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rust-bitcoin-unsafe-fast
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Improve the Instructions iterator for scripts 

- Rename the `iter` method to `instructions`.
- Add `instructions_minimal` for minimal-enforced iteration.
- Iterator has `Result<Instruction, Error>` as items.
This commit is contained in:
Steven Roose 2020-01-23 01:28:12 +00:00
parent c3a7d1b27c
commit fea09a0a94
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GPG Key ID: 2F2A88D7F8D68E87
3 changed files with 64 additions and 54 deletions
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11
fuzz/fuzz_targets/deserialize_script.rs
View File

@ -8,13 +8,14 @@ use bitcoin::consensus::encode;
fn do_test(data: &[u8]) {
let s: Result<script::Script, _> = encode::deserialize(data);
if let Ok(script) = s {
let _: Vec<script::Instruction> = script.iter(false).collect();
let enforce_min: Vec<script::Instruction> = script.iter(true).collect();
let _: Result<Vec<script::Instruction>, script::Error> = script.instructions().collect();
let mut b = script::Builder::new();
for ins in enforce_min {
match ins {
script::Instruction::Error(_) => return,
for ins in script.instructions_minimal() {
if ins.is_err() {
return;
}
match ins.ok().unwrap() {
script::Instruction::Op(op) => { b = b.push_opcode(op); }
script::Instruction::PushBytes(bytes) => {
// Any one-byte pushes, except -0, which can be interpreted as numbers, should be

99
src/blockdata/script.rs
View File

@ -329,10 +329,21 @@ impl Script {
/// opcodes, datapushes and errors. At most one error will be returned and then the
/// iterator will end. To instead iterate over the script as sequence of bytes, treat
/// it as a slice using `script[..]` or convert it to a vector using `into_bytes()`.
pub fn iter(&self, enforce_minimal: bool) -> Instructions {
///
/// To force minimal pushes, use [instructions_minimal].
pub fn instructions(&self) -> Instructions {
Instructions {
data: &self.0[..],
enforce_minimal: enforce_minimal,
enforce_minimal: false,
}
}
/// Iterate over the script in the form of `Instruction`s while enforcing
/// minimal pushes.
pub fn instructions_minimal(&self) -> Instructions {
Instructions {
data: &self.0[..],
enforce_minimal: true,
}
}
@ -437,8 +448,6 @@ pub enum Instruction<'a> {
PushBytes(&'a [u8]),
/// Some non-push opcode
Op(opcodes::All),
/// An opcode we were unable to parse
Error(Error)
}
/// Iterator over a script returning parsed opcodes
@ -448,9 +457,9 @@ pub struct Instructions<'a> {
}
impl<'a> Iterator for Instructions<'a> {
type Item = Instruction<'a>;
type Item = Result<Instruction<'a>, Error>;
fn next(&mut self) -> Option<Instruction<'a>> {
fn next(&mut self) -> Option<Result<Instruction<'a>, Error>> {
if self.data.is_empty() {
return None;
}
@ -460,93 +469,93 @@ impl<'a> Iterator for Instructions<'a> {
let n = n as usize;
if self.data.len() < n + 1 {
self.data = &[]; // Kill iterator so that it does not return an infinite stream of errors
return Some(Instruction::Error(Error::EarlyEndOfScript));
return Some(Err(Error::EarlyEndOfScript));
}
if self.enforce_minimal {
if n == 1 && (self.data[1] == 0x81 || (self.data[1] > 0 && self.data[1] <= 16)) {
self.data = &[];
return Some(Instruction::Error(Error::NonMinimalPush));
return Some(Err(Error::NonMinimalPush));
}
}
let ret = Some(Instruction::PushBytes(&self.data[1..n+1]));
let ret = Some(Ok(Instruction::PushBytes(&self.data[1..n+1])));
self.data = &self.data[n + 1..];
ret
}
opcodes::Class::Ordinary(opcodes::Ordinary::OP_PUSHDATA1) => {
if self.data.len() < 2 {
self.data = &[];
return Some(Instruction::Error(Error::EarlyEndOfScript));
return Some(Err(Error::EarlyEndOfScript));
}
let n = match read_uint(&self.data[1..], 1) {
Ok(n) => n,
Err(e) => {
self.data = &[];
return Some(Instruction::Error(e));
return Some(Err(e));
}
};
if self.data.len() < n + 2 {
self.data = &[];
return Some(Instruction::Error(Error::EarlyEndOfScript));
return Some(Err(Error::EarlyEndOfScript));
}
if self.enforce_minimal && n < 76 {
self.data = &[];
return Some(Instruction::Error(Error::NonMinimalPush));
return Some(Err(Error::NonMinimalPush));
}
let ret = Some(Instruction::PushBytes(&self.data[2..n+2]));
let ret = Some(Ok(Instruction::PushBytes(&self.data[2..n+2])));
self.data = &self.data[n + 2..];
ret
}
opcodes::Class::Ordinary(opcodes::Ordinary::OP_PUSHDATA2) => {
if self.data.len() < 3 {
self.data = &[];
return Some(Instruction::Error(Error::EarlyEndOfScript));
return Some(Err(Error::EarlyEndOfScript));
}
let n = match read_uint(&self.data[1..], 2) {
Ok(n) => n,
Err(e) => {
self.data = &[];
return Some(Instruction::Error(e));
return Some(Err(e));
}
};
if self.enforce_minimal && n < 0x100 {
self.data = &[];
return Some(Instruction::Error(Error::NonMinimalPush));
return Some(Err(Error::NonMinimalPush));
}
if self.data.len() < n + 3 {
self.data = &[];
return Some(Instruction::Error(Error::EarlyEndOfScript));
return Some(Err(Error::EarlyEndOfScript));
}
let ret = Some(Instruction::PushBytes(&self.data[3..n + 3]));
let ret = Some(Ok(Instruction::PushBytes(&self.data[3..n + 3])));
self.data = &self.data[n + 3..];
ret
}
opcodes::Class::Ordinary(opcodes::Ordinary::OP_PUSHDATA4) => {
if self.data.len() < 5 {
self.data = &[];
return Some(Instruction::Error(Error::EarlyEndOfScript));
return Some(Err(Error::EarlyEndOfScript));
}
let n = match read_uint(&self.data[1..], 4) {
Ok(n) => n,
Err(e) => {
self.data = &[];
return Some(Instruction::Error(e));
return Some(Err(e));
}
};
if self.enforce_minimal && n < 0x10000 {
self.data = &[];
return Some(Instruction::Error(Error::NonMinimalPush));
return Some(Err(Error::NonMinimalPush));
}
if self.data.len() < n + 5 {
self.data = &[];
return Some(Instruction::Error(Error::EarlyEndOfScript));
return Some(Err(Error::EarlyEndOfScript));
}
let ret = Some(Instruction::PushBytes(&self.data[5..n + 5]));
let ret = Some(Ok(Instruction::PushBytes(&self.data[5..n + 5])));
self.data = &self.data[n + 5..];
ret
}
// Everything else we can push right through
_ => {
let ret = Some(Instruction::Op(opcodes::All::from(self.data[0])));
let ret = Some(Ok(Instruction::Op(opcodes::All::from(self.data[0]))));
self.data = &self.data[1..];
ret
}
@ -676,8 +685,8 @@ impl Default for Builder {
impl From<Vec<u8>> for Builder {
fn from(v: Vec<u8>) -> Builder {
let script = Script(v.into_boxed_slice());
let last_op = match script.iter(false).last() {
Some(Instruction::Op(op)) => Some(op),
let last_op = match script.instructions().last() {
Some(Ok(Instruction::Op(op))) => Some(op),
_ => None,
};
Builder(script.into_bytes(), last_op)
@ -1009,31 +1018,31 @@ mod test {
let minimal = hex_script!("0169b2"); // minimal
let nonminimal_alt = hex_script!("026900b2"); // non-minimal number but minimal push (should be OK)
let v_zero: Vec<Instruction> = zero.iter(true).collect();
let v_zeropush: Vec<Instruction> = zeropush.iter(true).collect();
let v_zero: Result<Vec<Instruction>, Error> = zero.instructions_minimal().collect();
let v_zeropush: Result<Vec<Instruction>, Error> = zeropush.instructions_minimal().collect();
let v_min: Vec<Instruction> = minimal.iter(true).collect();
let v_nonmin: Vec<Instruction> = nonminimal.iter(true).collect();
let v_nonmin_alt: Vec<Instruction> = nonminimal_alt.iter(true).collect();
let slop_v_min: Vec<Instruction> = minimal.iter(false).collect();
let slop_v_nonmin: Vec<Instruction> = nonminimal.iter(false).collect();
let slop_v_nonmin_alt: Vec<Instruction> = nonminimal_alt.iter(false).collect();
let v_min: Result<Vec<Instruction>, Error> = minimal.instructions_minimal().collect();
let v_nonmin: Result<Vec<Instruction>, Error> = nonminimal.instructions_minimal().collect();
let v_nonmin_alt: Result<Vec<Instruction>, Error> = nonminimal_alt.instructions_minimal().collect();
let slop_v_min: Result<Vec<Instruction>, Error> = minimal.instructions().collect();
let slop_v_nonmin: Result<Vec<Instruction>, Error> = nonminimal.instructions().collect();
let slop_v_nonmin_alt: Result<Vec<Instruction>, Error> = nonminimal_alt.instructions().collect();
assert_eq!(
v_zero,
v_zero.unwrap(),
vec![
Instruction::PushBytes(&[]),
]
);
assert_eq!(
v_zeropush,
v_zeropush.unwrap(),
vec![
Instruction::PushBytes(&[0]),
]
);
assert_eq!(
v_min,
v_min.clone().unwrap(),
vec![
Instruction::PushBytes(&[105]),
Instruction::Op(opcodes::OP_NOP3),
@ -1041,23 +1050,21 @@ mod test {
);
assert_eq!(
v_nonmin,
vec![
Instruction::Error(Error::NonMinimalPush),
]
v_nonmin.err().unwrap(),
Error::NonMinimalPush
);
assert_eq!(
v_nonmin_alt,
v_nonmin_alt.clone().unwrap(),
vec![
Instruction::PushBytes(&[105, 0]),
Instruction::Op(opcodes::OP_NOP3),
]
);
assert_eq!(v_min, slop_v_min);
assert_eq!(v_min, slop_v_nonmin);
assert_eq!(v_nonmin_alt, slop_v_nonmin_alt);
assert_eq!(v_min.clone().unwrap(), slop_v_min.unwrap());
assert_eq!(v_min.unwrap(), slop_v_nonmin.unwrap());
assert_eq!(v_nonmin_alt.unwrap(), slop_v_nonmin_alt.unwrap());
}
#[test]

8
src/util/contracthash.rs
View File

@ -227,8 +227,11 @@ pub fn untemplate(script: &script::Script) -> Result<(Template, Vec<PublicKey>),
}
let mut mode = Mode::SeekingKeys;
for instruction in script.iter(false) {
match instruction {
for instruction in script.instructions() {
if let Err(e) = instruction {
return Err(Error::Script(e));
}
match instruction.unwrap() {
script::Instruction::PushBytes(data) => {
let n = data.len();
ret = match PublicKey::from_slice(data) {
@ -275,7 +278,6 @@ pub fn untemplate(script: &script::Script) -> Result<(Template, Vec<PublicKey>),
}
ret = ret.push_opcode(op);
}
script::Instruction::Error(e) => { return Err(Error::Script(e)); }
}
}
Ok((Template::from(&ret[..]), retkeys))