platform_hardware_interfaces/drm/1.0/default/CryptoPlugin.h
Edwin Wong a4e76aab23 [RESTRICT AUTOMERGE] Fix CryptoPlugin use after free vulnerability.
The shared memory buffer used by srcPtr can be freed by another
thread because it is not protected by a mutex. Subsequently,
a use after free AIGABRT can occur in a race condition.

SafetyNet logging is not added to avoid log spamming. The
mutex lock is called to setup for decryption, which is
called frequently.

The crash was reproduced on the device before the fix.
Verified the test passes after the fix.

Test: sts
  sts-tradefed run sts-engbuild-no-spl-lock -m StsHostTestCases --test android.security.sts.Bug_176495665#testPocBug_176495665

Test: push to device with target_hwasan-userdebug build
  adb shell /data/local/tmp/Bug-176495665_sts64

Bug: 176495665
Bug: 176444161
Change-Id: I4c83c44873eef960b654f387a3574fcad49c41a9
2021-04-02 21:50:49 +00:00

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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ANDROID_HARDWARE_DRM_V1_0__CRYPTOPLUGIN_H
#define ANDROID_HARDWARE_DRM_V1_0__CRYPTOPLUGIN_H
#include <android-base/thread_annotations.h>
#include <android/hardware/drm/1.0/ICryptoPlugin.h>
#include <android/hidl/memory/1.0/IMemory.h>
#include <hidl/Status.h>
#include <media/hardware/CryptoAPI.h>
#include <mutex>
namespace android {
namespace hardware {
namespace drm {
namespace V1_0 {
namespace implementation {
using ::android::hardware::drm::V1_0::DestinationBuffer;
using ::android::hardware::drm::V1_0::ICryptoPlugin;
using ::android::hardware::drm::V1_0::Mode;
using ::android::hardware::drm::V1_0::Pattern;
using ::android::hardware::drm::V1_0::SubSample;
using ::android::hardware::hidl_array;
using ::android::hardware::hidl_string;
using ::android::hardware::hidl_vec;
using ::android::hardware::Return;
using ::android::hardware::Void;
using ::android::hidl::memory::V1_0::IMemory;
using ::android::sp;
struct CryptoPlugin : public ICryptoPlugin {
CryptoPlugin(android::CryptoPlugin *plugin) : mLegacyPlugin(plugin) {}
~CryptoPlugin() {delete mLegacyPlugin;}
// Methods from ::android::hardware::drm::V1_0::ICryptoPlugin
// follow.
Return<bool> requiresSecureDecoderComponent(const hidl_string& mime)
override;
Return<void> notifyResolution(uint32_t width, uint32_t height) override;
Return<Status> setMediaDrmSession(const hidl_vec<uint8_t>& sessionId)
override;
Return<void> setSharedBufferBase(const ::android::hardware::hidl_memory& base,
uint32_t bufferId) override;
Return<void> decrypt(
bool secure, const hidl_array<uint8_t, 16>& keyId, const hidl_array<uint8_t, 16>& iv,
Mode mode, const Pattern& pattern, const hidl_vec<SubSample>& subSamples,
const SharedBuffer& source, uint64_t offset, const DestinationBuffer& destination,
decrypt_cb _hidl_cb) override NO_THREAD_SAFETY_ANALYSIS; // use unique_lock
private:
android::CryptoPlugin *mLegacyPlugin;
std::map<uint32_t, sp<IMemory>> mSharedBufferMap GUARDED_BY(mSharedBufferLock);
CryptoPlugin() = delete;
CryptoPlugin(const CryptoPlugin &) = delete;
void operator=(const CryptoPlugin &) = delete;
std::mutex mSharedBufferLock;
};
} // namespace implementation
} // namespace V1_0
} // namespace drm
} // namespace hardware
} // namespace android
#endif // ANDROID_HARDWARE_DRM_V1_0__CRYPTOPLUGIN_H