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-rw-r--r--encryptedfs_provisioning.c284
1 files changed, 284 insertions, 0 deletions
diff --git a/encryptedfs_provisioning.c b/encryptedfs_provisioning.c
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+/*
+ * Copyright (C) 2009 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 <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "encryptedfs_provisioning.h"
+#include "cutils/misc.h"
+#include "cutils/properties.h"
+#include "common.h"
+#include "mtdutils/mtdutils.h"
+#include "mtdutils/mounts.h"
+#include "roots.h"
+
+const char* encrypted_fs_enabled_property = "persist.security.secfs.enabled";
+const char* encrypted_fs_property_dir = "/data/property/";
+const char* encrypted_fs_system_dir = "/data/system/";
+const char* encrypted_fs_key_file_name = "/data/fs_key.dat";
+const char* encrypted_fs_salt_file_name = "/data/hash_salt.dat";
+const char* encrypted_fs_hash_file_src_name = "/data/system/password.key";
+const char* encrypted_fs_hash_file_dst_name = "/data/hash.dat";
+const char* encrypted_fs_entropy_file_src_name = "/data/system/entropy.dat";
+const char* encrypted_fs_entropy_file_dst_name = "/data/ported_entropy.dat";
+
+void get_property_file_name(char *buffer, const char *property_name) {
+ sprintf(buffer, "%s%s", encrypted_fs_property_dir, property_name);
+}
+
+int get_binary_file_contents(char *buffer, int buf_size, const char *file_name, int *out_size) {
+ FILE *in_file;
+ int read_bytes;
+
+ in_file = fopen(file_name, "r");
+ if (in_file == NULL) {
+ LOGE("Secure FS: error accessing key file.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ read_bytes = fread(buffer, 1, buf_size, in_file);
+ if (out_size == NULL) {
+ if (read_bytes != buf_size) {
+ // Error or unexpected data
+ fclose(in_file);
+ LOGE("Secure FS: error reading conmplete key.");
+ return ENCRYPTED_FS_ERROR;
+ }
+ } else {
+ *out_size = read_bytes;
+ }
+ fclose(in_file);
+ return ENCRYPTED_FS_OK;
+}
+
+int set_binary_file_contents(char *buffer, int buf_size, const char *file_name) {
+ FILE *out_file;
+ int write_bytes;
+
+ out_file = fopen(file_name, "w");
+ if (out_file == NULL) {
+ LOGE("Secure FS: error setting up key file.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ write_bytes = fwrite(buffer, 1, buf_size, out_file);
+ if (write_bytes != buf_size) {
+ // Error or unexpected data
+ fclose(out_file);
+ LOGE("Secure FS: error reading conmplete key.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ fclose(out_file);
+ return ENCRYPTED_FS_OK;
+}
+
+int get_text_file_contents(char *buffer, int buf_size, char *file_name) {
+ FILE *in_file;
+ char *read_data;
+
+ in_file = fopen(file_name, "r");
+ if (in_file == NULL) {
+ LOGE("Secure FS: error accessing properties.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ read_data = fgets(buffer, buf_size, in_file);
+ if (read_data == NULL) {
+ // Error or unexpected data
+ fclose(in_file);
+ LOGE("Secure FS: error accessing properties.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ fclose(in_file);
+ return ENCRYPTED_FS_OK;
+}
+
+int set_text_file_contents(char *buffer, char *file_name) {
+ FILE *out_file;
+ int result;
+
+ out_file = fopen(file_name, "w");
+ if (out_file == NULL) {
+ LOGE("Secure FS: error setting up properties.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ result = fputs(buffer, out_file);
+ if (result != 0) {
+ // Error or unexpected data
+ fclose(out_file);
+ LOGE("Secure FS: error setting up properties.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ fflush(out_file);
+ fclose(out_file);
+ return ENCRYPTED_FS_OK;
+}
+
+int read_encrypted_fs_boolean_property(const char *prop_name, int *value) {
+ char prop_file_name[PROPERTY_KEY_MAX + 32];
+ char prop_value[PROPERTY_VALUE_MAX];
+ int result;
+
+ get_property_file_name(prop_file_name, prop_name);
+ result = get_text_file_contents(prop_value, PROPERTY_VALUE_MAX, prop_file_name);
+
+ if (result < 0) {
+ return result;
+ }
+
+ if (strncmp(prop_value, "1", 1) == 0) {
+ *value = 1;
+ } else if (strncmp(prop_value, "0", 1) == 0) {
+ *value = 0;
+ } else {
+ LOGE("Secure FS: error accessing properties.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ return ENCRYPTED_FS_OK;
+}
+
+int write_encrypted_fs_boolean_property(const char *prop_name, int value) {
+ char prop_file_name[PROPERTY_KEY_MAX + 32];
+ char prop_value[PROPERTY_VALUE_MAX];
+ int result;
+
+ get_property_file_name(prop_file_name, prop_name);
+
+ // Create the directory if needed
+ mkdir(encrypted_fs_property_dir, 0755);
+ if (value == 1) {
+ result = set_text_file_contents("1", prop_file_name);
+ } else if (value == 0) {
+ result = set_text_file_contents("0", prop_file_name);
+ } else {
+ return ENCRYPTED_FS_ERROR;
+ }
+ if (result < 0) {
+ return result;
+ }
+
+ return ENCRYPTED_FS_OK;
+}
+
+int read_encrypted_fs_info(encrypted_fs_info *encrypted_fs_data) {
+ int result;
+ int value;
+ result = ensure_root_path_mounted("DATA:");
+ if (result != 0) {
+ LOGE("Secure FS: error mounting userdata partition.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ // Read the pre-generated encrypted FS key, password hash and salt.
+ result = get_binary_file_contents(encrypted_fs_data->key, ENCRYPTED_FS_KEY_SIZE,
+ encrypted_fs_key_file_name, NULL);
+ if (result != 0) {
+ LOGE("Secure FS: error reading generated file system key.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ result = get_binary_file_contents(encrypted_fs_data->salt, ENCRYPTED_FS_SALT_SIZE,
+ encrypted_fs_salt_file_name, &(encrypted_fs_data->salt_length));
+ if (result != 0) {
+ LOGE("Secure FS: error reading file system salt.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ result = get_binary_file_contents(encrypted_fs_data->hash, ENCRYPTED_FS_MAX_HASH_SIZE,
+ encrypted_fs_hash_file_src_name, &(encrypted_fs_data->hash_length));
+ if (result != 0) {
+ LOGE("Secure FS: error reading password hash.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ result = get_binary_file_contents(encrypted_fs_data->entropy, ENTROPY_MAX_SIZE,
+ encrypted_fs_entropy_file_src_name, &(encrypted_fs_data->entropy_length));
+ if (result != 0) {
+ LOGE("Secure FS: error reading ported entropy.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ result = ensure_root_path_unmounted("DATA:");
+ if (result != 0) {
+ LOGE("Secure FS: error unmounting data partition.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ return ENCRYPTED_FS_OK;
+}
+
+int restore_encrypted_fs_info(encrypted_fs_info *encrypted_fs_data) {
+ int result;
+ result = ensure_root_path_mounted("DATA:");
+ if (result != 0) {
+ LOGE("Secure FS: error mounting userdata partition.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ // Write the pre-generated secure FS key, password hash and salt.
+ result = set_binary_file_contents(encrypted_fs_data->key, ENCRYPTED_FS_KEY_SIZE,
+ encrypted_fs_key_file_name);
+ if (result != 0) {
+ LOGE("Secure FS: error writing generated file system key.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ result = set_binary_file_contents(encrypted_fs_data->salt, encrypted_fs_data->salt_length,
+ encrypted_fs_salt_file_name);
+ if (result != 0) {
+ LOGE("Secure FS: error writing file system salt.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ result = set_binary_file_contents(encrypted_fs_data->hash, encrypted_fs_data->hash_length,
+ encrypted_fs_hash_file_dst_name);
+ if (result != 0) {
+ LOGE("Secure FS: error writing password hash.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ result = set_binary_file_contents(encrypted_fs_data->entropy, encrypted_fs_data->entropy_length,
+ encrypted_fs_entropy_file_dst_name);
+ if (result != 0) {
+ LOGE("Secure FS: error writing ported entropy.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ // Set the secure FS properties to their respective values
+ result = write_encrypted_fs_boolean_property(encrypted_fs_enabled_property, encrypted_fs_data->mode);
+ if (result != 0) {
+ return result;
+ }
+
+ result = ensure_root_path_unmounted("DATA:");
+ if (result != 0) {
+ LOGE("Secure FS: error unmounting data partition.");
+ return ENCRYPTED_FS_ERROR;
+ }
+
+ return ENCRYPTED_FS_OK;
+}
+
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