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Fix NegativeArraySizeException in PfbParser #412

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Fix NegativeArraySizeException in PfbParser #412

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2 changes: 1 addition & 1 deletion fontbox/src/main/java/org/apache/fontbox/pfb/PfbParser.java
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Original file line number Diff line number Diff line change
Expand Up @@ -154,7 +154,7 @@ private void parsePfb(final byte[] pfb) throws IOException
size += in.read() << 16;
size += in.read() << 24;
LOG.debug("record type: {}, segment size: {}", recordType, size);
if (size > pfb.length)
if (size < 0 || size > pfb.length)
{
// PDFBOX-6044: avoid potential OOM
throw new IOException("record size " + size + " would be larger than the input");
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21 changes: 21 additions & 0 deletions fontbox/src/test/java/org/apache/fontbox/pfb/PfbParserTest.java
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Expand Up @@ -101,4 +101,25 @@ void testEmpty()
{
Assertions.assertThrows(IOException.class, () -> Type1Font.createWithPFB(new byte[0]));
}

/**
* Test that a PFB with a negative size field (integer overflow) throws IOException
* instead of NegativeArraySizeException. A crafted 18-byte PFB with size bytes
* 01 00 00 FF overflows the signed int to -16777215, bypassing the upper-bound check.
*/
@Test
void testNegativeRecordSize()
{
// 18-byte crafted PFB: start marker 0x80, ASCII type 0x01,
// size field 0x01 0x00 0x00 0xFF = -16777215 as signed int
byte[] crashInput = {
(byte) 0x80, 0x01, // header
0x01, 0x00, 0x00, (byte) 0xFF, // size: overflows to negative
(byte) 0xFF, (byte) 0xFF, (byte) 0xFF, // garbage data
(byte) 0xFF, (byte) 0xFF, (byte) 0xFF,
0x27, 0x05, (byte) 0xF8, (byte) 0xFF,
(byte) 0xD2, 0x40
};
Assertions.assertThrows(IOException.class, () -> new PfbParser(crashInput));
}
}