Compare the fingerprint before reading the partition

The update_verifier now compares the fingerprint of a partition before
performing the blocks read. If the fingerprint of the current system property
mismatches the one embedded in the care_map, verification of this partition
will be skipped. This is useful for the possible system only updates in the
future.

Bug: 114778109
Test: unit tests pass
Change-Id: Iea309148a05109b5810dfb533d94260d77ab8540
diff --git a/tests/component/update_verifier_test.cpp b/tests/component/update_verifier_test.cpp
index 543e427..2420c27 100644
--- a/tests/component/update_verifier_test.cpp
+++ b/tests/component/update_verifier_test.cpp
@@ -16,6 +16,7 @@
 
 #include <update_verifier/update_verifier.h>
 
+#include <functional>
 #include <string>
 #include <unordered_map>
 #include <vector>
@@ -37,8 +38,19 @@
     std::string verity_mode = android::base::GetProperty("ro.boot.veritymode", "");
     verity_supported = android::base::EqualsIgnoreCase(verity_mode, "enforcing");
 
+    care_map_prefix_ = care_map_dir_.path + "/care_map"s;
     care_map_pb_ = care_map_dir_.path + "/care_map.pb"s;
     care_map_txt_ = care_map_dir_.path + "/care_map.txt"s;
+    // Overrides the the care_map_prefix.
+    verifier_.set_care_map_prefix(care_map_prefix_);
+
+    property_id_ = "ro.build.fingerprint";
+    fingerprint_ = android::base::GetProperty(property_id_, "");
+    // Overrides the property_reader if we cannot read the given property on the device.
+    if (fingerprint_.empty()) {
+      fingerprint_ = "mock_fingerprint";
+      verifier_.set_property_reader([](const std::string& /* id */) { return "mock_fingerprint"; });
+    }
   }
 
   void TearDown() override {
@@ -58,6 +70,9 @@
       if (partition.find("ranges") != partition.end()) {
         info.set_ranges(partition.at("ranges"));
       }
+      if (partition.find("id") != partition.end()) {
+        info.set_id(partition.at("id"));
+      }
       if (partition.find("fingerprint") != partition.end()) {
         info.set_fingerprint(partition.at("fingerprint"));
       }
@@ -72,13 +87,16 @@
   UpdateVerifier verifier_;
 
   TemporaryDir care_map_dir_;
+  std::string care_map_prefix_;
   std::string care_map_pb_;
   std::string care_map_txt_;
+
+  std::string property_id_;
+  std::string fingerprint_;
 };
 
 TEST_F(UpdateVerifierTest, verify_image_no_care_map) {
-  // Non-existing care_map is allowed.
-  ASSERT_FALSE(verifier_.ParseCareMap("/doesntexist"));
+  ASSERT_FALSE(verifier_.ParseCareMap());
 }
 
 TEST_F(UpdateVerifierTest, verify_image_smoke) {
@@ -90,26 +108,26 @@
 
   std::string content = "system\n2,0,1";
   ASSERT_TRUE(android::base::WriteStringToFile(content, care_map_txt_));
-  ASSERT_TRUE(verifier_.ParseCareMap(care_map_txt_));
+  ASSERT_TRUE(verifier_.ParseCareMap());
   ASSERT_TRUE(verifier_.VerifyPartitions());
 
   // Leading and trailing newlines should be accepted.
   ASSERT_TRUE(android::base::WriteStringToFile("\n" + content + "\n\n", care_map_txt_));
-  ASSERT_TRUE(verifier_.ParseCareMap(care_map_txt_));
+  ASSERT_TRUE(verifier_.ParseCareMap());
   ASSERT_TRUE(verifier_.VerifyPartitions());
 }
 
 TEST_F(UpdateVerifierTest, verify_image_empty_care_map) {
-  ASSERT_FALSE(verifier_.ParseCareMap(care_map_txt_));
+  ASSERT_FALSE(verifier_.ParseCareMap());
 }
 
 TEST_F(UpdateVerifierTest, verify_image_wrong_lines) {
   // The care map file can have only 2 / 4 / 6 lines.
   ASSERT_TRUE(android::base::WriteStringToFile("line1", care_map_txt_));
-  ASSERT_FALSE(verifier_.ParseCareMap(care_map_txt_));
+  ASSERT_FALSE(verifier_.ParseCareMap());
 
   ASSERT_TRUE(android::base::WriteStringToFile("line1\nline2\nline3", care_map_txt_));
-  ASSERT_FALSE(verifier_.ParseCareMap(care_map_txt_));
+  ASSERT_FALSE(verifier_.ParseCareMap());
 }
 
 TEST_F(UpdateVerifierTest, verify_image_malformed_care_map) {
@@ -121,7 +139,7 @@
 
   std::string content = "system\n2,1,0";
   ASSERT_TRUE(android::base::WriteStringToFile(content, care_map_txt_));
-  ASSERT_FALSE(verifier_.ParseCareMap(care_map_txt_));
+  ASSERT_FALSE(verifier_.ParseCareMap());
 }
 
 TEST_F(UpdateVerifierTest, verify_image_legacy_care_map) {
@@ -133,7 +151,7 @@
 
   std::string content = "/dev/block/bootdevice/by-name/system\n2,1,0";
   ASSERT_TRUE(android::base::WriteStringToFile(content, care_map_txt_));
-  ASSERT_FALSE(verifier_.ParseCareMap(care_map_txt_));
+  ASSERT_FALSE(verifier_.ParseCareMap());
 }
 
 TEST_F(UpdateVerifierTest, verify_image_protobuf_care_map_smoke) {
@@ -144,12 +162,17 @@
   }
 
   std::vector<std::unordered_map<std::string, std::string>> partitions = {
-    { { "name", "system" }, { "ranges", "2,0,1" } },
+    {
+        { "name", "system" },
+        { "ranges", "2,0,1" },
+        { "id", property_id_ },
+        { "fingerprint", fingerprint_ },
+    },
   };
 
   std::string proto = ConstructProto(partitions);
   ASSERT_TRUE(android::base::WriteStringToFile(proto, care_map_pb_));
-  ASSERT_TRUE(verifier_.ParseCareMap(care_map_pb_));
+  ASSERT_TRUE(verifier_.ParseCareMap());
   ASSERT_TRUE(verifier_.VerifyPartitions());
 }
 
@@ -161,12 +184,16 @@
   }
 
   std::vector<std::unordered_map<std::string, std::string>> partitions = {
-    { { "ranges", "2,0,1" } },
+    {
+        { "ranges", "2,0,1" },
+        { "id", property_id_ },
+        { "fingerprint", fingerprint_ },
+    },
   };
 
   std::string proto = ConstructProto(partitions);
   ASSERT_TRUE(android::base::WriteStringToFile(proto, care_map_pb_));
-  ASSERT_FALSE(verifier_.ParseCareMap(care_map_pb_));
+  ASSERT_FALSE(verifier_.ParseCareMap());
 }
 
 TEST_F(UpdateVerifierTest, verify_image_protobuf_care_map_bad_ranges) {
@@ -177,10 +204,55 @@
   }
 
   std::vector<std::unordered_map<std::string, std::string>> partitions = {
-    { { "name", "system" }, { "ranges", "3,0,1" } },
+    {
+        { "name", "system" },
+        { "ranges", "3,0,1" },
+        { "id", property_id_ },
+        { "fingerprint", fingerprint_ },
+    },
   };
 
   std::string proto = ConstructProto(partitions);
   ASSERT_TRUE(android::base::WriteStringToFile(proto, care_map_pb_));
-  ASSERT_FALSE(verifier_.ParseCareMap(care_map_pb_));
+  ASSERT_FALSE(verifier_.ParseCareMap());
+}
+
+TEST_F(UpdateVerifierTest, verify_image_protobuf_empty_fingerprint) {
+  // This test relies on dm-verity support.
+  if (!verity_supported) {
+    GTEST_LOG_(INFO) << "Test skipped on devices without dm-verity support.";
+    return;
+  }
+
+  std::vector<std::unordered_map<std::string, std::string>> partitions = {
+    {
+        { "name", "system" },
+        { "ranges", "2,0,1" },
+    },
+  };
+
+  std::string proto = ConstructProto(partitions);
+  ASSERT_TRUE(android::base::WriteStringToFile(proto, care_map_pb_));
+  ASSERT_FALSE(verifier_.ParseCareMap());
+}
+
+TEST_F(UpdateVerifierTest, verify_image_protobuf_fingerprint_mismatch) {
+  // This test relies on dm-verity support.
+  if (!verity_supported) {
+    GTEST_LOG_(INFO) << "Test skipped on devices without dm-verity support.";
+    return;
+  }
+
+  std::vector<std::unordered_map<std::string, std::string>> partitions = {
+    {
+        { "name", "system" },
+        { "ranges", "2,0,1" },
+        { "id", property_id_ },
+        { "fingerprint", "unsupported_fingerprint" },
+    },
+  };
+
+  std::string proto = ConstructProto(partitions);
+  ASSERT_TRUE(android::base::WriteStringToFile(proto, care_map_pb_));
+  ASSERT_FALSE(verifier_.ParseCareMap());
 }