Adding utility to return the actual bit size of the key. Especially n…

…eeded for key such as X25519 where the size not in byte boundary
ruby · Oct 29, 2023 · 14db821 · 14db821
1 parent c9b48f9
commit 14db821
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diff --git a/ext/openssl/ossl_pkey.c b/ext/openssl/ossl_pkey.c
@@ -1666,6 +1666,23 @@ ossl_pkey_decrypt(int argc, VALUE *argv, VALUE self)
     return str;
 }
 
+
+/*
+ * Returns bit length of the PKEy
+ */ 
+static VALUE
+ossl_pkey_length_in_bits(VALUE self)
+{
+  EVP_PKEY * pkey;
+  int bits;
+
+  GetPKey(self, pkey);
+
+  bits = EVP_PKEY_get_bits(pkey);
+  return INT2NUM(bits);
+
+}
+
 /*
  * INIT
  */
@@ -1785,6 +1802,9 @@ Init_ossl_pkey(void)
     rb_define_method(cPKey, "encrypt", ossl_pkey_encrypt, -1);
     rb_define_method(cPKey, "decrypt", ossl_pkey_decrypt, -1);
 
+
+    rb_define_method(cPKey, "keysize_in_bits", ossl_pkey_length_in_bits, 0);
+
     id_private_q = rb_intern("private?");
 
     /*

diff --git a/test/openssl/test_pkey.rb b/test/openssl/test_pkey.rb
@@ -24,6 +24,7 @@ def test_generic_oid_inspect
     assert_instance_of OpenSSL::PKey::PKey, x25519
     assert_equal "X25519", x25519.oid
     assert_match %r{oid=X25519}, x25519.inspect
+    assert_equal 253, x25519.keysize_in_bits
   end
 
   def test_s_generate_parameters

diff --git a/test/openssl/test_pkey_dh.rb b/test/openssl/test_pkey_dh.rb
@@ -36,6 +36,9 @@ def test_derive_key
     assert_equal z, dh1.derive(dh2_pub)
     assert_equal z, dh2.derive(dh1_pub)
 
+    assert_equal(1024, dh1.keysize_in_bits)
+    assert_equal(1024, dh2.keysize_in_bits)
+
     assert_raise(OpenSSL::PKey::PKeyError) { params.derive(dh1_pub) }
     assert_raise(OpenSSL::PKey::PKeyError) { dh1_pub.derive(params) }
 

diff --git a/test/openssl/test_pkey_ec.rb b/test/openssl/test_pkey_ec.rb
@@ -76,16 +76,19 @@ def test_check_key
     assert_equal(true, key0.check_key)
     assert_equal(true, key0.private?)
     assert_equal(true, key0.public?)
+    assert_equal(256, key0.keysize_in_bits)
 
     key1 = OpenSSL::PKey.read(key0.public_to_der)
     assert_equal(true, key1.check_key)
     assert_equal(false, key1.private?)
     assert_equal(true, key1.public?)
+    assert_equal(256, key1.keysize_in_bits)
 
     key2 = OpenSSL::PKey.read(key0.private_to_der)
     assert_equal(true, key2.private?)
     assert_equal(true, key2.public?)
     assert_equal(true, key2.check_key)
+    assert_equal(256, key2.keysize_in_bits)
 
     # Behavior of EVP_PKEY_public_check changes between OpenSSL 1.1.1 and 3.0
     key4 = Fixtures.pkey("p256_too_large")