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prevent regexp expansion size overflow #90

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Merged
headius merged 1 commit into from
Oct 26, 2026
+27 −4
Merged

prevent regexp expansion size overflow #90

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14 changes: 10 additions & 4 deletions src/org/joni/ArrayCompiler.java
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Original file line number Diff line number Diff line change
Expand Up @@ -443,6 +443,12 @@ private void compileRangeRepeatNode(QuantifierNode qn, int targetLen, int emptyI

private static final int QUANTIFIER_EXPAND_LIMIT_SIZE = 50; // was 50

// MRI: regcomp.c IS_EXPAND_LIMIT_OK (since Ruby 4.0.8; 3.4.12 and 3.3.13)
// prevent nested repeats from bypassing the limit and exhausting heap
private static boolean isExpandLimitOK(int tlen, int n) {
return n <= 0 || tlen <= QUANTIFIER_EXPAND_LIMIT_SIZE / n;
}

private static boolean cknOn(int ckn) {
return ckn > 0;
}
Expand Down Expand Up @@ -660,7 +666,7 @@ private int compileNonCECLengthQuantifierNode(QuantifierNode qn) {
}

int len;
if (infinite && (qn.lower <= 1 || tlen * qn.lower <= QUANTIFIER_EXPAND_LIMIT_SIZE)) {
if (infinite && (qn.lower <= 1 || isExpandLimitOK(tlen, qn.lower))) {
if (qn.lower == 1 && tlen > QUANTIFIER_EXPAND_LIMIT_SIZE) {
len = OPSize.JUMP;
} else {
Expand All @@ -682,7 +688,7 @@ private int compileNonCECLengthQuantifierNode(QuantifierNode qn) {
} else if (qn.upper == 0 && qn.isRefered) { /* /(?<n>..){0}/ */
len = OPSize.JUMP + tlen;
} else if (!infinite && qn.greedy &&
(qn.upper == 1 || (tlen + OPSize.PUSH) * qn.upper <= QUANTIFIER_EXPAND_LIMIT_SIZE )) {
(qn.upper == 1 || isExpandLimitOK(tlen + OPSize.PUSH, qn.upper))) {
len = tlen * qn.lower;
len += (OPSize.PUSH + tlen) * (qn.upper - qn.lower);
} else if (!qn.greedy && qn.upper == 1 && qn.lower == 0) { /* '??' */
Expand Down Expand Up @@ -728,7 +734,7 @@ protected void compileNonCECQuantifierNode(QuantifierNode qn) {
} else {
modTLen = tlen;
}
if (infinite && (qn.lower <= 1 || tlen * qn.lower <= QUANTIFIER_EXPAND_LIMIT_SIZE)) {
if (infinite && (qn.lower <= 1 || isExpandLimitOK(tlen, qn.lower))) {
if (qn.lower == 1 && tlen > QUANTIFIER_EXPAND_LIMIT_SIZE) {
if (qn.greedy) {
if (qn.headExact != null) {
Expand Down Expand Up @@ -772,7 +778,7 @@ protected void compileNonCECQuantifierNode(QuantifierNode qn) {
addOpcodeRelAddr(OPCode.JUMP, tlen);
compileTree(qn.target);
} else if (!infinite && qn.greedy &&
(qn.upper == 1 || (tlen + OPSize.PUSH) * qn.upper <= QUANTIFIER_EXPAND_LIMIT_SIZE)) {
(qn.upper == 1 || isExpandLimitOK(tlen + OPSize.PUSH, qn.upper))) {
int n = qn.upper - qn.lower;
compileTreeNTimes(qn.target, qn.lower);

Expand Down
17 changes: 17 additions & 0 deletions test/org/joni/test/TestCornerCases.java
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Original file line number Diff line number Diff line change
Expand Up @@ -19,9 +19,14 @@
*/
package org.joni.test;

import static org.junit.Assert.assertEquals;

import java.nio.charset.StandardCharsets;

import org.jcodings.Encoding;
import org.jcodings.specific.ASCIIEncoding;
import org.joni.Config;
import org.joni.Matcher;
import org.joni.Option;
import org.joni.Regex;
import org.joni.Syntax;
Expand Down Expand Up @@ -56,4 +61,16 @@ public void test() throws Exception {
nfail++;
}
}

@org.junit.Test(timeout = 30000)
public void testNestedRepeatExpansionOverflow() {
byte[] input = "xxxxxxxxxx".getBytes(StandardCharsets.US_ASCII);
for (String source : new String[]{"(?:.{90000,}){90000}", "(?:.{46341,}){46341}",
"(?:.{90000,}){90000,}", "(?:.{46341,}){46341,}"}) {
byte[] pattern = source.getBytes(StandardCharsets.US_ASCII);
Regex regex = new Regex(pattern, 0, pattern.length, Option.DEFAULT, ASCIIEncoding.INSTANCE, Syntax.DEFAULT);
assertEquals(source, Matcher.FAILED, regex.matcher(input).search(0, input.length, Option.NONE));
}
}

}
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