From 9b8d75eacb8288f98f8697d7884123840f54c60c Mon Sep 17 00:00:00 2001
From: David Drysdale <drysdale@google.com>
Date: Tue, 5 Sep 2023 15:16:47 +0100
Subject: [PATCH] KeyMint: clarify EC_CURVE on import

Bug: 292318194
Test: VtsAidlKeyMintTargetTest
Change-Id: I4194b70f1da8816e19f231331c738050c2b7d59f
---
 .../security/keymint/IKeyMintDevice.aidl      |  6 ++++
 .../aidl/vts/functional/KeyMintTest.cpp       | 36 +++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/security/keymint/aidl/android/hardware/security/keymint/IKeyMintDevice.aidl b/security/keymint/aidl/android/hardware/security/keymint/IKeyMintDevice.aidl
index 2e4fc1572e..aeb0163977 100644
--- a/security/keymint/aidl/android/hardware/security/keymint/IKeyMintDevice.aidl
+++ b/security/keymint/aidl/android/hardware/security/keymint/IKeyMintDevice.aidl
@@ -379,6 +379,12 @@ interface IKeyMintDevice {
      *   validate it against the key material.  In the event of a mismatch, importKey must return
      *   ErrorCode::IMPORT_PARAMETER_MISMATCH.
      *
+     * o Tag::EC_CURVE is not necessary in the input parameters for import of EC keys. If not
+     *   provided the IKeyMintDevice must deduce the value from the provided key material and add
+     *   the tag and value to the key characteristics.  If Tag::EC_CURVE is provided, the
+     *   IKeyMintDevice must validate it against the key material.  In the event of a mismatch,
+     *   importKey must return ErrorCode::IMPORT_PARAMETER_MISMATCH.
+     *
      * o Tag::RSA_PUBLIC_EXPONENT (for RSA keys only) is not necessary in the input parameters.  If
      *   not provided, the IKeyMintDevice must deduce the value from the provided key material and
      *   add the tag and value to the key characteristics.  If Tag::RSA_PUBLIC_EXPONENT is provided,
diff --git a/security/keymint/aidl/vts/functional/KeyMintTest.cpp b/security/keymint/aidl/vts/functional/KeyMintTest.cpp
index 022dd3fe7d..0e5562d144 100644
--- a/security/keymint/aidl/vts/functional/KeyMintTest.cpp
+++ b/security/keymint/aidl/vts/functional/KeyMintTest.cpp
@@ -4147,6 +4147,42 @@ TEST_P(ImportKeyTest, EcdsaSuccess) {
     LocalVerifyMessage(message, signature, params);
 }
 
+/*
+ * ImportKeyTest.EcdsaSuccessCurveNotSpecified
+ *
+ * Verifies that importing and using an ECDSA P-256 key pair works correctly
+ * when the EC_CURVE is not explicitly specified.
+ */
+TEST_P(ImportKeyTest, EcdsaSuccessCurveNotSpecified) {
+    if (AidlVersion() < 4) {
+        /*
+         * The KeyMint spec before V4 was not clear as to whether EC_CURVE was optional on import of
+         * EC keys. However, this was not checked at the time so we can only be strict about
+         * checking this for implementations of KeyMint version 4 and above.
+         */
+        GTEST_SKIP() << "Skipping EC_CURVE on import only strict since KeyMint v4";
+    }
+
+    ASSERT_EQ(ErrorCode::OK, ImportKey(AuthorizationSetBuilder()
+                                               .Authorization(TAG_NO_AUTH_REQUIRED)
+                                               .Authorization(TAG_ALGORITHM, Algorithm::EC)
+                                               .SigningKey()
+                                               .Digest(Digest::SHA_2_256)
+                                               .SetDefaultValidity(),
+                                       KeyFormat::PKCS8, ec_256_key));
+
+    CheckCryptoParam(TAG_ALGORITHM, Algorithm::EC);
+    CheckCryptoParam(TAG_DIGEST, Digest::SHA_2_256);
+    CheckCryptoParam(TAG_EC_CURVE, EcCurve::P_256);
+
+    CheckOrigin();
+
+    string message(32, 'a');
+    auto params = AuthorizationSetBuilder().Digest(Digest::SHA_2_256);
+    string signature = SignMessage(message, params);
+    LocalVerifyMessage(message, signature, params);
+}
+
 /*
  * ImportKeyTest.EcdsaP256RFC5915Success
  *