1 /* 2 * Copyright (C) 2016 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #define TAG "ext4_utils" 18 19 #include "ext4_crypt_init_extensions.h" 20 #include "ext4_crypt.h" 21 22 #include <android-base/logging.h> 23 24 #include <string> 25 #include <vector> 26 27 #include <dirent.h> 28 #include <errno.h> 29 #include <sys/mount.h> 30 #include <sys/stat.h> 31 #include <unistd.h> 32 33 #include <android-base/file.h> 34 35 #include <cutils/klog.h> 36 #include <cutils/properties.h> 37 #include <cutils/sockets.h> 38 #include <logwrap/logwrap.h> 39 40 #include "key_control.h" 41 42 static const std::string arbitrary_sequence_number = "42"; 43 static const int vold_command_timeout_ms = 60 * 1000; 44 45 static void kernel_logger(android::base::LogId, android::base::LogSeverity severity, const char*, 46 const char*, unsigned int, const char* message) { 47 if (severity == android::base::ERROR || severity == android::base::FATAL) { 48 KLOG_ERROR(TAG, "%s\n", message); 49 } else if (severity == android::base::WARNING) { 50 KLOG_WARNING(TAG, "%s\n", message); 51 } else { 52 KLOG_INFO(TAG, "%s\n", message); 53 } 54 } 55 56 static void init_logging() { 57 android::base::SetLogger(kernel_logger); 58 } 59 60 int e4crypt_create_device_key(const char* dir, 61 int ensure_dir_exists(const char*)) 62 { 63 init_logging(); 64 65 // Make sure folder exists. Use make_dir to set selinux permissions. 66 std::string unencrypted_dir = std::string(dir) + e4crypt_unencrypted_folder; 67 if (ensure_dir_exists(unencrypted_dir.c_str())) { 68 KLOG_ERROR(TAG, "Failed to create %s (%s)\n", 69 unencrypted_dir.c_str(), 70 strerror(errno)); 71 return -1; 72 } 73 74 const char* argv[] = { "/system/bin/vdc", "--wait", "cryptfs", "enablefilecrypto" }; 75 int rc = android_fork_execvp(4, (char**) argv, NULL, false, true); 76 LOG(INFO) << "enablefilecrypto result: " << rc; 77 return rc; 78 } 79 80 int e4crypt_install_keyring() 81 { 82 init_logging(); 83 84 key_serial_t device_keyring = add_key("keyring", "e4crypt", 0, 0, 85 KEY_SPEC_SESSION_KEYRING); 86 87 if (device_keyring == -1) { 88 KLOG_ERROR(TAG, "Failed to create keyring (%s)\n", strerror(errno)); 89 return -1; 90 } 91 92 KLOG_INFO(TAG, "Keyring created with id %d in process %d\n", 93 device_keyring, getpid()); 94 95 return 0; 96 } 97 98 int e4crypt_do_init_user0() 99 { 100 init_logging(); 101 102 const char* argv[] = { "/system/bin/vdc", "--wait", "cryptfs", "init_user0" }; 103 int rc = android_fork_execvp(4, (char**) argv, NULL, false, true); 104 LOG(INFO) << "init_user0 result: " << rc; 105 return rc; 106 } 107 108 int e4crypt_set_directory_policy(const char* dir) 109 { 110 init_logging(); 111 112 // Only set policy on first level /data directories 113 // To make this less restrictive, consider using a policy file. 114 // However this is overkill for as long as the policy is simply 115 // to apply a global policy to all /data folders created via makedir 116 if (!dir || strncmp(dir, "/data/", 6) || strchr(dir + 6, '/')) { 117 return 0; 118 } 119 120 // Special case various directories that must not be encrypted, 121 // often because their subdirectories must be encrypted. 122 // This isn't a nice way to do this, see b/26641735 123 std::vector<std::string> directories_to_exclude = { 124 "lost+found", 125 "system_ce", "system_de", 126 "misc_ce", "misc_de", 127 "media", 128 "data", "user", "user_de", 129 }; 130 std::string prefix = "/data/"; 131 for (auto d: directories_to_exclude) { 132 if ((prefix + d) == dir) { 133 KLOG_INFO(TAG, "Not setting policy on %s\n", dir); 134 return 0; 135 } 136 } 137 138 std::string ref_filename = std::string("/data") + e4crypt_key_ref; 139 std::string policy; 140 if (!android::base::ReadFileToString(ref_filename, &policy)) { 141 KLOG_ERROR(TAG, "Unable to read system policy to set on %s\n", dir); 142 return -1; 143 } 144 145 auto type_filename = std::string("/data") + e4crypt_key_mode; 146 std::string contents_encryption_mode; 147 if (!android::base::ReadFileToString(type_filename, &contents_encryption_mode)) { 148 LOG(ERROR) << "Cannot read mode"; 149 } 150 151 KLOG_INFO(TAG, "Setting policy on %s\n", dir); 152 int result = e4crypt_policy_ensure(dir, policy.c_str(), policy.length(), 153 contents_encryption_mode.c_str()); 154 if (result) { 155 KLOG_ERROR(TAG, "Setting %02x%02x%02x%02x policy on %s failed!\n", 156 policy[0], policy[1], policy[2], policy[3], dir); 157 return -1; 158 } 159 160 return 0; 161 } 162
