fix catastrophic backtracking in email domain regex (#2099)

1 files changed, 11 insertions, 0 deletions

diff --git a/core/src/test/java/com/google/zxing/client/result/EmailAddressParsedResultTestCase.java b/core/src/test/java/com/google/zxing/client/result/EmailAddressParsedResultTestCase.java
index ea79c4272..d900d1ddc 100644
--- a/core/src/test/java/com/google/zxing/client/result/EmailAddressParsedResultTestCase.java
+++ b/core/src/test/java/com/google/zxing/client/result/EmailAddressParsedResultTestCase.java
@@ -52,6 +52,17 @@ public final class EmailAddressParsedResultTestCase extends Assert {
     assertTrue(EmailDoCoMoResultParser.isBasicallyValidEmailAddress("建設省.aZ456@Ab-cd9Z.co"));
   }
 
+  // A long run of address characters that never completes a valid domain must be rejected
+  // quickly; the previous pattern backtracked super-linearly on such input.
+  @Test(timeout = 5000L)
+  public void testNoCatastrophicBacktracking() {
+    StringBuilder sb = new StringBuilder("x@");
+    for (int i = 0; i < 5000; i++) {
+      sb.append('a');
+    }
+    assertFalse(EmailDoCoMoResultParser.isBasicallyValidEmailAddress(sb.toString()));
+  }
+
   @Test
   public void testEmailAddress() {
     doTest("srowen@example.org", "srowen@example.org", null, null);