+    }
+
+    result.reverse();
+
+    Ok(result)
+}
+
+fn double_sha256_checksum(data: &[u8]) -> Vec<u8> {
+    let mut sha2 = Sha256::new();
+    let mut tmp = [0u8; 32];
+    sha2.input(data);
+    sha2.result(&mut tmp);
+    let mut sha2 = Sha256::new();
+    sha2.input(&tmp);
+    sha2.result(&mut tmp);
+    tmp[0..4].to_vec()
+}
+
+fn c32_check_encode(version: u8, data: &[u8]) -> Result<String, Error> {
+    if version >= 32 {
+        return Err(Error::InvalidVersion(version))
+    }
+
+    let mut check_data = vec![version];
+    check_data.extend_from_slice(data);
+    let checksum = double_sha256_checksum(&check_data);
+
+    let mut encoding_data = data.to_vec();
+    encoding_data.extend_from_slice(&checksum);
+
+    // working with ascii strings is awful.
+    let mut c32_string = c32_encode(&encoding_data).into_bytes();
+    let version_char = C32_CHARACTERS.as_bytes()[version as usize];
+    c32_string.insert(0, version_char);
+
+    Ok(String::from_utf8(c32_string).unwrap())
+}
+
+fn c32_check_decode(check_data: &str) -> Result<(u8, Vec<u8>), Error> {
+    if check_data.len() < 2 {
+        return Err(Error::InvalidCrockford32)
+    }
+    let (version, data) = check_data.split_at(1);
+
+    let data_sum_bytes = c32_decode(data)?;
+    if data_sum_bytes.len() < 5 {
+        return Err(Error::InvalidCrockford32)
+    }
+
+    let (data_bytes, expected_sum) = data_sum_bytes.split_at(data_sum_bytes.len() - 4);
+
+    let mut check_data = c32_decode(version)?;
+    check_data.extend_from_slice(data_bytes);
+
+    let computed_sum = double_sha256_checksum(&check_data);
+    if computed_sum != expected_sum {
+        return Err(Error::InvalidChecksum(computed_sum, expected_sum.to_vec()))
+    }
+
+    let version = check_data[0];
+    let data = data_bytes.to_vec();
+    Ok((version, data))
+}
+
+pub fn c32_address_decode(c32_address_str: &str) -> Result<(u8, Vec<u8>), Error> {
+    if c32_address_str.len() <= 5 {
+        Err(Error::InvalidCrockford32)
+    } else {
+        c32_check_decode(&c32_address_str[1..])
+    }
+}
+
+pub fn c32_address(version: u8, data: &[u8]) -> Result<String, Error> {
+    let c32_string = c32_check_encode(version, data)?;
+    Ok(format!("S{}", c32_string))
+}
+
+mod test {
+    use util::hash::hex_bytes;
+    use super::*;
+
+    #[test]
+    fn test_addresses() {
+        let hex_strs = [
+            "a46ff88886c2ef9762d970b4d2c63678835bd39d",
+            "0000000000000000000000000000000000000000",
+            "0000000000000000000000000000000000000001",
+            "1000000000000000000000000000000000000001",
+            "1000000000000000000000000000000000000000"
+        ];
+
+        let versions = [
+            22,
+            0,
+            31,
+            20,
+            26,
+            21
+        ];
+
+        let c32_addrs = [
+            [
+                "SP2J6ZY48GV1EZ5V2V5RB9MP66SW86PYKKNRV9EJ7", 
+                "SP000000000000000000002Q6VF78",
+                "SP00000000000000000005JA84HQ",
+                "SP80000000000000000000000000000004R0CMNV", 
+                "SP800000000000000000000000000000033H8YKK"
+            ],
+            [
+                "S02J6ZY48GV1EZ5V2V5RB9MP66SW86PYKKPVKG2CE", 
+                "S0000000000000000000002AA028H", 
+                "S000000000000000000006EKBDDS", 
+                "S080000000000000000000000000000007R1QC00", 
+                "S080000000000000000000000000000003ENTGCQ"
+            ],
+            [
+                "SZ2J6ZY48GV1EZ5V2V5RB9MP66SW86PYKKQ9H6DPR", 
+                "SZ000000000000000000002ZE1VMN", 
+                "SZ00000000000000000005HZ3DVN", 
+                "SZ80000000000000000000000000000004XBV6MS", 
+                "SZ800000000000000000000000000000007VF5G0"
+            ],
+            [
+                "SM2J6ZY48GV1EZ5V2V5RB9MP66SW86PYKKQVX8X0G", 
+                "SM0000000000000000000062QV6X", 
+                "SM00000000000000000005VR75B2", 
+                "SM80000000000000000000000000000004WBEWKC", 
+                "SM80000000000000000000000000000000JGSYGV"
+            ],
+            [
+                "ST2J6ZY48GV1EZ5V2V5RB9MP66SW86PYKKQYAC0RQ", 
+                "ST000000000000000000002AMW42H", 
+                "ST000000000000000000042DB08Y", 
+                "ST80000000000000000000000000000006BYJ4R4", 
+                "ST80000000000000000000000000000002YBNPV3"
+            ],
+            [
+                "SN2J6ZY48GV1EZ5V2V5RB9MP66SW86PYKKP6D2ZK9", 
+                "SN000000000000000000003YDHWKJ", 
+                "SN00000000000000000005341MC8", 
+                "SN800000000000000000000000000000066KZWY0", 
+                "SN800000000000000000000000000000006H75AK"
+            ]
+        ];
+
+        for i in 0..hex_strs.len() {
+            for j in 0..versions.len() {
+                let h = hex_strs[i];
+                let v = versions[j];
+                let b = hex_bytes(h).unwrap();
+                let z = c32_address(v, &b).unwrap();
+
+                assert_eq!(z, c32_addrs[j][i]);
+
+                let (decoded_version, decoded_bytes) = c32_address_decode(&z).unwrap();
+                assert_eq!(decoded_version, v);
+                assert_eq!(decoded_bytes, b);
+            }
+        }
+    }
+
+    #[test]
+    fn test_simple() {
+        let hex_strings = &[
+              "a46ff88886c2ef9762d970b4d2c63678835bd39d",
+              "",
+              "0000000000000000000000000000000000000000",
+              "0000000000000000000000000000000000000001",
+              "1000000000000000000000000000000000000001",
+              "1000000000000000000000000000000000000000",
+              "01",
+              "22",
+              "0001",
+              "000001",
+              "00000001",
+              "10",
+              "0100",
+              "1000",
+              "010000",
+              "100000",
+              "01000000",
+              "10000000",
+              "0100000000"
+          ];
+        let c32_strs = [
+            "MHQZH246RBQSERPSE2TD5HHPF21NQMWX",
+             "",
+            "00000000000000000000",
+            "00000000000000000001",
+            "20000000000000000000000000000001",
+            "20000000000000000000000000000000",
+            "1",
+            "12",
+            "01",
+            "001",
+            "0001",
+            "G",
+            "80",
+            "400",
+            "2000",
+            "10000",
+            "G0000",
+            "800000",
+            "4000000"
+        ];
+
+        let results: Vec<_> = hex_strings.iter().zip(c32_strs.iter())
+            .map(|(hex_str, expected)|
+                 {
+                     let bytes = hex_bytes(hex_str).unwrap();
+                     let c32_encoded = c32_encode(&bytes);
+                     let decoded_bytes = c32_decode(&c32_encoded).unwrap();
+                     let result = (bytes, c32_encoded, decoded_bytes, expected);
+                     println!("{:?}", result);
+                     result
+                 }).collect();
+        for (bytes, c32_encoded, decoded_bytes, expected_c32) in results.iter() {
+            assert_eq!(bytes, decoded_bytes);
+            assert_eq!(c32_encoded, *expected_c32);
+        }
+    }
+}

src/address/mod.rs

@@ -17,4 +17,27 @@
  along with Blockstack. If not, see <http://www.gnu.org/licenses/>.
 */
 
+use std::error;
+use std::fmt;
+
 pub mod c32;
+
+#[derive(Debug)]
+pub enum Error {
+    InvalidCrockford32,
+    InvalidVersion(u8),
+    InvalidChecksum(Vec<u8>, Vec<u8>),
+    EmptyData
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{:?}", self)
+    }
+}
+
+impl error::Error for Error {
+    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
+        None
+    }
+}

src/main.rs

@@ -30,6 +30,7 @@ extern crate curve25519_dalek;
 extern crate ed25519_dalek;
 extern crate sha2;
 extern crate dirs;
+extern crate regex;
 
 #[macro_use] extern crate serde_derive;
 
@@ -38,7 +39,9 @@ mod burnchains;
 mod chainstate;
 mod core;
 mod vm;
+mod address;
 
+use std::fs;
 use std::env;
 use std::process;
 
@@ -82,6 +85,20 @@ fn main() {
         }
     }
 
+    if argv[1] == "exec_program" {
+        if argv.len() < 3 {
+            eprintln!("Usage: {} exec_program [program-file.scm]", argv[0]);
+            process::exit(1);
+        }
+        let program: String = fs::read_to_string(&argv[2])
+            .expect(&format!("Error reading file: {}", argv[2]));
+        match vm::execute(&program) {
+            Ok(result) => println!("{}", result),
+            Err(error) => println!("Program Execution Error: \n {}", error)
+        }
+        return
+    }
+
     if argv.len() < 4 {
         eprintln!("Usage: {} blockchain network working_dir", argv[0]);
         process::exit(1);