expr: Fix error message for large numbers as range index

Author: frendsick

src/uu/expr/src/syntax_tree.rs

@@ -303,13 +303,15 @@ where
 
     // Check if parsed quantifier is valid
     let re = Regex::new(r"^(\d*,\d*|\d+)$").expect("valid regular expression");
+    let is_natural_number = |string: &str| string.chars().all(|x| x.is_ascii_digit());
     if let Some(captures) = re.captures(&quantifier) {
         let matched = captures.at(0).unwrap_or_default();
         match matched.split_once(',') {
             Some(("", "")) => Ok(()),
             Some((x, "")) | Some(("", x)) => match x.parse::<i32>() {
                 Ok(x) if x <= i16::MAX.into() => Ok(()),
                 Ok(_) => Err(ExprError::TooBigRangeQuantifierIndex),
+                Err(_) if is_natural_number(x) => Err(ExprError::TooBigRangeQuantifierIndex),
                 Err(_) => Err(ExprError::InvalidBracketContent),
             },
             Some((f, l)) => match (f.parse::<i32>(), l.parse::<i32>()) {
@@ -318,11 +320,13 @@ where
                     Err(ExprError::TooBigRangeQuantifierIndex)
                 }
                 (Ok(_), Ok(_)) => Ok(()),
+                _ if is_natural_number(l) => Err(ExprError::TooBigRangeQuantifierIndex),
                 _ => Err(ExprError::InvalidBracketContent),
             },
             None => match matched.parse::<i32>() {
                 Ok(x) if x <= i16::MAX.into() => Ok(()),
                 Ok(_) => Err(ExprError::TooBigRangeQuantifierIndex),
+                Err(_) if is_natural_number(matched) => Err(ExprError::TooBigRangeQuantifierIndex),
                 Err(_) => Err(ExprError::InvalidBracketContent),
             },
         }

tests/by-util/test_expr.rs

@@ -472,6 +472,26 @@ fn test_regex_range_quantifier() {
         .args(&["ab", ":", "ab\\{\\}"])
         .fails()
         .stderr_only("expr: Invalid content of \\{\\}\n");
+    new_ucmd!()
+        .args(&["_", ":", "a\\{12345678901234567890\\}"])
+        .fails()
+        .stderr_only("expr: Regular expression too big\n");
+    new_ucmd!()
+        .args(&["_", ":", "a\\{12345678901234567890,\\}"])
+        .fails()
+        .stderr_only("expr: Regular expression too big\n");
+    new_ucmd!()
+        .args(&["_", ":", "a\\{,12345678901234567890\\}"])
+        .fails()
+        .stderr_only("expr: Regular expression too big\n");
+    new_ucmd!()
+        .args(&["_", ":", "a\\{1,12345678901234567890\\}"])
+        .fails()
+        .stderr_only("expr: Regular expression too big\n");
+    new_ucmd!()
+        .args(&["_", ":", "a\\{1,1234567890abcdef\\}"])
+        .fails()
+        .stderr_only("expr: Invalid content of \\{\\}\n");
 }
 
 #[test]