Prevent infinite loop in TestRegExp (#213)

sebastienros · Dec 1, 2021 · e01444a · e01444a
1 parent 1488954
commit e01444a
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Showing 2 changed files with 66 additions and 54 deletions.
diff --git a/src/Esprima/Scanner.cs b/src/Esprima/Scanner.cs
@@ -1,7 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Globalization;
-using System.Numerics;
+using System.Numerics;
 using System.Runtime.CompilerServices;
 using System.Text;
 using System.Text.RegularExpressions;
@@ -888,10 +888,10 @@ static string SafeSubstring(string s, int startIndex, int length)
         // https://tc39.github.io/ecma262/#sec-literals-numeric-literals
 
         public Token ScanHexLiteral(int start)
-        {
+        {
             var sb = GetStringBuilder();
             this.ScanLiteralPart(sb, Character.IsHexDigit);
-            var number = sb.ToString();
+            var number = sb.ToString();
 
             if (number.Length == 0)
             {
@@ -948,11 +948,11 @@ public Token ScanHexLiteral(int start)
         }
 
         public Token ScanBinaryLiteral(int start)
-        {
+        {
             char ch;
             var sb = GetStringBuilder();
             this.ScanLiteralPart(sb, c => c == '0' || c == '1');
-            var number = sb.ToString();
+            var number = sb.ToString();
 
             if (number.Length == 0)
             {
@@ -995,8 +995,8 @@ public Token ScanOctalLiteral(char prefix, int start)
             else
             {
                 ++Index;
-            }
-
+            }
+
             this.ScanLiteralPart(sb, Character.IsOctalDigit);
             var number = sb.ToString();
 
@@ -1056,37 +1056,37 @@ public bool IsImplicitOctalLiteral()
         }
 
         private void ScanLiteralPart(StringBuilder sb, Func<char, bool> check)
-        {
-            var charCode = Source.CharCodeAt(Index);
-            if (charCode == '_')
-            {
-                ThrowUnexpectedToken(Messages.NumericSeperatorNotAllowedHere);
-            }
-
-            while ((check(charCode) || charCode == '_'))
-            {
-                if (charCode != '_')
-                {
-                    sb.Append(charCode);
-                }
-                Index++;
-                var newCharCode = Source.CharCodeAt(Index);
-                if (charCode == '_' && newCharCode == '_')
-                {
-                    ThrowUnexpectedToken(Messages.NumericSeperatorOneUnderscore);
-                }
-
-                if (Eof())
-                {
-                    break;
-                }
-                charCode = newCharCode;
-            }
-
-            if (charCode == '_')
-            {
-                ThrowUnexpectedToken(Messages.NumericSeperatorNotAllowedHere);
-            }
+        {
+            var charCode = Source.CharCodeAt(Index);
+            if (charCode == '_')
+            {
+                ThrowUnexpectedToken(Messages.NumericSeperatorNotAllowedHere);
+            }
+
+            while ((check(charCode) || charCode == '_'))
+            {
+                if (charCode != '_')
+                {
+                    sb.Append(charCode);
+                }
+                Index++;
+                var newCharCode = Source.CharCodeAt(Index);
+                if (charCode == '_' && newCharCode == '_')
+                {
+                    ThrowUnexpectedToken(Messages.NumericSeperatorOneUnderscore);
+                }
+
+                if (Eof())
+                {
+                    break;
+                }
+                charCode = newCharCode;
+            }
+
+            if (charCode == '_')
+            {
+                ThrowUnexpectedToken(Messages.NumericSeperatorNotAllowedHere);
+            }
         }
 
         public Token ScanNumericLiteral()
@@ -1141,7 +1141,7 @@ public Token ScanNumericLiteral()
 
             if (ch == '.')
             {
-                sb.Append(Source[Index++]);
+                sb.Append(Source[Index++]);
                 this.ScanLiteralPart(sb, Character.IsDecimalDigit);
 
                 ch = Source.CharCodeAt(Index);
@@ -1165,21 +1165,21 @@ public Token ScanNumericLiteral()
                 {
                     ThrowUnexpectedToken();
                 }
-            }
-            else if (ch == 'n')
-            {
-                Index++;
-                var bigInt = BigInteger.Parse(sb.ToString());
-                return new Token
-                {
-                    Type = TokenType.BigIntLiteral,
-                    Value = bigInt,
-                    BigIntValue = bigInt,
-                    LineNumber = LineNumber,
-                    LineStart = LineStart,
-                    Start = start,
-                    End = Index
-                };
+            }
+            else if (ch == 'n')
+            {
+                Index++;
+                var bigInt = BigInteger.Parse(sb.ToString());
+                return new Token
+                {
+                    Type = TokenType.BigIntLiteral,
+                    Value = bigInt,
+                    BigIntValue = bigInt,
+                    LineNumber = LineNumber,
+                    LineStart = LineStart,
+                    Start = start,
+                    End = Index
+                };
             }
 
             if (Character.IsIdentifierStart(Source.CharCodeAt(Index)))
@@ -1640,6 +1640,10 @@ public Token ScanTemplate()
                             newPattern = newPattern.Substring(0, index) + @"\r?" + newPattern.Substring(index);
                             index += 4;
                         }
+                        else
+                        {
+                            index++;
+                        }
                     }
 
                     pattern = newPattern;

diff --git a/test/Esprima.Tests/ScannerTests.cs b/test/Esprima.Tests/ScannerTests.cs
@@ -24,5 +24,13 @@ public void CanScanMultiLineComment()
 
             Assert.Equal(new[] { "11-28" }, results);
         }
+
+        [Fact]
+        public void ShouldPreventInfiniteLoopWhenAdaptingMultiLine()
+        {
+            var scanner = new Scanner("", new ParserOptions { AdaptRegexp = true });
+            var regex = scanner.TestRegExp("\\$", "gm");
+            Assert.NotNull(regex);
+        }
     }
 }