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Merge pull request #11247 from erik-krogh/py-redosMod
Python: use the shared regex pack
This commit is contained in:
Erik Krogh Kristensen
@@ -0,0 +1,4 @@
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---
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category: minorAnalysis
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---
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* The ReDoS libraries in `semmle.code.python.security.regexp` has been moved to a shared pack inside the `shared/` folder, and the previous location has been deprecated.
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@@ -5,3 +5,5 @@ dbscheme: semmlecode.python.dbscheme
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extractor: python
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library: true
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upgrades: upgrades
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dependencies:
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codeql/regex: ${workspace}
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File diff suppressed because it is too large
Load Diff
@@ -2,155 +2,7 @@
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* Provides predicates for reasoning about bad tag filter vulnerabilities.
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*/
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import regexp.RegexpMatching
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/**
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* Holds if the regexp `root` should be tested against `str`.
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* Implements the `isRegexpMatchingCandidateSig` signature from `RegexpMatching`.
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* `ignorePrefix` toggles whether the regular expression should be treated as accepting any prefix if it's unanchored.
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* `testWithGroups` toggles whether it's tested which groups are filled by a given input string.
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*/
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private predicate isBadTagFilterCandidate(
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RootTerm root, string str, boolean ignorePrefix, boolean testWithGroups
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) {
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// the regexp must mention "<" and ">" explicitly.
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forall(string angleBracket | angleBracket = ["<", ">"] |
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any(RegExpConstant term | term.getValue().matches("%" + angleBracket + "%")).getRootTerm() =
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root
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) and
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ignorePrefix = true and
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(
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str = ["<!-- foo -->", "<!-- foo --!>", "<!- foo ->", "<foo>", "<script>"] and
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testWithGroups = true
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or
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str =
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[
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"<!-- foo -->", "<!- foo ->", "<!-- foo --!>", "<!-- foo\n -->", "<script>foo</script>",
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"<script \n>foo</script>", "<script >foo\n</script>", "<foo ></foo>", "<foo>",
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"<foo src=\"foo\"></foo>", "<script>", "<script src=\"foo\"></script>",
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"<script src='foo'></script>", "<SCRIPT>foo</SCRIPT>", "<script\tsrc=\"foo\"/>",
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"<script\tsrc='foo'></script>", "<sCrIpT>foo</ScRiPt>", "<script src=\"foo\">foo</script >",
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"<script src=\"foo\">foo</script foo=\"bar\">", "<script src=\"foo\">foo</script\t\n bar>"
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] and
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testWithGroups = false
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)
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}
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/**
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* A regexp that matches some string from the `isBadTagFilterCandidate` predicate.
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*/
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class HtmlMatchingRegExp extends RootTerm {
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HtmlMatchingRegExp() { RegexpMatching<isBadTagFilterCandidate/4>::matches(this, _) }
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/** Holds if this regexp matched `str`, where `str` is one of the string from `isBadTagFilterCandidate`. */
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predicate matches(string str) { RegexpMatching<isBadTagFilterCandidate/4>::matches(this, str) }
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/** Holds if this regexp fills capture group `g' when matching `str', where `str` is one of the string from `isBadTagFilterCandidate`. */
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predicate fillsCaptureGroup(string str, int g) {
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RegexpMatching<isBadTagFilterCandidate/4>::fillsCaptureGroup(this, str, g)
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}
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}
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/** DEPRECATED: Alias for HtmlMatchingRegExp */
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deprecated class HTMLMatchingRegExp = HtmlMatchingRegExp;
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/**
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* Holds if `regexp` matches some HTML tags, but misses some HTML tags that it should match.
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*
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* When adding a new case to this predicate, make sure the test string used in `matches(..)` calls are present in `HTMLMatchingRegExp::test` / `HTMLMatchingRegExp::testWithGroups`.
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*/
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predicate isBadRegexpFilter(HtmlMatchingRegExp regexp, string msg) {
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// CVE-2021-33829 - matching both "<!-- foo -->" and "<!-- foo --!>", but in different capture groups
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regexp.matches("<!-- foo -->") and
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regexp.matches("<!-- foo --!>") and
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exists(int a, int b | a != b |
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regexp.fillsCaptureGroup("<!-- foo -->", a) and
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// <!-- foo --> might be ambiguously parsed (matching both capture groups), and that is ok here.
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regexp.fillsCaptureGroup("<!-- foo --!>", b) and
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not regexp.fillsCaptureGroup("<!-- foo --!>", a) and
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msg =
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"Comments ending with --> are matched differently from comments ending with --!>. The first is matched with capture group "
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+ a + " and comments ending with --!> are matched with capture group " +
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strictconcat(int i | regexp.fillsCaptureGroup("<!-- foo --!>", i) | i.toString(), ", ") +
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"."
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)
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or
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// CVE-2020-17480 - matching "<!-- foo -->" and other tags, but not "<!-- foo --!>".
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exists(int group, int other |
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group != other and
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regexp.fillsCaptureGroup("<!-- foo -->", group) and
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regexp.fillsCaptureGroup("<foo>", other) and
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not regexp.matches("<!-- foo --!>") and
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not regexp.fillsCaptureGroup("<!-- foo -->", any(int i | i != group)) and
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not regexp.fillsCaptureGroup("<!- foo ->", group) and
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not regexp.fillsCaptureGroup("<foo>", group) and
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not regexp.fillsCaptureGroup("<script>", group) and
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msg =
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"This regular expression only parses --> (capture group " + group +
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") and not --!> as an HTML comment end tag."
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)
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or
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regexp.matches("<!-- foo -->") and
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not regexp.matches("<!-- foo\n -->") and
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not regexp.matches("<!- foo ->") and
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not regexp.matches("<foo>") and
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not regexp.matches("<script>") and
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msg = "This regular expression does not match comments containing newlines."
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or
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regexp.matches("<script>foo</script>") and
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regexp.matches("<script src=\"foo\"></script>") and
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not regexp.matches("<foo ></foo>") and
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(
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not regexp.matches("<script \n>foo</script>") and
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msg = "This regular expression matches <script></script>, but not <script \\n></script>"
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or
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not regexp.matches("<script >foo\n</script>") and
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msg = "This regular expression matches <script>...</script>, but not <script >...\\n</script>"
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)
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or
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regexp.matches("<script>foo</script>") and
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regexp.matches("<script src=\"foo\"></script>") and
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not regexp.matches("<script src='foo'></script>") and
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not regexp.matches("<foo>") and
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msg = "This regular expression does not match script tags where the attribute uses single-quotes."
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or
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regexp.matches("<script>foo</script>") and
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regexp.matches("<script src='foo'></script>") and
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not regexp.matches("<script src=\"foo\"></script>") and
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not regexp.matches("<foo>") and
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msg = "This regular expression does not match script tags where the attribute uses double-quotes."
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or
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regexp.matches("<script>foo</script>") and
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regexp.matches("<script src='foo'></script>") and
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not regexp.matches("<script\tsrc='foo'></script>") and
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not regexp.matches("<foo>") and
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not regexp.matches("<foo src=\"foo\"></foo>") and
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msg = "This regular expression does not match script tags where tabs are used between attributes."
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or
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regexp.matches("<script>foo</script>") and
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not RegExpFlags::isIgnoreCase(regexp) and
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not regexp.matches("<foo>") and
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not regexp.matches("<foo ></foo>") and
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(
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not regexp.matches("<SCRIPT>foo</SCRIPT>") and
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msg = "This regular expression does not match upper case <SCRIPT> tags."
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or
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not regexp.matches("<sCrIpT>foo</ScRiPt>") and
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regexp.matches("<SCRIPT>foo</SCRIPT>") and
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msg = "This regular expression does not match mixed case <sCrIpT> tags."
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)
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or
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regexp.matches("<script src=\"foo\"></script>") and
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not regexp.matches("<foo>") and
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not regexp.matches("<foo ></foo>") and
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(
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not regexp.matches("<script src=\"foo\">foo</script >") and
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msg = "This regular expression does not match script end tags like </script >."
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or
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not regexp.matches("<script src=\"foo\">foo</script foo=\"bar\">") and
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msg = "This regular expression does not match script end tags like </script foo=\"bar\">."
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or
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not regexp.matches("<script src=\"foo\">foo</script\t\n bar>") and
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msg = "This regular expression does not match script end tags like </script\\t\\n bar>."
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)
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}
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private import semmle.python.RegexTreeView::RegexTreeView as TreeView
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// BadTagFilterQuery should be used directly from the shared pack, and not from this file.
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deprecated import codeql.regex.nfa.BadTagFilterQuery::Make<TreeView> as Dep
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import Dep
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@@ -2,288 +2,7 @@
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* Classes and predicates for working with suspicious character ranges.
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*/
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// We don't need the NFA utils, just the regexp tree.
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// but the below is a nice shared library that exposes the API we need.
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import regexp.NfaUtils
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/**
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* Gets a rank for `range` that is unique for ranges in the same file.
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* Prioritizes ranges that match more characters.
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*/
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int rankRange(RegExpCharacterRange range) {
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range =
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rank[result](RegExpCharacterRange r, Location l, int low, int high |
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r.getLocation() = l and
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isRange(r, low, high)
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|
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r order by (high - low) desc, l.getStartLine(), l.getStartColumn()
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)
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}
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/** Holds if `range` spans from the unicode code points `low` to `high` (both inclusive). */
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predicate isRange(RegExpCharacterRange range, int low, int high) {
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exists(string lowc, string highc |
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range.isRange(lowc, highc) and
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low.toUnicode() = lowc and
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high.toUnicode() = highc
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)
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}
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/** Holds if `char` is an alpha-numeric character. */
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predicate isAlphanumeric(string char) {
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// written like this to avoid having a bindingset for the predicate
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char = [[48 .. 57], [65 .. 90], [97 .. 122]].toUnicode() // 0-9, A-Z, a-z
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}
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/**
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* Holds if the given ranges are from the same character class
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* and there exists at least one character matched by both ranges.
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*/
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predicate overlap(RegExpCharacterRange a, RegExpCharacterRange b) {
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exists(RegExpCharacterClass clz |
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a = clz.getAChild() and
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b = clz.getAChild() and
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a != b
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|
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exists(int alow, int ahigh, int blow, int bhigh |
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isRange(a, alow, ahigh) and
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isRange(b, blow, bhigh) and
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alow <= bhigh and
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blow <= ahigh
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)
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)
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}
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/**
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* Holds if `range` overlaps with the char class `escape` from the same character class.
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*/
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predicate overlapsWithCharEscape(RegExpCharacterRange range, RegExpCharacterClassEscape escape) {
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exists(RegExpCharacterClass clz, string low, string high |
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range = clz.getAChild() and
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escape = clz.getAChild() and
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range.isRange(low, high)
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|
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escape.getValue() = "w" and
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getInRange(low, high).regexpMatch("\\w")
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or
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escape.getValue() = "d" and
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getInRange(low, high).regexpMatch("\\d")
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or
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escape.getValue() = "s" and
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getInRange(low, high).regexpMatch("\\s")
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)
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}
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/** Gets the unicode code point for a `char`. */
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bindingset[char]
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int toCodePoint(string char) { result.toUnicode() = char }
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/** A character range that appears to be overly wide. */
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class OverlyWideRange extends RegExpCharacterRange {
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OverlyWideRange() {
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exists(int low, int high, int numChars |
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isRange(this, low, high) and
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numChars = (1 + high - low) and
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this.getRootTerm().isUsedAsRegExp() and
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numChars >= 10
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|
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// across the Z-a range (which includes backticks)
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toCodePoint("Z") >= low and
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toCodePoint("a") <= high
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or
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// across the 9-A range (which includes e.g. ; and ?)
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toCodePoint("9") >= low and
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toCodePoint("A") <= high
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or
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// a non-alphanumeric char as part of the range boundaries
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exists(int bound | bound = [low, high] | not isAlphanumeric(bound.toUnicode())) and
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// while still being ascii
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low < 128 and
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high < 128
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) and
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// allowlist for known ranges
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not this = allowedWideRanges()
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}
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/** Gets a string representation of a character class that matches the same chars as this range. */
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string printEquivalent() { result = RangePrinter::printEquivalentCharClass(this) }
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}
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/** Gets a range that should not be reported as an overly wide range. */
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RegExpCharacterRange allowedWideRanges() {
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// ~ is the last printable ASCII character, it's used right in various wide ranges.
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result.isRange(_, "~")
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or
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// the same with " " and "!". " " is the first printable character, and "!" is the first non-white-space printable character.
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result.isRange([" ", "!"], _)
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or
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// the `[@-_]` range is intentional
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result.isRange("@", "_")
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or
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// starting from the zero byte is a good indication that it's purposely matching a large range.
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result.isRange(0.toUnicode(), _)
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}
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/** Gets a char between (and including) `low` and `high`. */
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bindingset[low, high]
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private string getInRange(string low, string high) {
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result = [toCodePoint(low) .. toCodePoint(high)].toUnicode()
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}
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/** A module computing an equivalent character class for an overly wide range. */
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module RangePrinter {
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bindingset[char]
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bindingset[result]
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private string next(string char) {
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exists(int prev, int next |
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prev.toUnicode() = char and
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next.toUnicode() = result and
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next = prev + 1
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)
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}
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/** Gets the points where the parts of the pretty printed range should be cut off. */
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private string cutoffs() { result = ["A", "Z", "a", "z", "0", "9"] }
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/** Gets the char to use in the low end of a range for a given `cut` */
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private string lowCut(string cut) {
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cut = ["A", "a", "0"] and
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result = cut
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or
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cut = ["Z", "z", "9"] and
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result = next(cut)
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}
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/** Gets the char to use in the high end of a range for a given `cut` */
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private string highCut(string cut) {
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cut = ["Z", "z", "9"] and
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result = cut
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or
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cut = ["A", "a", "0"] and
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next(result) = cut
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}
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/** Gets the cutoff char used for a given `part` of a range when pretty-printing it. */
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private string cutoff(OverlyWideRange range, int part) {
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exists(int low, int high | isRange(range, low, high) |
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result =
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rank[part + 1](string cut |
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cut = cutoffs() and low < toCodePoint(cut) and toCodePoint(cut) < high
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|
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cut order by toCodePoint(cut)
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)
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)
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}
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/** Gets the number of parts we should print for a given `range`. */
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private int parts(OverlyWideRange range) { result = 1 + count(cutoff(range, _)) }
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/** Holds if the given part of a range should span from `low` to `high`. */
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private predicate part(OverlyWideRange range, int part, string low, string high) {
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// first part.
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part = 0 and
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(
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range.isRange(low, high) and
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parts(range) = 1
|
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or
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parts(range) >= 2 and
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range.isRange(low, _) and
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high = highCut(cutoff(range, part))
|
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)
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or
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// middle
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part >= 1 and
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||||
part < parts(range) - 1 and
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low = lowCut(cutoff(range, part - 1)) and
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high = highCut(cutoff(range, part))
|
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or
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// last.
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part = parts(range) - 1 and
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||||
low = lowCut(cutoff(range, part - 1)) and
|
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range.isRange(_, high)
|
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}
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/** Gets an escaped `char` for use in a character class. */
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bindingset[char]
|
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private string escape(string char) {
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exists(string reg | reg = "(\\[|\\]|\\\\|-|/)" |
|
||||
if char.regexpMatch(reg) then result = "\\" + char else result = char
|
||||
)
|
||||
}
|
||||
|
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/** Gets a part of the equivalent range. */
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private string printEquivalentCharClass(OverlyWideRange range, int part) {
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exists(string low, string high | part(range, part, low, high) |
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||||
if
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isAlphanumeric(low) and
|
||||
isAlphanumeric(high)
|
||||
then result = low + "-" + high
|
||||
else
|
||||
result =
|
||||
strictconcat(string char | char = getInRange(low, high) | escape(char) order by char)
|
||||
)
|
||||
}
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||||
|
||||
/** Gets the entire pretty printed equivalent range. */
|
||||
string printEquivalentCharClass(OverlyWideRange range) {
|
||||
result =
|
||||
strictconcat(string r, int part |
|
||||
r = "[" and part = -1 and exists(range)
|
||||
or
|
||||
r = printEquivalentCharClass(range, part)
|
||||
or
|
||||
r = "]" and part = parts(range)
|
||||
|
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||||
r order by part
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||||
)
|
||||
}
|
||||
}
|
||||
|
||||
/** Gets a char range that is overly large because of `reason`. */
|
||||
RegExpCharacterRange getABadRange(string reason, int priority) {
|
||||
result instanceof OverlyWideRange and
|
||||
priority = 0 and
|
||||
exists(string equiv | equiv = result.(OverlyWideRange).printEquivalent() |
|
||||
if equiv.length() <= 50
|
||||
then reason = "is equivalent to " + equiv
|
||||
else reason = "is equivalent to " + equiv.substring(0, 50) + "..."
|
||||
)
|
||||
or
|
||||
priority = 1 and
|
||||
exists(RegExpCharacterRange other |
|
||||
reason = "overlaps with " + other + " in the same character class" and
|
||||
rankRange(result) < rankRange(other) and
|
||||
overlap(result, other)
|
||||
)
|
||||
or
|
||||
priority = 2 and
|
||||
exists(RegExpCharacterClassEscape escape |
|
||||
reason = "overlaps with " + escape + " in the same character class" and
|
||||
overlapsWithCharEscape(result, escape)
|
||||
)
|
||||
or
|
||||
reason = "is empty" and
|
||||
priority = 3 and
|
||||
exists(int low, int high |
|
||||
isRange(result, low, high) and
|
||||
low > high
|
||||
)
|
||||
}
|
||||
|
||||
/** Holds if `range` matches suspiciously many characters. */
|
||||
predicate problem(RegExpCharacterRange range, string reason) {
|
||||
reason =
|
||||
strictconcat(string m, int priority |
|
||||
range = getABadRange(m, priority)
|
||||
|
|
||||
m, ", and " order by priority desc
|
||||
) and
|
||||
// specifying a range using an escape is usually OK.
|
||||
not range.getAChild() instanceof RegExpEscape and
|
||||
// Unicode escapes in strings are interpreted before it turns into a regexp,
|
||||
// so e.g. [\u0001-\uFFFF] will just turn up as a range between two constants.
|
||||
// We therefore exclude these ranges.
|
||||
range.getRootTerm().getParent() instanceof RegExpLiteral and
|
||||
// is used as regexp (mostly for JS where regular expressions are parsed eagerly)
|
||||
range.getRootTerm().isUsedAsRegExp()
|
||||
}
|
||||
private import semmle.python.RegexTreeView::RegexTreeView as TreeView
|
||||
// OverlyLargeRangeQuery should be used directly from the shared pack, and not from this file.
|
||||
deprecated import codeql.regex.OverlyLargeRangeQuery::Make<TreeView> as Dep
|
||||
import Dep
|
||||
|
||||
@@ -11,7 +11,7 @@ private import semmle.python.dataflow.new.TaintTracking
|
||||
private import semmle.python.Concepts
|
||||
private import semmle.python.dataflow.new.RemoteFlowSources
|
||||
private import semmle.python.dataflow.new.BarrierGuards
|
||||
private import semmle.python.RegexTreeView
|
||||
private import semmle.python.RegexTreeView::RegexTreeView as TreeView
|
||||
private import semmle.python.ApiGraphs
|
||||
|
||||
/**
|
||||
@@ -20,6 +20,9 @@ private import semmle.python.ApiGraphs
|
||||
* vulnerabilities, as well as extension points for adding your own.
|
||||
*/
|
||||
module PolynomialReDoS {
|
||||
private import TreeView
|
||||
import codeql.regex.nfa.SuperlinearBackTracking::Make<TreeView>
|
||||
|
||||
/**
|
||||
* A data flow source for "polynomial regular expression denial of service (ReDoS)" vulnerabilities.
|
||||
*/
|
||||
|
||||
@@ -62,284 +62,7 @@
|
||||
* a suffix `x` (possible empty) that is most likely __not__ accepted.
|
||||
*/
|
||||
|
||||
import NfaUtils
|
||||
|
||||
/**
|
||||
* Holds if state `s` might be inside a backtracking repetition.
|
||||
*/
|
||||
pragma[noinline]
|
||||
private predicate stateInsideBacktracking(State s) {
|
||||
s.getRepr().getParent*() instanceof MaybeBacktrackingRepetition
|
||||
}
|
||||
|
||||
/**
|
||||
* A infinitely repeating quantifier that might backtrack.
|
||||
*/
|
||||
private class MaybeBacktrackingRepetition extends InfiniteRepetitionQuantifier {
|
||||
MaybeBacktrackingRepetition() {
|
||||
exists(RegExpTerm child |
|
||||
child instanceof RegExpAlt or
|
||||
child instanceof RegExpQuantifier
|
||||
|
|
||||
child.getParent+() = this
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* A state in the product automaton.
|
||||
*/
|
||||
private newtype TStatePair =
|
||||
/**
|
||||
* We lazily only construct those states that we are actually
|
||||
* going to need: `(q, q)` for every fork state `q`, and any
|
||||
* pair of states that can be reached from a pair that we have
|
||||
* already constructed. To cut down on the number of states,
|
||||
* we only represent states `(q1, q2)` where `q1` is lexicographically
|
||||
* no bigger than `q2`.
|
||||
*
|
||||
* States are only constructed if both states in the pair are
|
||||
* inside a repetition that might backtrack.
|
||||
*/
|
||||
MkStatePair(State q1, State q2) {
|
||||
isFork(q1, _, _, _, _) and q2 = q1
|
||||
or
|
||||
(step(_, _, _, q1, q2) or step(_, _, _, q2, q1)) and
|
||||
rankState(q1) <= rankState(q2)
|
||||
}
|
||||
|
||||
/**
|
||||
* Gets a unique number for a `state`.
|
||||
* Is used to create an ordering of states, where states with the same `toString()` will be ordered differently.
|
||||
*/
|
||||
private int rankState(State state) {
|
||||
state =
|
||||
rank[result](State s, Location l |
|
||||
stateInsideBacktracking(s) and
|
||||
l = s.getRepr().getLocation()
|
||||
|
|
||||
s order by l.getStartLine(), l.getStartColumn(), s.toString()
|
||||
)
|
||||
}
|
||||
|
||||
/**
|
||||
* A state in the product automaton.
|
||||
*/
|
||||
private class StatePair extends TStatePair {
|
||||
State q1;
|
||||
State q2;
|
||||
|
||||
StatePair() { this = MkStatePair(q1, q2) }
|
||||
|
||||
/** Gets a textual representation of this element. */
|
||||
string toString() { result = "(" + q1 + ", " + q2 + ")" }
|
||||
|
||||
/** Gets the first component of the state pair. */
|
||||
State getLeft() { result = q1 }
|
||||
|
||||
/** Gets the second component of the state pair. */
|
||||
State getRight() { result = q2 }
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds for `(fork, fork)` state pairs when `isFork(fork, _, _, _, _)` holds.
|
||||
*
|
||||
* Used in `statePairDistToFork`
|
||||
*/
|
||||
private predicate isStatePairFork(StatePair p) {
|
||||
exists(State fork | p = MkStatePair(fork, fork) and isFork(fork, _, _, _, _))
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if there are transitions from the components of `q` to the corresponding
|
||||
* components of `r`.
|
||||
*
|
||||
* Used in `statePairDistToFork`
|
||||
*/
|
||||
private predicate reverseStep(StatePair r, StatePair q) { step(q, _, _, r) }
|
||||
|
||||
/**
|
||||
* Gets the minimum length of a path from `q` to `r` in the
|
||||
* product automaton.
|
||||
*/
|
||||
private int statePairDistToFork(StatePair q, StatePair r) =
|
||||
shortestDistances(isStatePairFork/1, reverseStep/2)(r, q, result)
|
||||
|
||||
/**
|
||||
* Holds if there are transitions from `q` to `r1` and from `q` to `r2`
|
||||
* labelled with `s1` and `s2`, respectively, where `s1` and `s2` do not
|
||||
* trivially have an empty intersection.
|
||||
*
|
||||
* This predicate only holds for states associated with regular expressions
|
||||
* that have at least one repetition quantifier in them (otherwise the
|
||||
* expression cannot be vulnerable to ReDoS attacks anyway).
|
||||
*/
|
||||
pragma[noopt]
|
||||
private predicate isFork(State q, InputSymbol s1, InputSymbol s2, State r1, State r2) {
|
||||
stateInsideBacktracking(q) and
|
||||
exists(State q1, State q2 |
|
||||
q1 = epsilonSucc*(q) and
|
||||
delta(q1, s1, r1) and
|
||||
q2 = epsilonSucc*(q) and
|
||||
delta(q2, s2, r2) and
|
||||
// Use pragma[noopt] to prevent intersect(s1,s2) from being the starting point of the join.
|
||||
// From (s1,s2) it would find a huge number of intermediate state pairs (q1,q2) originating from different literals,
|
||||
// and discover at the end that no `q` can reach both `q1` and `q2` by epsilon transitions.
|
||||
exists(intersect(s1, s2))
|
||||
|
|
||||
s1 != s2
|
||||
or
|
||||
r1 != r2
|
||||
or
|
||||
r1 = r2 and q1 != q2
|
||||
or
|
||||
// If q can reach itself by epsilon transitions, then there are two distinct paths to the q1/q2 state:
|
||||
// one that uses the loop and one that doesn't. The engine will separately attempt to match with each path,
|
||||
// despite ending in the same state. The "fork" thus arises from the choice of whether to use the loop or not.
|
||||
// To avoid every state in the loop becoming a fork state,
|
||||
// we arbitrarily pick the InfiniteRepetitionQuantifier state as the canonical fork state for the loop
|
||||
// (every epsilon-loop must contain such a state).
|
||||
//
|
||||
// We additionally require that the there exists another InfiniteRepetitionQuantifier `mid` on the path from `q` to itself.
|
||||
// This is done to avoid flagging regular expressions such as `/(a?)*b/` - that only has polynomial runtime, and is detected by `js/polynomial-redos`.
|
||||
// The below code is therefore a heuristic, that only flags regular expressions such as `/(a*)*b/`,
|
||||
// and does not flag regular expressions such as `/(a?b?)c/`, but the latter pattern is not used frequently.
|
||||
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)
|
||||
}
|
||||
|
||||
/**
|
||||
* Gets the state pair `(q1, q2)` or `(q2, q1)`; note that only
|
||||
* one or the other is defined.
|
||||
*/
|
||||
private StatePair mkStatePair(State q1, State q2) {
|
||||
result = MkStatePair(q1, q2) or result = MkStatePair(q2, q1)
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if there are transitions from the components of `q` to the corresponding
|
||||
* components of `r` labelled with `s1` and `s2`, respectively.
|
||||
*/
|
||||
private predicate step(StatePair q, InputSymbol s1, InputSymbol s2, StatePair r) {
|
||||
exists(State r1, State r2 | step(q, s1, s2, r1, r2) and r = mkStatePair(r1, r2))
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if there are transitions from the components of `q` to `r1` and `r2`
|
||||
* labelled with `s1` and `s2`, respectively.
|
||||
*
|
||||
* We only consider transitions where the resulting states `(r1, r2)` are both
|
||||
* inside a repetition that might backtrack.
|
||||
*/
|
||||
pragma[noopt]
|
||||
private predicate step(StatePair q, InputSymbol s1, InputSymbol s2, State r1, State r2) {
|
||||
exists(State q1, State q2 | q.getLeft() = q1 and q.getRight() = q2 |
|
||||
deltaClosed(q1, s1, r1) and
|
||||
deltaClosed(q2, s2, r2) and
|
||||
// use noopt to force the join on `intersect` to happen last.
|
||||
exists(intersect(s1, s2))
|
||||
) and
|
||||
stateInsideBacktracking(r1) and
|
||||
stateInsideBacktracking(r2)
|
||||
}
|
||||
|
||||
private newtype TTrace =
|
||||
Nil() or
|
||||
Step(InputSymbol s1, InputSymbol s2, TTrace t) { isReachableFromFork(_, _, s1, s2, t, _) }
|
||||
|
||||
/**
|
||||
* A list of pairs of input symbols that describe a path in the product automaton
|
||||
* starting from some fork state.
|
||||
*/
|
||||
private class Trace extends TTrace {
|
||||
/** Gets a textual representation of this element. */
|
||||
string toString() {
|
||||
this = Nil() and result = "Nil()"
|
||||
or
|
||||
exists(InputSymbol s1, InputSymbol s2, Trace t | this = Step(s1, s2, t) |
|
||||
result = "Step(" + s1 + ", " + s2 + ", " + t + ")"
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if `r` is reachable from `(fork, fork)` under input `w`, and there is
|
||||
* a path from `r` back to `(fork, fork)` with `rem` steps.
|
||||
*/
|
||||
private predicate isReachableFromFork(State fork, StatePair r, Trace w, int rem) {
|
||||
exists(InputSymbol s1, InputSymbol s2, Trace v |
|
||||
isReachableFromFork(fork, r, s1, s2, v, rem) and
|
||||
w = Step(s1, s2, v)
|
||||
)
|
||||
}
|
||||
|
||||
private predicate isReachableFromFork(
|
||||
State fork, StatePair r, InputSymbol s1, InputSymbol s2, Trace v, int rem
|
||||
) {
|
||||
// base case
|
||||
exists(State q1, State q2 |
|
||||
isFork(fork, s1, s2, q1, q2) and
|
||||
r = MkStatePair(q1, q2) and
|
||||
v = Nil() and
|
||||
rem = statePairDistToFork(r, MkStatePair(fork, fork))
|
||||
)
|
||||
or
|
||||
// recursive case
|
||||
exists(StatePair p |
|
||||
isReachableFromFork(fork, p, v, rem + 1) and
|
||||
step(p, s1, s2, r) and
|
||||
rem = statePairDistToFork(r, MkStatePair(fork, fork))
|
||||
)
|
||||
}
|
||||
|
||||
/**
|
||||
* Gets a state in the product automaton from which `(fork, fork)` is
|
||||
* reachable in zero or more epsilon transitions.
|
||||
*/
|
||||
private StatePair getAForkPair(State fork) {
|
||||
isFork(fork, _, _, _, _) and
|
||||
result = MkStatePair(epsilonPred*(fork), epsilonPred*(fork))
|
||||
}
|
||||
|
||||
/** An implementation of a chain containing chars for use by `Concretizer`. */
|
||||
private module CharTreeImpl implements CharTree {
|
||||
class CharNode = Trace;
|
||||
|
||||
CharNode getPrev(CharNode t) { t = Step(_, _, result) }
|
||||
|
||||
/** Holds if `n` is a trace that is used by `concretize` in `isPumpable`. */
|
||||
predicate isARelevantEnd(CharNode n) {
|
||||
exists(State f | isReachableFromFork(f, getAForkPair(f), n, _))
|
||||
}
|
||||
|
||||
string getChar(CharNode t) {
|
||||
exists(InputSymbol s1, InputSymbol s2 | t = Step(s1, s2, _) | result = intersect(s1, s2))
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if `fork` is a pumpable fork with word `w`.
|
||||
*/
|
||||
private predicate isPumpable(State fork, string w) {
|
||||
exists(StatePair q, Trace t |
|
||||
isReachableFromFork(fork, q, t, _) and
|
||||
q = getAForkPair(fork) and
|
||||
w = Concretizer<CharTreeImpl>::concretize(t)
|
||||
)
|
||||
}
|
||||
|
||||
/** Holds if `state` has exponential ReDoS */
|
||||
predicate hasReDoSResult = ReDoSPruning<isPumpable/2>::hasReDoSResult/4;
|
||||
private import semmle.python.RegexTreeView::RegexTreeView as TreeView
|
||||
// ExponentialBackTracking should be used directly from the shared pack, and not from this file.
|
||||
deprecated private import codeql.regex.nfa.ExponentialBackTracking::Make<TreeView> as Dep
|
||||
import Dep
|
||||
|
||||
File diff suppressed because it is too large
Load Diff
@@ -1,75 +0,0 @@
|
||||
/**
|
||||
* Provides Python-specific definitions for use in the NfaUtils module.
|
||||
*/
|
||||
|
||||
import python
|
||||
import semmle.python.RegexTreeView
|
||||
|
||||
/**
|
||||
* Holds if `term` is an escape class representing e.g. `\d`.
|
||||
* `clazz` is which character class it represents, e.g. "d" for `\d`.
|
||||
*/
|
||||
predicate isEscapeClass(RegExpTerm term, string clazz) {
|
||||
exists(RegExpCharacterClassEscape escape | term = escape | escape.getValue() = clazz)
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if `term` is a possessive quantifier.
|
||||
* As python's regexes do not support possessive quantifiers, this never holds, but is used by the shared library.
|
||||
*/
|
||||
predicate isPossessive(RegExpQuantifier term) { none() }
|
||||
|
||||
/**
|
||||
* Holds if the regex that `term` is part of is used in a way that ignores any leading prefix of the input it's matched against.
|
||||
* Not yet implemented for Python.
|
||||
*/
|
||||
predicate matchesAnyPrefix(RegExpTerm term) { any() }
|
||||
|
||||
/**
|
||||
* Holds if the regex that `term` is part of is used in a way that ignores any trailing suffix of the input it's matched against.
|
||||
* Not yet implemented for Python.
|
||||
*/
|
||||
predicate matchesAnySuffix(RegExpTerm term) { any() }
|
||||
|
||||
/**
|
||||
* Holds if the regular expression should not be considered.
|
||||
*
|
||||
* We make the pragmatic performance optimization to ignore regular expressions in files
|
||||
* that does not belong to the project code (such as installed dependencies).
|
||||
*/
|
||||
predicate isExcluded(RegExpParent parent) {
|
||||
not exists(parent.getRegex().getLocation().getFile().getRelativePath())
|
||||
or
|
||||
// Regexes with many occurrences of ".*" may cause the polynomial ReDoS computation to explode, so
|
||||
// we explicitly exclude these.
|
||||
count(int i | exists(parent.getRegex().getText().regexpFind("\\.\\*", i, _)) | i) > 10
|
||||
}
|
||||
|
||||
/**
|
||||
* A module containing predicates for determining which flags a regular expression have.
|
||||
*/
|
||||
module RegExpFlags {
|
||||
/**
|
||||
* Holds if `root` has the `i` flag for case-insensitive matching.
|
||||
*/
|
||||
predicate isIgnoreCase(RegExpTerm root) {
|
||||
root.isRootTerm() and
|
||||
root.getLiteral().isIgnoreCase()
|
||||
}
|
||||
|
||||
/**
|
||||
* Gets the flags for `root`, or the empty string if `root` has no flags.
|
||||
*/
|
||||
string getFlags(RegExpTerm root) {
|
||||
root.isRootTerm() and
|
||||
result = root.getLiteral().getFlags()
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if `root` has the `s` flag for multi-line matching.
|
||||
*/
|
||||
predicate isDotAll(RegExpTerm root) {
|
||||
root.isRootTerm() and
|
||||
root.getLiteral().isDotAll()
|
||||
}
|
||||
}
|
||||
@@ -3,155 +3,7 @@
|
||||
* and for testing which capture groups are filled when a particular regexp matches a string.
|
||||
*/
|
||||
|
||||
import NfaUtils
|
||||
|
||||
/** A root term */
|
||||
class RootTerm extends RegExpTerm {
|
||||
RootTerm() { this.isRootTerm() }
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if it should be tested whether `root` matches `str`.
|
||||
*
|
||||
* If `ignorePrefix` is true, then a regexp without a start anchor will be treated as if it had a start anchor.
|
||||
* E.g. a regular expression `/foo$/` will match any string that ends with "foo",
|
||||
* but if `ignorePrefix` is true, it will only match "foo".
|
||||
*
|
||||
* If `testWithGroups` is true, then the `RegexpMatching::fillsCaptureGroup` predicate can be used to determine which capture
|
||||
* groups are filled by a string.
|
||||
*/
|
||||
signature predicate isRegexpMatchingCandidateSig(
|
||||
RootTerm root, string str, boolean ignorePrefix, boolean testWithGroups
|
||||
);
|
||||
|
||||
/**
|
||||
* A module for determining if a regexp matches a given string,
|
||||
* and reasoning about which capture groups are filled by a given string.
|
||||
*
|
||||
* The module parameter `isCandidate` determines which strings should be tested,
|
||||
* and the results can be read from the `matches` and `fillsCaptureGroup` predicates.
|
||||
*/
|
||||
module RegexpMatching<isRegexpMatchingCandidateSig/4 isCandidate> {
|
||||
/**
|
||||
* Gets a state the regular expression `reg` can be in after matching the `i`th char in `str`.
|
||||
* The regular expression is modeled as a non-determistic finite automaton,
|
||||
* the regular expression can therefore be in multiple states after matching a character.
|
||||
*
|
||||
* It's a forward search to all possible states, and there is thus no guarantee that the state is on a path to an accepting state.
|
||||
*/
|
||||
private State getAState(RootTerm reg, int i, string str, boolean ignorePrefix) {
|
||||
// start state, the -1 position before any chars have been matched
|
||||
i = -1 and
|
||||
isCandidate(reg, str, ignorePrefix, _) and
|
||||
result.getRepr().getRootTerm() = reg and
|
||||
isStartState(result)
|
||||
or
|
||||
// recursive case
|
||||
result = getAStateAfterMatching(reg, _, str, i, _, ignorePrefix)
|
||||
}
|
||||
|
||||
/**
|
||||
* Gets the next state after the `prev` state from `reg`.
|
||||
* `prev` is the state after matching `fromIndex` chars in `str`,
|
||||
* and the result is the state after matching `toIndex` chars in `str`.
|
||||
*
|
||||
* This predicate is used as a step relation in the forwards search (`getAState`),
|
||||
* and also as a step relation in the later backwards search (`getAStateThatReachesAccept`).
|
||||
*/
|
||||
private State getAStateAfterMatching(
|
||||
RootTerm reg, State prev, string str, int toIndex, int fromIndex, boolean ignorePrefix
|
||||
) {
|
||||
// the basic recursive case - outlined into a noopt helper to make performance work out.
|
||||
result = getAStateAfterMatchingAux(reg, prev, str, toIndex, fromIndex, ignorePrefix)
|
||||
or
|
||||
// we can skip past word boundaries if the next char is a non-word char.
|
||||
fromIndex = toIndex and
|
||||
prev.getRepr() instanceof RegExpWordBoundary and
|
||||
prev = getAState(reg, toIndex, str, ignorePrefix) and
|
||||
after(prev.getRepr()) = result and
|
||||
str.charAt(toIndex + 1).regexpMatch("\\W") // \W matches any non-word char.
|
||||
}
|
||||
|
||||
pragma[noopt]
|
||||
private State getAStateAfterMatchingAux(
|
||||
RootTerm reg, State prev, string str, int toIndex, int fromIndex, boolean ignorePrefix
|
||||
) {
|
||||
prev = getAState(reg, fromIndex, str, ignorePrefix) and
|
||||
fromIndex = toIndex - 1 and
|
||||
exists(string char | char = str.charAt(toIndex) | specializedDeltaClosed(prev, char, result)) and
|
||||
not discardedPrefixStep(prev, result, ignorePrefix)
|
||||
}
|
||||
|
||||
/** Holds if a step from `prev` to `next` should be discarded when the `ignorePrefix` flag is set. */
|
||||
private predicate discardedPrefixStep(State prev, State next, boolean ignorePrefix) {
|
||||
prev = mkMatch(any(RegExpRoot r)) and
|
||||
ignorePrefix = true and
|
||||
next = prev
|
||||
}
|
||||
|
||||
// The `deltaClosed` relation specialized to the chars that exists in strings tested by a `MatchedRegExp`.
|
||||
private predicate specializedDeltaClosed(State prev, string char, State next) {
|
||||
deltaClosed(prev, specializedGetAnInputSymbolMatching(char), next)
|
||||
}
|
||||
|
||||
// The `getAnInputSymbolMatching` relation specialized to the chars that exists in strings tested by a `MatchedRegExp`.
|
||||
pragma[noinline]
|
||||
private InputSymbol specializedGetAnInputSymbolMatching(string char) {
|
||||
exists(string s, RootTerm r | isCandidate(r, s, _, _) | char = s.charAt(_)) and
|
||||
result = getAnInputSymbolMatching(char)
|
||||
}
|
||||
|
||||
/**
|
||||
* Gets the `i`th state on a path to the accepting state when `reg` matches `str`.
|
||||
* Starts with an accepting state as found by `getAState` and searches backwards
|
||||
* to the start state through the reachable states (as found by `getAState`).
|
||||
*
|
||||
* This predicate satisfies the invariant that the result state can be reached with `i` steps from a start state,
|
||||
* and an accepting state can be found after (`str.length() - 1 - i`) steps from the result.
|
||||
* The result state is therefore always on a valid path where `reg` accepts `str`.
|
||||
*
|
||||
* This predicate is only used to find which capture groups a regular expression has filled,
|
||||
* and thus the search is only performed for the strings in the `testWithGroups(..)` predicate.
|
||||
*/
|
||||
private State getAStateThatReachesAccept(RootTerm reg, int i, string str, boolean ignorePrefix) {
|
||||
// base case, reaches an accepting state from the last state in `getAState(..)`
|
||||
isCandidate(reg, str, ignorePrefix, true) and
|
||||
i = str.length() - 1 and
|
||||
result = getAState(reg, i, str, ignorePrefix) and
|
||||
epsilonSucc*(result) = Accept(_)
|
||||
or
|
||||
// recursive case. `next` is the next state to be matched after matching `prev`.
|
||||
// this predicate is doing a backwards search, so `prev` is the result we are looking for.
|
||||
exists(State next, State prev, int fromIndex, int toIndex |
|
||||
next = getAStateThatReachesAccept(reg, toIndex, str, ignorePrefix) and
|
||||
next = getAStateAfterMatching(reg, prev, str, toIndex, fromIndex, ignorePrefix) and
|
||||
i = fromIndex and
|
||||
result = prev
|
||||
)
|
||||
}
|
||||
|
||||
/** Gets the capture group number that `term` belongs to. */
|
||||
private int group(RegExpTerm term) {
|
||||
exists(RegExpGroup grp | grp.getNumber() = result | term.getParent*() = grp)
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if `reg` matches `str`, where `str` is in the `isCandidate` predicate.
|
||||
*/
|
||||
predicate matches(RootTerm reg, string str) {
|
||||
exists(State state | state = getAState(reg, str.length() - 1, str, _) |
|
||||
epsilonSucc*(state) = Accept(_)
|
||||
)
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if matching `str` against `reg` may fill capture group number `g`.
|
||||
* Only holds if `str` is in the `testWithGroups` predicate.
|
||||
*/
|
||||
predicate fillsCaptureGroup(RootTerm reg, string str, int g) {
|
||||
exists(State s |
|
||||
s = getAStateThatReachesAccept(reg, _, str, _) and
|
||||
g = group(s.getRepr())
|
||||
)
|
||||
}
|
||||
}
|
||||
private import semmle.python.RegexTreeView::RegexTreeView as TreeView
|
||||
// RegexpMatching should be used directly from the shared pack, and not from this file.
|
||||
deprecated import codeql.regex.nfa.RegexpMatching::Make<TreeView> as Dep
|
||||
import Dep
|
||||
|
||||
@@ -1,11 +1,4 @@
|
||||
/**
|
||||
* Provides classes for working with regular expressions that can
|
||||
* perform backtracking in superlinear time.
|
||||
*/
|
||||
|
||||
import NfaUtils
|
||||
|
||||
/*
|
||||
* This module implements the analysis described in the paper:
|
||||
* Valentin Wustholz, Oswaldo Olivo, Marijn J. H. Heule, and Isil Dillig:
|
||||
* Static Detection of DoS Vulnerabilities in
|
||||
@@ -42,377 +35,7 @@ import NfaUtils
|
||||
* It also doesn't find all transitions in the product automaton, which can cause false negatives.
|
||||
*/
|
||||
|
||||
/**
|
||||
* Gets any root (start) state of a regular expression.
|
||||
*/
|
||||
private State getRootState() { result = mkMatch(any(RegExpRoot r)) }
|
||||
|
||||
private newtype TStateTuple =
|
||||
MkStateTuple(State q1, State q2, State q3) {
|
||||
// starts at (pivot, pivot, succ)
|
||||
isStartLoops(q1, q3) and q1 = q2
|
||||
or
|
||||
step(_, _, _, _, q1, q2, q3) and FeasibleTuple::isFeasibleTuple(q1, q2, q3)
|
||||
}
|
||||
|
||||
/**
|
||||
* A state in the product automaton.
|
||||
* The product automaton contains 3-tuples of states.
|
||||
*
|
||||
* We lazily only construct those states that we are actually
|
||||
* going to need.
|
||||
* Either a start state `(pivot, pivot, succ)`, or a state
|
||||
* where there exists a transition from an already existing state.
|
||||
*
|
||||
* The exponential variant of this query (`js/redos`) uses an optimization
|
||||
* trick where `q1 <= q2`. This trick cannot be used here as the order
|
||||
* of the elements matter.
|
||||
*/
|
||||
class StateTuple extends TStateTuple {
|
||||
State q1;
|
||||
State q2;
|
||||
State q3;
|
||||
|
||||
StateTuple() { this = MkStateTuple(q1, q2, q3) }
|
||||
|
||||
/**
|
||||
* Gest a string representation of this tuple.
|
||||
*/
|
||||
string toString() { result = "(" + q1 + ", " + q2 + ", " + q3 + ")" }
|
||||
|
||||
/**
|
||||
* Holds if this tuple is `(r1, r2, r3)`.
|
||||
*/
|
||||
pragma[noinline]
|
||||
predicate isTuple(State r1, State r2, State r3) { r1 = q1 and r2 = q2 and r3 = q3 }
|
||||
}
|
||||
|
||||
/**
|
||||
* A module for determining feasible tuples for the product automaton.
|
||||
*
|
||||
* The implementation is split into many predicates for performance reasons.
|
||||
*/
|
||||
private module FeasibleTuple {
|
||||
/**
|
||||
* Holds if the tuple `(r1, r2, r3)` might be on path from a start-state to an end-state in the product automaton.
|
||||
*/
|
||||
pragma[inline]
|
||||
predicate isFeasibleTuple(State r1, State r2, State r3) {
|
||||
// The first element is either inside a repetition (or the start state itself)
|
||||
isRepetitionOrStart(r1) and
|
||||
// The last element is inside a repetition
|
||||
stateInsideRepetition(r3) and
|
||||
// The states are reachable in the NFA in the order r1 -> r2 -> r3
|
||||
delta+(r1) = r2 and
|
||||
delta+(r2) = r3 and
|
||||
// The first element can reach a beginning (the "pivot" state in a `(pivot, succ)` pair).
|
||||
canReachABeginning(r1) and
|
||||
// The last element can reach a target (the "succ" state in a `(pivot, succ)` pair).
|
||||
canReachATarget(r3)
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if `s` is either inside a repetition, or is the start state (which is a repetition).
|
||||
*/
|
||||
pragma[noinline]
|
||||
private predicate isRepetitionOrStart(State s) { stateInsideRepetition(s) or s = getRootState() }
|
||||
|
||||
/**
|
||||
* Holds if state `s` might be inside a backtracking repetition.
|
||||
*/
|
||||
pragma[noinline]
|
||||
private predicate stateInsideRepetition(State s) {
|
||||
s.getRepr().getParent*() instanceof InfiniteRepetitionQuantifier
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if there exists a path in the NFA from `s` to a "pivot" state
|
||||
* (from a `(pivot, succ)` pair that starts the search).
|
||||
*/
|
||||
pragma[noinline]
|
||||
private predicate canReachABeginning(State s) {
|
||||
delta+(s) = any(State pivot | isStartLoops(pivot, _))
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if there exists a path in the NFA from `s` to a "succ" state
|
||||
* (from a `(pivot, succ)` pair that starts the search).
|
||||
*/
|
||||
pragma[noinline]
|
||||
private predicate canReachATarget(State s) { delta+(s) = any(State succ | isStartLoops(_, succ)) }
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if `pivot` and `succ` are a pair of loops that could be the beginning of a quadratic blowup.
|
||||
*
|
||||
* There is a slight implementation difference compared to the paper: this predicate requires that `pivot != succ`.
|
||||
* The case where `pivot = succ` causes exponential backtracking and is handled by the `js/redos` query.
|
||||
*/
|
||||
predicate isStartLoops(State pivot, State succ) {
|
||||
pivot != succ and
|
||||
succ.getRepr() instanceof InfiniteRepetitionQuantifier and
|
||||
delta+(pivot) = succ and
|
||||
(
|
||||
pivot.getRepr() instanceof InfiniteRepetitionQuantifier
|
||||
or
|
||||
pivot = mkMatch(any(RegExpRoot root))
|
||||
)
|
||||
}
|
||||
|
||||
/**
|
||||
* Gets a state for which there exists a transition in the NFA from `s'.
|
||||
*/
|
||||
State delta(State s) { delta(s, _, result) }
|
||||
|
||||
/**
|
||||
* Holds if there are transitions from the components of `q` to the corresponding
|
||||
* components of `r` labelled with `s1`, `s2`, and `s3`, respectively.
|
||||
*/
|
||||
pragma[noinline]
|
||||
predicate step(StateTuple q, InputSymbol s1, InputSymbol s2, InputSymbol s3, StateTuple r) {
|
||||
exists(State r1, State r2, State r3 |
|
||||
step(q, s1, s2, s3, r1, r2, r3) and r = MkStateTuple(r1, r2, r3)
|
||||
)
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if there are transitions from the components of `q` to `r1`, `r2`, and `r3
|
||||
* labelled with `s1`, `s2`, and `s3`, respectively.
|
||||
*/
|
||||
pragma[noopt]
|
||||
predicate step(
|
||||
StateTuple q, InputSymbol s1, InputSymbol s2, InputSymbol s3, State r1, State r2, State r3
|
||||
) {
|
||||
exists(State q1, State q2, State q3 | q.isTuple(q1, q2, q3) |
|
||||
deltaClosed(q1, s1, r1) and
|
||||
deltaClosed(q2, s2, r2) and
|
||||
deltaClosed(q3, s3, r3) and
|
||||
// use noopt to force the join on `getAThreewayIntersect` to happen last.
|
||||
exists(getAThreewayIntersect(s1, s2, s3))
|
||||
)
|
||||
}
|
||||
|
||||
/**
|
||||
* Gets a char that is matched by all the edges `s1`, `s2`, and `s3`.
|
||||
*
|
||||
* The result is not complete, and might miss some combination of edges that share some character.
|
||||
*/
|
||||
pragma[noinline]
|
||||
string getAThreewayIntersect(InputSymbol s1, InputSymbol s2, InputSymbol s3) {
|
||||
result = minAndMaxIntersect(s1, s2) and result = [intersect(s2, s3), intersect(s1, s3)]
|
||||
or
|
||||
result = minAndMaxIntersect(s1, s3) and result = [intersect(s2, s3), intersect(s1, s2)]
|
||||
or
|
||||
result = minAndMaxIntersect(s2, s3) and result = [intersect(s1, s2), intersect(s1, s3)]
|
||||
}
|
||||
|
||||
/**
|
||||
* Gets the minimum and maximum characters that intersect between `a` and `b`.
|
||||
* This predicate is used to limit the size of `getAThreewayIntersect`.
|
||||
*/
|
||||
pragma[noinline]
|
||||
string minAndMaxIntersect(InputSymbol a, InputSymbol b) {
|
||||
result = [min(intersect(a, b)), max(intersect(a, b))]
|
||||
}
|
||||
|
||||
private newtype TTrace =
|
||||
Nil() or
|
||||
Step(InputSymbol s1, InputSymbol s2, InputSymbol s3, TTrace t) {
|
||||
isReachableFromStartTuple(_, _, t, s1, s2, s3, _, _)
|
||||
}
|
||||
|
||||
/**
|
||||
* A list of tuples of input symbols that describe a path in the product automaton
|
||||
* starting from some start state.
|
||||
*/
|
||||
class Trace extends TTrace {
|
||||
/**
|
||||
* Gets a string representation of this Trace that can be used for debug purposes.
|
||||
*/
|
||||
string toString() {
|
||||
this = Nil() and result = "Nil()"
|
||||
or
|
||||
exists(InputSymbol s1, InputSymbol s2, InputSymbol s3, Trace t | this = Step(s1, s2, s3, t) |
|
||||
result = "Step(" + s1 + ", " + s2 + ", " + s3 + ", " + t + ")"
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if there exists a transition from `r` to `q` in the product automaton.
|
||||
* Notice that the arguments are flipped, and thus the direction is backwards.
|
||||
*/
|
||||
pragma[noinline]
|
||||
predicate tupleDeltaBackwards(StateTuple q, StateTuple r) { step(r, _, _, _, q) }
|
||||
|
||||
/**
|
||||
* Holds if `tuple` is an end state in our search.
|
||||
* That means there exists a pair of loops `(pivot, succ)` such that `tuple = (pivot, succ, succ)`.
|
||||
*/
|
||||
predicate isEndTuple(StateTuple tuple) { tuple = getAnEndTuple(_, _) }
|
||||
|
||||
/**
|
||||
* Gets the minimum length of a path from `r` to some an end state `end`.
|
||||
*
|
||||
* The implementation searches backwards from the end-tuple.
|
||||
* This approach was chosen because it is way more efficient if the first predicate given to `shortestDistances` is small.
|
||||
* The `end` argument must always be an end state.
|
||||
*/
|
||||
int distBackFromEnd(StateTuple r, StateTuple end) =
|
||||
shortestDistances(isEndTuple/1, tupleDeltaBackwards/2)(end, r, result)
|
||||
|
||||
/**
|
||||
* Holds if there exists a pair of repetitions `(pivot, succ)` in the regular expression such that:
|
||||
* `tuple` is reachable from `(pivot, pivot, succ)` in the product automaton,
|
||||
* and there is a distance of `dist` from `tuple` to the nearest end-tuple `(pivot, succ, succ)`,
|
||||
* and a path from a start-state to `tuple` follows the transitions in `trace`.
|
||||
*/
|
||||
private predicate isReachableFromStartTuple(
|
||||
State pivot, State succ, StateTuple tuple, Trace trace, int dist
|
||||
) {
|
||||
exists(InputSymbol s1, InputSymbol s2, InputSymbol s3, Trace v |
|
||||
isReachableFromStartTuple(pivot, succ, v, s1, s2, s3, tuple, dist) and
|
||||
trace = Step(s1, s2, s3, v)
|
||||
)
|
||||
}
|
||||
|
||||
private predicate isReachableFromStartTuple(
|
||||
State pivot, State succ, Trace trace, InputSymbol s1, InputSymbol s2, InputSymbol s3,
|
||||
StateTuple tuple, int dist
|
||||
) {
|
||||
// base case.
|
||||
exists(State q1, State q2, State q3 |
|
||||
isStartLoops(pivot, succ) and
|
||||
step(MkStateTuple(pivot, pivot, succ), s1, s2, s3, tuple) and
|
||||
tuple = MkStateTuple(q1, q2, q3) and
|
||||
trace = Nil() and
|
||||
dist = distBackFromEnd(tuple, MkStateTuple(pivot, succ, succ))
|
||||
)
|
||||
or
|
||||
// recursive case
|
||||
exists(StateTuple p |
|
||||
isReachableFromStartTuple(pivot, succ, p, trace, dist + 1) and
|
||||
dist = distBackFromEnd(tuple, MkStateTuple(pivot, succ, succ)) and
|
||||
step(p, s1, s2, s3, tuple)
|
||||
)
|
||||
}
|
||||
|
||||
/**
|
||||
* Gets the tuple `(pivot, succ, succ)` from the product automaton.
|
||||
*/
|
||||
StateTuple getAnEndTuple(State pivot, State succ) {
|
||||
isStartLoops(pivot, succ) and
|
||||
result = MkStateTuple(pivot, succ, succ)
|
||||
}
|
||||
|
||||
/** An implementation of a chain containing chars for use by `Concretizer`. */
|
||||
private module CharTreeImpl implements CharTree {
|
||||
class CharNode = Trace;
|
||||
|
||||
CharNode getPrev(CharNode t) { t = Step(_, _, _, result) }
|
||||
|
||||
/** Holds if `n` is used in `isPumpable`. */
|
||||
predicate isARelevantEnd(CharNode n) {
|
||||
exists(State pivot, State succ |
|
||||
isReachableFromStartTuple(pivot, succ, getAnEndTuple(pivot, succ), n, _)
|
||||
)
|
||||
}
|
||||
|
||||
string getChar(CharNode t) {
|
||||
exists(InputSymbol s1, InputSymbol s2, InputSymbol s3 | t = Step(s1, s2, s3, _) |
|
||||
result = getAThreewayIntersect(s1, s2, s3)
|
||||
)
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if matching repetitions of `pump` can:
|
||||
* 1) Transition from `pivot` back to `pivot`.
|
||||
* 2) Transition from `pivot` to `succ`.
|
||||
* 3) Transition from `succ` to `succ`.
|
||||
*
|
||||
* From theorem 3 in the paper linked in the top of this file we can therefore conclude that
|
||||
* the regular expression has polynomial backtracking - if a rejecting suffix exists.
|
||||
*
|
||||
* This predicate is used by `SuperLinearReDoSConfiguration`, and the final results are
|
||||
* available in the `hasReDoSResult` predicate.
|
||||
*/
|
||||
predicate isPumpable(State pivot, State succ, string pump) {
|
||||
exists(StateTuple q, Trace t |
|
||||
isReachableFromStartTuple(pivot, succ, q, t, _) and
|
||||
q = getAnEndTuple(pivot, succ) and
|
||||
pump = Concretizer<CharTreeImpl>::concretize(t)
|
||||
)
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if states starting in `state` can have polynomial backtracking with the string `pump`.
|
||||
*/
|
||||
predicate isReDoSCandidate(State state, string pump) { isPumpable(_, state, pump) }
|
||||
|
||||
/**
|
||||
* Holds if repetitions of `pump` at `t` will cause polynomial backtracking.
|
||||
*/
|
||||
predicate polynomialReDoS(RegExpTerm t, string pump, string prefixMsg, RegExpTerm prev) {
|
||||
exists(State s, State pivot |
|
||||
ReDoSPruning<isReDoSCandidate/2>::hasReDoSResult(t, pump, s, prefixMsg) and
|
||||
isPumpable(pivot, s, _) and
|
||||
prev = pivot.getRepr()
|
||||
)
|
||||
}
|
||||
|
||||
/**
|
||||
* Gets a message for why `term` can cause polynomial backtracking.
|
||||
*/
|
||||
string getReasonString(RegExpTerm term, string pump, string prefixMsg, RegExpTerm prev) {
|
||||
polynomialReDoS(term, pump, prefixMsg, prev) and
|
||||
result =
|
||||
"Strings " + prefixMsg + "with many repetitions of '" + pump +
|
||||
"' can start matching anywhere after the start of the preceeding " + prev
|
||||
}
|
||||
|
||||
/**
|
||||
* A term that may cause a regular expression engine to perform a
|
||||
* polynomial number of match attempts, relative to the input length.
|
||||
*/
|
||||
class PolynomialBackTrackingTerm extends InfiniteRepetitionQuantifier {
|
||||
string reason;
|
||||
string pump;
|
||||
string prefixMsg;
|
||||
RegExpTerm prev;
|
||||
|
||||
PolynomialBackTrackingTerm() {
|
||||
reason = getReasonString(this, pump, prefixMsg, prev) and
|
||||
// there might be many reasons for this term to have polynomial backtracking - we pick the shortest one.
|
||||
reason = min(string msg | msg = getReasonString(this, _, _, _) | msg order by msg.length(), msg)
|
||||
}
|
||||
|
||||
/**
|
||||
* Holds if all non-empty successors to the polynomial backtracking term matches the end of the line.
|
||||
*/
|
||||
predicate isAtEndLine() {
|
||||
forall(RegExpTerm succ | this.getSuccessor+() = succ and not matchesEpsilon(succ) |
|
||||
succ instanceof RegExpDollar
|
||||
)
|
||||
}
|
||||
|
||||
/**
|
||||
* Gets the string that should be repeated to cause this regular expression to perform polynomially.
|
||||
*/
|
||||
string getPumpString() { result = pump }
|
||||
|
||||
/**
|
||||
* Gets a message for which prefix a matching string must start with for this term to cause polynomial backtracking.
|
||||
*/
|
||||
string getPrefixMessage() { result = prefixMsg }
|
||||
|
||||
/**
|
||||
* Gets a predecessor to `this`, which also loops on the pump string, and thereby causes polynomial backtracking.
|
||||
*/
|
||||
RegExpTerm getPreviousLoop() { result = prev }
|
||||
|
||||
/**
|
||||
* Gets the reason for the number of match attempts.
|
||||
*/
|
||||
string getReason() { result = reason }
|
||||
}
|
||||
private import semmle.python.RegexTreeView::RegexTreeView as TreeView
|
||||
// SuperlinearBackTracking should be used directly from the shared pack, and not from this file.
|
||||
deprecated private import codeql.regex.nfa.SuperlinearBackTracking::Make<TreeView> as Dep
|
||||
import Dep
|
||||
|
||||
@@ -12,8 +12,9 @@
|
||||
* external/cwe/cwe-020
|
||||
*/
|
||||
|
||||
import semmle.python.security.OverlyLargeRangeQuery
|
||||
private import semmle.python.RegexTreeView::RegexTreeView as TreeView
|
||||
import codeql.regex.OverlyLargeRangeQuery::Make<TreeView>
|
||||
|
||||
from RegExpCharacterRange range, string reason
|
||||
from TreeView::RegExpCharacterRange range, string reason
|
||||
where problem(range, reason)
|
||||
select range, "Suspicious character range that " + reason + "."
|
||||
|
||||
@@ -14,7 +14,8 @@
|
||||
* external/cwe/cwe-186
|
||||
*/
|
||||
|
||||
import semmle.python.security.BadTagFilterQuery
|
||||
private import semmle.python.RegexTreeView::RegexTreeView as TreeView
|
||||
import codeql.regex.nfa.BadTagFilterQuery::Make<TreeView>
|
||||
|
||||
from HtmlMatchingRegExp regexp, string msg
|
||||
where msg = min(string m | isBadRegexpFilter(regexp, m) | m order by m.length(), m) // there might be multiple, we arbitrarily pick the shortest one
|
||||
|
||||
@@ -14,7 +14,6 @@
|
||||
*/
|
||||
|
||||
import python
|
||||
import semmle.python.security.regexp.SuperlinearBackTracking
|
||||
import semmle.python.security.dataflow.PolynomialReDoSQuery
|
||||
import DataFlow::PathGraph
|
||||
|
||||
|
||||
@@ -14,10 +14,10 @@
|
||||
* external/cwe/cwe-400
|
||||
*/
|
||||
|
||||
import python
|
||||
import semmle.python.security.regexp.ExponentialBackTracking
|
||||
private import semmle.python.RegexTreeView::RegexTreeView as TreeView
|
||||
import codeql.regex.nfa.ExponentialBackTracking::Make<TreeView>
|
||||
|
||||
from RegExpTerm t, string pump, State s, string prefixMsg
|
||||
from TreeView::RegExpTerm t, string pump, State s, string prefixMsg
|
||||
where
|
||||
hasReDoSResult(t, pump, s, prefixMsg) and
|
||||
// exclude verbose mode regexes for now
|
||||
|
||||
@@ -1,2 +1,2 @@
|
||||
| test.py:8:12:8:23 | Str | test.py:8:21:8:23 | \\s+ | Strings with many repetitions of ' ' can start matching anywhere after the start of the preceeding \\s+$ |
|
||||
| test.py:9:14:9:29 | Str | test.py:9:27:9:29 | \\d+ | Strings with many repetitions of '99' can start matching anywhere after the start of the preceeding \\d+ |
|
||||
| test.py:9:14:9:29 | Str | test.py:9:27:9:29 | \\d+ | Strings starting with '0.9' and with many repetitions of '99' can start matching anywhere after the start of the preceeding \\d+ |
|
||||
|
||||
@@ -1,5 +1,6 @@
|
||||
import python
|
||||
import semmle.python.security.regexp.SuperlinearBackTracking
|
||||
private import semmle.python.RegexTreeView::RegexTreeView as TreeView
|
||||
import codeql.regex.nfa.SuperlinearBackTracking::Make<TreeView>
|
||||
|
||||
from PolynomialBackTrackingTerm t
|
||||
select t.getRegex(), t, t.getReason()
|
||||
select t.(TreeView::RegExpTerm).getRegex(), t, t.getReason()
|
||||
|
||||
@@ -16,4 +16,4 @@ nodes
|
||||
subpaths
|
||||
#select
|
||||
| test.py:8:30:8:33 | ControlFlowNode for text | test.py:2:26:2:32 | ControlFlowNode for ImportMember | test.py:8:30:8:33 | ControlFlowNode for text | This $@ that depends on a $@ may run slow on strings with many repetitions of ' '. | test.py:8:21:8:23 | \\s+ | regular expression | test.py:2:26:2:32 | ControlFlowNode for ImportMember | user-provided value |
|
||||
| test.py:9:32:9:35 | ControlFlowNode for text | test.py:2:26:2:32 | ControlFlowNode for ImportMember | test.py:9:32:9:35 | ControlFlowNode for text | This $@ that depends on a $@ may run slow on strings with many repetitions of '99'. | test.py:9:27:9:29 | \\d+ | regular expression | test.py:2:26:2:32 | ControlFlowNode for ImportMember | user-provided value |
|
||||
| test.py:9:32:9:35 | ControlFlowNode for text | test.py:2:26:2:32 | ControlFlowNode for ImportMember | test.py:9:32:9:35 | ControlFlowNode for text | This $@ that depends on a $@ may run slow on strings starting with '0.9' and with many repetitions of '99'. | test.py:9:27:9:29 | \\d+ | regular expression | test.py:2:26:2:32 | ControlFlowNode for ImportMember | user-provided value |
|
||||
|
||||
@@ -2,20 +2,20 @@
|
||||
| KnownCVEs.py:30:24:31:25 | .* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of ','. |
|
||||
| KnownCVEs.py:35:18:35:81 | ([-/:,#%.'"\\s!\\w]\|\\w-\\w\|'[\\s\\w]+'\\s*\|"[\\s\\w]+"\|\\([\\d,%\\.\\s]+\\))* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '"\\t"'. |
|
||||
| redos.py:6:28:6:42 | (?:__\|[\\s\\S])+? | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '__'. |
|
||||
| redos.py:6:52:6:68 | (?:\\*\\*\|[\\s\\S])+? | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '**'. |
|
||||
| redos.py:21:34:21:53 | (?:[^"\\\\]\|\\\\\\\\\|\\\\.)+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '\\\\\\\\'. |
|
||||
| redos.py:21:57:21:76 | (?:[^'\\\\]\|\\\\\\\\\|\\\\.)+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '\\\\\\\\'. |
|
||||
| redos.py:21:81:21:100 | (?:[^)\\\\]\|\\\\\\\\\|\\\\.)+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '\\\\\\\\'. |
|
||||
| redos.py:33:64:33:65 | .* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '\|\|\\n'. |
|
||||
| redos.py:6:52:6:68 | (?:\\*\\*\|[\\s\\S])+? | This part of the regular expression may cause exponential backtracking on strings starting with '*' and containing many repetitions of '**'. |
|
||||
| redos.py:21:34:21:53 | (?:[^"\\\\]\|\\\\\\\\\|\\\\.)+ | This part of the regular expression may cause exponential backtracking on strings starting with '\\t"' and containing many repetitions of '\\\\\\\\'. |
|
||||
| redos.py:21:57:21:76 | (?:[^'\\\\]\|\\\\\\\\\|\\\\.)+ | This part of the regular expression may cause exponential backtracking on strings starting with '\\t'' and containing many repetitions of '\\\\\\\\'. |
|
||||
| redos.py:21:81:21:100 | (?:[^)\\\\]\|\\\\\\\\\|\\\\.)+ | This part of the regular expression may cause exponential backtracking on strings starting with '\\t(' and containing many repetitions of '\\\\\\\\'. |
|
||||
| redos.py:33:64:33:65 | .* | This part of the regular expression may cause exponential backtracking on strings starting with '!\|\\n-\|\\n' and containing many repetitions of '\|\|\\n'. |
|
||||
| redos.py:38:33:38:42 | (\\\\\\/\|.)*? | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '\\\\/'. |
|
||||
| redos.py:43:37:43:38 | .* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '#'. |
|
||||
| redos.py:43:37:43:38 | .* | This part of the regular expression may cause exponential backtracking on strings starting with '#' and containing many repetitions of '#'. |
|
||||
| redos.py:49:41:49:43 | .*? | This part of the regular expression may cause exponential backtracking on strings starting with '"' and containing many repetitions of '""'. |
|
||||
| redos.py:49:47:49:49 | .*? | This part of the regular expression may cause exponential backtracking on strings starting with ''' and containing many repetitions of ''''. |
|
||||
| redos.py:54:47:54:49 | .*? | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of ']['. |
|
||||
| redos.py:54:80:54:82 | .*? | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of ']['. |
|
||||
| redos.py:54:47:54:49 | .*? | This part of the regular expression may cause exponential backtracking on strings starting with '$[' and containing many repetitions of ']['. |
|
||||
| redos.py:54:80:54:82 | .*? | This part of the regular expression may cause exponential backtracking on strings starting with '$.$[' and containing many repetitions of ']['. |
|
||||
| redos.py:60:25:60:30 | [a-z]+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
|
||||
| redos.py:61:25:61:30 | [a-z]* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
|
||||
| redos.py:62:53:62:64 | [a-zA-Z0-9]+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '0'. |
|
||||
| redos.py:62:53:62:64 | [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'. |
|
||||
| redos.py:63:26:63:33 | ([a-z])+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'aa'. |
|
||||
| redos.py:68:26:68:41 | [\\w#:.~>+()\\s-]+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '\\t'. |
|
||||
| redos.py:68:48:68:50 | .*? | This part of the regular expression may cause exponential backtracking on strings starting with '[' and containing many repetitions of ']['. |
|
||||
@@ -51,7 +51,6 @@
|
||||
| redos.py:196:91:196:92 | ,? | This part of the regular expression may cause exponential backtracking on strings starting with '{[A(A)A: ' and containing many repetitions of ',A: '. |
|
||||
| redos.py:199:25:199:26 | a+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
|
||||
| redos.py:199:28:199:29 | b+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'b'. |
|
||||
| redos.py:202:26:202:32 | (a+a?)* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
|
||||
| redos.py:202:27:202:28 | a+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
|
||||
| redos.py:205:25:205:26 | a+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
|
||||
| redos.py:211:25:211:26 | a+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
|
||||
@@ -71,16 +70,16 @@
|
||||
| redos.py:268:28:268:39 | ([\ufffd\ufffd]\|[\ufffd\ufffd])* | This part of the regular expression may cause exponential backtracking on strings starting with 'foo' and containing many repetitions of '\ufffd'. |
|
||||
| redos.py:271:28:271:41 | ((\ufffd\|\ufffd)\|(\ufffd\|\ufffd))* | This part of the regular expression may cause exponential backtracking on strings starting with 'foo' and containing many repetitions of '\ufffd'. |
|
||||
| redos.py:274:31:274:32 | b+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'b'. |
|
||||
| redos.py:277:48:277:50 | \\s* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '""\\t0='. |
|
||||
| redos.py:277:48:277:50 | \\s* | This part of the regular expression may cause exponential backtracking on strings starting with '<0\\t0=' and containing many repetitions of '""\\t0='. |
|
||||
| redos.py:283:26:283:27 | a+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
|
||||
| redos.py:286:26:286:27 | a+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
|
||||
| redos.py:292:26:292:27 | a+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
|
||||
| redos.py:295:35:295:36 | a+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
|
||||
| redos.py:301:100:301:101 | e+ | This part of the regular expression may cause exponential backtracking on strings starting with ';00000000000000' and containing many repetitions of 'e'. |
|
||||
| redos.py:301:100:301:101 | e+ | This part of the regular expression may cause exponential backtracking on strings starting with '00000000000000' and containing many repetitions of 'e'. |
|
||||
| redos.py:304:28:304:29 | c+ | This part of the regular expression may cause exponential backtracking on strings starting with 'ab' and containing many repetitions of 'c'. |
|
||||
| redos.py:307:28:307:30 | \\s+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of '\\t'. |
|
||||
| redos.py:310:26:310:34 | ([^/]\|X)+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'X'. |
|
||||
| redos.py:313:30:313:34 | [^Y]+ | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'Xx'. |
|
||||
| redos.py:313:30:313:34 | [^Y]+ | This part of the regular expression may cause exponential backtracking on strings starting with 'x' and containing many repetitions of 'Xx'. |
|
||||
| redos.py:316:25:316:26 | a* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'a'. |
|
||||
| redos.py:319:28:319:33 | [\\w-]* | This part of the regular expression may cause exponential backtracking on strings starting with 'foo' and containing many repetitions of '-'. |
|
||||
| redos.py:322:25:322:29 | (ab)* | This part of the regular expression may cause exponential backtracking on strings containing many repetitions of 'ab'. |
|
||||
|
||||
@@ -166,7 +166,7 @@ module Make<RegexTreeViewSig TreeImpl> {
|
||||
min(RelevantRegExpTerm t |
|
||||
str = getCanonicalizationString(t)
|
||||
|
|
||||
t order by getTermLocationString(t)
|
||||
t order by getTermLocationString(t), t.toString()
|
||||
)
|
||||
}
|
||||
|
||||
@@ -949,7 +949,7 @@ module Make<RegexTreeViewSig TreeImpl> {
|
||||
isStartState(s) and
|
||||
getRoot(s.getRepr()) = root
|
||||
|
|
||||
s order by getTermLocationString(s.getRepr())
|
||||
s order by getTermLocationString(s.getRepr()), s.getRepr().toString()
|
||||
)
|
||||
)
|
||||
}
|
||||
@@ -1047,7 +1047,7 @@ module Make<RegexTreeViewSig TreeImpl> {
|
||||
isCandidate(s, _) and
|
||||
s.getRepr() instanceof InfiniteRepetitionQuantifier
|
||||
|
|
||||
s order by getTermLocationString(s.getRepr())
|
||||
s order by getTermLocationString(s.getRepr()), s.getRepr().toString()
|
||||
)
|
||||
)
|
||||
}
|
||||
|
||||
Reference in New Issue
Block a user