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reject out-of-range quantifier counts in RegexParser #64

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reject out-of-range quantifier counts in RegexParser #64

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8 changes: 4 additions & 4 deletions src/main/java/org/apache/xmlbeans/impl/regex/RegexParser.java
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Original file line number Diff line number Diff line change
Expand Up @@ -604,9 +604,9 @@ Token parseFactor() throws ParseException {
min = ch -'0';
while (off < this.regexlen
&& (ch = this.regex.charAt(off++)) >= '0' && ch <= '9') {
min = min*10 +ch-'0';
if (min < 0)
if (min > (Integer.MAX_VALUE - (ch-'0')) / 10)
throw ex("parser.quantifier.5", this.offset);
min = min*10 +ch-'0';
}
}
else {
Expand All @@ -625,9 +625,9 @@ else if ((ch = this.regex.charAt(off++)) >= '0' && ch <= '9') {
while (off < this.regexlen
&& (ch = this.regex.charAt(off++)) >= '0'
&& ch <= '9') {
max = max*10 +ch-'0';
if (max < 0)
if (max > (Integer.MAX_VALUE - (ch-'0')) / 10)
throw ex("parser.quantifier.5", this.offset);
max = max*10 +ch-'0';
}

if (min > max)
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19 changes: 19 additions & 0 deletions src/test/java/misc/checkin/RegularExpressionTest.java
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Expand Up @@ -15,12 +15,14 @@

package misc.checkin;

import org.apache.xmlbeans.impl.regex.ParseException;
import org.apache.xmlbeans.impl.regex.RegularExpression;
import org.junit.jupiter.api.Test;

import java.util.Random;

import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;

public class RegularExpressionTest {
Expand All @@ -44,6 +46,23 @@ void testLookbehindRangeAtInputEnd() {
assertFalse(new RegularExpression("x(?<=[a-c])").matches("xc"));
}

@Test
void testQuantifierOverflow() {
// a {min,max} count larger than Integer.MAX_VALUE overflowed the int
// accumulator. the only guard was a post-multiply min<0/max<0 check, so
// counts that wrapped to a non-negative value slipped through: "a{4294967296}"
// parsed as "a{0}" (matched the empty string) and "a{1,4294967298}" as "a{1,2}",
// while bigger ones such as "a{99999999999}" blew the heap at match time.
assertThrows(ParseException.class, () -> new RegularExpression("a{4294967296}"));
assertThrows(ParseException.class, () -> new RegularExpression("a{4294967297}"));
assertThrows(ParseException.class, () -> new RegularExpression("a{99999999999}"));
assertThrows(ParseException.class, () -> new RegularExpression("a{1,4294967298}"));
// counts up to Integer.MAX_VALUE are representable and must still parse
new RegularExpression("a{2147483647}");
new RegularExpression("a{0,2147483647}");
assertTrue(new RegularExpression("a{2,4}").matches("aaa"));
}


private static final String AB = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
private static final Random rnd = new Random();
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