avb_manager.cpp - trusty/app/avb - Git at Google

 /*
  * Copyright 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.
  */

 #include "avb_manager.h"

 #include <string.h>
 #include <uapi/err.h>

 #include "secure_storage_interface.h"

 #define DEBUG 0

 const unsigned int kRollbackSlotMax = 32;

 static const uint32_t kAvbVersion = 1;
 static const char* kAvbRollbackFilename = "avb.rollback";
 static const unsigned int kPermanentAttributesLengthMax = 2048;
 static const char* kPermanentAttributesFilename = "avb.ppa";
 static const char* kLockStateFile = "avb.lock_state";
 static const unsigned int kStorageIdLengthMax = 64;

 static const uint32_t kTypeMask = 0xF000;
 static const unsigned int kTypeShift = 12;

 // Helper function to get |filename| and |slot| and based on type flag
 // in |raw_slot|. |filename| is assumed to be allocated with
 // kStorageIdLengthMax bytes.
 static int GetFilenameAndSlot(uint32_t raw_slot,
                               char filename[kStorageIdLengthMax],
                               uint32_t* slot) {
     // Upper 16 bits should not be set
     if (raw_slot & 0xFFFF0000) {
         TLOGE("Error: Slot value %u invalid\n", raw_slot);
         return ERR_NOT_VALID;
     }
     // Mask type flag from raw slot to get index
     *slot = raw_slot & ~kTypeMask;
     if (*slot >= kRollbackSlotMax) {
         TLOGE("Error: Slot value %u larger than supported %u\n", *slot,
               kRollbackSlotMax);
         return ERR_NOT_VALID;
     }
     // Choose correct file for rollback index type
     strcpy(filename, kAvbRollbackFilename);
     int index_type = (raw_slot & kTypeMask) >> kTypeShift;
     char postfix[4];
     snprintf(postfix, 4, ".%01X", index_type);
     strcat(filename, postfix);
     return NO_ERROR;
 }

 namespace avb {

 void AvbManager::ReadRollbackIndex(const RollbackIndexRequest& request,
                                    RollbackIndexResponse* response) {
     uint32_t slot;
     char filename[kStorageIdLengthMax];
     if (GetFilenameAndSlot(request.get_slot(), filename, &slot) < 0) {
         response->set_error(AvbError::kInvalid);
         TLOGE("Error: Invalid slot value: %u\n", request.get_slot());
         return;
     }

     int rc = storage_->open(filename);
     if (rc < 0) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: failed to open file %s: %d\n", filename, rc);
         return;
     }
     uint64_t size;
     rc = storage_->get_file_size(&size);
     if (rc < 0) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: failed to get size of file %s: %d\n", filename, rc);
         return;
     }

     // If no valid rollback counter file is found, initialize to 0
     uint64_t rollback_counter;
     if (size < kRollbackSlotMax * sizeof(uint64_t)) {
         TLOGD("No valid rollback index file found. Initializing to 0\n");
         uint64_t write_buf[kRollbackSlotMax] = {0};
         rc = storage_->write(0, write_buf, sizeof(write_buf));
         rollback_counter = 0;
     } else {
         TLOGD("Rollback index file found\n");
         rc = storage_->read(sizeof(rollback_counter) * slot, &rollback_counter,
                             sizeof(rollback_counter));
     }

     if (rc < 0) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: reading storage object: %d\n", rc);
         return;
     }

     if (static_cast<size_t>(rc) < sizeof(rollback_counter)) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: invalid object size: %d\n", rc);
         return;
     }

     response->set_value(rollback_counter);
 }

 void AvbManager::WriteRollbackIndex(const RollbackIndexRequest& request,
                                     RollbackIndexResponse* response) {
     uint32_t slot;
     char filename[kStorageIdLengthMax];
     if (GetFilenameAndSlot(request.get_slot(), filename, &slot) < 0) {
         response->set_error(AvbError::kInvalid);
         TLOGE("Error: Invalid slot value: %u\n", request.get_slot());
         return;
     }

     int rc = storage_->open(filename);
     if (rc < 0) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: failed to open file %s: %d\n", filename, rc);
         return;
     }
     uint64_t size;
     rc = storage_->get_file_size(&size);
     if (rc < 0) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: failed to get size of file %s: %d\n", filename, rc);
         return;
     }

     // If no valid rollback counter file is found, initialize to 0
     uint64_t request_value = request.get_value();
     if (static_cast<size_t>(size) < kRollbackSlotMax * sizeof(uint64_t)) {
         TLOGD("No valid rollback index file found. Initializing to 0\n");
         uint64_t write_buf[kRollbackSlotMax] = {0};
         write_buf[slot] = request_value;
         rc = storage_->write(0, write_buf, sizeof(write_buf));
     } else {
         uint64_t rollback_counter;
         TLOGD("Found a rollback index file\n");
         rc = storage_->read(sizeof(rollback_counter) * slot, &rollback_counter,
                             sizeof(rollback_counter));

         // Write value to specified slot in file
         if (request_value < rollback_counter) {
             response->set_error(AvbError::kInvalid);
             TLOGE("Error: Requested write [%lu] is less than existing counter value "
                   "[%lu]\n",
                   static_cast<long unsigned>(request_value),
                   static_cast<long unsigned>(rollback_counter));
             response->set_value(rollback_counter);
             return;
         }
         rc = storage_->write(sizeof(request_value) * slot, &request_value,
                              sizeof(request_value));
     }

     if (rc < 0) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: accessing storage object [%d]\n", rc);
         return;
     }

     if (static_cast<size_t>(rc) < sizeof(request_value)) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: invalid object size [%d]\n", rc);
         return;
     }

     response->set_value(request_value);
 }

 void AvbManager::GetVersion(const GetVersionRequest& request,
                             GetVersionResponse* response) {
     response->set_version(kAvbVersion);
 }

 void AvbManager::ReadPermanentAttributes(
         const ReadPermanentAttributesRequest& request,
         ReadPermanentAttributesResponse* response) {
     int rc = storage_->open(kPermanentAttributesFilename);
     if (rc < 0) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: failed to open attributes file: %d\n", rc);
         return;
     }

     // Read permanent product attributes
     UniquePtr<uint8_t[]> attributes(new uint8_t[kPermanentAttributesLengthMax]);
     rc = storage_->read(0, attributes.get(), kPermanentAttributesLengthMax);
     if (rc <= 0) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: %s attributes file [%d]\n",
               rc == 0 ? "missing" : "accessing", rc);
         return;
     }
     uint32_t attributes_size = static_cast<uint32_t>(rc);
     response->set_attributes_buf(attributes.get(), attributes_size);
 }

 void AvbManager::WritePermanentAttributes(
         const WritePermanentAttributesRequest& request,
         WritePermanentAttributesResponse* response) {
     int rc = storage_->open(kPermanentAttributesFilename);
     if (rc < 0) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: failed to open attributes file: %d\n", rc);
         return;
     }
     uint64_t size;
     rc = storage_->get_file_size(&size);
     if (rc < 0) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: failed to get size of attributes file: %d\n", rc);
         return;
     }

     if (size) {
         response->set_error(AvbError::kInvalid);
         TLOGE("Error: Permanent attributes already set!\n");
         return;
     }
     // New file, write serialized permanent product attributes to storage
     uint32_t attributes_size = request.get_attributes_size();
     uint8_t* attributes = request.get_attributes_buf();
     rc = storage_->write(0, attributes, attributes_size);

     if (rc < 0 || static_cast<size_t>(rc) < attributes_size) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: accessing storage object [%d]\n", rc);
         return;
     }
 }

 void AvbManager::ReadLockState(const ReadLockStateRequest& request,
                                ReadLockStateResponse* response) {
     int rc = storage_->open(kLockStateFile);
     if (rc < 0) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: failed to open lock state file: %d\n", rc);
         return;
     }
     uint64_t size;
     rc = storage_->get_file_size(&size);
     if (rc < 0) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: failed to get size of lock state file: %d\n", rc);
         return;
     }

     uint8_t lock_state = 1;
     if (size == 0) {
         // No lock state found, assume initial state is locked and write it
         rc = storage_->write(0, &lock_state, sizeof(lock_state));
     } else {
         rc = storage_->read(0, &lock_state, sizeof(lock_state));
     }
     if (rc < 0 || static_cast<size_t>(rc) < sizeof(lock_state)) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: accessing storage object [%d]\n", rc);
         return;
     }
     response->set_lock_state(lock_state);
 }

 void AvbManager::WriteLockState(const WriteLockStateRequest& request,
                                 WriteLockStateResponse* response) {
     // Only 0 and 1 are valid lock states
     uint8_t request_lock_state = request.get_lock_state();
     if (request_lock_state != 0 && request_lock_state != 1) {
         response->set_error(AvbError::kInvalid);
         TLOGE("Error: invalid lock state requested: %d\n", request_lock_state);
         return;
     }

     int rc = storage_->open(kLockStateFile);
     if (rc < 0) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: failed to open lock state file: %d\n", rc);
         return;
     }

     // Try to read existing lock state
     uint8_t stored_lock_state = 0xFF;
     storage_->read(0, &stored_lock_state, sizeof(stored_lock_state));

     // If no lock state file was found, or the device is changing lock state,
     // clear rollback index data
     if (stored_lock_state != request_lock_state) {
         if (DeleteRollbackIndexFiles() < 0) {
             response->set_error(AvbError::kInternal);
             TLOGE("Error: clearing rollback index data\n");
             return;
         }
     }

     // Write new lock state
     rc = storage_->write(0, &request_lock_state, sizeof(request_lock_state));
     if (rc < 0 || static_cast<size_t>(rc) < sizeof(request_lock_state)) {
         response->set_error(AvbError::kInternal);
         TLOGE("Error: accessing storage object [%d]\n", rc);
         return;
     }
 }

 // Rollback counters are stored in files avb.rollback.{0..F}. When a device
 // changes lock state, data in rollback index files must be deleted.
 int AvbManager::DeleteRollbackIndexFiles() {
     char filename[kStorageIdLengthMax];
     char postfix[4];
     int rc = NO_ERROR;

     for (unsigned int i = 0x0; i <= 0xF; ++i) {
         strcpy(filename, kAvbRollbackFilename);
         snprintf(postfix, 4, ".%01X", i);
         strcat(filename, postfix);
         int storage_rc = storage_->delete_file(filename);
         if (storage_rc < 0 && storage_rc != ERR_NOT_FOUND) {
             rc = storage_rc;
             TLOGE("Error: deleting file %s: %d\n", filename, rc);
             continue;
         }
     }
     return rc;
 }

 };  // namespace avb
	/*
	* Copyright 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.
	*/

	#include "avb_manager.h"

	#include <string.h>
	#include <uapi/err.h>

	#include "secure_storage_interface.h"

	#define DEBUG 0

	const unsigned int kRollbackSlotMax = 32;

	static const uint32_t kAvbVersion = 1;
	static const char* kAvbRollbackFilename = "avb.rollback";
	static const unsigned int kPermanentAttributesLengthMax = 2048;
	static const char* kPermanentAttributesFilename = "avb.ppa";
	static const char* kLockStateFile = "avb.lock_state";
	static const unsigned int kStorageIdLengthMax = 64;

	static const uint32_t kTypeMask = 0xF000;
	static const unsigned int kTypeShift = 12;

	// Helper function to get \|filename\| and \|slot\| and based on type flag
	// in \|raw_slot\|. \|filename\| is assumed to be allocated with
	// kStorageIdLengthMax bytes.
	static int GetFilenameAndSlot(uint32_t raw_slot,
	char filename[kStorageIdLengthMax],
	uint32_t* slot) {
	// Upper 16 bits should not be set
	if (raw_slot & 0xFFFF0000) {
	TLOGE("Error: Slot value %u invalid\n", raw_slot);
	return ERR_NOT_VALID;
	}
	// Mask type flag from raw slot to get index
	*slot = raw_slot & ~kTypeMask;
	if (*slot >= kRollbackSlotMax) {
	TLOGE("Error: Slot value %u larger than supported %u\n", *slot,
	kRollbackSlotMax);
	return ERR_NOT_VALID;
	}
	// Choose correct file for rollback index type
	strcpy(filename, kAvbRollbackFilename);
	int index_type = (raw_slot & kTypeMask) >> kTypeShift;
	char postfix[4];
	snprintf(postfix, 4, ".%01X", index_type);
	strcat(filename, postfix);
	return NO_ERROR;
	}

	namespace avb {

	void AvbManager::ReadRollbackIndex(const RollbackIndexRequest& request,
	RollbackIndexResponse* response) {
	uint32_t slot;
	char filename[kStorageIdLengthMax];
	if (GetFilenameAndSlot(request.get_slot(), filename, &slot) < 0) {
	response->set_error(AvbError::kInvalid);
	TLOGE("Error: Invalid slot value: %u\n", request.get_slot());
	return;
	}

	int rc = storage_->open(filename);
	if (rc < 0) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: failed to open file %s: %d\n", filename, rc);
	return;
	}
	uint64_t size;
	rc = storage_->get_file_size(&size);
	if (rc < 0) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: failed to get size of file %s: %d\n", filename, rc);
	return;
	}

	// If no valid rollback counter file is found, initialize to 0
	uint64_t rollback_counter;
	if (size < kRollbackSlotMax * sizeof(uint64_t)) {
	TLOGD("No valid rollback index file found. Initializing to 0\n");
	uint64_t write_buf[kRollbackSlotMax] = {0};
	rc = storage_->write(0, write_buf, sizeof(write_buf));
	rollback_counter = 0;
	} else {
	TLOGD("Rollback index file found\n");
	rc = storage_->read(sizeof(rollback_counter) * slot, &rollback_counter,
	sizeof(rollback_counter));
	}

	if (rc < 0) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: reading storage object: %d\n", rc);
	return;
	}

	if (static_cast<size_t>(rc) < sizeof(rollback_counter)) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: invalid object size: %d\n", rc);
	return;
	}

	response->set_value(rollback_counter);
	}

	void AvbManager::WriteRollbackIndex(const RollbackIndexRequest& request,
	RollbackIndexResponse* response) {
	uint32_t slot;
	char filename[kStorageIdLengthMax];
	if (GetFilenameAndSlot(request.get_slot(), filename, &slot) < 0) {
	response->set_error(AvbError::kInvalid);
	TLOGE("Error: Invalid slot value: %u\n", request.get_slot());
	return;
	}

	int rc = storage_->open(filename);
	if (rc < 0) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: failed to open file %s: %d\n", filename, rc);
	return;
	}
	uint64_t size;
	rc = storage_->get_file_size(&size);
	if (rc < 0) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: failed to get size of file %s: %d\n", filename, rc);
	return;
	}

	// If no valid rollback counter file is found, initialize to 0
	uint64_t request_value = request.get_value();
	if (static_cast<size_t>(size) < kRollbackSlotMax * sizeof(uint64_t)) {
	TLOGD("No valid rollback index file found. Initializing to 0\n");
	uint64_t write_buf[kRollbackSlotMax] = {0};
	write_buf[slot] = request_value;
	rc = storage_->write(0, write_buf, sizeof(write_buf));
	} else {
	uint64_t rollback_counter;
	TLOGD("Found a rollback index file\n");
	rc = storage_->read(sizeof(rollback_counter) * slot, &rollback_counter,
	sizeof(rollback_counter));

	// Write value to specified slot in file
	if (request_value < rollback_counter) {
	response->set_error(AvbError::kInvalid);
	TLOGE("Error: Requested write [%lu] is less than existing counter value "
	"[%lu]\n",
	static_cast<long unsigned>(request_value),
	static_cast<long unsigned>(rollback_counter));
	response->set_value(rollback_counter);
	return;
	}
	rc = storage_->write(sizeof(request_value) * slot, &request_value,
	sizeof(request_value));
	}

	if (rc < 0) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: accessing storage object [%d]\n", rc);
	return;
	}

	if (static_cast<size_t>(rc) < sizeof(request_value)) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: invalid object size [%d]\n", rc);
	return;
	}

	response->set_value(request_value);
	}

	void AvbManager::GetVersion(const GetVersionRequest& request,
	GetVersionResponse* response) {
	response->set_version(kAvbVersion);
	}

	void AvbManager::ReadPermanentAttributes(
	const ReadPermanentAttributesRequest& request,
	ReadPermanentAttributesResponse* response) {
	int rc = storage_->open(kPermanentAttributesFilename);
	if (rc < 0) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: failed to open attributes file: %d\n", rc);
	return;
	}

	// Read permanent product attributes
	UniquePtr<uint8_t[]> attributes(new uint8_t[kPermanentAttributesLengthMax]);
	rc = storage_->read(0, attributes.get(), kPermanentAttributesLengthMax);
	if (rc <= 0) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: %s attributes file [%d]\n",
	rc == 0 ? "missing" : "accessing", rc);
	return;
	}
	uint32_t attributes_size = static_cast<uint32_t>(rc);
	response->set_attributes_buf(attributes.get(), attributes_size);
	}

	void AvbManager::WritePermanentAttributes(
	const WritePermanentAttributesRequest& request,
	WritePermanentAttributesResponse* response) {
	int rc = storage_->open(kPermanentAttributesFilename);
	if (rc < 0) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: failed to open attributes file: %d\n", rc);
	return;
	}
	uint64_t size;
	rc = storage_->get_file_size(&size);
	if (rc < 0) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: failed to get size of attributes file: %d\n", rc);
	return;
	}

	if (size) {
	response->set_error(AvbError::kInvalid);
	TLOGE("Error: Permanent attributes already set!\n");
	return;
	}
	// New file, write serialized permanent product attributes to storage
	uint32_t attributes_size = request.get_attributes_size();
	uint8_t* attributes = request.get_attributes_buf();
	rc = storage_->write(0, attributes, attributes_size);

	if (rc < 0 \|\| static_cast<size_t>(rc) < attributes_size) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: accessing storage object [%d]\n", rc);
	return;
	}
	}

	void AvbManager::ReadLockState(const ReadLockStateRequest& request,
	ReadLockStateResponse* response) {
	int rc = storage_->open(kLockStateFile);
	if (rc < 0) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: failed to open lock state file: %d\n", rc);
	return;
	}
	uint64_t size;
	rc = storage_->get_file_size(&size);
	if (rc < 0) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: failed to get size of lock state file: %d\n", rc);
	return;
	}

	uint8_t lock_state = 1;
	if (size == 0) {
	// No lock state found, assume initial state is locked and write it
	rc = storage_->write(0, &lock_state, sizeof(lock_state));
	} else {
	rc = storage_->read(0, &lock_state, sizeof(lock_state));
	}
	if (rc < 0 \|\| static_cast<size_t>(rc) < sizeof(lock_state)) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: accessing storage object [%d]\n", rc);
	return;
	}
	response->set_lock_state(lock_state);
	}

	void AvbManager::WriteLockState(const WriteLockStateRequest& request,
	WriteLockStateResponse* response) {
	// Only 0 and 1 are valid lock states
	uint8_t request_lock_state = request.get_lock_state();
	if (request_lock_state != 0 && request_lock_state != 1) {
	response->set_error(AvbError::kInvalid);
	TLOGE("Error: invalid lock state requested: %d\n", request_lock_state);
	return;
	}

	int rc = storage_->open(kLockStateFile);
	if (rc < 0) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: failed to open lock state file: %d\n", rc);
	return;
	}

	// Try to read existing lock state
	uint8_t stored_lock_state = 0xFF;
	storage_->read(0, &stored_lock_state, sizeof(stored_lock_state));

	// If no lock state file was found, or the device is changing lock state,
	// clear rollback index data
	if (stored_lock_state != request_lock_state) {
	if (DeleteRollbackIndexFiles() < 0) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: clearing rollback index data\n");
	return;
	}
	}

	// Write new lock state
	rc = storage_->write(0, &request_lock_state, sizeof(request_lock_state));
	if (rc < 0 \|\| static_cast<size_t>(rc) < sizeof(request_lock_state)) {
	response->set_error(AvbError::kInternal);
	TLOGE("Error: accessing storage object [%d]\n", rc);
	return;
	}
	}

	// Rollback counters are stored in files avb.rollback.{0..F}. When a device
	// changes lock state, data in rollback index files must be deleted.
	int AvbManager::DeleteRollbackIndexFiles() {
	char filename[kStorageIdLengthMax];
	char postfix[4];
	int rc = NO_ERROR;

	for (unsigned int i = 0x0; i <= 0xF; ++i) {
	strcpy(filename, kAvbRollbackFilename);
	snprintf(postfix, 4, ".%01X", i);
	strcat(filename, postfix);
	int storage_rc = storage_->delete_file(filename);
	if (storage_rc < 0 && storage_rc != ERR_NOT_FOUND) {
	rc = storage_rc;
	TLOGE("Error: deleting file %s: %d\n", filename, rc);
	continue;
	}
	}
	return rc;
	}

	}; // namespace avb