Use BoringSSL's public API in keymaster_hidl_hal_test

Reaching into the struct will fail to build in the future when we make
the struct opaque. Use the public APIs instead.

Test: mm, treehugger
Change-Id: I78cbf5e66f0c4a891049edd187c8705ad163f658
diff --git a/keymaster/3.0/vts/functional/keymaster_hidl_hal_test.cpp b/keymaster/3.0/vts/functional/keymaster_hidl_hal_test.cpp
index 554afe7..65b3dfa 100644
--- a/keymaster/3.0/vts/functional/keymaster_hidl_hal_test.cpp
+++ b/keymaster/3.0/vts/functional/keymaster_hidl_hal_test.cpp
@@ -2617,10 +2617,11 @@
     EVP_PKEY_Ptr pkey(d2i_PUBKEY(nullptr /* alloc new */, &p, exported.size()));
     RSA_Ptr rsa(EVP_PKEY_get1_RSA(pkey.get()));
 
-    size_t modulus_len = BN_num_bytes(rsa->n);
+    const BIGNUM* n = RSA_get0_n(rsa.get());
+    size_t modulus_len = BN_num_bytes(n);
     ASSERT_EQ(1024U / 8, modulus_len);
     std::unique_ptr<uint8_t[]> modulus_buf(new uint8_t[modulus_len]);
-    BN_bn2bin(rsa->n, modulus_buf.get());
+    BN_bn2bin(n, modulus_buf.get());
 
     // The modulus is too big to encrypt.
     string message(reinterpret_cast<const char*>(modulus_buf.get()), modulus_len);
@@ -2632,10 +2633,12 @@
     EXPECT_EQ(ErrorCode::INVALID_ARGUMENT, Finish(message, &result));
 
     // One smaller than the modulus is okay.
-    BN_sub(rsa->n, rsa->n, BN_value_one());
-    modulus_len = BN_num_bytes(rsa->n);
+    BIGNUM_Ptr n_minus_1(BN_new());
+    ASSERT_TRUE(n_minus_1);
+    ASSERT_TRUE(BN_sub(n_minus_1.get(), n, BN_value_one()));
+    modulus_len = BN_num_bytes(n_minus_1.get());
     ASSERT_EQ(1024U / 8, modulus_len);
-    BN_bn2bin(rsa->n, modulus_buf.get());
+    BN_bn2bin(n_minus_1.get(), modulus_buf.get());
     message = string(reinterpret_cast<const char*>(modulus_buf.get()), modulus_len);
     EXPECT_EQ(ErrorCode::OK, Begin(KeyPurpose::ENCRYPT, params));
     EXPECT_EQ(ErrorCode::OK, Finish(message, &result));
diff --git a/keymaster/4.0/vts/functional/keymaster_hidl_hal_test.cpp b/keymaster/4.0/vts/functional/keymaster_hidl_hal_test.cpp
index b709904..96580c0 100644
--- a/keymaster/4.0/vts/functional/keymaster_hidl_hal_test.cpp
+++ b/keymaster/4.0/vts/functional/keymaster_hidl_hal_test.cpp
@@ -2449,10 +2449,11 @@
     EVP_PKEY_Ptr pkey(d2i_PUBKEY(nullptr /* alloc new */, &p, exported.size()));
     RSA_Ptr rsa(EVP_PKEY_get1_RSA(pkey.get()));
 
-    size_t modulus_len = BN_num_bytes(rsa->n);
+    const BIGNUM* n = RSA_get0_n(rsa.get());
+    size_t modulus_len = BN_num_bytes(n);
     ASSERT_EQ(2048U / 8, modulus_len);
     std::unique_ptr<uint8_t[]> modulus_buf(new uint8_t[modulus_len]);
-    BN_bn2bin(rsa->n, modulus_buf.get());
+    BN_bn2bin(n, modulus_buf.get());
 
     // The modulus is too big to encrypt.
     string message(reinterpret_cast<const char*>(modulus_buf.get()), modulus_len);
@@ -2464,10 +2465,12 @@
     EXPECT_EQ(ErrorCode::INVALID_ARGUMENT, Finish(message, &result));
 
     // One smaller than the modulus is okay.
-    BN_sub(rsa->n, rsa->n, BN_value_one());
-    modulus_len = BN_num_bytes(rsa->n);
+    BIGNUM_Ptr n_minus_1(BN_new());
+    ASSERT_TRUE(n_minus_1);
+    ASSERT_TRUE(BN_sub(n_minus_1.get(), n, BN_value_one()));
+    modulus_len = BN_num_bytes(n_minus_1.get());
     ASSERT_EQ(2048U / 8, modulus_len);
-    BN_bn2bin(rsa->n, modulus_buf.get());
+    BN_bn2bin(n_minus_1.get(), modulus_buf.get());
     message = string(reinterpret_cast<const char*>(modulus_buf.get()), modulus_len);
     EXPECT_EQ(ErrorCode::OK, Begin(KeyPurpose::ENCRYPT, params));
     EXPECT_EQ(ErrorCode::OK, Finish(message, &result));