JCE: throw correct IllegalArgumentException from WolfCryptRandom.engineGenerateSeed(), add HashDRBG aliases Hash_DRBG and DRBG

Author: cconlon

README_JCE.md

@@ -99,7 +99,7 @@ The JCE provider currently supports the following algorithms:
 
     SecureRandom Class
         DEFAULT (maps to HashDRBG)
-        HashDRBG
+        HashDRBG (aliased also as: Hash_DRBG, DRBG)
 
     Cipher Class
         AES/CBC/NoPadding

jni/include/com_wolfssl_wolfcrypt_Rng.h

@@ -132,12 +132,17 @@ JNIEXPORT void JNICALL Java_com_wolfssl_wolfcrypt_Rng_rngGenerateBlock__Ljava_ni
 
     buffer = getDirectBufferAddress(env, buffer_buffer);
 
-    ret = (!rng || !buffer)
-        ? BAD_FUNC_ARG
-        : wc_RNG_GenerateBlock(rng, buffer + position, size);
+    if (rng == NULL || buffer == NULL) {
+        ret = BAD_FUNC_ARG;
+    }
 
-    if (ret != 0)
+    if (ret == 0) {
+        ret = wc_RNG_GenerateBlock(rng, buffer + position, size);
+    }
+
+    if (ret != 0) {
         throwWolfCryptExceptionFromError(env, ret);
+    }
 
     LogStr("wc_RNG_GenerateBlock(rng=%p, buffer, size) = %d\n", rng, ret);
     LogStr("output[%u]: [%p]\n", (word32)size, buffer);
@@ -164,11 +169,17 @@ JNIEXPORT void JNICALL Java_com_wolfssl_wolfcrypt_Rng_rngGenerateBlock___3BII(
 
     buffer = getByteArray(env, buffer_buffer);
 
-    ret = (!rng || !buffer)
-        ? BAD_FUNC_ARG
-        : wc_RNG_GenerateBlock(rng, buffer + offset, length);
-    if (ret != 0)
+    if (rng == NULL || buffer == NULL) {
+        ret = BAD_FUNC_ARG;
+    }
+
+    if (ret == 0) {
+        ret = wc_RNG_GenerateBlock(rng, buffer + offset, length);
+    }
+
+    if (ret != 0) {
         throwWolfCryptExceptionFromError(env, ret);
+    }
 
     LogStr("wc_RNG_GenerateBlock(rng=%p, buffer, length) = %d\n", rng, ret);
     LogStr("output[%u]: [%p]\n", (word32)length, buffer);
@@ -180,3 +191,9 @@ JNIEXPORT void JNICALL Java_com_wolfssl_wolfcrypt_Rng_rngGenerateBlock___3BII(
 #endif
 }
 
+JNIEXPORT jint JNICALL Java_com_wolfssl_wolfcrypt_Rng_getRNG_1MAX_1BLOCK_1LEN
+  (JNIEnv* env, jclass jcl)
+{
+    return RNG_MAX_BLOCK_LEN;
+}
+

jni/jni_rng.c

@@ -117,6 +117,10 @@ private void registerServices() {
                 "com.wolfssl.provider.jce.WolfCryptRandom");
         put("SecureRandom.HashDRBG",
                 "com.wolfssl.provider.jce.WolfCryptRandom");
+        put("SecureRandom.Hash_DRBG",
+                "com.wolfssl.provider.jce.WolfCryptRandom");
+        put("SecureRandom.DRBG",
+                "com.wolfssl.provider.jce.WolfCryptRandom");
 
         /* Signature */
         if (FeatureDetect.Md5Enabled()) {

src/main/java/com/wolfssl/provider/jce/WolfCryptProvider.java

@@ -52,7 +52,18 @@ public WolfCryptRandom() {
     }
 
     @Override
-    protected synchronized byte[] engineGenerateSeed(int numBytes) {
+    protected synchronized byte[] engineGenerateSeed(int numBytes)
+        throws IllegalArgumentException {
+
+        if (numBytes < 0) {
+            throw new IllegalArgumentException("numBytes must be non-negative");
+        }
+
+        if (numBytes > Rng.RNG_MAX_BLOCK_LEN) {
+            throw new IllegalArgumentException(
+                "numBytes too large. wolfCrypt max is " +
+                Rng.RNG_MAX_BLOCK_LEN);
+        }
 
         return rng.generateBlock(numBytes);
     }

src/main/java/com/wolfssl/provider/jce/WolfCryptRandom.java

@@ -28,6 +28,10 @@
  */
 public class Rng extends NativeStruct {
 
+    /* Maximum generate block length for wolfCrypt */
+    public static int RNG_MAX_BLOCK_LEN =
+        Rng.getRNG_MAX_BLOCK_LEN();
+
     /**
      * Malloc native JNI Rng structure
      *
@@ -45,6 +49,7 @@ public class Rng extends NativeStruct {
     private native void rngGenerateBlock(ByteBuffer buffer, int offset,
             int length);
     private native void rngGenerateBlock(byte[] buffer, int offset, int length);
+    private static native int getRNG_MAX_BLOCK_LEN();
 
     /* Lock to prevent concurrent access to native WC_RNG */
     private final Object rngLock = new Object();

src/main/java/com/wolfssl/wolfcrypt/Rng.java

@@ -79,6 +79,14 @@ public void testGetRandomFromProvider()
         /* DEFAULT */
         rand = SecureRandom.getInstance("DEFAULT", "wolfJCE");
         assertNotNull(rand);
+
+        /* Hash_DRBG alias */
+        rand = SecureRandom.getInstance("Hash_DRBG", "wolfJCE");
+        assertNotNull(rand);
+
+        /* DRBG alias */
+        rand = SecureRandom.getInstance("DRBG", "wolfJCE");
+        assertNotNull(rand);
     }
 
     @Test
@@ -279,5 +287,63 @@ public void testSetSeed()
         rand.setSeed(seed);
     }
 
+    @Test
+    public void testGenerateSeedWithNegativeArgument()
+        throws NoSuchProviderException, NoSuchAlgorithmException {
+
+        SecureRandom rand = SecureRandom.getInstance("HashDRBG", "wolfJCE");
+
+        try {
+            rand.generateSeed(-1);
+            fail("Expected IllegalArgumentException for negative seed length");
+
+        } catch (IllegalArgumentException e) {
+            /* Expected exception */
+        }
+    }
+
+    @Test
+    public void testGenerateSeedWithTooLargeArgument()
+        throws NoSuchProviderException, NoSuchAlgorithmException {
+
+        SecureRandom rand = SecureRandom.getInstance("HashDRBG", "wolfJCE");
+
+        /* Get the maximum block length from Rng class */
+        int maxLen = com.wolfssl.wolfcrypt.Rng.RNG_MAX_BLOCK_LEN;
+
+        try {
+            rand.generateSeed(maxLen + 1);
+            fail("Expected IllegalArgumentException for too large length");
+        } catch (IllegalArgumentException e) {
+            /* Expected exception */
+        }
+    }
+
+    @Test
+    public void testGenerateSeedWithValidMaxArgument()
+        throws NoSuchProviderException, NoSuchAlgorithmException {
+
+        SecureRandom rand = SecureRandom.getInstance("HashDRBG", "wolfJCE");
+
+        /* Get the maximum block length from Rng class */
+        int maxLen = com.wolfssl.wolfcrypt.Rng.RNG_MAX_BLOCK_LEN;
+
+        /* This should succeed */
+        byte[] seed = rand.generateSeed(maxLen);
+        assertNotNull(seed);
+        assertEquals(maxLen, seed.length);
+    }
+
+    @Test
+    public void testGenerateSeedWithZeroArgument()
+        throws NoSuchProviderException, NoSuchAlgorithmException {
+
+        SecureRandom rand = SecureRandom.getInstance("HashDRBG", "wolfJCE");
+
+        /* Zero length should be valid */
+        byte[] seed = rand.generateSeed(0);
+        assertNotNull(seed);
+        assertEquals(0, seed.length);
+    }
 }