support nested stars in js/ReDoS

javascript/ql/src/Performance/ReDoS.ql

@@ -172,6 +172,21 @@ predicate isFork(State q, InputSymbol s1, InputSymbol s2, State r1, State r2) {
     r1 != r2
     or
     r1 = r2 and q1 != q2
+    or
+    r1 = r2 and	
+    q1 = q2 and	
+    epsilonSucc+(q) = q and	
+    exists(RegExpTerm term | term = q.getRepr() | term instanceof InfiniteRepetitionQuantifier) and	
+    (	
+      // One of the mid states is an infinite quantifier itself	
+      exists(State mid, RegExpTerm term |	
+        mid = epsilonSucc+(q) and	
+        term = mid.getRepr() and	
+        term instanceof InfiniteRepetitionQuantifier	and
+        q = epsilonSucc+(mid) and	
+        not mid = q
+      )	
+    )
   ) and
   stateInsideBacktracking(r1) and
   stateInsideBacktracking(r2)

javascript/ql/test/query-tests/Performance/ReDoS/ReDoS.expected

@@ -25,6 +25,7 @@
 | regexplib/email.js:5:24:5:35 | [a-zA-Z0-9]+ | This part of the regular expression may cause exponential backtracking on strings starting with '0' and containing many repetitions of '0'. |
 | regexplib/email.js:5:63:5:74 | [a-zA-Z0-9]+ | This part of the regular expression may cause exponential backtracking on strings starting with '0@0' and containing many repetitions of '0'. |
 | regexplib/email.js:6:10:6:35 | (?:[a-zA-Z0-9][\\.\\-\\+_]?)* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '0'. |
+| regexplib/email.js:13:36:13:44 | [a-zA-Z]* | This part of the regular expression may cause exponential backtracking on strings starting with 'A' and containing many repetitions of 'A'. |
 | regexplib/email.js:25:67:25:78 | [a-zA-Z0-9]+ | This part of the regular expression may cause exponential backtracking on strings starting with '0' and containing many repetitions of '0'. |
 | regexplib/email.js:25:106:25:117 | [a-zA-Z0-9]+ | This part of the regular expression may cause exponential backtracking on strings starting with '0@0' and containing many repetitions of '0'. |
 | regexplib/email.js:25:212:25:223 | [a-zA-Z0-9]+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '0'. |
@@ -36,6 +37,7 @@
 | regexplib/email.js:34:24:34:35 | [a-zA-Z0-9]+ | This part of the regular expression may cause exponential backtracking on strings starting with '0' and containing many repetitions of '0'. |
 | regexplib/email.js:34:63:34:74 | [a-zA-Z0-9]+ | This part of the regular expression may cause exponential backtracking on strings starting with '0@0' and containing many repetitions of '0'. |
 | regexplib/markup.js:3:451:3:453 | .+? | This part of the regular expression may cause exponential backtracking on strings starting with '<?i:q ' and containing many repetitions of 'a '. |
+| regexplib/markup.js:7:15:7:21 | [^\\\\"]* | This part of the regular expression may cause exponential backtracking on strings starting with '"!' and containing many repetitions of '!'. |
 | regexplib/markup.js:13:6:13:12 | [^"']+? | This part of the regular expression may cause exponential backtracking on strings starting with '<' and containing many repetitions of '!'. |
 | regexplib/markup.js:13:14:13:16 | .+? | This part of the regular expression may cause exponential backtracking on strings starting with '<' and containing many repetitions of 'a"'. |
 | regexplib/markup.js:17:17:17:19 | .*? | This part of the regular expression may cause exponential backtracking on strings starting with '<a ="' and containing many repetitions of '" ="'. |
@@ -45,6 +47,7 @@
 | regexplib/markup.js:53:29:53:56 | [a-zA-Z0-9\|:\|\\/\|=\|-\|.\|\\?\|&]* | This part of the regular expression may cause exponential backtracking on strings starting with '[a=' and containing many repetitions of '='. |
 | regexplib/markup.js:56:23:56:25 | \\w+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
 | regexplib/markup.js:56:132:56:134 | \\s* | This part of the regular expression may cause exponential backtracking on strings starting with 'a[@a=''' and containing many repetitions of ' @a<""'. |
+| regexplib/misc.js:4:36:4:44 | [a-zA-Z]* | This part of the regular expression may cause exponential backtracking on strings starting with 'A' and containing many repetitions of 'A'. |
 | regexplib/misc.js:15:56:15:118 | (([^\\\\/:\\*\\?"\\\|<>\\. ])\|([^\\\\/:\\*\\?"\\\|<>]*[^\\\\/:\\*\\?"\\\|<>\\. ]))? | This part of the regular expression may cause exponential backtracking on strings starting with '!' and containing many repetitions of '!\\\\!'. |
 | regexplib/misc.js:24:56:24:118 | (([^\\\\/:\\*\\?"\\\|<>\\. ])\|([^\\\\/:\\*\\?"\\\|<>]*[^\\\\/:\\*\\?"\\\|<>\\. ]))? | This part of the regular expression may cause exponential backtracking on strings starting with '!' and containing many repetitions of '!\\\\!'. |
 | regexplib/misc.js:79:3:79:25 | (\\/w\|\\/W\|[^<>+?$%{}&])+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '/W'. |
@@ -55,8 +58,10 @@
 | regexplib/misc.js:148:23:148:29 | [^"'=]+ | This part of the regular expression may cause exponential backtracking on strings starting with '<! ' and containing many repetitions of '! '. |
 | regexplib/misc.js:173:4:173:11 | ([a-z])+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'aa'. |
 | regexplib/strings.js:19:31:19:57 | [a-z&#230;&#248;&#229;0-9]+ | This part of the regular expression may cause exponential backtracking on strings starting with '#@' and containing many repetitions of '#'. |
+| regexplib/strings.js:47:3:47:5 | \\S* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '!'. |
 | regexplib/strings.js:57:17:57:19 | \\d+ | This part of the regular expression may cause exponential backtracking on strings starting with '?se[' and containing many repetitions of '9'. |
 | regexplib/strings.js:81:17:81:19 | \\d+ | This part of the regular expression may cause exponential backtracking on strings starting with '?se[' and containing many repetitions of '9'. |
+| regexplib/strings.js:91:3:91:5 | \\S* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '!'. |
 | regexplib/uri.js:3:128:3:129 | .* | This part of the regular expression may cause exponential backtracking on strings starting with 'ftp://    /' and containing many repetitions of '/'. |
 | regexplib/uri.js:3:193:3:198 | [^\\#]+ | This part of the regular expression may cause exponential backtracking on strings starting with 'ftp://      a=' and containing many repetitions of '"0='. |
 | regexplib/uri.js:3:200:3:215 | (?:\\&?\\w+\\=\\w+)* | This part of the regular expression may cause exponential backtracking on strings starting with 'ftp://      a="' and containing many repetitions of 'a=0'. |
@@ -81,6 +86,7 @@
 | tst.js:52:37:52:39 | .*? | This part of the regular expression may cause exponential backtracking on strings starting with '$[' and containing many repetitions of ']['. |
 | tst.js:52:70:52:72 | .*? | This part of the regular expression may cause exponential backtracking on strings starting with '$.$[' and containing many repetitions of ']['. |
 | tst.js:58:15:58:20 | [a-z]+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
+| tst.js:59:15:59:20 | [a-z]* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
 | tst.js:60:43:60:54 | [a-zA-Z0-9]+ | This part of the regular expression may cause exponential backtracking on strings starting with '0' and containing many repetitions of '0'. |
 | tst.js:61:16:61:23 | ([a-z])+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'aa'. |
 | tst.js:66:16:66:31 | [\\w#:.~>+()\\s-]+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '\\t'. |
@@ -147,10 +153,15 @@
 | tst.js:305:18:305:20 | \\s+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of ' '. |
 | tst.js:308:16:308:24 | ([^/]\|X)+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'X'. |
 | tst.js:311:20:311:24 | [^Y]+ | This part of the regular expression may cause exponential backtracking on strings starting with 'x' and containing many repetitions of 'Xx'. |
+| tst.js:314:15:314:16 | a* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
+| tst.js:317:18:317:23 | [\\w-]* | This part of the regular expression may cause exponential backtracking on strings starting with 'foo' and containing many repetitions of '-'. |
+| tst.js:320:15:320:19 | (ab)* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'ab'. |
 | tst.js:323:14:323:20 | (a?a?)* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
 | tst.js:332:14:332:22 | (?:a\|a?)+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
 | tst.js:338:17:338:45 | (([a-c]\|[c-d])T(e?e?e?e?\|X))+ | This part of the regular expression may cause exponential backtracking on strings starting with 'PRE' and containing many repetitions of 'cTX'. |
 | tst.js:341:16:341:19 | (a)+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'aa'. |
 | tst.js:344:16:344:17 | b+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'bb'. |
+| tst.js:350:15:350:16 | a* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
 | tst.js:351:15:351:16 | a+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
+| tst.js:352:15:352:16 | a* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
 | tst.js:353:15:353:16 | a+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |

javascript/ql/test/query-tests/Performance/ReDoS/tst.js

@@ -56,7 +56,7 @@ var good6 = /(a|.)*/;
 
 // Testing the NFA - only some of the below are detected.
 var bad7 = /^([a-z]+)+$/;
-var bad8 = /^([a-z]*)*$/; // NOT detected
+var bad8 = /^([a-z]*)*$/;
 var bad9 = /^([a-zA-Z0-9])(([\\-.]|[_]+)?([a-zA-Z0-9]+))*(@){1}[a-z0-9]+[.]{1}(([a-z]{2,3})|([a-z]{2,3}[.]{1}[a-z]{2,3}))$/;
 var bad10 = /^(([a-z])+.)+[A-Z]([a-z])+$/;
 
@@ -310,13 +310,13 @@ var good36 = /(([^/]|X)+)(\/[^]*)*$/;
 // GOOD - but we spuriously conclude that a rejecting suffix exists. 
 var good37 = /^((x([^Y]+)?)*(Y|$))/;
 
-// NOT GOOD - but not detected
+// NOT GOOD
 var bad68 = /(a*)+b/;
 
-// NOT GOOD - but not detected
+// NOT GOOD
 var bad69 = /foo([\w-]*)+bar/;
 
-// NOT GOOD - but not detected
+// NOT GOOD
 var bad70 = /((ab)*)+c/;
 
 // NOT GOOD
@@ -347,7 +347,7 @@ var bad78 = /^(b+.)+$/;
 var good39 = /a*b/;
 
 // All 4 bad combinations of nested * and +
-var bad79 = /(a*)*b/; // not detected
+var bad79 = /(a*)*b/;
 var bad80 = /(a+)*b/;
-var bad81 = /(a*)+b/; // not detected
+var bad81 = /(a*)+b/;
 var bad82 = /(a+)+b/;