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fix: guard exponent parsing against end-of-input in readNumber0 #7832

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fix: guard exponent parsing against end-of-input in readNumber0 #7832

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12 changes: 9 additions & 3 deletions core/src/main/java/com/alibaba/fastjson2/JSONReaderUTF16.java
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Original file line number Diff line number Diff line change
Expand Up @@ -4005,16 +4005,18 @@ public final void readNumber0() {
if (ch == 'e' || ch == 'E') {
boolean negativeExp = false;
int expValue = 0;
ch = chars[offset++];
boolean expValid = false;
ch = offset == end ? EOI : chars[offset++];

if (ch == '-') {
negativeExp = true;
ch = chars[offset++];
ch = offset == end ? EOI : chars[offset++];
} else if (ch == '+') {
ch = chars[offset++];
ch = offset == end ? EOI : chars[offset++];
}

while (ch >= '0' && ch <= '9') {
expValid = true;
valid = true;
int byteVal = (ch - '0');
expValue = expValue * 10 + byteVal;
Expand All @@ -4033,6 +4035,10 @@ public final void readNumber0() {
expValue = -expValue;
}

if (!expValid) {
throw new JSONException(info("illegal input"));
}

this.exponent = (short) expValue;
if (valueType != JSON_TYPE_BIG_DEC) {
valueType = JSON_TYPE_DEC;
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12 changes: 9 additions & 3 deletions core/src/main/java/com/alibaba/fastjson2/JSONReaderUTF8.java
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Original file line number Diff line number Diff line change
Expand Up @@ -5484,16 +5484,18 @@ public final void readNumber0() {
if (ch == 'e' || ch == 'E') {
boolean negativeExp = false;
int expValue = 0;
ch = bytes[offset++];
boolean expValid = false;
ch = offset == end ? EOI : bytes[offset++];

if (ch == '-') {
negativeExp = true;
ch = bytes[offset++];
ch = offset == end ? EOI : bytes[offset++];
} else if (ch == '+') {
ch = (char) bytes[offset++];
ch = offset == end ? EOI : bytes[offset++];
}

while (ch >= '0' && ch <= '9') {
expValid = true;
valid = true;
int byteVal = (ch - '0');
expValue = expValue * 10 + byteVal;
Expand All @@ -5512,6 +5514,10 @@ public final void readNumber0() {
expValue = -expValue;
}

if (!expValid) {
throw new JSONException(info("illegal input"));
}

this.exponent = (short) expValue;
if (valueType != JSON_TYPE_BIG_DEC) {
valueType = JSON_TYPE_DEC;
Expand Down
32 changes: 32 additions & 0 deletions core/src/test/java/com/alibaba/fastjson2/issues_7000/Issue7807.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,32 @@
package com.alibaba.fastjson2.issues_7000;

import com.alibaba.fastjson2.JSON;
import com.alibaba.fastjson2.JSONException;
import org.junit.jupiter.api.Test;

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

/**
* Issue 7807: JSON.parse on a document that ends inside a number's exponent
* throws ArrayIndexOutOfBoundsException instead of JSONException.
*
* Regression: readNumber0 reads the exponent sign/digits without an
* end-of-input guard, so "1e", "1e-" and "1e+" (and their uppercase / fraction
* variants) overflow the byte/char buffer.
*/
public class Issue7807 {
@Test
public void testTruncatedExponentThrowsJSONException() {
String[] inputs = {
"1e", "1E",
"1e-", "1E-", "1e+", "1E+",
"1.0e", "1.0E", "1.0e-", "1.0e+",
"-1e", "-1E", "-1e-", "-1e+",
};
for (String input : inputs) {
assertThrows(JSONException.class,
() -> JSON.parse(input),
"expected JSONException for input: " + input);
}
}
}