Merge pull request #63 from cconlon/infer

Fix potential deadlock / thread safety issues reported by Infer

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

@@ -233,7 +233,8 @@ public class WolfCryptKeyAgreement extends KeyAgreementSpi {
                         "shared secret");
                 }
 
-                tmp = this.dh.makeSharedSecret(this.dh);
+                /* public key has been stored inside this.dh already */
+                tmp = this.dh.makeSharedSecret();
                 if (tmp == null) {
                     throw new RuntimeException("Error when creating DH " +
                             "shared secret");

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

@@ -233,6 +233,29 @@ public class Dh extends NativeStruct {
         }
     }
 
+    /**
+     * Generate DH shared secret using private and public key stored in
+     * this object.
+     *
+     * @return shared secret as byte array
+     *
+     * @throws WolfCryptException if native operation fails
+     * @throws IllegalStateException if this object has no stored private
+     *         and public keys
+     */
+    public synchronized byte[] makeSharedSecret()
+        throws WolfCryptException, IllegalStateException {
+
+        byte[] publicKey = getPublicKey();
+
+        if (publicKey == null) {
+            throw new IllegalStateException(
+                "Dh object has no public key");
+        }
+
+        return makeSharedSecret(publicKey);
+    }
+
     /**
      * Generate DH shared secret
      *
@@ -246,15 +269,42 @@ public class Dh extends NativeStruct {
     public synchronized byte[] makeSharedSecret(Dh pubKey)
         throws WolfCryptException, IllegalStateException {
 
-        byte[] publicKey = pubKey.getPublicKey();
+        byte[] publicKey = null;
 
-        if (privateKey != null || publicKey != null) {
+        if (pubKey == null) {
-            synchronized (pointerLock) {
-                return wc_DhAgree(privateKey, publicKey);
-            }
-        } else {
             throw new IllegalStateException(
-                "No available key to perform the operation");
+                "Provided public key is null");
+        }
+
+        return makeSharedSecret(pubKey.getPublicKey());
+    }
+
+    /**
+     * Generate DH shared secret using internal private key and
+     * externally-provided public key as byte array.
+     *
+     * @param pubKey public key to use for secret generation
+     *
+     * @return shared secret as byte array
+     *
+     * @throws WolfCryptException if native operation fails
+     * @throws IllegalStateException if object has no key
+     */
+    public synchronized byte[] makeSharedSecret(byte[] pubKey)
+        throws WolfCryptException, IllegalStateException {
+
+        if (pubKey == null) {
+            throw new IllegalStateException(
+                "Provided public key is null");
+        }
+
+        if (this.privateKey == null) {
+            throw new IllegalStateException(
+                "Dh object has no private key");
+        }
+
+        synchronized (pointerLock) {
+            return wc_DhAgree(this.privateKey, pubKey);
         }
     }
 }

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

@@ -52,8 +52,10 @@ public abstract class NativeStruct extends WolfObject {
      * @return pointer to native structure
      */
     public long getNativeStruct() {
+        synchronized (pointerLock) {
             return this.pointer;
         }
+    }
 
     /**
      * Set pointer to native structure

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

@@ -201,12 +201,12 @@ public class Rsa extends NativeStruct {
      */
     protected void willUseKey(boolean priv) throws IllegalStateException {
 
+        synchronized (stateLock) {
             if (priv && !hasPrivateKey) {
                 throw new IllegalStateException(
                         "No available private key to perform the operation");
             }
 
-        synchronized (stateLock) {
             if (state != WolfCryptState.READY) {
                 throw new IllegalStateException(
                         "No available key to perform the operation");