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LUCENE-3820: limiting the amount of input for pattern matching to go past exponential time patterns, even if they happen. A nice catch from Mike too -- un-ignore testNastyPattern and look at processing time go wild with each additional input character... 

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1294797 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Dawid Weiss 2012-02-28 19:26:05 +00:00
parent 6f40a126e6
commit 8c2e3cef8f
1 changed files with 26 additions and 4 deletions
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28
modules/analysis/common/src/test/org/apache/lucene/analysis/pattern/TestPatternReplaceCharFilter.java
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@ -20,6 +20,7 @@ package org.apache.lucene.analysis.pattern;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;
@ -31,6 +32,7 @@ import org.apache.lucene.analysis.MockTokenizer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.util._TestUtil;
import org.junit.Ignore;
/**
* Tests {@link PatternReplaceCharFilter}
@ -276,6 +278,26 @@ public class TestPatternReplaceCharFilter extends BaseTokenStreamTestCase {
return Pattern.compile( p );
}
/**
* A demonstration of how backtracking regular expressions can lead to relatively
* easy DoS attacks.
*
* @see "http://swtch.com/~rsc/regexp/regexp1.html"
*/
@Ignore
public void testNastyPattern() throws Exception {
Pattern p = Pattern.compile("(c.+)*xy");
String input = "[;<!--aecbbaa-->< febcfdc fbb = \"fbeeebff\" fc = dd >\\';<eefceceaa e= babae\" eacbaff =\"fcfaccacd\" = bcced>>>< bccaafe edb = ecfccdff\" <?</script>< edbd ebbcd=\"faacfcc\" aeca= bedbc ceeaac =adeafde aadccdaf = \"afcc ffda=aafbe &#x16921ed5\"1843785582']";
for (int i = 0; i < input.length(); i++) {
Matcher matcher = p.matcher(input.substring(0, i));
long t = System.currentTimeMillis();
if (matcher.find()) {
System.out.println(matcher.group());
}
System.out.println(i + " > " + (System.currentTimeMillis() - t) / 1000.0);
}
}
/** blast some random strings through the analyzer */
public void testRandomStrings() throws Exception {
int numPatterns = atLeast(100);
@ -296,9 +318,9 @@ public class TestPatternReplaceCharFilter extends BaseTokenStreamTestCase {
return new PatternReplaceCharFilter(p, replacement, CharReader.get(reader));
}
};
long s = System.currentTimeMillis();
checkRandomData(random, a, 1000 * RANDOM_MULTIPLIER, true); // only ascii
System.out.println((System.currentTimeMillis() - s) / 1000.0 + " > " + p);
checkRandomData(random, a, 1000 * RANDOM_MULTIPLIER,
/* max input length. don't make it longer -- exponential processing
* time for certain patterns. */ 40, true); // only ascii
}
}