COSE unprotected parameters are a map not a bstr

As per RFC 8152 section 3, the unprotected parameters in the headers
of COSE objects are just encoded as a map, not as a bstr that contains
the CBOR-encoding of a map.

Test: TreeHugger presubmit
Change-Id: Id4eeb023d3a81ad1398d78d410c8224bf941f9b1
diff --git a/security/keymint/aidl/vts/functional/VtsRemotelyProvisionedComponentTests.cpp b/security/keymint/aidl/vts/functional/VtsRemotelyProvisionedComponentTests.cpp
index db53a8f..50e6cce 100644
--- a/security/keymint/aidl/vts/functional/VtsRemotelyProvisionedComponentTests.cpp
+++ b/security/keymint/aidl/vts/functional/VtsRemotelyProvisionedComponentTests.cpp
@@ -97,9 +97,9 @@
     ASSERT_NE(protParms, nullptr);
     ASSERT_EQ(cppbor::prettyPrint(protParms->value()), "{\n  1 : 5,\n}");
 
-    auto unprotParms = coseMac0->asArray()->get(kCoseMac0UnprotectedParams)->asBstr();
+    auto unprotParms = coseMac0->asArray()->get(kCoseMac0UnprotectedParams)->asMap();
     ASSERT_NE(unprotParms, nullptr);
-    ASSERT_EQ(unprotParms->value().size(), 0);
+    ASSERT_EQ(unprotParms->size(), 0);
 
     auto payload = coseMac0->asArray()->get(kCoseMac0Payload)->asBstr();
     ASSERT_NE(payload, nullptr);
@@ -150,9 +150,9 @@
     ASSERT_NE(protParms, nullptr);
     ASSERT_EQ(cppbor::prettyPrint(protParms->value()), "{\n  1 : 5,\n}");
 
-    auto unprotParms = coseMac0->asArray()->get(kCoseMac0UnprotectedParams)->asBstr();
+    auto unprotParms = coseMac0->asArray()->get(kCoseMac0UnprotectedParams)->asMap();
     ASSERT_NE(unprotParms, nullptr);
-    ASSERT_EQ(unprotParms->value().size(), 0);
+    ASSERT_EQ(unprotParms->size(), 0);
 
     auto payload = coseMac0->asArray()->get(kCoseMac0Payload)->asBstr();
     ASSERT_NE(payload, nullptr);
@@ -279,7 +279,7 @@
                                          .add(ALGORITHM, HMAC_256)
                                          .canonicalize()
                                          .encode())
-                            .add(cppbor::Bstr())             // unprotected
+                            .add(cppbor::Map())              // unprotected
                             .add(cppbor::Array().encode())   // payload (keysToSign)
                             .add(std::move(keysToSignMac));  // tag
 
@@ -364,7 +364,7 @@
                                          .add(ALGORITHM, HMAC_256)
                                          .canonicalize()
                                          .encode())
-                            .add(cppbor::Bstr())             // unprotected
+                            .add(cppbor::Map())              // unprotected
                             .add(cborKeysToSign_.encode())   // payload
                             .add(std::move(keysToSignMac));  // tag