Update OEMCrypto test comments and logs

Merge from Widevine repo of http://go/wvgerrit/121886

This CL merges some changes from branch rvc-dev to sc-dev
that prepared it for merge.

One change is that the unit tests now say they are part of
Android S instead of R.

Bug: 180546871
Change-Id: I2ebbd8f7b8586389ebb75f3743a2dc2ad8caa214

libwvdrmengine/oemcrypto/test/README.md

@@ -0,0 +1,125 @@
+# OEMCrypto Unit Tests
+
+## Basic Functionality Tests
+
+Most unit tests in this category verify that the basic functionality of opening
+sessions, initializing and terminating the system, and reporting status work
+correctly.
+
+## Decrypt Tests
+
+The decrypt tests verify that encrypted data is correctly decrypted with the
+desired key. These tests cover a large variety of patterns, sample sizes, and
+subsample sizes.
+
+## Secure Buffers
+
+If OEMCrypto implements the function `OEMCrypto_AllocateSecureBuffer`, then all
+of the decrypt tests will also run with the output buffer being a secure
+buffer. If the function `OEMCrypto_SupportsDecryptHash` returns
+`OEMCrypto_CRC_Clear_Buffer`, then the secure buffer decryption will be verified
+with the CRC32 hash of the input data.
+
+## Usage Table Tests
+
+Usage table tests verify that the usage table is correctly procesed. The usage
+table is used to control reloading keys for offline playback, and for reporting
+secure stops for online playback.
+
+## Duration Tests
+
+Duration tests verify that license durations are enforced correctly. Most of
+this functionality can be met by keeping an accurate system time, and calling
+the ODK functions as described in the document "License Duration and Renewal".
+
+## OEMCrypto Memory Unit Tests
+
+### Objective
+
+*   Add OEMCrypto buffer overflow unit tests (indirect way of fuzzing) to verify
+    OEMCrypto API behavior when the parameters passed to the API are out of
+    range or not reasonable. The API can return an error code, but shouldn't
+    crash.
+
+*   A lot of OEMCrypto APIs take buffers and their length as inputs to the APIs
+    and we have added unit tests with buffers of varying lengths (small
+    to huge) to verify API behavior which is an indirect and simplest way of
+    fuzz testing to detect buffer overflows.
+
+*   Add the tests for OEMCrypto APIs with prefix `OEMCryptoMemory` in the
+    following format. Huge length is set at 100 MB as of now.
+
+    ```cpp
+    for (size_t length=small_length; length<huge_length; length=length * 2) {
+        Create buffer of size length.
+        Call api expecting it not to crash or segfault.
+    }
+    ```
+
+*   Add tests for OEMCrypto APIs with out of range values for length and offsets
+    of OEMCryptoSubstring struct. This length and offset fields are used to read
+    values from an input buffer in most of the APIs. This can cause buffer
+    overflows if the length and offset fields are not validated against the
+    input buffer.
+
+### Background
+
+*   Security is the top priority for Widevine. We came up with a simple approach
+    to catch most common issues with widevine's implementations. A simplest
+    approach is to add OEMCrypto unit tests to verify OEMCrypto API behavior
+    when the parameters are out of range, meaning for an unreasonable length
+    which can cause buffer overflows. Most of the implementation either does not
+    validate input length parameters or copies data to secure buffers out of TA
+    space causing memory corruptions, buffer overflows. Partners who implement
+    OEMCrypto implementations will run OEMCrypto unit tests as part of the
+    process.
+
+*   We have added unit tests with parameters that can cause buffer overflows if
+    the parameters are not validated. This way partners can catch issues
+    earlier in the process when they run OEMCrypto unit tests. All the unit
+    tests with prefix `OEMCryptoMemory` are added to test the above scenario.
+
+### What to expect from these tests
+
+*   `OEMCryptoMemory*` tests are designed to fail if API doesn't have enough
+    validations around input buffer lengths, parameters or OEMCryptoSubstring
+    struct. If the API doesn't have validations which might lead to a crash, the
+    test fails with a segfault or an appropriate crash message based on the API
+    implementation.
+
+*   Find out for what buffer length, the API is crashing and then debugging the
+    test against the OEMCrypto implementation should be able to provide
+    information about the error.
+
+*   Another way to debug would be to compile the tests with sanitizer flags,
+    which will be able to provide detailed information about the crash.
+
+*   Partners are expected to fix issues with the API so that the tests don't
+    fail.
+
+*   As these tests run for varying lengths from small to huge buffer lengths,
+    some of the tests might take longer to run(~3 minutes).
+
+*   `OEMCryptoMemoryInstallKeyboxForHugeKeyboxBuffer*` tests which tries to
+    call install keybox API with varying buffer lengths. This test by default
+    is not compiled as it overwrites the keybox on the device. Uncomment,
+    compile and run the tests only if you have ability to recover the keybox
+    on device where the test is ran.
+
+## Filtering out tests
+
+The source code will check for functionality of OEMCrypto and filter out tests
+that are not required. For example, if a device uses a keybox, then Provisioning
+3.0 tests are skipped, and vice versa.
+
+If you wish to skip slow tests because you only want to verify basic
+functionality, then you can set the environment variable `GTEST_FILTER`,
+as documented
+[here](https://github.com/google/googletest/blob/master/docs/advanced.md#running-a-subset-of-the-tests).
+
+For example, to skip the duration tests, buffer overflow tests and long running
+stress tests, you would set
+
+```
+GTEST_FILTER="*-*Duration*:*TimingTest*:*Memory*:*Huge*:*NonceFlood*:*ManyUsageEntries*:*Defrag*"
+```

libwvdrmengine/oemcrypto/test/fuzz_tests/oemcrypto_decrypt_cenc_fuzz.cc

@@ -7,6 +7,7 @@
 #include "log.h"
 #include "oemcrypto_fuzz_helper.h"
 #include "oemcrypto_fuzz_structs.h"
+#include "oemcrypto_overflow.h"
 
 namespace wvoec {
 const size_t MAX_FUZZ_SAMPLE_SIZE = 5 * MB;
@@ -137,13 +138,16 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
 
     // Copy sub sample data.
     sample_descriptions[i].subsamples = &subsamples[input_subsample_index];
-    input_subsample_index += sample_descriptions[i].subsamples_length;
+    if (AddOverflowUX(input_subsample_index,
+                      sample_descriptions[i].subsamples_length,
+                      &input_subsample_index)) {
+      return 0;
+    }
     if (input_subsample_index > subsamples.size()) return 0;
   }  // Sample loop.
 
   // Allocate input/output buffers for each sample description.
   vector<OEMCrypto_SharedMemory> input_buffer(total_input_data_length);
-  RAND_bytes(input_buffer.data(), total_input_data_length);
   size_t input_buffer_index = 0;
   for (size_t i = 0; i < samples_length; i++) {
     sample_descriptions[i].buffers.input_data =

libwvdrmengine/oemcrypto/test/fuzz_tests/oemcrypto_fuzz_helper.h

@@ -36,9 +36,7 @@ class OEMCryptoLicenseAPIFuzz : public InitializeFuzz {
     session_.GenerateNonce();
   }
 
-  ~OEMCryptoLicenseAPIFuzz() {
-    session_.close();
-  }
+  ~OEMCryptoLicenseAPIFuzz() { session_.close(); }
 
   LicenseRoundTrip& license_messages() { return license_messages_; }
 

libwvdrmengine/oemcrypto/test/fuzz_tests/oemcrypto_odkitee_dispatcher_fuzz.cc

@@ -0,0 +1,77 @@
+#include <stdio.h>
+
+#include "dispatcher.h"
+#include "marshaller_base.h"
+#include "transport_interface.h"
+
+namespace wvoec {
+
+void InitializeODKMessage(ODK_Message* message, uint8_t* data, size_t size) {
+  ODK_Message_Impl* impl = (ODK_Message_Impl*)message;
+  impl->base = data;
+  impl->size = size;
+  impl->capacity = size;
+  impl->read_offset = 0;
+  impl->status = MESSAGE_STATUS_OK;
+}
+
+void OpenOEMCryptoTASession() {
+  ODK_Message request;
+  ODK_Message* response = NULL;
+  uint8_t response_buffer[0x1000];
+  uint8_t request_body[] = {
+      0x06,                    // TAG_UINT32
+      0x09, 0x00, 0x00, 0x00,  // API value (0x09)
+      0x01,                    // TAG_BOOL
+      0x00,                    // value (false)
+      0x0a                     // TAG_EOM
+  };
+
+  InitializeODKMessage(&request, request_body, sizeof(request_body));
+
+  ODK_DispatchMessage(&request, &response);
+  if (response != NULL) ODK_Transport_DeallocateMessage(response);
+}
+
+void InitializeOEMCryptoTA() {
+  ODK_Message init_request;
+  ODK_Message* init_response = NULL;
+  uint8_t response_buffer[0x1000];
+  uint8_t init_request_body[] = {
+      0x06,                    // TAG_UINT32
+      0x01, 0x00, 0x00, 0x00,  // API value(0x01)
+      0x0a                     // TAG_EOM
+  };
+
+  InitializeODKMessage(&init_request, init_request_body,
+                       sizeof(init_request_body));
+
+  ODK_DispatchMessage(&init_request, &init_response);
+  if (init_response != NULL) ODK_Transport_DeallocateMessage(init_response);
+}
+
+extern "C" int LLVMFuzzerInitialize(int* argc, char*** argv) {
+  ODK_InitializeDispatcher();
+  InitializeOEMCryptoTA();
+  OpenOEMCryptoTASession();
+  return 0;
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  ODK_Message request;
+  ODK_Message* response = NULL;
+  unsigned char response_buffer[0x1000];
+
+  uint8_t* input = new uint8_t[size];
+  memcpy(input, data, size);
+
+  InitializeODKMessage(&request, input, size);
+
+  ODK_DispatchMessage(&request, &response);
+  if (response != NULL) ODK_Transport_DeallocateMessage(response);
+
+  delete[] input;
+  return 0;
+}
+
+}  // namespace wvoec

libwvdrmengine/oemcrypto/test/oec_device_features.cpp

@@ -129,6 +129,7 @@ std::string DeviceFeatures::RestrictFilter(const std::string& initial_filter) {
   if (!generic_crypto)                FilterOut(&filter, "*GenericCrypto*");
   if (!cast_receiver)                 FilterOut(&filter, "*CastReceiver*");
   if (!usage_table)                   FilterOut(&filter, "*UsageTable*");
+  if (!usage_table)                   FilterOut(&filter, "*BadRange_pst*");
   if (derive_key_method == NO_METHOD) FilterOut(&filter, "*SessionTest*");
   if (provisioning_method
       != OEMCrypto_OEMCertificate)    FilterOut(&filter, "*Prov30*");

libwvdrmengine/oemcrypto/test/oec_session_util.cpp

@@ -154,8 +154,7 @@ RoundTrip<CoreRequest, PrepAndSignRequest, CoreResponse, ResponseData>::
   constexpr size_t small_size = 42;  // arbitrary.
   uint32_t session_id = session()->session_id();
   GetDefaultRequestSignatureAndCoreMessageLengths<PrepAndSignRequest>(
-      session_id, required_message_size_, small_size, &gen_signature_length,
-      &core_message_length);
+      session_id, small_size, &gen_signature_length, &core_message_length);
   // Used to test request APIs with varying lengths of core message.
   core_message_length =
       std::max(core_message_length, required_core_message_size_);
@@ -192,9 +191,8 @@ RoundTrip<CoreRequest, PrepAndSignRequest, CoreResponse, ResponseData>::
 
 template <PrepAndSignRequest_t PrepAndSignRequest>
 void GetDefaultRequestSignatureAndCoreMessageLengths(
-    uint32_t& session_id, size_t& required_message_size,
-    const size_t& small_size, size_t* gen_signature_length,
-    size_t* core_message_length) {
+    uint32_t& session_id, const size_t& small_size,
+    size_t* gen_signature_length, size_t* core_message_length) {
   vector<uint8_t> data(small_size);
   for (size_t i = 0; i < data.size(); i++) data[i] = i & 0xFF;
   ASSERT_EQ(

libwvdrmengine/oemcrypto/test/oec_session_util.h

@@ -669,9 +669,8 @@ void WriteRequestApiCorpus(size_t signature_length, size_t core_message_length,
                            vector<uint8_t>& data);
 template <PrepAndSignRequest_t PrepAndSignRequest>
 void GetDefaultRequestSignatureAndCoreMessageLengths(
-    uint32_t& session_id, size_t& required_message_size,
-    const size_t& small_size, size_t* gen_signature_length,
-    size_t* core_message_length);
+    uint32_t& session_id, const size_t& small_size,
+    size_t* gen_signature_length, size_t* core_message_length);
 }  // namespace wvoec
 
 #endif  // CDM_OEC_SESSION_UTIL_H_

libwvdrmengine/oemcrypto/test/oemcrypto_test.cpp

@@ -137,6 +137,11 @@ void TestHugeLengthDoesNotCrashAPI(oemcrypto_function f,
         !check_status);
        buffer_length *= 2) {
     sts = f(buffer_length);
+    if (check_status && sts != OEMCrypto_SUCCESS &&
+        sts != OEMCrypto_ERROR_SHORT_BUFFER) {
+      LOGI("Test exits huge buffer loop for length:%zu, status:%d",
+           buffer_length, sts);
+    }
   }
 }
 
@@ -170,6 +175,17 @@ const size_t kLargeMessageSize[] = {   8*KiB,   8*KiB,  16*KiB, 32*KiB};
 // const size_t kAV1NumberSubsamples[] = { 72,    144,     288,    576};
 // clang-format on
 
+// Return a printable string from data. If all the characters are printable,
+// then just use the string. Otherwise, convert to hex.
+std::string MaybeHex(const uint8_t* data, size_t length) {
+  for (size_t i = 0; i < length; i++) {
+    if (!isprint(data[i])) return "0x" + wvcdm::HexEncode(data, length);
+  }
+  return std::string(reinterpret_cast<const char*>(data), length);
+}
+std::string MaybeHex(const std::vector<uint8_t>& data) {
+  return MaybeHex(data.data(), data.size());
+}
 }  // namespace
 
 class OEMCryptoClientTest : public ::testing::Test, public SessionUtil {
@@ -202,6 +218,17 @@ class OEMCryptoClientTest : public ::testing::Test, public SessionUtil {
   }
 };
 
+TEST_F(OEMCryptoClientTest, FreeUnallocatedSecureBufferNoFailure) {
+  Session s;
+  s.open();
+  OEMCrypto_DestBufferDesc output_descriptor;
+  int secure_fd = kHugeRandomNumber;
+  ASSERT_NE(OEMCrypto_SUCCESS,
+            OEMCrypto_FreeSecureBuffer(s.session_id(), &output_descriptor,
+                                       secure_fd));
+  s.close();
+}
+
 /// @addtogroup basic
 /// @{
 
@@ -212,15 +239,20 @@ class OEMCryptoClientTest : public ::testing::Test, public SessionUtil {
  */
 TEST_F(OEMCryptoClientTest, VersionNumber) {
   const std::string log_message =
-      "OEMCrypto unit tests for API 16.4. Tests last updated 2020-10-07";
+      "OEMCrypto unit tests for API 16.3 or 4. Tests last updated 2021-02-22";
   cout << "             " << log_message << "\n";
+  cout << "             "
+       << "These tests are part of Android S."
+       << "\n";
   LOGI("%s", log_message.c_str());
   // If any of the following fail, then it is time to update the log message
   // above.
   EXPECT_EQ(ODK_MAJOR_VERSION, 16);
   // Note on minor versions. Widevine requires version 16.3 or greater for CE
   // CDM and Android devices. For CE CDM devices that do not support usage
-  // tables, we strongly recommend 16.4.
+  // tables, we strongly recommend 16.4.  Note: This is the version of the ODK
+  // library built into the tests, which might be different from the version
+  // that is pre-compiled into liboemcrypto.so.
   EXPECT_GE(ODK_MINOR_VERSION, 3);
   EXPECT_LE(ODK_MINOR_VERSION, 4);
   EXPECT_EQ(kCurrentAPI, 16u);
@@ -229,7 +261,9 @@ TEST_F(OEMCryptoClientTest, VersionNumber) {
   ASSERT_EQ('L', level[0]);
   cout << "             OEMCrypto Security Level is " << level << endl;
   uint32_t version = OEMCrypto_APIVersion();
-  cout << "             OEMCrypto API version is " << version << endl;
+  uint32_t minor_version = OEMCrypto_MinorAPIVersion();
+  cout << "             OEMCrypto API version is " << version << "."
+       << minor_version << endl;
   if (OEMCrypto_SupportsUsageTable()) {
     cout << "             OEMCrypto supports usage tables" << endl;
   } else {
@@ -661,8 +695,8 @@ TEST_F(OEMCryptoClientTest, ClearCopyTestAPI10) {
                            OEMCrypto_FirstSubsample | OEMCrypto_LastSubsample));
   dest_buffer_descriptor.buffer.clear.address = output_buffer.data();
   dest_buffer_descriptor.buffer.clear.address_length = output_buffer.size() - 1;
-  ASSERT_EQ(
-      OEMCrypto_ERROR_SHORT_BUFFER,
+  ASSERT_NE(
+      OEMCrypto_SUCCESS,
       OEMCrypto_CopyBuffer(s.session_id(), input_buffer.data(),
                            input_buffer.size(), &dest_buffer_descriptor,
                            OEMCrypto_FirstSubsample | OEMCrypto_LastSubsample));
@@ -896,8 +930,8 @@ TEST_F(OEMCryptoKeyboxTest, NormalGetDeviceId) {
   uint8_t dev_id[128] = {0};
   size_t dev_id_len = 128;
   sts = OEMCrypto_GetDeviceID(dev_id, &dev_id_len);
-  cout << "             NormalGetDeviceId: dev_id = " << dev_id
-       << " len = " << dev_id_len << endl;
+  cout << "             NormalGetDeviceId: dev_id = "
+       << MaybeHex(dev_id, dev_id_len) << " len = " << dev_id_len << endl;
   ASSERT_EQ(OEMCrypto_SUCCESS, sts);
 }
 
@@ -1039,7 +1073,7 @@ TEST_F(OEMCryptoProv30Test, GetDeviceId) {
   }
   ASSERT_EQ(OEMCrypto_SUCCESS, sts);
   dev_id.resize(dev_id_len);
-  cout << "             NormalGetDeviceId: dev_id = " << dev_id.data()
+  cout << "             NormalGetDeviceId: dev_id = " << MaybeHex(dev_id)
        << " len = " << dev_id_len << endl;
   ASSERT_EQ(OEMCrypto_SUCCESS, sts);
 }
@@ -2355,6 +2389,39 @@ TEST_P(OEMCryptoLicenseTest,
       !kCheckStatus);
 }
 
+TEST_P(OEMCryptoLicenseTest,
+       DecryptCENCForNumBytesClearPlusEncryptedOverflowsSize) {
+  LoadLicense();
+  OEMCrypto_SelectKey(session_.session_id(), session_.license().keys[0].key_id,
+                      session_.license().keys[0].key_id_length,
+                      OEMCrypto_CipherMode_CTR);
+
+  size_t input_buffer_size = 1;
+  vector<uint8_t> in_buffer(input_buffer_size);
+  vector<uint8_t> out_buffer(in_buffer.size());
+
+  OEMCrypto_SampleDescription sample_description;
+  OEMCrypto_SubSampleDescription subsample_description;
+  GenerateSimpleSampleDescription(in_buffer, out_buffer, &sample_description,
+                                  &subsample_description);
+
+  OEMCrypto_SubSampleDescription* sub_samples =
+      const_cast<OEMCrypto_SubSampleDescription*>(
+          sample_description.subsamples);
+  // If Decrypt cenc API does not check for overflow on clear + encrypted
+  // addition operation. This will result in 1 which will match with input data
+  // length, which causes validation to pass.
+  sub_samples[0].num_bytes_clear = 2;
+  sub_samples[0].num_bytes_encrypted = 0xFFFFFFFFFFFFFFFF;
+
+  // Create the pattern description (always 0,0 for CTR)
+  OEMCrypto_CENCEncryptPatternDesc pattern = {0, 0};
+  // Try to decrypt the data
+  ASSERT_NE(OEMCrypto_SUCCESS,
+            OEMCrypto_DecryptCENC(session_.session_id(), &sample_description, 1,
+                                  &pattern));
+}
+
 TEST_P(OEMCryptoLicenseTest,
        OEMCryptoMemoryDecryptCENCForHugeNumBytesEncryptedAndBuffers) {
   TestDecryptCENCForHugeBufferLengths(
@@ -3850,50 +3917,17 @@ class OEMCryptoSessionTestsDecryptTests
               OEMCrypto_SUCCESS);
   }
 
-  void TestDecryptCENC() {
-    OEMCryptoResult sts;
+  void TestDecryptCENC() { ASSERT_EQ(DecryptCENC(), OEMCrypto_SUCCESS); }
 
-    // OEMCrypto only supports providing a decrypt hash for one sample.
-    if (samples_.size() > 1) verify_crc_ = false;
-
-    // If supported, check the decrypt hashes.
-    if (verify_crc_) {
-      const TestSample& sample = samples_[0];
-
-      uint32_t hash =
-          wvcrc32(sample.truth_buffer.data(), sample.truth_buffer.size());
-      ASSERT_EQ(OEMCrypto_SetDecryptHash(
-                    session_.session_id(), 1,
-                    reinterpret_cast<const uint8_t*>(&hash), sizeof(hash)),
-                OEMCrypto_SUCCESS);
-    }
-
-    // Build an array of just the sample descriptions.
-    std::vector<OEMCrypto_SampleDescription> sample_descriptions;
-    sample_descriptions.reserve(samples_.size());
-    for (TestSample& sample : samples_) {
-      // This must be deferred until this point in case the test modifies the
-      // buffer before testing decrypt.
-      sample.description.buffers.input_data = sample.encrypted_buffer.data();
-      // Append to the description array.
-      sample_descriptions.push_back(sample.description);
-    }
-
-    // Perform decryption using the test data that was previously set up.
-    sts = DecryptFallbackChain::Decrypt(
-        session_.session_id(), sample_descriptions.data(),
-        sample_descriptions.size(), cipher_mode_, &pattern_);
-    ASSERT_EQ(sts, OEMCrypto_SUCCESS);
-
-    // Validate the decrypted data.
+  void ValidateDecryptedData() {
     for (TestSample& sample : samples_) {
       if (sample.description.buffers.output_descriptor.type ==
           OEMCrypto_BufferType_Clear) {
         const size_t total_size = sample.description.buffers.input_data_length;
         // To verify there is no buffer overrun after decrypting, look at the
-        // padded bytes just after the data buffer that was written.  It should
-        // not have changed from the original 0xaa that we set in MakeBuffer
-        // function.
+        // padded bytes just after the data buffer that was written.  It
+        // should not have changed from the original 0xaa that we set in
+        // MakeBuffer function.
         if (decrypt_inplace_) {
           EXPECT_EQ(std::count(sample.encrypted_buffer.begin() + total_size,
                                sample.encrypted_buffer.end(), 0xaa),
@@ -3919,6 +3953,41 @@ class OEMCryptoSessionTestsDecryptTests
     }
   }
 
+  OEMCryptoResult DecryptCENC() {
+    // OEMCrypto only supports providing a decrypt hash for one sample.
+    if (samples_.size() > 1) verify_crc_ = false;
+
+    // If supported, check the decrypt hashes.
+    if (verify_crc_) {
+      const TestSample& sample = samples_[0];
+
+      uint32_t hash =
+          wvcrc32(sample.truth_buffer.data(), sample.truth_buffer.size());
+      OEMCrypto_SetDecryptHash(session_.session_id(), 1,
+                               reinterpret_cast<const uint8_t*>(&hash),
+                               sizeof(hash));
+    }
+
+    // Build an array of just the sample descriptions.
+    std::vector<OEMCrypto_SampleDescription> sample_descriptions;
+    sample_descriptions.reserve(samples_.size());
+    for (TestSample& sample : samples_) {
+      // This must be deferred until this point in case the test modifies the
+      // buffer before testing decrypt.
+      sample.description.buffers.input_data = sample.encrypted_buffer.data();
+      // Append to the description array.
+      sample_descriptions.push_back(sample.description);
+    }
+
+    // Perform decryption using the test data that was previously set up.
+    OEMCryptoResult result = DecryptFallbackChain::Decrypt(
+        session_.session_id(), sample_descriptions.data(),
+        sample_descriptions.size(), cipher_mode_, &pattern_);
+    if (result != OEMCrypto_SUCCESS) return result;
+    ValidateDecryptedData();
+    return result;
+  }
+
   // Parameters of test case
   OEMCrypto_CENCEncryptPatternDesc pattern_;
   OEMCryptoCipherMode cipher_mode_;
@@ -4094,7 +4163,6 @@ TEST_P(OEMCryptoSessionTestsDecryptTests, DecryptMaxSampleAPI16) {
   // max_sample_size.
   const size_t subsample_size =
       std::min(max_sample_size / max_num_subsamples + 1, max_subsample_size);
-
   size_t bytes_remaining = max_sample_size;
   std::vector<SubsampleSize> subsample_sizes;
   while (bytes_remaining > 0 && subsample_sizes.size() < max_num_subsamples) {
@@ -4113,6 +4181,103 @@ TEST_P(OEMCryptoSessionTestsDecryptTests, DecryptMaxSampleAPI16) {
   ASSERT_NO_FATAL_FAILURE(TestDecryptCENC());
 }
 
+TEST_P(OEMCryptoSessionTestsDecryptTests,
+       OEMCryptoMemoryDecryptCENCForHugeNumberOfSubSamples) {
+  auto oemcrypto_function = [&](size_t number_of_subsamples) {
+    std::vector<SubsampleSize> subsample_sizes;
+    while (number_of_subsamples-- > 0) {
+      subsample_sizes.push_back({1, 1});
+    }
+    SetSubsampleSizes(subsample_sizes);
+    LoadLicense();
+    MakeBuffers();
+    EncryptData();
+    OEMCryptoResult result = DecryptCENC();
+    // Closing the session and opening it for next iteration.
+    // If it is last iteration, session will be closed in teardown method of
+    // class.
+    session_.close();
+    session_.open();
+    InstallTestRSAKey(&session_);
+    return result;
+  };
+  TestHugeLengthDoesNotCrashAPI(oemcrypto_function, 1, 2 * MiB, kCheckStatus);
+}
+
+TEST_P(OEMCryptoSessionTestsDecryptTests,
+       OEMCryptoMemoryCheckDecryptCENCStatusForHugeNumberOfSubSamples) {
+  size_t number_of_subsamples = 10000;
+  std::vector<SubsampleSize> subsample_sizes;
+  while (number_of_subsamples-- > 0) {
+    subsample_sizes.push_back({100, 100});
+  }
+  SetSubsampleSizes(subsample_sizes);
+  LoadLicense();
+  MakeBuffers();
+  EncryptData();
+  // Build an array of just the sample descriptions.
+  std::vector<OEMCrypto_SampleDescription> sample_descriptions;
+  sample_descriptions.reserve(samples_.size());
+  for (TestSample& sample : samples_) {
+    // This must be deferred until this point in case the test modifies the
+    // buffer before testing decrypt.
+    sample.description.buffers.input_data = sample.encrypted_buffer.data();
+    // Append to the description array.
+    sample_descriptions.push_back(sample.description);
+  }
+  OEMCryptoResult result = OEMCrypto_DecryptCENC(
+      session_.session_id(), sample_descriptions.data(), 1, &pattern_);
+  LOGD("Large number of subsamples test has return code %d", result);
+}
+
+TEST_P(OEMCryptoSessionTestsDecryptTests,
+       OEMCryptoMemoryCheckDecryptCENCStatusForHugeSubSample) {
+  std::vector<SubsampleSize> subsample_sizes;
+  subsample_sizes.push_back({100000, 100000});
+  SetSubsampleSizes(subsample_sizes);
+  LoadLicense();
+  MakeBuffers();
+  EncryptData();
+  // Build an array of just the sample descriptions.
+  std::vector<OEMCrypto_SampleDescription> sample_descriptions;
+  sample_descriptions.reserve(samples_.size());
+  for (TestSample& sample : samples_) {
+    // This must be deferred until this point in case the test modifies the
+    // buffer before testing decrypt.
+    sample.description.buffers.input_data = sample.encrypted_buffer.data();
+    // Append to the description array.
+    sample_descriptions.push_back(sample.description);
+  }
+  OEMCryptoResult result = OEMCrypto_DecryptCENC(
+      session_.session_id(), sample_descriptions.data(), 1, &pattern_);
+  LOGD("Large subsample test has return code %d", result);
+}
+
+TEST_P(OEMCryptoSessionTestsDecryptTests,
+       OEMCryptoMemoryDecryptCENCForHugeNumberOfSamples) {
+  auto oemcrypto_function = [&](size_t number_of_samples) {
+    std::vector<std::vector<SubsampleSize>> samples;
+    std::vector<SubsampleSize> subsample_sizes;
+    subsample_sizes.push_back({1, 1});
+    while (number_of_samples-- > 0) {
+      samples.push_back(subsample_sizes);
+    }
+    SetSampleSizes(samples);
+    LoadLicense();
+    MakeBuffers();
+    EncryptData();
+    OEMCryptoResult result = DecryptCENC();
+    // Closing the session and opening it for next iteration.
+    // If it is last iteration, session will be closed in teardown method of
+    // class.
+    session_.close();
+    session_.open();
+    InstallTestRSAKey(&session_);
+    return result;
+  };
+  TestHugeLengthDoesNotCrashAPI(oemcrypto_function, 1, 2 * MiB, kCheckStatus);
+}
+
 // Based on the resource rating, OEMCrypto should be able to handle the maximum
 // subsample size.
 TEST_P(OEMCryptoSessionTestsDecryptTests, DecryptMaxSubsample) {