diff options
| -rw-r--r-- | NEWS | 3 | ||||
| -rw-r--r-- | ext/openssl/ossl_cipher.c | 48 | ||||
| -rw-r--r-- | test/test_cipher.rb | 33 |
3 files changed, 81 insertions, 3 deletions
@@ -62,6 +62,9 @@ Updates since Ruby 2.3 using AEAD ciphers. [Bug #8667] [Bug #10420] [GH ruby/ruby#569] [GH ruby/openssl#58] + - OpenSSL::Cipher#auth_tag_len= is added. This sets the authentication tag + length to be generated by an AEAD cipher. + * OpenSSL::Engine - OpenSSL::Engine.cleanup does nothing when built with OpenSSL 1.1.0. diff --git a/ext/openssl/ossl_cipher.c b/ext/openssl/ossl_cipher.c index 83c43904..1f29c9bd 100644 --- a/ext/openssl/ossl_cipher.c +++ b/ext/openssl/ossl_cipher.c @@ -36,6 +36,7 @@ */ VALUE cCipher; VALUE eCipherError; +static ID id_auth_tag_len; static VALUE ossl_cipher_alloc(VALUE klass); static void ossl_cipher_free(void *ptr); @@ -565,8 +566,9 @@ ossl_cipher_set_auth_data(VALUE self, VALUE data) * then set on the decryption cipher to authenticate the contents of the * ciphertext against changes. If the optional integer parameter +tag_len+ is * given, the returned tag will be +tag_len+ bytes long. If the parameter is - * omitted, the maximum length of 16 bytes will be returned. For maximum - * security, the default of 16 bytes should be chosen. + * omitted, the default length of 16 bytes or the length previously set by + * #auth_tag_len= will be used. For maximum security, the longest possible + * should be chosen. * * The tag may only be retrieved after calling Cipher#final. */ @@ -577,7 +579,10 @@ ossl_cipher_get_auth_tag(int argc, VALUE *argv, VALUE self) EVP_CIPHER_CTX *ctx; int tag_len = 16; - if (rb_scan_args(argc, argv, "01", &vtag_len) == 1) + rb_scan_args(argc, argv, "01", &vtag_len); + if (NIL_P(vtag_len)) + vtag_len = rb_attr_get(self, id_auth_tag_len); + if (!NIL_P(vtag_len)) tag_len = NUM2INT(vtag_len); GetCipher(self, ctx); @@ -603,6 +608,9 @@ ossl_cipher_get_auth_tag(int argc, VALUE *argv, VALUE self) * decrypting any of the ciphertext. After all decryption is * performed, the tag is verified automatically in the call to * Cipher#final. + * + * For OCB mode, the tag length must be supplied with #auth_tag_len= + * beforehand. */ static VALUE ossl_cipher_set_auth_tag(VALUE self, VALUE vtag) @@ -627,6 +635,36 @@ ossl_cipher_set_auth_tag(VALUE self, VALUE vtag) /* * call-seq: + * cipher.auth_tag_len = Integer -> Integer + * + * Sets the length of the authentication tag to be generated or to be given for + * AEAD ciphers that requires it as in input parameter. Note that not all AEAD + * ciphers support this method. + * + * In OCB mode, the length must be supplied both when encrypting and when + * decrypting, and must be before specifying an IV. + */ +static VALUE +ossl_cipher_set_auth_tag_len(VALUE self, VALUE vlen) +{ + int tag_len = NUM2INT(vlen); + EVP_CIPHER_CTX *ctx; + + GetCipher(self, ctx); + if (!(EVP_CIPHER_CTX_flags(ctx) & EVP_CIPH_FLAG_AEAD_CIPHER)) + ossl_raise(eCipherError, "AEAD not supported by this cipher"); + + if (!EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG, tag_len, NULL)) + ossl_raise(eCipherError, "unable to set authentication tag length"); + + /* for #auth_tag */ + rb_ivar_set(self, id_auth_tag_len, INT2NUM(tag_len)); + + return vlen; +} + +/* + * call-seq: * cipher.authenticated? -> boolean * * Indicated whether this Cipher instance uses an Authenticated Encryption @@ -675,6 +713,7 @@ ossl_cipher_set_iv_length(VALUE self, VALUE iv_length) #define ossl_cipher_set_auth_data rb_f_notimplement #define ossl_cipher_get_auth_tag rb_f_notimplement #define ossl_cipher_set_auth_tag rb_f_notimplement +#define ossl_cipher_set_auth_tag_len rb_f_notimplement #define ossl_cipher_is_authenticated rb_f_notimplement #define ossl_cipher_set_iv_length rb_f_notimplement #endif @@ -1000,6 +1039,7 @@ Init_ossl_cipher(void) rb_define_method(cCipher, "auth_data=", ossl_cipher_set_auth_data, 1); rb_define_method(cCipher, "auth_tag=", ossl_cipher_set_auth_tag, 1); rb_define_method(cCipher, "auth_tag", ossl_cipher_get_auth_tag, -1); + rb_define_method(cCipher, "auth_tag_len=", ossl_cipher_set_auth_tag_len, 1); rb_define_method(cCipher, "authenticated?", ossl_cipher_is_authenticated, 0); rb_define_method(cCipher, "key_len=", ossl_cipher_set_key_length, 1); rb_define_method(cCipher, "key_len", ossl_cipher_key_length, 0); @@ -1008,4 +1048,6 @@ Init_ossl_cipher(void) rb_define_method(cCipher, "iv_len", ossl_cipher_iv_length, 0); rb_define_method(cCipher, "block_size", ossl_cipher_block_size, 0); rb_define_method(cCipher, "padding=", ossl_cipher_set_padding, 1); + + id_auth_tag_len = rb_intern_const("auth_tag_len"); } diff --git a/test/test_cipher.rb b/test/test_cipher.rb index 1c6c8586..74c5394f 100644 --- a/test/test_cipher.rb +++ b/test/test_cipher.rb @@ -284,6 +284,39 @@ class OpenSSL::TestCipher < OpenSSL::TestCase end + def test_aes_ocb_tag_len + pt = "You should all use Authenticated Encryption!" + cipher = OpenSSL::Cipher.new("aes-128-ocb").encrypt + cipher.auth_tag_len = 14 + cipher.iv_len = 8 + key = cipher.random_key + iv = cipher.random_iv + cipher.auth_data = "aad" + ct = cipher.update(pt) + cipher.final + tag = cipher.auth_tag + assert_equal(14, tag.size) + + decipher = OpenSSL::Cipher.new("aes-128-ocb").decrypt + decipher.auth_tag_len = 14 + decipher.auth_tag = tag + decipher.iv_len = 8 + decipher.key = key + decipher.iv = iv + decipher.auth_data = "aad" + assert_equal(pt, decipher.update(ct) + decipher.final) + + decipher = OpenSSL::Cipher.new("aes-128-ocb").decrypt + decipher.auth_tag_len = 9 + decipher.auth_tag = tag[0, 9] + decipher.iv_len = 8 + decipher.key = key + decipher.iv = iv + decipher.auth_data = "aad" + assert_raise(OpenSSL::Cipher::CipherError) { + decipher.update(ct) + decipher.final + } + end if has_cipher?("aes-128-ocb") + private def new_encryptor(algo) |