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Fix: issue when multiple forks happen #1763

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Dec 5, 2024
Merged

Fix: issue when multiple forks happen #1763

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149 changes: 123 additions & 26 deletions rust/src/nasl/interpreter/call.rs
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -41,36 +41,49 @@ impl<'a> Interpreter<'a> {
);
self.register_mut().create_root_child(named);
let result = match self.ctxconfigs.nasl_fn_execute(name, self.register()).await {
Some(r) => {
if let Ok(NaslValue::Fork(mut x)) = r {
Ok(if let Some(r) = x.pop() {
// this is a proposal for the case that the caller is immediately executing
// if not the position needs to be reset
if self.index == 0 {
let position = self.position().current_init_statement();
for i in x {
tracing::trace!(return_value=?i, return_position=?self.position(), interpreter_position=?position, "creating interpreter instance" );
self.run_specific.push(RunSpecific {
register: self.register().clone(),
position: position.clone(),
skip_until_return: Some((self.position().clone(), i)),
});
}
Some(Ok(NaslValue::Fork(x))) if self.index == 0 && !x.is_empty() => {
let mut additional = Vec::with_capacity(x.len() - 1);
let root_pos = self.run_specific[0].position.clone();

for (vi, v) in x.iter().enumerate() {
for (rsi, rs) in self.run_specific.iter_mut().enumerate() {
let mut pos = root_pos.clone();
// needs to be reduced because a previous down statement enhanced the number
pos.reduce_last();

if vi == 0 {
rs.skip_until_return.push((pos, v.clone()));
} else {
tracing::trace!(
index = self.index,
"we only allow expanding of executions (fork) on root instance"
);
let position = pos.current_init_statement();
let mut skip_until_return = rs
.skip_until_return
.iter()
.filter(|(p, _)| p != &pos)
.cloned()
.collect::<Vec<_>>();
skip_until_return.push((pos.clone(), v.clone()));
tracing::trace!(run_specific_index=rsi, value_index=vi, value=?v, ?pos, ?skip_until_return, ?rs.skip_until_return, "new fork");

additional.push(RunSpecific {
register: rs.register.clone(),
position: position.clone(),
skip_until_return,
});
}
tracing::trace!(return_value=?r, "returning interpreter instance" );
r
} else {
NaslValue::Null
})
} else {
r.map_err(|x| FunctionError::new(name, x).into())
}
}
self.run_specific.extend(additional);
Ok(x[0].clone())
}

Some(Ok(NaslValue::Fork(x))) if self.index == 0 && x.is_empty() => {
Ok(NaslValue::Null)
}

Some(Ok(NaslValue::Fork(_))) => {
unreachable!("NaslValue::Fork must only occur on root instance, all other cases should return a value within run_specific")
}
Some(r) => r.map_err(|x| FunctionError::new(name, x).into()),
None => {
let found = self
.register()
Expand Down Expand Up @@ -117,4 +130,88 @@ mod tests {
t.ok("test(a: 1);", 1);
t.ok("test();", 0);
}

#[test]
#[tracing_test::traced_test]
fn multiple_forks() {
let mut t = TestBuilder::default();
t.run_all(
r#"
set_kb_item(name: "port", value: 1);
set_kb_item(name: "port", value: 2);
set_kb_item(name: "host", value: "a");
set_kb_item(name: "host", value: "b");
get_kb_item("port");
get_kb_item("host");
"#,
);

assert_eq!(t.results().len(), 10);
let results: Vec<_> = t
.results()
.into_iter()
.skip(4)
.filter_map(|x| x.ok())
.collect();

assert_eq!(
results,
vec![
1.into(),
2.into(),
"a".into(),
"a".into(),
"b".into(),
"b".into(),
]
);
}
#[test]
#[tracing_test::traced_test]
fn empty_fork() {
let mut t = TestBuilder::default();
t.run_all(
r#"
get_kb_item("port") + ":" + get_kb_item("host");
"#,
);

let results: Vec<_> = t
.results()
.into_iter()
.filter_map(|x| x.ok())
.collect();

assert_eq!(
results,
vec!["\0:\0".into()]
);
}

#[test]
#[tracing_test::traced_test]
fn multiple_forks_on_one_line() {
let mut t = TestBuilder::default();
t.run_all(
r#"
set_kb_item(name: "port", value: 1);
set_kb_item(name: "port", value: 2);
set_kb_item(name: "host", value: "a");
set_kb_item(name: "host", value: "b");
get_kb_item("port") + ":" + get_kb_item("host");
"#,
);

let results: Vec<_> = t
.results()
.into_iter()
.skip(4)
.filter_map(|x| x.ok())
.collect();

assert_eq!(
results,
vec!["1:a".into(), "2:a".into(), "1:b".into(), "2:b".into(),]
);
}
}
88 changes: 58 additions & 30 deletions rust/src/nasl/interpreter/interpreter.rs
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -25,6 +25,20 @@ pub(crate) struct Position {
index: Vec<usize>,
}

impl std::fmt::Display for Position {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(
f,
"{}",
self.index
.iter()
.map(|x| x.to_string())
.collect::<Vec<String>>()
.join(".")
)
}
}

impl Position {
pub fn new(index: usize) -> Self {
Self { index: vec![index] }
Expand All @@ -34,8 +48,20 @@ impl Position {
self.index.push(0);
}

pub fn reduce_last(&mut self) {
if let Some(last) = self.index.last_mut() {
if *last > 0 {
*last -= 1;
}
}
}

pub fn down(&mut self) -> Option<usize> {
self.index.pop()
let result = self.index.pop();
if let Some(last) = self.index.last_mut() {
*last += 1;
}
result
}

pub fn current_init_statement(&self) -> Self {
Expand All @@ -57,7 +83,7 @@ impl Position {
pub(crate) struct RunSpecific {
pub(crate) register: Register,
pub(crate) position: Position,
pub(crate) skip_until_return: Option<(Position, NaslValue)>,
pub(crate) skip_until_return: Vec<(Position, NaslValue)>,
}

/// Used to interpret a Statement
Expand All @@ -78,7 +104,7 @@ impl<'a> Interpreter<'a> {
let root_run = RunSpecific {
register,
position: Position::new(0),
skip_until_return: None,
skip_until_return: Vec::new(),
};
Interpreter {
run_specific: vec![root_run],
Expand Down Expand Up @@ -165,9 +191,6 @@ impl<'a> Interpreter<'a> {
stmt: &Statement,
max_attempts: usize,
) -> InterpretResult {
if let Some(last) = self.position_mut().index.last_mut() {
*last += 1;
}
self.index = 0;
self.retry_resolve(stmt, max_attempts).await
}
Expand Down Expand Up @@ -206,28 +229,37 @@ impl<'a> Interpreter<'a> {
}
}

/// Interprets a Statement
pub(crate) async fn resolve(&mut self, statement: &Statement) -> InterpretResult {
self.position_mut().up();
tracing::trace!(position=?self.position(), statement=statement.to_string(), "executing");
// On a fork statement run we skip until the root index is reached. Between the root index
// of the return value and the position of the return value the interpretation is
// continued. This is done because the client just executes higher statements.
if let Some((cp, rv)) = &self.skip_until_return() {
tracing::trace!(check_position=?cp);
//// Checks for skip_until_return and returns the value if the current position is in the list
/// if the root index is smaller than the current position it will return None this is done to
/// prevent unnecessary statement execution and has to be seen as guardian functionality.
fn may_return_value(&mut self) -> Option<NaslValue> {
for (cp, value) in self.skip_until_return().iter() {
if self.position().root_index() < cp.root_index() {
tracing::trace!("skip execution");
self.position_mut().down();
return Ok(NaslValue::Null);
return Some(NaslValue::Null);
}
if cp == self.position() {
tracing::trace!(return=?rv, "skip execution and returning");
let rv = rv.clone();
self.set_skip_until_return(None);
self.position_mut().down();
return Ok(rv);
return Some(value.clone());
}
}
None
}

/// Interprets a Statement
pub(crate) async fn resolve(&mut self, statement: &Statement) -> InterpretResult {
self.position_mut().up();
let span = tracing::span!(tracing::Level::WARN, "resolve",
statement=statement.to_string(),
index=self.index,
position=%self.position(),
run_specific_len=self.run_specific.len(),
skipped_value_pos=?self.skip_until_return(), );
let _enter = span.enter();
if let Some(val) = self.may_return_value() {
tracing::trace!(returns=?val, "skipped" );
self.position_mut().down();
return Ok(val);
}
tracing::trace!("executing");

let results = {
match statement.kind() {
Expand Down Expand Up @@ -339,13 +371,8 @@ impl<'a> Interpreter<'a> {
rs.register = val;
}

pub(crate) fn set_skip_until_return(&mut self, val: Option<(Position, NaslValue)>) {
let rs = &mut self.run_specific[self.index];
rs.skip_until_return = val;
}

pub(crate) fn skip_until_return(&self) -> Option<&(Position, NaslValue)> {
self.run_specific[self.index].skip_until_return.as_ref()
pub(crate) fn skip_until_return(&self) -> &[(Position, NaslValue)] {
&self.run_specific[self.index].skip_until_return
}

async fn resolve_exit(&mut self, statement: &Statement) -> Result<NaslValue, InterpretError> {
Expand Down Expand Up @@ -439,4 +466,5 @@ impl<'a> Interpreter<'a> {
),
}
}

}
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