Revert "Revert "Enforce a default policy on packages without <overlayable>""

This reverts commit 6ce5b00f2ac8307ab8cce1deb79e1e39d8b1b8b7.

Bug: 127835630
Test: manual and idmap2_tests
diff --git a/cmds/idmap2/tests/IdmapTests.cpp b/cmds/idmap2/tests/IdmapTests.cpp
index bbfbad9..8d65428 100644
--- a/cmds/idmap2/tests/IdmapTests.cpp
+++ b/cmds/idmap2/tests/IdmapTests.cpp
@@ -173,20 +173,27 @@
   ASSERT_THAT(idmap, IsNull());
 }
 
-TEST(IdmapTests, CreateIdmapFromApkAssets) {
-  const std::string target_apk_path(GetTestDataPath() + "/target/target.apk");
-  std::unique_ptr<const ApkAssets> target_apk = ApkAssets::Load(target_apk_path);
+void CreateIdmap(const StringPiece& target_apk_path, const StringPiece& overlay_apk_path,
+                 const PolicyBitmask& fulfilled_policies, bool enforce_overlayable,
+                 std::unique_ptr<const Idmap>* out_idmap) {
+  std::unique_ptr<const ApkAssets> target_apk = ApkAssets::Load(target_apk_path.to_string());
   ASSERT_THAT(target_apk, NotNull());
 
-  const std::string overlay_apk_path(GetTestDataPath() + "/overlay/overlay.apk");
-  std::unique_ptr<const ApkAssets> overlay_apk = ApkAssets::Load(overlay_apk_path);
+  std::unique_ptr<const ApkAssets> overlay_apk = ApkAssets::Load(overlay_apk_path.to_string());
   ASSERT_THAT(overlay_apk, NotNull());
 
   std::stringstream error;
-  std::unique_ptr<const Idmap> idmap =
-      Idmap::FromApkAssets(target_apk_path, *target_apk, overlay_apk_path, *overlay_apk,
-                           PolicyFlags::POLICY_PUBLIC, /* enforce_overlayable */ true, error);
-  ASSERT_THAT(idmap, NotNull());
+  *out_idmap =
+      Idmap::FromApkAssets(target_apk_path.to_string(), *target_apk, overlay_apk_path.to_string(),
+                           *overlay_apk, fulfilled_policies, enforce_overlayable, error);
+}
+
+TEST(IdmapTests, CreateIdmapFromApkAssets) {
+  std::unique_ptr<const Idmap> idmap;
+  std::string target_apk_path = GetTestDataPath() + "/target/target.apk";
+  std::string overlay_apk_path = GetTestDataPath() + "/overlay/overlay.apk";
+  CreateIdmap(target_apk_path, overlay_apk_path, PolicyFlags::POLICY_PUBLIC,
+              /* enforce_overlayable */ true, &idmap);
 
   ASSERT_THAT(idmap->GetHeader(), NotNull());
   ASSERT_EQ(idmap->GetHeader()->GetMagic(), 0x504d4449U);
@@ -226,19 +233,12 @@
 
 // Overlays should abide by all overlayable restrictions if enforcement of overlayable is enabled.
 TEST(IdmapOverlayableTests, CreateIdmapFromApkAssetsPolicySystemPublic) {
-  const std::string target_apk_path(GetTestDataPath() + "/target/target.apk");
-  std::unique_ptr<const ApkAssets> target_apk = ApkAssets::Load(target_apk_path);
-  ASSERT_THAT(target_apk, NotNull());
-
-  const std::string overlay_apk_path(GetTestDataPath() + "/system-overlay/system-overlay.apk");
-  std::unique_ptr<const ApkAssets> overlay_apk = ApkAssets::Load(overlay_apk_path);
-  ASSERT_THAT(overlay_apk, NotNull());
-
-  std::stringstream error;
-  std::unique_ptr<const Idmap> idmap =
-      Idmap::FromApkAssets(target_apk_path, *target_apk, overlay_apk_path, *overlay_apk,
-                           PolicyFlags::POLICY_SYSTEM_PARTITION | PolicyFlags::POLICY_PUBLIC,
-                           /* enforce_overlayable */ true, error);
+  std::unique_ptr<const Idmap> idmap;
+  std::string target_apk_path = GetTestDataPath() + "/target/target.apk";
+  std::string overlay_apk_path = GetTestDataPath() + "/system-overlay/system-overlay.apk";
+  CreateIdmap(target_apk_path, overlay_apk_path,
+              PolicyFlags::POLICY_SYSTEM_PARTITION | PolicyFlags::POLICY_PUBLIC,
+              /* enforce_overlayable */ true, &idmap);
   ASSERT_THAT(idmap, NotNull());
 
   const std::vector<std::unique_ptr<const IdmapData>>& dataBlocks = idmap->GetData();
@@ -263,21 +263,12 @@
 }
 
 TEST(IdmapOverlayableTests, CreateIdmapFromApkAssetsPolicySignature) {
-  const std::string target_apk_path(GetTestDataPath() + "/target/target.apk");
-  std::unique_ptr<const ApkAssets> target_apk = ApkAssets::Load(target_apk_path);
-  ASSERT_THAT(target_apk, NotNull());
-
-  const std::string overlay_apk_path(GetTestDataPath() +
-                                     "/signature-overlay/signature-overlay.apk");
-  std::unique_ptr<const ApkAssets> overlay_apk = ApkAssets::Load(overlay_apk_path);
-  ASSERT_THAT(overlay_apk, NotNull());
-
-  uint32_t policy_flags = PolicyFlags::POLICY_PUBLIC | PolicyFlags::POLICY_SIGNATURE;
-
-  std::stringstream error;
-  std::unique_ptr<const Idmap> idmap =
-      Idmap::FromApkAssets(target_apk_path, *target_apk, overlay_apk_path, *overlay_apk,
-                           policy_flags, /* enforce_overlayable */ true, error);
+  std::unique_ptr<const Idmap> idmap;
+  std::string target_apk_path = GetTestDataPath() + "/target/target.apk";
+  std::string overlay_apk_path = GetTestDataPath() + "/signature-overlay/signature-overlay.apk";
+  CreateIdmap(target_apk_path, overlay_apk_path,
+              PolicyFlags::POLICY_PUBLIC | PolicyFlags::POLICY_SIGNATURE,
+              /* enforce_overlayable */ true, &idmap);
   ASSERT_THAT(idmap, NotNull());
 
   const std::vector<std::unique_ptr<const IdmapData>>& dataBlocks = idmap->GetData();
@@ -298,52 +289,15 @@
   ASSERT_EQ(types[0]->GetEntry(0), 0x0000U);  // string/policy_signature
 }
 
-TEST(IdmapOverlayableTests, CreateIdmapFromApkAssetsPolicySignatureNotFulfilled) {
-  const std::string target_apk_path(GetTestDataPath() + "/target/target.apk");
-  std::unique_ptr<const ApkAssets> target_apk = ApkAssets::Load(target_apk_path);
-  ASSERT_THAT(target_apk, NotNull());
-
-  const std::string overlay_apk_path(GetTestDataPath() +
-                                     "/signature-overlay/signature-overlay.apk");
-  std::unique_ptr<const ApkAssets> overlay_apk = ApkAssets::Load(overlay_apk_path);
-  ASSERT_THAT(overlay_apk, NotNull());
-
-  uint32_t policy_flags = PolicyFlags::POLICY_PUBLIC;
-
-  std::stringstream error;
-  std::unique_ptr<const Idmap> idmap =
-      Idmap::FromApkAssets(target_apk_path, *target_apk, overlay_apk_path, *overlay_apk,
-                           policy_flags, /* enforce_overlayable */ true, error);
-  ASSERT_THAT(idmap, NotNull());
-
-  const std::vector<std::unique_ptr<const IdmapData>>& dataBlocks = idmap->GetData();
-  ASSERT_EQ(dataBlocks.size(), 1U);
-
-  const std::unique_ptr<const IdmapData>& data = dataBlocks[0];
-
-  ASSERT_EQ(data->GetHeader()->GetTargetPackageId(), 0x7fU);
-  ASSERT_EQ(data->GetHeader()->GetTypeCount(), 0U);
-
-  const std::vector<std::unique_ptr<const IdmapData::TypeEntry>>& types = data->GetTypeEntries();
-  ASSERT_EQ(types.size(), 0U);  // can't overlay, so contains nothing
-}
-
 // Overlays should abide by all overlayable restrictions if enforcement of overlayable is enabled.
 TEST(IdmapOverlayableTests, CreateIdmapFromApkAssetsPolicySystemPublicInvalid) {
-  const std::string target_apk_path(GetTestDataPath() + "/target/target.apk");
-  std::unique_ptr<const ApkAssets> target_apk = ApkAssets::Load(target_apk_path);
-  ASSERT_THAT(target_apk, NotNull());
-
-  const std::string overlay_apk_path(GetTestDataPath() +
-                                     "/system-overlay-invalid/system-overlay-invalid.apk");
-  std::unique_ptr<const ApkAssets> overlay_apk = ApkAssets::Load(overlay_apk_path);
-  ASSERT_THAT(overlay_apk, NotNull());
-
-  std::stringstream error;
-  std::unique_ptr<const Idmap> idmap =
-      Idmap::FromApkAssets(target_apk_path, *target_apk, overlay_apk_path, *overlay_apk,
-                           PolicyFlags::POLICY_SYSTEM_PARTITION | PolicyFlags::POLICY_PUBLIC,
-                           /* enforce_overlayable */ true, error);
+  std::unique_ptr<const Idmap> idmap;
+  std::string target_apk_path = GetTestDataPath() + "/target/target.apk";
+  std::string overlay_apk_path =
+      GetTestDataPath() + "/system-overlay-invalid/system-overlay-invalid.apk";
+  CreateIdmap(target_apk_path, overlay_apk_path,
+              PolicyFlags::POLICY_SYSTEM_PARTITION | PolicyFlags::POLICY_PUBLIC,
+              /* enforce_overlayable */ true, &idmap);
   ASSERT_THAT(idmap, NotNull());
 
   const std::vector<std::unique_ptr<const IdmapData>>& dataBlocks = idmap->GetData();
@@ -369,20 +323,13 @@
 
 // Overlays should ignore all overlayable restrictions if enforcement of overlayable is disabled.
 TEST(IdmapOverlayableTests, CreateIdmapFromApkAssetsPolicySystemPublicInvalidIgnoreOverlayable) {
-  const std::string target_apk_path(GetTestDataPath() + "/target/target.apk");
-  std::unique_ptr<const ApkAssets> target_apk = ApkAssets::Load(target_apk_path);
-  ASSERT_THAT(target_apk, NotNull());
-
-  const std::string overlay_apk_path(GetTestDataPath() +
-                                     "/system-overlay-invalid/system-overlay-invalid.apk");
-  std::unique_ptr<const ApkAssets> overlay_apk = ApkAssets::Load(overlay_apk_path);
-  ASSERT_THAT(overlay_apk, NotNull());
-
-  std::stringstream error;
-  std::unique_ptr<const Idmap> idmap =
-      Idmap::FromApkAssets(target_apk_path, *target_apk, overlay_apk_path, *overlay_apk,
-                           PolicyFlags::POLICY_SYSTEM_PARTITION | PolicyFlags::POLICY_PUBLIC,
-                           /* enforce_overlayable */ false, error);
+  std::unique_ptr<const Idmap> idmap;
+  std::string target_apk_path = GetTestDataPath() + "/target/target.apk";
+  std::string overlay_apk_path =
+      GetTestDataPath() + "/system-overlay-invalid/system-overlay-invalid.apk";
+  CreateIdmap(target_apk_path, overlay_apk_path,
+              PolicyFlags::POLICY_SYSTEM_PARTITION | PolicyFlags::POLICY_PUBLIC,
+              /* enforce_overlayable */ false, &idmap);
   ASSERT_THAT(idmap, NotNull());
 
   const std::vector<std::unique_ptr<const IdmapData>>& dataBlocks = idmap->GetData();
@@ -409,63 +356,13 @@
   ASSERT_EQ(types[0]->GetEntry(6), 0x0006U);  // string/policy_system_vendor
 }
 
-// The resources of APKs that do not include an overlayable declaration should not restrict what
-// resources can be overlaid.
-TEST(IdmapOverlayableTests, CreateIdmapFromApkAssetsNoDefinedOverlayable) {
-  const std::string target_apk_path(GetTestDataPath() + "/target/target-no-overlayable.apk");
-  std::unique_ptr<const ApkAssets> target_apk = ApkAssets::Load(target_apk_path);
-  ASSERT_THAT(target_apk, NotNull());
-
-  const std::string overlay_apk_path(GetTestDataPath() +
-                                     "/system-overlay-invalid/system-overlay-invalid.apk");
-  std::unique_ptr<const ApkAssets> overlay_apk = ApkAssets::Load(overlay_apk_path);
-  ASSERT_THAT(overlay_apk, NotNull());
-
-  std::stringstream error;
-  std::unique_ptr<const Idmap> idmap =
-      Idmap::FromApkAssets(target_apk_path, *target_apk, overlay_apk_path, *overlay_apk,
-                           PolicyFlags::POLICY_PUBLIC, /* enforce_overlayable */ true, error);
-  ASSERT_THAT(idmap, NotNull());
-
-  const std::vector<std::unique_ptr<const IdmapData>>& dataBlocks = idmap->GetData();
-  ASSERT_EQ(dataBlocks.size(), 1U);
-
-  const std::unique_ptr<const IdmapData>& data = dataBlocks[0];
-
-  ASSERT_EQ(data->GetHeader()->GetTargetPackageId(), 0x7fU);
-  ASSERT_EQ(data->GetHeader()->GetTypeCount(), 1U);
-
-  const std::vector<std::unique_ptr<const IdmapData::TypeEntry>>& types = data->GetTypeEntries();
-  ASSERT_EQ(types.size(), 1U);
-
-  ASSERT_EQ(types[0]->GetTargetTypeId(), 0x02U);
-  ASSERT_EQ(types[0]->GetOverlayTypeId(), 0x01U);
-  ASSERT_EQ(types[0]->GetEntryCount(), 7U);
-  ASSERT_EQ(types[0]->GetEntryOffset(), 3U);
-  ASSERT_EQ(types[0]->GetEntry(0), 0x0000U);  // string/not_overlayable
-  ASSERT_EQ(types[0]->GetEntry(1), 0x0001U);  // string/other
-  ASSERT_EQ(types[0]->GetEntry(2), 0x0002U);  // string/policy_product
-  ASSERT_EQ(types[0]->GetEntry(3), 0x0003U);  // string/policy_public
-  ASSERT_EQ(types[0]->GetEntry(4), 0x0004U);  // string/string/policy_signature
-  ASSERT_EQ(types[0]->GetEntry(5), 0x0005U);  // string/policy_system
-  ASSERT_EQ(types[0]->GetEntry(6), 0x0006U);  // string/policy_system_vendor
-}
-
-// The resources of APKs that do not include an overlayable declaration should not restrict what
-// resources can be overlaid.
+// Overlays that do not specify a target <overlayable> can overlay resources defined as overlayable.
 TEST(IdmapOverlayableTests, CreateIdmapFromApkAssetsNoDefinedOverlayableAndNoTargetName) {
-  const std::string target_apk_path(GetTestDataPath() + "/target/target-no-overlayable.apk");
-  std::unique_ptr<const ApkAssets> target_apk = ApkAssets::Load(target_apk_path);
-  ASSERT_THAT(target_apk, NotNull());
-
-  const std::string overlay_apk_path(GetTestDataPath() + "/overlay/overlay-no-name.apk");
-  std::unique_ptr<const ApkAssets> overlay_apk = ApkAssets::Load(overlay_apk_path);
-  ASSERT_THAT(overlay_apk, NotNull());
-
-  std::stringstream error;
-  std::unique_ptr<const Idmap> idmap =
-      Idmap::FromApkAssets(target_apk_path, *target_apk, overlay_apk_path, *overlay_apk,
-                           PolicyFlags::POLICY_PUBLIC, /* enforce_overlayable */ true, error);
+  std::unique_ptr<const Idmap> idmap;
+  std::string target_apk_path = GetTestDataPath() + "/target/target-no-overlayable.apk";
+  std::string overlay_apk_path = GetTestDataPath() + "/overlay/overlay-no-name.apk";
+  CreateIdmap(target_apk_path, overlay_apk_path, PolicyFlags::POLICY_PUBLIC,
+              /* enforce_overlayable */ false, &idmap);
   ASSERT_THAT(idmap, NotNull());
 
   const std::vector<std::unique_ptr<const IdmapData>>& dataBlocks = idmap->GetData();
@@ -483,16 +380,81 @@
   ASSERT_EQ(types[0]->GetOverlayTypeId(), 0x01U);
   ASSERT_EQ(types[0]->GetEntryCount(), 1U);
   ASSERT_EQ(types[0]->GetEntryOffset(), 0U);
-  ASSERT_EQ(types[0]->GetEntry(0), 0x0000U);
+  ASSERT_EQ(types[0]->GetEntry(0), 0x0000U);  // string/int1
 
   ASSERT_EQ(types[1]->GetTargetTypeId(), 0x02U);
   ASSERT_EQ(types[1]->GetOverlayTypeId(), 0x02U);
   ASSERT_EQ(types[1]->GetEntryCount(), 4U);
   ASSERT_EQ(types[1]->GetEntryOffset(), 10U);
-  ASSERT_EQ(types[1]->GetEntry(0), 0x0000U);
-  ASSERT_EQ(types[1]->GetEntry(1), kNoEntry);
-  ASSERT_EQ(types[1]->GetEntry(2), 0x0001U);
-  ASSERT_EQ(types[1]->GetEntry(3), 0x0002U);
+  ASSERT_EQ(types[1]->GetEntry(0), 0x0000U);   // string/str1
+  ASSERT_EQ(types[1]->GetEntry(1), kNoEntry);  // string/str2
+  ASSERT_EQ(types[1]->GetEntry(2), 0x0001U);   // string/str3
+  ASSERT_EQ(types[1]->GetEntry(3), 0x0002U);   // string/str4
+}
+
+// Overlays that are not pre-installed and are not signed with the same signature as the target
+// cannot overlay packages that have not defined overlayable resources.
+TEST(IdmapOverlayableTests, CreateIdmapFromApkAssetsDefaultPoliciesPublicFail) {
+  std::unique_ptr<const Idmap> idmap;
+  std::string target_apk_path = GetTestDataPath() + "/target/target-no-overlayable.apk";
+  std::string overlay_apk_path = GetTestDataPath() + "/overlay/overlay-no-name.apk";
+  CreateIdmap(target_apk_path, overlay_apk_path, PolicyFlags::POLICY_PUBLIC,
+              /* enforce_overlayable */ true, &idmap);
+  ASSERT_THAT(idmap, IsNull());
+}
+
+// Overlays that are pre-installed or are signed with the same signature as the target can overlay
+// packages that have not defined overlayable resources.
+TEST(IdmapOverlayableTests, CreateIdmapFromApkAssetsDefaultPolicies) {
+  std::unique_ptr<const Idmap> idmap;
+  std::string target_apk_path = GetTestDataPath() + "/target/target-no-overlayable.apk";
+  std::string overlay_apk_path =
+      GetTestDataPath() + "/system-overlay-invalid/system-overlay-invalid.apk";
+
+  auto CheckEntries = [&]() -> void {
+    const std::vector<std::unique_ptr<const IdmapData>>& dataBlocks = idmap->GetData();
+    ASSERT_EQ(dataBlocks.size(), 1U);
+
+    const std::unique_ptr<const IdmapData>& data = dataBlocks[0];
+
+    ASSERT_EQ(data->GetHeader()->GetTargetPackageId(), 0x7fU);
+    ASSERT_EQ(data->GetHeader()->GetTypeCount(), 1U);
+
+    const std::vector<std::unique_ptr<const IdmapData::TypeEntry>>& types = data->GetTypeEntries();
+    ASSERT_EQ(types.size(), 1U);
+
+    ASSERT_EQ(types[0]->GetTargetTypeId(), 0x02U);
+    ASSERT_EQ(types[0]->GetOverlayTypeId(), 0x01U);
+    ASSERT_EQ(types[0]->GetEntryCount(), 7U);
+    ASSERT_EQ(types[0]->GetEntryOffset(), 3U);
+    ASSERT_EQ(types[0]->GetEntry(0), 0x0000U);  // string/not_overlayable
+    ASSERT_EQ(types[0]->GetEntry(1), 0x0001U);  // string/other
+    ASSERT_EQ(types[0]->GetEntry(2), 0x0002U);  // string/policy_product
+    ASSERT_EQ(types[0]->GetEntry(3), 0x0003U);  // string/policy_public
+    ASSERT_EQ(types[0]->GetEntry(4), 0x0004U);  // string/string/policy_signature
+    ASSERT_EQ(types[0]->GetEntry(5), 0x0005U);  // string/policy_system
+    ASSERT_EQ(types[0]->GetEntry(6), 0x0006U);  // string/policy_system_vendor
+  };
+
+  CreateIdmap(target_apk_path, overlay_apk_path, PolicyFlags::POLICY_SIGNATURE,
+              /* enforce_overlayable */ true, &idmap);
+  ASSERT_THAT(idmap, NotNull());
+  CheckEntries();
+
+  CreateIdmap(target_apk_path, overlay_apk_path, PolicyFlags::POLICY_PRODUCT_PARTITION,
+              /* enforce_overlayable */ true, &idmap);
+  ASSERT_THAT(idmap, NotNull());
+  CheckEntries();
+
+  CreateIdmap(target_apk_path, overlay_apk_path, PolicyFlags::POLICY_SYSTEM_PARTITION,
+              /* enforce_overlayable */ true, &idmap);
+  ASSERT_THAT(idmap, NotNull());
+  CheckEntries();
+
+  CreateIdmap(target_apk_path, overlay_apk_path, PolicyFlags::POLICY_VENDOR_PARTITION,
+              /* enforce_overlayable */ true, &idmap);
+  ASSERT_THAT(idmap, NotNull());
+  CheckEntries();
 }
 
 TEST(IdmapTests, FailToCreateIdmapFromApkAssetsIfPathTooLong) {