Don't check for MGF_DIGEST tag on keys

Rely on the KeyMint VTS tests to police the correct population of this
tag, as there are too many special cases to check here.

Bug: 347810234
Test: keystore2_client_tests
Change-Id: Ie7225d2eea2ab7ef24e036f1e5d824457cdb777c
diff --git a/keystore2/test_utils/key_generations.rs b/keystore2/test_utils/key_generations.rs
index fdb2afb..cf0c4f0 100644
--- a/keystore2/test_utils/key_generations.rs
+++ b/keystore2/test_utils/key_generations.rs
@@ -424,13 +424,25 @@
             return true;
         }
 
-        // Ignore below parameters if the backend is Keymaster and not KeyMint.
-        // Keymaster does not support these parameters. These key parameters are introduced in
-        // KeyMint1.0.
+        // `Tag::RSA_OAEP_MGF_DIGEST` was added in KeyMint 1.0, but the KeyMint VTS tests didn't
+        // originally check for its presence and so some implementations of early versions (< 3) of
+        // the KeyMint HAL don't include it (cf. b/297306437 and aosp/2758513).
+        //
+        // Given that Keymaster implementations will also omit this tag, skip the check for it
+        // altogether (and rely on the updated KeyMint VTS tests to ensure that up-level KeyMint
+        // implementations correctly populate this tag).
+        if matches!(key_param.tag, Tag::RSA_OAEP_MGF_DIGEST) {
+            return true;
+        }
+
         if sl.is_keymaster() {
-            if matches!(key_param.tag, Tag::RSA_OAEP_MGF_DIGEST | Tag::USAGE_COUNT_LIMIT) {
+            // `Tag::USAGE_COUNT_LIMIT` was added in KeyMint 1.0, so don't check for it if the
+            // underlying device is a Keymaster implementation.
+            if matches!(key_param.tag, Tag::USAGE_COUNT_LIMIT) {
                 return true;
             }
+            // `KeyPurpose::ATTEST_KEY` was added in KeyMint 1.0, so don't check for it if the
+            // underlying device is a Keymaster implementation.
             if key_param.tag == Tag::PURPOSE
                 && key_param.value == KeyParameterValue::KeyPurpose(KeyPurpose::ATTEST_KEY)
             {