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Commit 5081f587 authored by David Anderson's avatar David Anderson Committed by Android Build Coastguard Worker
Browse files

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

Ignore-AOSP-First: security fix
Bug: 368069390
Test: libdm_test
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:a48086d28966c20794c3a04af83cdf13af268dcc)
Merged-In: I40b9a0129e58b1a0f116ca29f0ee66f91a27a73d
Change-Id: I40b9a0129e58b1a0f116ca29f0ee66f91a27a73d
parent a915b479

fs_mgr/libdm/dm.cpp

+14 −0
Original line number Diff line number Diff line
@@ -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;

    }

fs_mgr/libdm/dm_test.cpp

+29 −0
Original line number Diff line number Diff line
@@ -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);

}