libdm: Redact keys from dm-crypt targets when calling GetTable.HEADt13.0

Ignore-AOSP-First: security fix
Bug: 368069390
Test: libdm_test
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:034e2dd670e8bc81e35da74235c3d97f06556fa4)
Merged-In: I40b9a0129e58b1a0f116ca29f0ee66f91a27a73d
Change-Id: I40b9a0129e58b1a0f116ca29f0ee66f91a27a73d

2 files changed, 43 insertions, 0 deletions

diff --git a/fs_mgr/libdm/dm.cpp b/fs_mgr/libdm/dm.cpp
index 4034e30ab9..6da7b48b60 100644
--- a/fs_mgr/libdm/dm.cpp
+++ b/fs_mgr/libdm/dm.cpp
@@ -512,6 +512,17 @@ bool DeviceMapper::GetTableInfo(const std::string& name, std::vector<TargetInfo>
     return GetTable(name, DM_STATUS_TABLE_FLAG, table);
 }
 
+void RedactTableInfo(const struct dm_target_spec& spec, std::string* data) {
+    if (DeviceMapper::GetTargetType(spec) == "crypt") {
+        auto parts = android::base::Split(*data, " ");
+        if (parts.size() < 2) {
+            return;
+        }
+        parts[1] = "redacted";
+        *data = android::base::Join(parts, " ");
+    }
+}
+
 // private methods of DeviceMapper
 bool DeviceMapper::GetTable(const std::string& name, uint32_t flags,
                             std::vector<TargetInfo>* table) {
@@ -550,6 +561,9 @@ bool DeviceMapper::GetTable(const std::string& name, uint32_t flags,
             // Note: we use c_str() to eliminate any extra trailing 0s.
             data = std::string(&buffer[data_offset], next_cursor - data_offset).c_str();
         }
+        if (flags & DM_STATUS_TABLE_FLAG) {
+            RedactTableInfo(*spec, &data);
+        }
         table->emplace_back(*spec, data);
         cursor = next_cursor;
     }
diff --git a/fs_mgr/libdm/dm_test.cpp b/fs_mgr/libdm/dm_test.cpp
index 541f254cbc..f4c9784da8 100644
--- a/fs_mgr/libdm/dm_test.cpp
+++ b/fs_mgr/libdm/dm_test.cpp
@@ -690,3 +690,32 @@ TEST(libdm, CreateEmptyDevice) {
     // Empty device should be in suspended state.
     ASSERT_EQ(DmDeviceState::SUSPENDED, dm.GetState("empty-device"));
 }
+
+TEST(libdm, RedactDmCrypt) {
+    static constexpr uint64_t kImageSize = 65536;
+    static constexpr const char* kTestName = "RedactDmCrypt";
+    unique_fd temp_file(CreateTempFile("file_1", kImageSize));
+    ASSERT_GE(temp_file, 0);
+
+    LoopDevice loop(temp_file, 10s);
+    ASSERT_TRUE(loop.valid());
+
+    static constexpr const char* kAlgorithm = "aes-cbc-essiv:sha256";
+    static constexpr const char* kKey = "0e64ef514e6a1315b1f6390cb57c9e6a";
+
+    auto target = std::make_unique<DmTargetCrypt>(0, kImageSize / 512, kAlgorithm, kKey, 0,
+                                                  loop.device(), 0);
+    target->AllowDiscards();
+
+    DmTable table;
+    table.AddTarget(std::move(target));
+
+    auto& dm = DeviceMapper::Instance();
+    std::string crypt_path;
+    ASSERT_TRUE(dm.CreateDevice(kTestName, table, &crypt_path, 10s));
+
+    std::vector<DeviceMapper::TargetInfo> targets;
+    ASSERT_TRUE(dm.GetTableInfo(kTestName, &targets));
+    ASSERT_EQ(targets.size(), 1);
+    EXPECT_EQ(targets[0].data.find(kKey), std::string::npos);
+}