Hello.
I would like to contribute for JDK-8216012.
The cause of this problem is RSAKeyPairGenerator that doesn't check
the public exponent even though the algorithm of rsa key generation
can use only odd exponent number.
To generate a KeyPair, the RSAKeyPairGenerator finds two random primes
P and Q, and calculate Phi = (P - 1) * (Q - 1). If Phi is not relative
prime to exponent, RSAKeyPairGenerator retry from the first.
The value of Phi must be an even number because P and Q are odd numbers.
If exponent is an even number, the greatest common divisor cannot
be 1 because one of common divisors is 2 which is bigger than 1.
Therefore, generateKeyPair() method of RSAKeyPairGenerator cannot exit
the retrying loop.
To solve this problem, I propose to check whether the public exponent
is even number.
Please sponsor the following change.
diff --git
a/src/java.base/share/classes/sun/security/rsa/RSAKeyPairGenerator.java
b/src/java.base/share/classes/sun/security/rsa/RSAKeyPairGenerator.java
---
a/src/java.base/share/classes/sun/security/rsa/RSAKeyPairGenerator.java
+++
b/src/java.base/share/classes/sun/security/rsa/RSAKeyPairGenerator.java
@@ -96,6 +96,10 @@
throw new InvalidAlgorithmParameterException
("Public exponent must be 3 or larger");
}
+ if (!tmpPublicExponent.testBit(0)) {
+ throw new InvalidAlgorithmParameterException
+ ("Public exponent must be an odd number");
+ }
if (tmpPublicExponent.bitLength() > tmpKeySize) {
throw new InvalidAlgorithmParameterException
("Public exponent must be smaller than key
size");
diff --git
a/test/jdk/sun/security/rsa/TestKeyPairGeneratorExponent.java
b/test/jdk/sun/security/rsa/TestKeyPairGeneratorExponent.java
new file mode 100644
--- /dev/null
+++ b/test/jdk/sun/security/rsa/TestKeyPairGeneratorExponent.java
@@ -0,0 +1,65 @@
+import java.math.BigInteger;
+
+import java.security.*;
+import java.security.interfaces.*;
+import java.security.spec.*;
+
+/**
+ * @test
+ * @bug 8216012
+ * @summary Tests the RSA public key exponent for KeyPairGenerator
+ * @run main/timeout=60 TestKeyPairGeneratorExponent
+ */
+public class TestKeyPairGeneratorExponent {
+ private static int keyLen = 512;
+
+ private static BigInteger[] validExponents = new BigInteger[] {
+ RSAKeyGenParameterSpec.F0,
+ RSAKeyGenParameterSpec.F4,
+ // Since 512-bit exponent is larger than modulus, fails in
RSAPublicKeyImpl.checkExponentRange().
+ BigInteger.ONE.shiftLeft(keyLen - 1).subtract(BigInteger.ONE)
+ };
+
+ private static BigInteger[] invalidExponents = new BigInteger[] {
+ BigInteger.valueOf(-1),
+ BigInteger.ZERO,
+ BigInteger.ONE,
+ // 8216012: An even number causes infinite loop.
+ BigInteger.valueOf(4),
+ BigInteger.ONE.shiftLeft(keyLen)
+ };
+
+ public static void testValidExponents(KeyPairGenerator kpg,
BigInteger exponent) {
+ try {
+ kpg.initialize(new RSAKeyGenParameterSpec(keyLen,
exponent));
+ kpg.generateKeyPair();
+ } catch(InvalidAlgorithmParameterException iape){
+ throw new RuntimeException("Unexpected Exception: " +
iape);
+ }
+ }
+
+ public static void testInvalidExponents(KeyPairGenerator kpg,
BigInteger exponent) {
+ try {
+ kpg.initialize(new RSAKeyGenParameterSpec(keyLen,
exponent));
+ kpg.generateKeyPair();
+ throw new RuntimeException("Expected
InvalidAlgorithmParameterException was not thrown.");
+ } catch(InvalidAlgorithmParameterException iape){
+ // Expected InvalidAlgorithmParameterException was
thrown.OK
+ }
+ }
+
+ public static void main(String[] args) throws Exception {
+ Provider provider = Security.getProvider("SunRsaSign");
+ KeyPairGenerator kpg;
+
+ for(BigInteger validExponent : validExponents) {
+ kpg = KeyPairGenerator.getInstance("RSA", provider);
+ testValidExponents(kpg, validExponent);
+ }
+
+ for(BigInteger invalidExponent : invalidExponents) {
+ kpg = KeyPairGenerator.getInstance("RSA", provider);
+ testInvalidExponents(kpg, invalidExponent);
+ }
+ }
+}
Regards,
Masanori Yano
