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fix(interpreter): prevent arithmetic overflow panics #443

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Merged
chaliy merged 1 commit into from
Mar 1, 2026
Merged

fix(interpreter): prevent arithmetic overflow panics #443

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78 changes: 69 additions & 9 deletions crates/bashkit/src/interpreter/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -7340,7 +7340,9 @@ impl Interpreter {
{
let left = self.parse_arithmetic_impl(&expr[..i - 1], arith_depth + 1);
let right = self.parse_arithmetic_impl(&expr[i + 1..], arith_depth + 1);
return left << right;
// THREAT[TM-DOS-029]: clamp shift to 0..=63 to prevent panic
let shift = right.clamp(0, 63) as u32;
return left.wrapping_shl(shift);
}
'>' if depth == 0
&& i > 0
Expand All @@ -7350,7 +7352,9 @@ impl Interpreter {
{
let left = self.parse_arithmetic_impl(&expr[..i - 1], arith_depth + 1);
let right = self.parse_arithmetic_impl(&expr[i + 1..], arith_depth + 1);
return left >> right;
// THREAT[TM-DOS-029]: clamp shift to 0..=63 to prevent panic
let shift = right.clamp(0, 63) as u32;
return left.wrapping_shr(shift);
}
_ => {}
}
Expand Down Expand Up @@ -7378,10 +7382,11 @@ impl Interpreter {
}
let left = self.parse_arithmetic_impl(&expr[..i], arith_depth + 1);
let right = self.parse_arithmetic_impl(&expr[i + 1..], arith_depth + 1);
// THREAT[TM-DOS-029]: wrapping to prevent overflow panic
return if chars[i] == '+' {
left + right
left.wrapping_add(right)
} else {
left - right
left.wrapping_sub(right)
};
}
_ => {}
Expand All @@ -7404,22 +7409,24 @@ impl Interpreter {
}
let left = self.parse_arithmetic_impl(&expr[..i], arith_depth + 1);
let right = self.parse_arithmetic_impl(&expr[i + 1..], arith_depth + 1);
return left * right;
// THREAT[TM-DOS-029]: wrapping to prevent overflow panic
return left.wrapping_mul(right);
}
'/' | '%' if depth == 0 => {
let left = self.parse_arithmetic_impl(&expr[..i], arith_depth + 1);
let right = self.parse_arithmetic_impl(&expr[i + 1..], arith_depth + 1);
// THREAT[TM-DOS-029]: wrapping to prevent i64::MIN / -1 panic
return match chars[i] {
'/' => {
if right != 0 {
left / right
left.wrapping_div(right)
} else {
0
}
}
'%' => {
if right != 0 {
left % right
left.wrapping_rem(right)
} else {
0
}
Expand All @@ -7441,7 +7448,9 @@ impl Interpreter {
let left = self.parse_arithmetic_impl(&expr[..i], arith_depth + 1);
// Right-associative: parse from i+2 onward (may contain more **)
let right = self.parse_arithmetic_impl(&expr[i + 2..], arith_depth + 1);
return left.pow(right as u32);
// THREAT[TM-DOS-029]: clamp exponent to 0..=63 to prevent panic/hang
let exp = right.clamp(0, 63) as u32;
return left.wrapping_pow(exp);
}
_ => {}
}
Expand All @@ -7451,7 +7460,10 @@ impl Interpreter {
if let Some(rest) = expr.strip_prefix('-') {
let rest = rest.trim();
if !rest.is_empty() {
return -self.parse_arithmetic_impl(rest, arith_depth + 1);
// THREAT[TM-DOS-029]: wrapping to prevent i64::MIN negation panic
return self
.parse_arithmetic_impl(rest, arith_depth + 1)
.wrapping_neg();
}
}
if let Some(rest) = expr.strip_prefix('~') {
Expand Down Expand Up @@ -9314,4 +9326,52 @@ mod tests {
let result = run_script("set a b c\necho $#\necho $1 $2 $3").await;
assert_eq!(result.stdout, "3\na b c\n");
}

#[tokio::test]
async fn test_arithmetic_exponent_negative_no_panic() {
let result = run_script("echo $(( 2 ** -1 ))").await;
assert_eq!(result.exit_code, 0);
}

#[tokio::test]
async fn test_arithmetic_exponent_large_no_panic() {
let result = run_script("echo $(( 2 ** 100 ))").await;
assert_eq!(result.exit_code, 0);
}

#[tokio::test]
async fn test_arithmetic_shift_large_no_panic() {
let result = run_script("echo $(( 1 << 64 ))").await;
assert_eq!(result.exit_code, 0);
}

#[tokio::test]
async fn test_arithmetic_shift_negative_no_panic() {
let result = run_script("echo $(( 1 << -1 ))").await;
assert_eq!(result.exit_code, 0);
}

#[tokio::test]
async fn test_arithmetic_div_min_neg1_no_panic() {
let result = run_script("echo $(( -9223372036854775808 / -1 ))").await;
assert_eq!(result.exit_code, 0);
}

#[tokio::test]
async fn test_arithmetic_mod_min_neg1_no_panic() {
let result = run_script("echo $(( -9223372036854775808 % -1 ))").await;
assert_eq!(result.exit_code, 0);
}

#[tokio::test]
async fn test_arithmetic_overflow_add_no_panic() {
let result = run_script("echo $(( 9223372036854775807 + 1 ))").await;
assert_eq!(result.exit_code, 0);
}

#[tokio::test]
async fn test_arithmetic_overflow_mul_no_panic() {
let result = run_script("echo $(( 9223372036854775807 * 2 ))").await;
assert_eq!(result.exit_code, 0);
}
}
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