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Merge pull request #397 from stevenroose/script-iter 

Improve the Instructions iterator for scripts
This commit is contained in:
Elichai Turkel 2020-09-09 19:06:05 +03:00 committed by GitHub
parent c8c187efd2 fea09a0a94
commit a44ba2d878
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GPG Key ID: 4AEE18F83AFDEB23
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]) { fn do_test(data: &[u8]) {
let s: Result<script::Script, _> = encode::deserialize(data); let s: Result<script::Script, _> = encode::deserialize(data);
if let Ok(script) = s { if let Ok(script) = s {
let _: Vec<script::Instruction> = script.iter(false).collect(); let _: Result<Vec<script::Instruction>, script::Error> = script.instructions().collect();
let enforce_min: Vec<script::Instruction> = script.iter(true).collect();
let mut b = script::Builder::new(); let mut b = script::Builder::new();
for ins in enforce_min { for ins in script.instructions_minimal() {
match ins { if ins.is_err() {
script::Instruction::Error(_) => return, return;
}
match ins.ok().unwrap() {
script::Instruction::Op(op) => { b = b.push_opcode(op); } script::Instruction::Op(op) => { b = b.push_opcode(op); }
script::Instruction::PushBytes(bytes) => { script::Instruction::PushBytes(bytes) => {
// Any one-byte pushes, except -0, which can be interpreted as numbers, should be // 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 /// 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 /// 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()`. /// 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 { Instructions {
data: &self.0[..], 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]), PushBytes(&'a [u8]),
/// Some non-push opcode /// Some non-push opcode
Op(opcodes::All), Op(opcodes::All),
/// An opcode we were unable to parse
Error(Error)
} }
/// Iterator over a script returning parsed opcodes /// Iterator over a script returning parsed opcodes
@ -448,9 +457,9 @@ pub struct Instructions<'a> {
} }
impl<'a> Iterator for 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() { if self.data.is_empty() {
return None; return None;
} }
@ -460,93 +469,93 @@ impl<'a> Iterator for Instructions<'a> {
let n = n as usize; let n = n as usize;
if self.data.len() < n + 1 { if self.data.len() < n + 1 {
self.data = &[]; // Kill iterator so that it does not return an infinite stream of errors 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 self.enforce_minimal {
if n == 1 && (self.data[1] == 0x81 || (self.data[1] > 0 && self.data[1] <= 16)) { if n == 1 && (self.data[1] == 0x81 || (self.data[1] > 0 && self.data[1] <= 16)) {
self.data = &[]; 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..]; self.data = &self.data[n + 1..];
ret ret
} }
opcodes::Class::Ordinary(opcodes::Ordinary::OP_PUSHDATA1) => { opcodes::Class::Ordinary(opcodes::Ordinary::OP_PUSHDATA1) => {
if self.data.len() < 2 { if self.data.len() < 2 {
self.data = &[]; self.data = &[];
return Some(Instruction::Error(Error::EarlyEndOfScript)); return Some(Err(Error::EarlyEndOfScript));
} }
let n = match read_uint(&self.data[1..], 1) { let n = match read_uint(&self.data[1..], 1) {
Ok(n) => n, Ok(n) => n,
Err(e) => { Err(e) => {
self.data = &[]; self.data = &[];
return Some(Instruction::Error(e)); return Some(Err(e));
} }
}; };
if self.data.len() < n + 2 { if self.data.len() < n + 2 {
self.data = &[]; self.data = &[];
return Some(Instruction::Error(Error::EarlyEndOfScript)); return Some(Err(Error::EarlyEndOfScript));
} }
if self.enforce_minimal && n < 76 { if self.enforce_minimal && n < 76 {
self.data = &[]; 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..]; self.data = &self.data[n + 2..];
ret ret
} }
opcodes::Class::Ordinary(opcodes::Ordinary::OP_PUSHDATA2) => { opcodes::Class::Ordinary(opcodes::Ordinary::OP_PUSHDATA2) => {
if self.data.len() < 3 { if self.data.len() < 3 {
self.data = &[]; self.data = &[];
return Some(Instruction::Error(Error::EarlyEndOfScript)); return Some(Err(Error::EarlyEndOfScript));
} }
let n = match read_uint(&self.data[1..], 2) { let n = match read_uint(&self.data[1..], 2) {
Ok(n) => n, Ok(n) => n,
Err(e) => { Err(e) => {
self.data = &[]; self.data = &[];
return Some(Instruction::Error(e)); return Some(Err(e));
} }
}; };
if self.enforce_minimal && n < 0x100 { if self.enforce_minimal && n < 0x100 {
self.data = &[]; self.data = &[];
return Some(Instruction::Error(Error::NonMinimalPush)); return Some(Err(Error::NonMinimalPush));
} }
if self.data.len() < n + 3 { if self.data.len() < n + 3 {
self.data = &[]; 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..]; self.data = &self.data[n + 3..];
ret ret
} }
opcodes::Class::Ordinary(opcodes::Ordinary::OP_PUSHDATA4) => { opcodes::Class::Ordinary(opcodes::Ordinary::OP_PUSHDATA4) => {
if self.data.len() < 5 { if self.data.len() < 5 {
self.data = &[]; self.data = &[];
return Some(Instruction::Error(Error::EarlyEndOfScript)); return Some(Err(Error::EarlyEndOfScript));
} }
let n = match read_uint(&self.data[1..], 4) { let n = match read_uint(&self.data[1..], 4) {
Ok(n) => n, Ok(n) => n,
Err(e) => { Err(e) => {
self.data = &[]; self.data = &[];
return Some(Instruction::Error(e)); return Some(Err(e));
} }
}; };
if self.enforce_minimal && n < 0x10000 { if self.enforce_minimal && n < 0x10000 {
self.data = &[]; self.data = &[];
return Some(Instruction::Error(Error::NonMinimalPush)); return Some(Err(Error::NonMinimalPush));
} }
if self.data.len() < n + 5 { if self.data.len() < n + 5 {
self.data = &[]; 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..]; self.data = &self.data[n + 5..];
ret ret
} }
// Everything else we can push right through // 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..]; self.data = &self.data[1..];
ret ret
} }
@ -676,8 +685,8 @@ impl Default for Builder {
impl From<Vec<u8>> for Builder { impl From<Vec<u8>> for Builder {
fn from(v: Vec<u8>) -> Builder { fn from(v: Vec<u8>) -> Builder {
let script = Script(v.into_boxed_slice()); let script = Script(v.into_boxed_slice());
let last_op = match script.iter(false).last() { let last_op = match script.instructions().last() {
Some(Instruction::Op(op)) => Some(op), Some(Ok(Instruction::Op(op))) => Some(op),
_ => None, _ => None,
}; };
Builder(script.into_bytes(), last_op) Builder(script.into_bytes(), last_op)
@ -1009,31 +1018,31 @@ mod test {
let minimal = hex_script!("0169b2"); // minimal let minimal = hex_script!("0169b2"); // minimal
let nonminimal_alt = hex_script!("026900b2"); // non-minimal number but minimal push (should be OK) 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_zero: Result<Vec<Instruction>, Error> = zero.instructions_minimal().collect();
let v_zeropush: Vec<Instruction> = zeropush.iter(true).collect(); let v_zeropush: Result<Vec<Instruction>, Error> = zeropush.instructions_minimal().collect();
let v_min: Vec<Instruction> = minimal.iter(true).collect(); let v_min: Result<Vec<Instruction>, Error> = minimal.instructions_minimal().collect();
let v_nonmin: Vec<Instruction> = nonminimal.iter(true).collect(); let v_nonmin: Result<Vec<Instruction>, Error> = nonminimal.instructions_minimal().collect();
let v_nonmin_alt: Vec<Instruction> = nonminimal_alt.iter(true).collect(); let v_nonmin_alt: Result<Vec<Instruction>, Error> = nonminimal_alt.instructions_minimal().collect();
let slop_v_min: Vec<Instruction> = minimal.iter(false).collect(); let slop_v_min: Result<Vec<Instruction>, Error> = minimal.instructions().collect();
let slop_v_nonmin: Vec<Instruction> = nonminimal.iter(false).collect(); let slop_v_nonmin: Result<Vec<Instruction>, Error> = nonminimal.instructions().collect();
let slop_v_nonmin_alt: Vec<Instruction> = nonminimal_alt.iter(false).collect(); let slop_v_nonmin_alt: Result<Vec<Instruction>, Error> = nonminimal_alt.instructions().collect();
assert_eq!( assert_eq!(
v_zero, v_zero.unwrap(),
vec![ vec![
Instruction::PushBytes(&[]), Instruction::PushBytes(&[]),
] ]
); );
assert_eq!( assert_eq!(
v_zeropush, v_zeropush.unwrap(),
vec![ vec![
Instruction::PushBytes(&[0]), Instruction::PushBytes(&[0]),
] ]
); );
assert_eq!( assert_eq!(
v_min, v_min.clone().unwrap(),
vec![ vec![
Instruction::PushBytes(&[105]), Instruction::PushBytes(&[105]),
Instruction::Op(opcodes::OP_NOP3), Instruction::Op(opcodes::OP_NOP3),
@ -1041,23 +1050,21 @@ mod test {
); );
assert_eq!( assert_eq!(
v_nonmin, v_nonmin.err().unwrap(),
vec![ Error::NonMinimalPush
Instruction::Error(Error::NonMinimalPush),
]
); );
assert_eq!( assert_eq!(
v_nonmin_alt, v_nonmin_alt.clone().unwrap(),
vec![ vec![
Instruction::PushBytes(&[105, 0]), Instruction::PushBytes(&[105, 0]),
Instruction::Op(opcodes::OP_NOP3), Instruction::Op(opcodes::OP_NOP3),
] ]
); );
assert_eq!(v_min, slop_v_min); assert_eq!(v_min.clone().unwrap(), slop_v_min.unwrap());
assert_eq!(v_min, slop_v_nonmin); assert_eq!(v_min.unwrap(), slop_v_nonmin.unwrap());
assert_eq!(v_nonmin_alt, slop_v_nonmin_alt); assert_eq!(v_nonmin_alt.unwrap(), slop_v_nonmin_alt.unwrap());
} }
#[test] #[test]

8
src/util/contracthash.rs
View File

@ -220,8 +220,11 @@ pub fn untemplate(script: &script::Script) -> Result<(Template, Vec<PublicKey>),
} }
let mut mode = Mode::SeekingKeys; let mut mode = Mode::SeekingKeys;
for instruction in script.iter(false) { for instruction in script.instructions() {
match instruction { if let Err(e) = instruction {
return Err(Error::Script(e));
}
match instruction.unwrap() {
script::Instruction::PushBytes(data) => { script::Instruction::PushBytes(data) => {
let n = data.len(); let n = data.len();
ret = match PublicKey::from_slice(data) { ret = match PublicKey::from_slice(data) {
@ -268,7 +271,6 @@ pub fn untemplate(script: &script::Script) -> Result<(Template, Vec<PublicKey>),
} }
ret = ret.push_opcode(op); ret = ret.push_opcode(op);
} }
script::Instruction::Error(e) => { return Err(Error::Script(e)); }
} }
} }
Ok((Template::from(&ret[..]), retkeys)) Ok((Template::from(&ret[..]), retkeys))