284 lines
8.7 KiB
C
284 lines
8.7 KiB
C
/*
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* Copyright (C) 2009 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/mount.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include "encryptedfs_provisioning.h"
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#include "cutils/misc.h"
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#include "cutils/properties.h"
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#include "common.h"
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#include "mtdutils/mtdutils.h"
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#include "mounts.h"
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#include "roots.h"
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const char* encrypted_fs_enabled_property = "persist.security.secfs.enabled";
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const char* encrypted_fs_property_dir = "/data/property/";
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const char* encrypted_fs_system_dir = "/data/system/";
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const char* encrypted_fs_key_file_name = "/data/fs_key.dat";
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const char* encrypted_fs_salt_file_name = "/data/hash_salt.dat";
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const char* encrypted_fs_hash_file_src_name = "/data/system/password.key";
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const char* encrypted_fs_hash_file_dst_name = "/data/hash.dat";
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const char* encrypted_fs_entropy_file_src_name = "/data/system/entropy.dat";
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const char* encrypted_fs_entropy_file_dst_name = "/data/ported_entropy.dat";
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void get_property_file_name(char *buffer, const char *property_name) {
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sprintf(buffer, "%s%s", encrypted_fs_property_dir, property_name);
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}
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int get_binary_file_contents(char *buffer, int buf_size, const char *file_name, int *out_size) {
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FILE *in_file;
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int read_bytes;
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in_file = fopen(file_name, "r");
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if (in_file == NULL) {
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LOGE("Secure FS: error accessing key file.");
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return ENCRYPTED_FS_ERROR;
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}
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read_bytes = fread(buffer, 1, buf_size, in_file);
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if (out_size == NULL) {
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if (read_bytes != buf_size) {
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// Error or unexpected data
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fclose(in_file);
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LOGE("Secure FS: error reading conmplete key.");
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return ENCRYPTED_FS_ERROR;
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}
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} else {
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*out_size = read_bytes;
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}
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fclose(in_file);
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return ENCRYPTED_FS_OK;
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}
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int set_binary_file_contents(char *buffer, int buf_size, const char *file_name) {
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FILE *out_file;
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int write_bytes;
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out_file = fopen(file_name, "w");
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if (out_file == NULL) {
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LOGE("Secure FS: error setting up key file.");
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return ENCRYPTED_FS_ERROR;
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}
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write_bytes = fwrite(buffer, 1, buf_size, out_file);
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if (write_bytes != buf_size) {
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// Error or unexpected data
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fclose(out_file);
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LOGE("Secure FS: error reading conmplete key.");
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return ENCRYPTED_FS_ERROR;
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}
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fclose(out_file);
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return ENCRYPTED_FS_OK;
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}
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int get_text_file_contents(char *buffer, int buf_size, char *file_name) {
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FILE *in_file;
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char *read_data;
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in_file = fopen(file_name, "r");
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if (in_file == NULL) {
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LOGE("Secure FS: error accessing properties.");
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return ENCRYPTED_FS_ERROR;
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}
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read_data = fgets(buffer, buf_size, in_file);
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if (read_data == NULL) {
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// Error or unexpected data
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fclose(in_file);
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LOGE("Secure FS: error accessing properties.");
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return ENCRYPTED_FS_ERROR;
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}
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fclose(in_file);
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return ENCRYPTED_FS_OK;
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}
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int set_text_file_contents(char *buffer, char *file_name) {
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FILE *out_file;
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int result;
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out_file = fopen(file_name, "w");
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if (out_file == NULL) {
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LOGE("Secure FS: error setting up properties.");
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return ENCRYPTED_FS_ERROR;
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}
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result = fputs(buffer, out_file);
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if (result != 0) {
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// Error or unexpected data
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fclose(out_file);
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LOGE("Secure FS: error setting up properties.");
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return ENCRYPTED_FS_ERROR;
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}
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fflush(out_file);
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fclose(out_file);
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return ENCRYPTED_FS_OK;
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}
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int read_encrypted_fs_boolean_property(const char *prop_name, int *value) {
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char prop_file_name[PROPERTY_KEY_MAX + 32];
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char prop_value[PROPERTY_VALUE_MAX];
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int result;
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get_property_file_name(prop_file_name, prop_name);
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result = get_text_file_contents(prop_value, PROPERTY_VALUE_MAX, prop_file_name);
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if (result < 0) {
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return result;
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}
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if (strncmp(prop_value, "1", 1) == 0) {
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*value = 1;
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} else if (strncmp(prop_value, "0", 1) == 0) {
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*value = 0;
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} else {
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LOGE("Secure FS: error accessing properties.");
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return ENCRYPTED_FS_ERROR;
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}
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return ENCRYPTED_FS_OK;
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}
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int write_encrypted_fs_boolean_property(const char *prop_name, int value) {
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char prop_file_name[PROPERTY_KEY_MAX + 32];
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char prop_value[PROPERTY_VALUE_MAX];
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int result;
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get_property_file_name(prop_file_name, prop_name);
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// Create the directory if needed
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mkdir(encrypted_fs_property_dir, 0755);
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if (value == 1) {
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result = set_text_file_contents("1", prop_file_name);
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} else if (value == 0) {
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result = set_text_file_contents("0", prop_file_name);
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} else {
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return ENCRYPTED_FS_ERROR;
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}
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if (result < 0) {
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return result;
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}
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return ENCRYPTED_FS_OK;
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}
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int read_encrypted_fs_info(encrypted_fs_info *encrypted_fs_data) {
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int result;
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int value;
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result = ensure_path_mounted("/data");
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if (result != 0) {
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LOGE("Secure FS: error mounting userdata partition.");
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return ENCRYPTED_FS_ERROR;
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}
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// Read the pre-generated encrypted FS key, password hash and salt.
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result = get_binary_file_contents(encrypted_fs_data->key, ENCRYPTED_FS_KEY_SIZE,
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encrypted_fs_key_file_name, NULL);
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if (result != 0) {
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LOGE("Secure FS: error reading generated file system key.");
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return ENCRYPTED_FS_ERROR;
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}
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result = get_binary_file_contents(encrypted_fs_data->salt, ENCRYPTED_FS_SALT_SIZE,
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encrypted_fs_salt_file_name, &(encrypted_fs_data->salt_length));
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if (result != 0) {
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LOGE("Secure FS: error reading file system salt.");
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return ENCRYPTED_FS_ERROR;
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}
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result = get_binary_file_contents(encrypted_fs_data->hash, ENCRYPTED_FS_MAX_HASH_SIZE,
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encrypted_fs_hash_file_src_name, &(encrypted_fs_data->hash_length));
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if (result != 0) {
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LOGE("Secure FS: error reading password hash.");
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return ENCRYPTED_FS_ERROR;
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}
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result = get_binary_file_contents(encrypted_fs_data->entropy, ENTROPY_MAX_SIZE,
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encrypted_fs_entropy_file_src_name, &(encrypted_fs_data->entropy_length));
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if (result != 0) {
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LOGE("Secure FS: error reading ported entropy.");
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return ENCRYPTED_FS_ERROR;
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}
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result = ensure_path_unmounted("/data");
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if (result != 0) {
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LOGE("Secure FS: error unmounting data partition.");
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return ENCRYPTED_FS_ERROR;
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}
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return ENCRYPTED_FS_OK;
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}
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int restore_encrypted_fs_info(encrypted_fs_info *encrypted_fs_data) {
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int result;
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result = ensure_path_mounted("/data");
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if (result != 0) {
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LOGE("Secure FS: error mounting userdata partition.");
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return ENCRYPTED_FS_ERROR;
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}
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// Write the pre-generated secure FS key, password hash and salt.
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result = set_binary_file_contents(encrypted_fs_data->key, ENCRYPTED_FS_KEY_SIZE,
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encrypted_fs_key_file_name);
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if (result != 0) {
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LOGE("Secure FS: error writing generated file system key.");
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return ENCRYPTED_FS_ERROR;
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}
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result = set_binary_file_contents(encrypted_fs_data->salt, encrypted_fs_data->salt_length,
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encrypted_fs_salt_file_name);
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if (result != 0) {
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LOGE("Secure FS: error writing file system salt.");
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return ENCRYPTED_FS_ERROR;
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}
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result = set_binary_file_contents(encrypted_fs_data->hash, encrypted_fs_data->hash_length,
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encrypted_fs_hash_file_dst_name);
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if (result != 0) {
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LOGE("Secure FS: error writing password hash.");
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return ENCRYPTED_FS_ERROR;
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}
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result = set_binary_file_contents(encrypted_fs_data->entropy, encrypted_fs_data->entropy_length,
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encrypted_fs_entropy_file_dst_name);
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if (result != 0) {
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LOGE("Secure FS: error writing ported entropy.");
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return ENCRYPTED_FS_ERROR;
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}
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// Set the secure FS properties to their respective values
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result = write_encrypted_fs_boolean_property(encrypted_fs_enabled_property, encrypted_fs_data->mode);
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if (result != 0) {
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return result;
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}
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result = ensure_path_unmounted("/data");
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if (result != 0) {
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LOGE("Secure FS: error unmounting data partition.");
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return ENCRYPTED_FS_ERROR;
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}
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return ENCRYPTED_FS_OK;
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}
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