[fix] add Cipher#auth_data(arg) override (Rails 7.x compat)

Author: kares

src/main/java/org/jruby/ext/openssl/Cipher.java

@@ -715,7 +715,6 @@ public Cipher(Ruby runtime, RubyClass type) {
     private int generateKeyLength = -1;
     private int ivLength = -1;
     private boolean encryptMode = true;
-    //private IRubyObject[] modeParams;
     private boolean cipherInited = false;
     private byte[] key;
     private byte[] realIV;
@@ -1265,11 +1264,24 @@ public IRubyObject set_padding(IRubyObject padding) {
     }
 
     private transient ByteList auth_tag;
+    private int auth_tag_len = 16;
 
     @JRubyMethod(name = "auth_tag")
     public IRubyObject auth_tag(final ThreadContext context) {
+        return getAuthTag(context, auth_tag_len);
+    }
+
+    @JRubyMethod(name = "auth_tag")
+    public IRubyObject auth_tag(final ThreadContext context, IRubyObject tag_len) {
+        return getAuthTag(context, tag_len.convertToInteger().getIntValue());
+    }
+
+    private IRubyObject getAuthTag(final ThreadContext context, final int tag_len) {
         if ( auth_tag != null ) {
-            return RubyString.newString(context.runtime, auth_tag);
+            if (auth_tag.length() <= tag_len) {
+                return RubyString.newString(context.runtime, auth_tag);
+            }
+            return RubyString.newString(context.runtime, (ByteList) auth_tag.subSequence(0, tag_len));
         }
         if ( ! isAuthDataMode() ) {
             throw newCipherError(context.runtime, "authentication tag not supported by this cipher");
@@ -1287,14 +1299,18 @@ public IRubyObject set_auth_tag(final ThreadContext context, final IRubyObject t
         return auth_tag;
     }
 
+    @JRubyMethod(name = "auth_tag_len=")
+    public IRubyObject set_auth_tag_len(IRubyObject tag_len) {
+        this.auth_tag_len = tag_len.convertToInteger().getIntValue();
+        return tag_len;
+    }
+
     private boolean isAuthDataMode() { // Authenticated Encryption with Associated Data (AEAD)
         return "GCM".equalsIgnoreCase(cryptoMode) || "CCM".equalsIgnoreCase(cryptoMode);
     }
 
-    private static final int MAX_AUTH_TAG_LENGTH = 16;
-
     private int getAuthTagLength() {
-        return Math.min(MAX_AUTH_TAG_LENGTH, this.key.length); // in bytes
+        return Math.min(auth_tag_len, this.key.length); // in bytes
     }
 
     private transient ByteList auth_data;
@@ -1346,22 +1362,10 @@ public IRubyObject random_iv(final ThreadContext context) {
         this.set_iv(context, str); return str;
     }
 
-    //String getAlgorithm() {
-    //    return this.cipher.getAlgorithm();
-    //}
-
     final String getName() {
         return this.name;
     }
 
-    //String getCryptoBase() {
-    //    return this.cryptoBase;
-    //}
-
-    //String getCryptoMode() {
-    //    return this.cryptoMode;
-    //}
-
     final int getKeyLength() {
         return keyLength;
     }

src/test/ruby/test_cipher.rb

@@ -363,41 +363,39 @@ def test_aes_128_gcm
     #assert_equal "", cipher.final
   end
 
-  def test_aes_gcm
+  def test_aes_gcm_custom
     ['aes-128-gcm', 'aes-192-gcm', 'aes-256-gcm'].each do |algo|
       pt = "You should all use Authenticated Encryption!"
-      cipher, key, iv = new_encryptor(algo)
+      cipher, key, iv = new_random_encryptor(algo)
 
       cipher.auth_data = "aad"
       ct  = cipher.update(pt) + cipher.final
       tag = cipher.auth_tag
       assert_equal(16, tag.size)
 
-      decipher = new_decryptor(algo, key, iv)
+      decipher = new_decryptor(algo, key: key, iv: iv)
       decipher.auth_tag = tag
       decipher.auth_data = "aad"
 
       assert_equal(pt, decipher.update(ct) + decipher.final)
     end
   end
 
-  def new_encryptor(algo)
+  def test_authenticated
+    cipher = OpenSSL::Cipher.new('aes-128-gcm')
+    assert_predicate(cipher, :authenticated?)
+    cipher = OpenSSL::Cipher.new('aes-128-cbc')
+    assert_not_predicate(cipher, :authenticated?)
+  end
+
+  def new_random_encryptor(algo)
     cipher = OpenSSL::Cipher.new(algo)
     cipher.encrypt
     key = cipher.random_key
     iv = cipher.random_iv
     [cipher, key, iv]
   end
-  private :new_encryptor
-
-  def new_decryptor(algo, key, iv)
-    OpenSSL::Cipher.new(algo).tap do |cipher|
-      cipher.decrypt
-      cipher.key = key
-      cipher.iv = iv
-    end
-  end
-  private :new_decryptor
+  private :new_random_encryptor
 
   def test_aes_128_gcm_with_auth_tag
     cipher = OpenSSL::Cipher.new('aes-128-gcm')
@@ -498,4 +496,80 @@ def test_encrypt_aes_256_cbc_invalid_buffer
     assert_raise(TypeError) { cipher.update('bar' * 10, buffer) }
   end
 
+  def test_aes_gcm
+    # GCM spec Appendix B Test Case 4
+    key = ["feffe9928665731c6d6a8f9467308308"].pack("H*")
+    iv =  ["cafebabefacedbaddecaf888"].pack("H*")
+    aad = ["feedfacedeadbeeffeedfacedeadbeef" \
+           "abaddad2"].pack("H*")
+    pt =  ["d9313225f88406e5a55909c5aff5269a" \
+           "86a7a9531534f7da2e4c303d8a318a72" \
+           "1c3c0c95956809532fcf0e2449a6b525" \
+           "b16aedf5aa0de657ba637b39"].pack("H*")
+    ct =  ["42831ec2217774244b7221b784d0d49c" \
+           "e3aa212f2c02a4e035c17e2329aca12e" \
+           "21d514b25466931c7d8f6a5aac84aa05" \
+           "1ba30b396a0aac973d58e091"].pack("H*")
+    tag = ["5bc94fbc3221a5db94fae95ae7121a47"].pack("H*")
+
+    cipher = new_encryptor("aes-128-gcm", key: key, iv: iv, auth_data: aad)
+    # TODO JOpenSSL should raise
+    # assert_raise(OpenSSL::Cipher::CipherError, 'unable to set authentication tag length: failed to get parameter') do
+    #   cipher.auth_tag_len = 16
+    # end
+    assert_equal ct, cipher.update(pt) << cipher.final
+    assert_equal tag, cipher.auth_tag
+    cipher = new_decryptor("aes-128-gcm", key: key, iv: iv, auth_tag: tag, auth_data: aad)
+    # TODO JOpenSSL should raise
+    # assert_raise(OpenSSL::Cipher::CipherError, 'unable to set authentication tag length: failed to get parameter') do
+    #   cipher.auth_tag_len = 16
+    # end
+    assert_equal pt, cipher.update(ct) << cipher.final
+
+    # truncated tag is accepted
+    cipher = new_encryptor("aes-128-gcm", key: key, iv: iv, auth_data: aad)
+    assert_equal ct, cipher.update(pt) << cipher.final
+    assert_equal tag[0, 8], cipher.auth_tag(8)
+    assert_equal tag, cipher.auth_tag
+
+    # NOTE: MRI seems to just ignore the invalid tag?!
+    # cipher = new_decryptor("aes-128-gcm", key: key, iv: iv, auth_tag: tag[0, 8], auth_data: aad)
+    # assert_equal pt, cipher.update(ct) << cipher.final
+
+    # wrong tag is rejected
+    tag2 = tag.dup
+    tag2.setbyte(-1, (tag2.getbyte(-1) + 1) & 0xff)
+    cipher = new_decryptor("aes-128-gcm", key: key, iv: iv, auth_tag: tag2, auth_data: aad)
+    cipher.update(ct)
+    assert_raise(OpenSSL::Cipher::CipherError) { cipher.final }
+
+    # wrong aad is rejected
+    aad2 = aad[0..-2] << aad[-1].succ
+    cipher = new_decryptor("aes-128-gcm", key: key, iv: iv, auth_tag: tag, auth_data: aad2)
+    cipher.update(ct)
+    assert_raise(OpenSSL::Cipher::CipherError) { cipher.final }
+
+    # wrong ciphertext is rejected
+    ct2 = ct[0..-2] << ct[-1].succ
+    cipher = new_decryptor("aes-128-gcm", key: key, iv: iv, auth_tag: tag, auth_data: aad)
+    cipher.update(ct2)
+    assert_raise(OpenSSL::Cipher::CipherError) { cipher.final }
+  end
+
+  private
+
+  def new_encryptor(algo, **kwargs)
+    OpenSSL::Cipher.new(algo).tap do |cipher|
+      cipher.encrypt
+      kwargs.each {|k, v| cipher.send(:"#{k}=", v) }
+    end
+  end
+
+  def new_decryptor(algo, **kwargs)
+    OpenSSL::Cipher.new(algo).tap do |cipher|
+      cipher.decrypt
+      kwargs.each {|k, v| cipher.send(:"#{k}=", v) }
+    end
+  end
+
 end