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8282252: Improve BigInteger/Decimal validation

Browse source 
Reviewed-by: jboes, rhalade, skoivu, bpb, smarks
This commit is contained in:
Joe Darcy 2022-03-14 23:39:22 +00:00 • committed by Henry Jen
parent ecfb6bce5a
commit 25e88b21af
5 changed files with 378 additions and 57 deletions
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63
src/java.base/share/classes/java/math/BigDecimal.java
View file

@ -31,6 +31,10 @@ package java.math;
import static java.math.BigInteger.LONG_MASK;
import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.ObjectStreamException;
import java.io.StreamCorruptedException;
import java.util.Arrays;
import java.util.Objects;
@ -1047,6 +1051,15 @@ public class BigDecimal extends Number implements Comparable<BigDecimal> {
this.precision = prec;
}
/**
* Accept no subclasses.
*/
private static BigInteger toStrictBigInteger(BigInteger val) {
return (val.getClass() == BigInteger.class) ?
val :
new BigInteger(val.toByteArray().clone());
}
/**
* Translates a {@code BigInteger} into a {@code BigDecimal}.
* The scale of the {@code BigDecimal} is zero.
@ -1056,8 +1069,8 @@ public class BigDecimal extends Number implements Comparable<BigDecimal> {
*/
public BigDecimal(BigInteger val) {
scale = 0;
intVal = val;
intCompact = compactValFor(val);
intVal = toStrictBigInteger(val);
intCompact = compactValFor(intVal);
}
/**
@ -1071,7 +1084,7 @@ public class BigDecimal extends Number implements Comparable<BigDecimal> {
* @since 1.5
*/
public BigDecimal(BigInteger val, MathContext mc) {
this(val,0,mc);
this(toStrictBigInteger(val), 0, mc);
}
/**
@ -1085,8 +1098,8 @@ public class BigDecimal extends Number implements Comparable<BigDecimal> {
*/
public BigDecimal(BigInteger unscaledVal, int scale) {
// Negative scales are now allowed
this.intVal = unscaledVal;
this.intCompact = compactValFor(unscaledVal);
this.intVal = toStrictBigInteger(unscaledVal);
this.intCompact = compactValFor(this.intVal);
this.scale = scale;
}
@ -1104,6 +1117,7 @@ public class BigDecimal extends Number implements Comparable<BigDecimal> {
* @since 1.5
*/
public BigDecimal(BigInteger unscaledVal, int scale, MathContext mc) {
unscaledVal = toStrictBigInteger(unscaledVal);
long compactVal = compactValFor(unscaledVal);
int mcp = mc.precision;
int prec = 0;
@ -4253,9 +4267,13 @@ public class BigDecimal extends Number implements Comparable<BigDecimal> {
= unsafe.objectFieldOffset(BigDecimal.class, "intCompact");
private static final long intValOffset
= unsafe.objectFieldOffset(BigDecimal.class, "intVal");
private static final long scaleOffset
= unsafe.objectFieldOffset(BigDecimal.class, "scale");
static void setIntCompact(BigDecimal bd, long val) {
unsafe.putLong(bd, intCompactOffset, val);
static void setIntValAndScale(BigDecimal bd, BigInteger intVal, int scale) {
unsafe.putReference(bd, intValOffset, intVal);
unsafe.putInt(bd, scaleOffset, scale);
unsafe.putLong(bd, intCompactOffset, compactValFor(intVal));
}
static void setIntValVolatile(BigDecimal bd, BigInteger val) {
@ -4274,15 +4292,30 @@ public class BigDecimal extends Number implements Comparable<BigDecimal> {
@java.io.Serial
private void readObject(java.io.ObjectInputStream s)
throws IOException, ClassNotFoundException {
// Read in all fields
s.defaultReadObject();
// validate possibly bad fields
if (intVal == null) {
String message = "BigDecimal: null intVal in stream";
throw new java.io.StreamCorruptedException(message);
// [all values of scale are now allowed]
// prepare to read the fields
ObjectInputStream.GetField fields = s.readFields();
BigInteger serialIntVal = (BigInteger) fields.get("intVal", null);
// Validate field data
if (serialIntVal == null) {
throw new StreamCorruptedException("Null or missing intVal in BigDecimal stream");
}
UnsafeHolder.setIntCompact(this, compactValFor(intVal));
// Validate provenance of serialIntVal object
serialIntVal = toStrictBigInteger(serialIntVal);
// Any integer value is valid for scale
int serialScale = fields.get("scale", 0);
UnsafeHolder.setIntValAndScale(this, serialIntVal, serialScale);
}
/**
* Serialization without data not supported for this class.
*/
@java.io.Serial
private void readObjectNoData()
throws ObjectStreamException {
throw new InvalidObjectException("Deserialized BigDecimal objects need data");
}
/**

47
src/java.base/share/classes/java/math/BigInteger.java
View file

@ -30,9 +30,11 @@
package java.math;
import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectStreamField;
import java.io.ObjectStreamException;
import java.util.Arrays;
import java.util.Objects;
import java.util.Random;
@ -4836,17 +4838,21 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
// prepare to read the alternate persistent fields
ObjectInputStream.GetField fields = s.readFields();
// Read the alternate persistent fields that we care about
int sign = fields.get("signum", -2);
byte[] magnitude = (byte[])fields.get("magnitude", null);
// Read and validate the alternate persistent fields that we
// care about, signum and magnitude
// Validate signum
// Read and validate signum
int sign = fields.get("signum", -2);
if (sign < -1 || sign > 1) {
String message = "BigInteger: Invalid signum value";
if (fields.defaulted("signum"))
message = "BigInteger: Signum not present in stream";
throw new java.io.StreamCorruptedException(message);
}
// Read and validate magnitude
byte[] magnitude = (byte[])fields.get("magnitude", null);
magnitude = magnitude.clone(); // defensive copy
int[] mag = stripLeadingZeroBytes(magnitude, 0, magnitude.length);
if ((mag.length == 0) != (sign == 0)) {
String message = "BigInteger: signum-magnitude mismatch";
@ -4855,18 +4861,24 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
throw new java.io.StreamCorruptedException(message);
}
// Commit final fields via Unsafe
UnsafeHolder.putSign(this, sign);
// Calculate mag field from magnitude and discard magnitude
UnsafeHolder.putMag(this, mag);
if (mag.length >= MAX_MAG_LENGTH) {
try {
checkRange();
} catch (ArithmeticException e) {
throw new java.io.StreamCorruptedException("BigInteger: Out of the supported range");
}
// Equivalent to checkRange() on mag local without assigning
// this.mag field
if (mag.length > MAX_MAG_LENGTH ||
(mag.length == MAX_MAG_LENGTH && mag[0] < 0)) {
throw new java.io.StreamCorruptedException("BigInteger: Out of the supported range");
}
// Commit final fields via Unsafe
UnsafeHolder.putSignAndMag(this, sign, mag);
}
/**
* Serialization without data not supported for this class.
*/
@java.io.Serial
private void readObjectNoData()
throws ObjectStreamException {
throw new InvalidObjectException("Deserialized BigInteger objects need data");
}
// Support for resetting final fields while deserializing
@ -4878,11 +4890,8 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
private static final long magOffset
= unsafe.objectFieldOffset(BigInteger.class, "mag");
static void putSign(BigInteger bi, int sign) {
static void putSignAndMag(BigInteger bi, int sign, int[] magnitude) {
unsafe.putInt(bi, signumOffset, sign);
}
static void putMag(BigInteger bi, int[] magnitude) {
unsafe.putReference(bi, magOffset, magnitude);
}
}