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Fix infinite loop due to integer overflow when reading large strings #1350

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Fix infinite loop due to integer overflow when reading large strings #1350

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19fa4b8
Fix infinite loop due to integer overflow when reading large strings
adamjshook Oct 21, 2024
0c96b0a
Add TestLargeString.java
adamjshook Oct 21, 2024
f6034ce
Merge branch '2.19' into 2.19
cowtowncoder Oct 22, 2024
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9 changes: 8 additions & 1 deletion src/main/java/com/fasterxml/jackson/core/json/UTF8StreamJsonParser.java
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Original file line number Diff line number Diff line change
Expand Up @@ -2544,7 +2544,14 @@ private final void _finishString2(char[] outBuf, int outPtr)
outBuf = _textBuffer.finishCurrentSegment();
outPtr = 0;
}
final int max = Math.min(_inputEnd, (ptr + (outBuf.length - outPtr)));

int max;
try {
max = Math.min(_inputEnd, Math.addExact(ptr, outBuf.length - outPtr));
} catch (ArithmeticException ex) {
max = Integer.MAX_VALUE;
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Is there any way that this could be set to something like the StreamReadConstraints max number size? For people who might set a bigger max number size but that don't go for the absolute max.

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eg would _inputEnd work?

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Yes, either _inputEnd or _streamReadConstraints.getMaxStringLength() will fix the issue. Do you have a preference?

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min of both?

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actually, looking at the code Integer.MAX_VALUE looks like a good fallback

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Okay, I think Integer.MAX_VALUE would be fine since we're just trying to prevent an overflow here. max would generally be larger than the max string length or _inputEnd. Verification that we don't go beyond the max string length happens when data is read.

}

while (ptr < max) {
c = inputBuffer[ptr++] & 0xFF;
if (codes[c] != 0) {
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32 changes: 32 additions & 0 deletions src/test/java/com/fasterxml/jackson/core/json/TestLargeString.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,32 @@
package com.fasterxml.jackson.core.json;

import com.fasterxml.jackson.core.*;
import net.bytebuddy.utility.RandomString;
import org.junit.jupiter.api.Test;

import java.io.ByteArrayOutputStream;

import static org.junit.jupiter.api.Assertions.assertEquals;

class TestLargeString extends JUnit5TestBase {

@Test
void testLargeStringDeserialization() throws Exception
{
String largeString = RandomString.make(Integer.MAX_VALUE - 1024);
JsonFactory f = JsonFactory.builder()
.streamReadConstraints(StreamReadConstraints.builder()
.maxStringLength(Integer.MAX_VALUE)
.build())
.build();
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
JsonGenerator g = f.createGenerator(bytes);
g.writeString(largeString);
g.close();

JsonParser parser = f.createParser(bytes.toByteArray());
String parsedString = parser.nextTextValue();

assertEquals(largeString, parsedString);
}
}
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