Catch exception and return false in cases where std::regex_match thro…

…ws. (#10861) Signed-off-by: Antonio Vicente <avd@google.com>
envoyproxy · Apr 21, 2020 · b268183 · b268183
1 parent ed55058
commit b268183
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diff --git a/source/common/common/regex.cc b/source/common/common/regex.cc
@@ -19,7 +19,11 @@ class CompiledStdMatcher : public CompiledMatcher {
 
  // CompiledMatcher
  bool match(absl::string_view value) const override {
- return std::regex_match(value.begin(), value.end(), regex_);
+ try {
+ return std::regex_match(value.begin(), value.end(), regex_);
+ } catch (const std::regex_error& e) {
+ return false;
+ }
  }
 
  // CompiledMatcher

diff --git a/test/common/common/regex_test.cc b/test/common/common/regex_test.cc
@@ -15,6 +15,9 @@ TEST(Utility, ParseStdRegex) {
  EXPECT_THROW_WITH_REGEX(Utility::parseStdRegex("(+invalid)"), EnvoyException,
  "Invalid regex '\\(\\+invalid\\)': .+");
 
+ EXPECT_THROW_WITH_REGEX(Utility::parseStdRegexAsCompiledMatcher("(+invalid)"), EnvoyException,
+ "Invalid regex '\\(\\+invalid\\)': .+");
+
  {
  std::regex regex = Utility::parseStdRegex("x*");
  EXPECT_NE(0, regex.flags() & std::regex::optimize);
@@ -25,6 +28,15 @@ TEST(Utility, ParseStdRegex) {
  EXPECT_NE(0, regex.flags() & std::regex::icase);
  EXPECT_EQ(0, regex.flags() & std::regex::optimize);
  }
+
+ {
+ // Regression test to cover high-complexity regular expressions that throw on std::regex_match.
+ // Note that not all std::regex_match implementations will throw when matching against the
+ // expression below, but at least clang 9.0.0 under linux does.
+ auto matcher = Utility::parseStdRegexAsCompiledMatcher(
+ "|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||");
+ EXPECT_FALSE(matcher->match("0"));
+ }
 }
 
 TEST(Utility, ParseRegex) {