/* * Copyright (C) 2016 - 2020 The TeamWin Recovery 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 "Decrypt.h" #include "FsCrypt.h" #include #include #include #include #include #include #include #ifndef HAVE_LIBKEYUTILS #include "key_control.h" #else #include #endif #include "keystore_client.pb.h" #include "Weaver1.h" #include "cutils/properties.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "keystore_client.pb.h" #include #include extern "C" { #include "crypto_scrypt.h" } #include "fscrypt_policy.h" #include "HashPassword.h" #include "KeyStorage.h" using android::security::keystore::IKeystoreService; using keystore::KeystoreResponsePromise; using keystore::OperationResultPromise; using android::security::keymaster::OperationResult; using android::hardware::keymaster::V4_0::support::blob2hidlVec; // Store main DE raw ref / policy extern std::string de_raw_ref; extern std::map s_de_key_raw_refs; extern std::map s_ce_key_raw_refs; inline std::string hidlVec2String(const ::keystore::hidl_vec& value) { return std::string(reinterpret_cast(&value[0]), value.size()); } static bool lookup_ref_key_internal(std::map& key_map, const uint8_t* policy, userid_t* user_id) { char policy_string_hex[FS_KEY_DESCRIPTOR_SIZE_HEX]; char key_map_hex[FS_KEY_DESCRIPTOR_SIZE_HEX]; policy_to_hex(policy, policy_string_hex); for (std::map::iterator it=key_map.begin(); it!=key_map.end(); ++it) { policy_to_hex(reinterpret_cast(&it->second[0]), key_map_hex); std::string key_map_hex_string = std::string(key_map_hex); if (key_map_hex_string == policy_string_hex) { *user_id = it->first; return true; } } return false; } extern "C" bool lookup_ref_key(const uint8_t* policy, uint8_t* policy_type) { userid_t user_id = 0; char policy_string_hex[FS_KEY_DESCRIPTOR_SIZE_HEX]; char de_raw_ref_hex[FS_KEY_DESCRIPTOR_SIZE_HEX]; policy_to_hex(policy, policy_string_hex); policy_to_hex(reinterpret_cast(&de_raw_ref[0]), de_raw_ref_hex); std::string de_raw_ref_hex_string = std::string(de_raw_ref_hex); std::string policy_type_string; if (policy_string_hex == de_raw_ref_hex_string) { policy_type_string = "0DK"; memcpy(policy_type, policy_type_string.data(), policy_type_string.size()); return true; } if (!lookup_ref_key_internal(s_de_key_raw_refs, policy, &user_id)) { if (!lookup_ref_key_internal(s_ce_key_raw_refs, policy, &user_id)) { return false; } else policy_type_string = "0CE" + std::to_string(user_id); } else policy_type_string = "0DE" + std::to_string(user_id); memcpy(policy_type, policy_type_string.data(), policy_type_string.size()); return true; } extern "C" bool lookup_ref_tar(const uint8_t* policy_type, uint8_t* policy) { std::string policy_type_string = std::string((char *) policy_type); char policy_hex[FS_KEY_DESCRIPTOR_SIZE_HEX]; policy_to_hex(policy_type, policy_hex); // Current encryption fscrypt policy is v1 (which is stored as version 0e) if (policy_type_string.substr(0,1) != "0") { printf("Unexpected version %c\n", policy_type[0]); return false; } if (policy_type_string.substr(1, 2) == "DK") { memcpy(policy, de_raw_ref.data(), de_raw_ref.size()); return true; } userid_t user_id = atoi(policy_type_string.substr(3, 4).c_str()); std::string raw_ref; if (policy_type_string.substr(1, 1) == "D") { if (lookup_key_ref(s_de_key_raw_refs, user_id, &raw_ref)) { memcpy(policy, raw_ref.data(), raw_ref.size()); } else return false; } else if (policy_type_string.substr(1, 1) == "C") { if (lookup_key_ref(s_ce_key_raw_refs, user_id, &raw_ref)) { memcpy(policy, raw_ref.data(), raw_ref.size()); } else return false; } else { printf("unknown policy type '%s'\n", policy_type); return false; } return true; } bool Decrypt_DE() { if (!fscrypt_initialize_systemwide_keys()) { // this deals with the overarching device encryption printf("fscrypt_initialize_systemwide_keys returned fail\n"); return false; } if (!fscrypt_init_user0()) { printf("fscrypt_init_user0 returned fail\n"); return false; } return true; } // Crappy functions for debugging, please ignore unless you need to debug // void output_hex(const std::string& in) { // const char *buf = in.data(); // char hex[in.size() * 2 + 1]; // unsigned int index; // for (index = 0; index < in.size(); index++) // sprintf(&hex[2 * index], "%02X", buf[index]); // printf("%s", hex); // } // void output_hex(const char* buf, const int size) { // char hex[size * 2 + 1]; // int index; // for (index = 0; index < size; index++) // sprintf(&hex[2 * index], "%02X", buf[index]); // printf("%s", hex); // } // void output_hex(const unsigned char* buf, const int size) { // char hex[size * 2 + 1]; // int index; // for (index = 0; index < size; index++) // sprintf(&hex[2 * index], "%02X", buf[index]); // printf("%s", hex); // } // void output_hex(std::vector* vec) { // char hex[3]; // unsigned int index; // for (index = 0; index < vec->size(); index++) { // sprintf(&hex[0], "%02X", vec->at(index)); // printf("%s", hex); // } // } /* An alternative is to use: * sqlite3 /data/system/locksettings.db "SELECT value FROM locksettings WHERE name='sp-handle' AND user=0;" * but we really don't want to include the 1.1MB libsqlite in TWRP. We scan the spblob folder for the * password data file (*.pwd) and get the handle from the filename instead. This is a replacement for * https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/LockSettingsService.java#2017 * We never use this data as an actual long. We always use it as a string. */ bool Find_Handle(const std::string& spblob_path, std::string& handle_str) { DIR* dir = opendir(spblob_path.c_str()); if (!dir) { printf("Error opening '%s'\n", spblob_path.c_str()); return false; } struct dirent* de = 0; while ((de = readdir(dir)) != 0) { if (strcmp(de->d_name, ".") == 0 || strcmp(de->d_name, "..") == 0) continue; size_t len = strlen(de->d_name); if (len <= 4) continue; char* p = de->d_name; p += len - 4; if (strncmp(p, ".pwd", 4) == 0) { handle_str = de->d_name; handle_str = handle_str.substr(0, len - 4); //*handle = strtoull(handle_str.c_str(), 0 , 16); closedir(dir); return true; } } closedir(dir); return false; } /* This is the structure of the data in the password data (*.pwd) file which the structure can be found * https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#187 */ struct password_data_struct { int password_type; unsigned char scryptN; unsigned char scryptR; unsigned char scryptP; int salt_len; void* salt; int handle_len; void* password_handle; }; /* C++ replacement for * https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#764 */ bool Get_Password_Data(const std::string& spblob_path, const std::string& handle_str, password_data_struct *pwd) { std::string pwd_file = spblob_path + handle_str + ".pwd"; std::string pwd_data; if (!android::base::ReadFileToString(pwd_file, &pwd_data)) { printf("Failed to read '%s'\n", pwd_file.c_str()); return false; } // output_hex(pwd_data.data(), pwd_data.size());printf("\n"); const int* intptr = (const int*)pwd_data.data(); pwd->password_type = *intptr; endianswap(&pwd->password_type); //printf("password type %i\n", pwd->password_type); // 2 was PIN, 1 for pattern, 2 also for password, -1 for default password const unsigned char* byteptr = (const unsigned char*)pwd_data.data() + sizeof(int); pwd->scryptN = *byteptr; byteptr++; pwd->scryptR = *byteptr; byteptr++; pwd->scryptP = *byteptr; byteptr++; intptr = (const int*)byteptr; pwd->salt_len = *intptr; endianswap(&pwd->salt_len); if (pwd->salt_len != 0) { pwd->salt = malloc(pwd->salt_len); if (!pwd->salt) { printf("Get_Password_Data malloc salt\n"); return false; } memcpy(pwd->salt, intptr + 1, pwd->salt_len); intptr++; byteptr = (const unsigned char*)intptr; byteptr += pwd->salt_len; } else { printf("Get_Password_Data salt_len is 0\n"); return false; } intptr = (const int*)byteptr; pwd->handle_len = *intptr; endianswap(&pwd->handle_len); if (pwd->handle_len != 0) { pwd->password_handle = malloc(pwd->handle_len); if (!pwd->password_handle) { printf("Get_Password_Data malloc password_handle\n"); return false; } memcpy(pwd->password_handle, intptr + 1, pwd->handle_len); } else { printf("Get_Password_Data handle_len is 0\n"); // Not an error if using weaver } return true; } /* C++ replacement for * https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#765 * called here * https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#1050 */ bool Get_Password_Token(const password_data_struct *pwd, const std::string& Password, unsigned char* password_token) { if (!password_token) { printf("password_token is null\n"); return false; } unsigned int N = 1 << pwd->scryptN; unsigned int r = 1 << pwd->scryptR; unsigned int p = 1 << pwd->scryptP; //printf("N %i r %i p %i\n", N, r, p); int ret = crypto_scrypt(reinterpret_cast(Password.data()), Password.size(), reinterpret_cast(pwd->salt), pwd->salt_len, N, r, p, password_token, 32); if (ret != 0) { printf("scrypt error\n"); return false; } return true; } // Data structure for the *.weaver file, see Get_Weaver_Data below struct weaver_data_struct { unsigned char version; int slot; }; /* C++ replacement for * https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#501 * called here * https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#768 */ bool Get_Weaver_Data(const std::string& spblob_path, const std::string& handle_str, weaver_data_struct *wd) { std::string weaver_file = spblob_path + handle_str + ".weaver"; std::string weaver_data; if (!android::base::ReadFileToString(weaver_file, &weaver_data)) { printf("Failed to read '%s'\n", weaver_file.c_str()); return false; } // output_hex(weaver_data.data(), weaver_data.size());printf("\n"); const unsigned char* byteptr = (const unsigned char*)weaver_data.data(); wd->version = *byteptr; // printf("weaver version %i\n", wd->version); const int* intptr = (const int*)weaver_data.data() + sizeof(unsigned char); wd->slot = *intptr; //endianswap(&wd->slot); not needed // printf("weaver slot %i\n", wd->slot); return true; } namespace android { // On Android 8.0 for some reason init can't seem to completely stop keystore // so we have to kill it too if it doesn't die on its own. static void kill_keystore() { DIR* dir = opendir("/proc"); if (dir) { struct dirent* de = 0; while ((de = readdir(dir)) != 0) { if (strcmp(de->d_name, ".") == 0 || strcmp(de->d_name, "..") == 0) continue; int pid = -1; int ret = sscanf(de->d_name, "%d", &pid); if (ret == 1) { char cmdpath[PATH_MAX]; sprintf(cmdpath, "/proc/%d/cmdline", pid); FILE* file = fopen(cmdpath, "r"); size_t task_size = PATH_MAX; char task[PATH_MAX]; char* p = task; if (getline(&p, &task_size, file) > 0) { if (strstr(task, "keystore") != 0) { printf("keystore pid %d found, sending kill.\n", pid); kill(pid, SIGINT); usleep(5000); kill(pid, SIGKILL); } } fclose(file); } } closedir(dir); } } // The keystore holds a file open on /data so we have to stop / kill it // if we want to be able to unmount /data for things like formatting. static void stop_keystore() { printf("Stopping keystore...\n"); property_set("ctl.stop", "keystore"); usleep(5000); kill_keystore(); } /* These next 2 functions try to get the keystore service 50 times because * the keystore is not always ready when TWRP boots */ android::sp getKeystoreBinder() { android::sp sm = android::defaultServiceManager(); return sm->getService(String16("android.security.keystore")); } android::sp getKeystoreBinderRetry() { printf("Starting keystore...\n"); property_set("ctl.start", "keystore"); int retry_count = 50; android::sp binder = getKeystoreBinder(); while (binder == NULL && retry_count) { printf("Waiting for keystore service... %i\n", retry_count--); sleep(1); binder = getKeystoreBinder(); } return binder; } namespace keystore { #define SYNTHETIC_PASSWORD_VERSION_V1 1 #define SYNTHETIC_PASSWORD_VERSION_V2 2 #define SYNTHETIC_PASSWORD_VERSION_V3 3 #define SYNTHETIC_PASSWORD_PASSWORD_BASED 0 #define SYNTHETIC_PASSWORD_KEY_PREFIX "USRSKEY_synthetic_password_" #define USR_PRIVATE_KEY_PREFIX "USRPKEY_synthetic_password_" static std::string mKey_Prefix; /* The keystore alias subid is sometimes the same as the handle, but not always. * In the case of handle 0c5303fd2010fe29, the alias subid used c5303fd2010fe29 * without the leading 0. We could try to parse the data from a previous * keystore request, but I think this is an easier solution because there * is little to no documentation on the format of data we get back from * the keystore in this instance. We also want to copy everything to a temp * folder so that any key upgrades that might take place do not actually * upgrade the keys on the data partition. We rename all 1000 uid files to 0 * to pass the keystore permission checks. */ bool Find_Keystore_Alias_SubID_And_Prep_Files(const userid_t user_id, std::string& keystoreid, const std::string& handle_str) { char path_c[PATH_MAX]; sprintf(path_c, "/data/misc/keystore/user_%d", user_id); char user_dir[PATH_MAX]; sprintf(user_dir, "user_%d", user_id); std::string source_path = "/data/misc/keystore/"; source_path += user_dir; std::string handle_sub = handle_str; while (handle_sub.substr(0,1) == "0") { std::string temp = handle_sub.substr(1); handle_sub = temp; } mKey_Prefix = ""; mkdir("/tmp/misc", 0755); mkdir("/tmp/misc/keystore", 0755); std::string destination_path = "/tmp/misc/keystore/"; destination_path += user_dir; if (mkdir(destination_path.c_str(), 0755) && errno != EEXIST) { printf("failed to mkdir '%s' %s\n", destination_path.c_str(), strerror(errno)); return false; } destination_path += "/"; DIR* dir = opendir(source_path.c_str()); if (!dir) { printf("Error opening '%s'\n", source_path.c_str()); return false; } source_path += "/"; struct dirent* de = 0; size_t prefix_len = strlen(SYNTHETIC_PASSWORD_KEY_PREFIX); bool found_subid = false; bool has_pkey = false; // PKEY has priority over SKEY while ((de = readdir(dir)) != 0) { if (strcmp(de->d_name, ".") == 0 || strcmp(de->d_name, "..") == 0) continue; if (!found_subid) { size_t len = strlen(de->d_name); if (len <= prefix_len) continue; if (strstr(de->d_name, SYNTHETIC_PASSWORD_KEY_PREFIX) && !has_pkey) mKey_Prefix = SYNTHETIC_PASSWORD_KEY_PREFIX; else if (strstr(de->d_name, USR_PRIVATE_KEY_PREFIX)) { mKey_Prefix = USR_PRIVATE_KEY_PREFIX; has_pkey = true; } else continue; if (strstr(de->d_name, handle_sub.c_str())) { keystoreid = handle_sub; printf("keystoreid matched handle_sub: '%s'\n", keystoreid.c_str()); found_subid = true; } else { std::string file = de->d_name; std::size_t found = file.find_last_of("_"); if (found != std::string::npos) { keystoreid = file.substr(found + 1); // printf("possible keystoreid: '%s'\n", keystoreid.c_str()); //found_subid = true; // we'll keep going in hopes that we find a pkey or a match to the handle_sub } } } std::string src = source_path; src += de->d_name; std::ifstream srcif(src.c_str(), std::ios::binary); std::string dst = destination_path; dst += de->d_name; std::size_t source_uid = dst.find("1000"); if (source_uid != std::string::npos) dst.replace(source_uid, 4, "0"); std::ofstream dstof(dst.c_str(), std::ios::binary); printf("copying '%s' to '%s'\n", src.c_str(), dst.c_str()); dstof << srcif.rdbuf(); srcif.close(); dstof.close(); } closedir(dir); if (!found_subid && !mKey_Prefix.empty() && !keystoreid.empty()) found_subid = true; return found_subid; } /* C++ replacement for function of the same name * https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#867 * returning an empty string indicates an error */ std::string unwrapSyntheticPasswordBlob(const std::string& spblob_path, const std::string& handle_str, const userid_t user_id, const void* application_id, const size_t application_id_size, uint32_t auth_token_len) { std::string disk_decryption_secret_key = ""; android::ProcessState::self()->startThreadPool(); std::string keystore_alias_subid; // Can be stored in user 0, so check for both. if (!Find_Keystore_Alias_SubID_And_Prep_Files(user_id, keystore_alias_subid, handle_str) && !Find_Keystore_Alias_SubID_And_Prep_Files(0, keystore_alias_subid, handle_str)) { printf("failed to scan keystore alias subid and prep keystore files\n"); return disk_decryption_secret_key; } // First get the keystore service android::sp binder = getKeystoreBinderRetry(); android::sp service = interface_cast(binder); if (service == NULL) { printf("error: could not connect to keystore service\n"); return disk_decryption_secret_key; } if (auth_token_len > 0) { printf("Starting keystore_auth service...\n"); property_set("ctl.start", "keystore_auth"); } // Read the data from the .spblob file per: https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#869 std::string spblob_file = spblob_path + handle_str + ".spblob"; std::string spblob_data; if (!android::base::ReadFileToString(spblob_file, &spblob_data)) { printf("Failed to read '%s'\n", spblob_file.c_str()); return disk_decryption_secret_key; } unsigned char* byteptr = (unsigned char*)spblob_data.data(); if (*byteptr != SYNTHETIC_PASSWORD_VERSION_V2 && *byteptr != SYNTHETIC_PASSWORD_VERSION_V1 && *byteptr != SYNTHETIC_PASSWORD_VERSION_V3) { printf("Unsupported synthetic password version %i\n", *byteptr); return disk_decryption_secret_key; } const unsigned char* synthetic_password_version = byteptr; byteptr++; if (*byteptr != SYNTHETIC_PASSWORD_PASSWORD_BASED) { printf("spblob data is not SYNTHETIC_PASSWORD_PASSWORD_BASED\n"); return disk_decryption_secret_key; } byteptr++; // Now we're pointing to the blob data itself if (*synthetic_password_version == SYNTHETIC_PASSWORD_VERSION_V2 || *synthetic_password_version == SYNTHETIC_PASSWORD_VERSION_V3) { printf("spblob v2 / v3\n"); /* Version 2 / 3 of the spblob is basically the same as version 1, but the order of getting the intermediate key and disk decryption key have been flip-flopped * as seen in https://android.googlesource.com/platform/frameworks/base/+/5025791ac6d1538224e19189397de8d71dcb1a12 */ /* First decrypt call found in * https://android.googlesource.com/platform/frameworks/base/+/android-8.1.0_r18/services/core/java/com/android/server/locksettings/SyntheticPasswordCrypto.java#135 * We will use https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/keystore/java/android/security/keystore/AndroidKeyStoreCipherSpiBase.java * and https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/keystore/java/android/security/keystore/AndroidKeyStoreAuthenticatedAESCipherSpi.java * First we set some algorithm parameters as seen in two places: * https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/keystore/java/android/security/keystore/AndroidKeyStoreAuthenticatedAESCipherSpi.java#297 * https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/keystore/java/android/security/keystore/AndroidKeyStoreAuthenticatedAESCipherSpi.java#216 */ // When using secdis (aka not weaver) you must supply an auth token to the keystore prior to the begin operation if (auth_token_len > 0) { /*::keystore::KeyStoreServiceReturnCode auth_result = service->addAuthToken(auth_token, auth_token_len); if (!auth_result.isOk()) { // The keystore checks the uid of the calling process and will return a permission denied on this operation for user 0 printf("keystore error adding auth token\n"); return disk_decryption_secret_key; }*/ // The keystore refuses to allow the root user to supply auth tokens, so we write the auth token to a file earlier and // run a separate service that runs user the system user to add the auth token. We wait for the auth token file to be // deleted by the keymaster_auth service and check for a /auth_error file in case of errors. We quit after after a while if // the /auth_token file never gets deleted. int auth_wait_count = 20; while (access("/auth_token", F_OK) == 0 && auth_wait_count-- > 0) usleep(5000); if (auth_wait_count == 0 || access("/auth_error", F_OK) == 0) { printf("error during keymaster_auth service\n"); /* If you are getting this error, make sure that you have the keymaster_auth service defined in your init scripts, preferrably in init.recovery.{ro.hardware}.rc * service keystore_auth /system/bin/keystore_auth * disabled * oneshot * user system * group root * seclabel u:r:recovery:s0 * * And check dmesg for error codes regarding this service if needed. */ return disk_decryption_secret_key; } } int32_t ret; size_t maclen = 128; unsigned char* iv = (unsigned char*)byteptr; // The IV is the first 12 bytes of the spblob ::keystore::hidl_vec iv_hidlvec; iv_hidlvec.setToExternal((unsigned char*)byteptr, 12); // printf("iv: "); output_hex((const unsigned char*)iv, 12); printf("\n"); std::string keystore_alias = mKey_Prefix; keystore_alias += keystore_alias_subid; String16 keystore_alias16(keystore_alias.data(), keystore_alias.size()); int32_t error_code; unsigned char* cipher_text = (unsigned char*)byteptr + 12; // The cipher text comes immediately after the IV std::string cipher_text_str(byteptr, byteptr + spblob_data.size() - 14); ::keystore::hidl_vec cipher_text_hidlvec; ::keystore::AuthorizationSetBuilder begin_params; cipher_text_hidlvec.setToExternal(cipher_text, spblob_data.size() - 14 /* 1 each for version and SYNTHETIC_PASSWORD_PASSWORD_BASED and 12 for the iv */); begin_params.Authorization(::keystore::TAG_ALGORITHM, ::keystore::Algorithm::AES); begin_params.Authorization(::keystore::TAG_BLOCK_MODE, ::keystore::BlockMode::GCM); begin_params.Padding(::keystore::PaddingMode::NONE); begin_params.Authorization(::keystore::TAG_NONCE, iv_hidlvec); begin_params.Authorization(::keystore::TAG_MAC_LENGTH, maclen); ::keystore::hidl_vec entropy; // No entropy is needed for decrypt entropy.resize(0); android::security::keymaster::KeymasterArguments empty_params; android::hardware::keymaster::V4_0::KeyPurpose decryptPurpose = android::hardware::keymaster::V4_0::KeyPurpose::DECRYPT; android::sp decryptAuthToken(new android::BBinder); android::sp promise = new OperationResultPromise; auto future = promise->get_future(); auto binder_result = service->begin(promise, decryptAuthToken, keystore_alias16, (int32_t)decryptPurpose, true, android::security::keymaster::KeymasterArguments(begin_params.hidl_data()), entropy, -1, &error_code); if (!binder_result.isOk()) { printf("communication error while calling keystore\n"); return disk_decryption_secret_key; } ::keystore::KeyStoreNativeReturnCode rc(error_code); if (!rc.isOk()) { printf("Keystore begin returned: %u\n", error_code); return disk_decryption_secret_key; } OperationResult result = future.get(); auto handle = std::move(result.token); // The cipher.doFinal call triggers an update to the keystore followed by a finish https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordCrypto.java#64 // See also https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/keystore/java/android/security/keystore/KeyStoreCryptoOperationChunkedStreamer.java#208 future = {}; promise = new OperationResultPromise(); future = promise->get_future(); binder_result = service->update(promise, handle, empty_params, cipher_text_hidlvec, &error_code); rc = ::keystore::KeyStoreNativeReturnCode(error_code); if (!rc.isOk()) { printf("Keystore update returned: %d\n", error_code); return disk_decryption_secret_key; } result = future.get(); if (!result.resultCode.isOk()) { printf("update failed: %d\n", error_code); return disk_decryption_secret_key; } size_t keystore_result_size = result.data.size(); unsigned char* keystore_result = (unsigned char*)malloc(keystore_result_size); if (!keystore_result) { printf("malloc on keystore_result\n"); return disk_decryption_secret_key; } memcpy(keystore_result, &result.data[0], result.data.size()); future = {}; promise = new OperationResultPromise(); future = promise->get_future(); std::tie(rc, keyBlob, charBlob, lockedEntry) = mKeyStore->getKeyForName(name8, callingUid, TYPE_KEYMASTER_10); auto hidlInput = blob2hidlVec(input_data); ::keystore::hidl_vec signature; binder_result = service->finish(promise, handle, empty_params, hidlInput, signature, entropy, &error_code); if (!binder_result.isOk()) { printf("communication error while calling keystore\n"); free(keystore_result); return disk_decryption_secret_key; } rc = ::keystore::KeyStoreNativeReturnCode(error_code); if (!rc.isOk()) { printf("Keystore finish returned: %d\n", error_code); return disk_decryption_secret_key; } result = future.get(); if (!result.resultCode.isOk()) { printf("finish failed: %d\n", error_code); return disk_decryption_secret_key; } stop_keystore(); /* Now we do the second decrypt call as seen in: * https://android.googlesource.com/platform/frameworks/base/+/android-8.1.0_r18/services/core/java/com/android/server/locksettings/SyntheticPasswordCrypto.java#136 */ const unsigned char* intermediate_iv = keystore_result; // printf("intermediate_iv: "); output_hex((const unsigned char*)intermediate_iv, 12); printf("\n"); const unsigned char* intermediate_cipher_text = (const unsigned char*)keystore_result + 12; // The cipher text comes immediately after the IV int cipher_size = keystore_result_size - 12; // First we personalize as seen https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordCrypto.java#102 void* personalized_application_id = PersonalizedHashBinary(PERSONALISATION_APPLICATION_ID, (const char*)application_id, application_id_size); if (!personalized_application_id) { return disk_decryption_secret_key; } // printf("personalized application id: "); output_hex((unsigned char*)personalized_application_id, SHA512_DIGEST_LENGTH); printf("\n"); // Now we'll decrypt using openssl AES/GCM/NoPadding OpenSSL_add_all_ciphers(); int actual_size=0, final_size=0; EVP_CIPHER_CTX *d_ctx = EVP_CIPHER_CTX_new(); const unsigned char* key = (const unsigned char*)personalized_application_id; // The key is the now personalized copy of the application ID // printf("key: "); output_hex((const unsigned char*)key, 32); printf("\n"); EVP_DecryptInit(d_ctx, EVP_aes_256_gcm(), key, intermediate_iv); unsigned char* secret_key = (unsigned char*)malloc(cipher_size); if (!secret_key) { printf("malloc failure on secret key\n"); return disk_decryption_secret_key; } EVP_DecryptUpdate(d_ctx, secret_key, &actual_size, intermediate_cipher_text, cipher_size); unsigned char tag[AES_BLOCK_SIZE]; EVP_CIPHER_CTX_ctrl(d_ctx, EVP_CTRL_GCM_SET_TAG, 16, tag); EVP_DecryptFinal_ex(d_ctx, secret_key + actual_size, &final_size); EVP_CIPHER_CTX_free(d_ctx); free(personalized_application_id); free(keystore_result); int secret_key_real_size = actual_size - 16; // printf("secret key: "); output_hex((const unsigned char*)secret_key, secret_key_real_size); printf("\n"); // The payload data from the keystore update is further personalized at https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#153 // We now have the disk decryption key! if (*synthetic_password_version == SYNTHETIC_PASSWORD_VERSION_V3) { // V3 uses SP800 instead of SHA512 disk_decryption_secret_key = PersonalizedHashSP800(PERSONALIZATION_FBE_KEY, PERSONALISATION_CONTEXT, (const char*)secret_key, secret_key_real_size); } else { disk_decryption_secret_key = PersonalizedHash(PERSONALIZATION_FBE_KEY, (const char*)secret_key, secret_key_real_size); } // printf("disk_decryption_secret_key: '%s'\n", disk_decryption_secret_key.c_str()); free(secret_key); return disk_decryption_secret_key; } return disk_decryption_secret_key; } }} #define PASSWORD_TOKEN_SIZE 32 /* C++ replacement for * https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#992 * called here * https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#813 */ bool Get_Secdis(const std::string& spblob_path, const std::string& handle_str, std::string& secdis_data) { std::string secdis_file = spblob_path + handle_str + ".secdis"; if (!android::base::ReadFileToString(secdis_file, &secdis_data)) { printf("Failed to read '%s'\n", secdis_file.c_str()); return false; } // output_hex(secdis_data.data(), secdis_data.size());printf("\n"); return true; } // C++ replacement for https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#1033 userid_t fakeUid(const userid_t uid) { return 100000 + uid; } bool Is_Weaver(const std::string& spblob_path, const std::string& handle_str) { std::string weaver_file = spblob_path + handle_str + ".weaver"; struct stat st; if (stat(weaver_file.c_str(), &st) == 0) return true; return false; } bool Free_Return(bool retval, void* weaver_key, password_data_struct* pwd) { if (weaver_key) free(weaver_key); if (pwd->salt) free(pwd->salt); if (pwd->password_handle) free(pwd->password_handle); return retval; } /* Decrypt_User_Synth_Pass is the TWRP C++ equivalent to spBasedDoVerifyCredential * https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/LockSettingsService.java#1998 */ bool Decrypt_User_Synth_Pass(const userid_t user_id, const std::string& Password) { bool retval = false; void* weaver_key = NULL; password_data_struct pwd; pwd.salt = NULL; pwd.salt_len = 0; pwd.password_handle = NULL; pwd.handle_len = 0; char application_id[PASSWORD_TOKEN_SIZE + SHA512_DIGEST_LENGTH]; uint32_t auth_token_len = 0; std::string secret; // this will be the disk decryption key that is sent to vold std::string token = "!"; // there is no token used for this kind of decrypt, key escrow is handled by weaver int flags = FLAG_STORAGE_DE; if (user_id == 0) flags = FLAG_STORAGE_DE; else flags = FLAG_STORAGE_CE; char spblob_path_char[PATH_MAX]; sprintf(spblob_path_char, "/data/system_de/%d/spblob/", user_id); std::string spblob_path = spblob_path_char; long handle = 0; std::string handle_str; // Get the handle: https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/LockSettingsService.java#2017 if (!Find_Handle(spblob_path, handle_str)) { printf("Error getting handle\n"); return Free_Return(retval, weaver_key, &pwd); } // printf("Handle is '%s'\n", handle_str.c_str()); // Now we begin driving unwrapPasswordBasedSyntheticPassword from: https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#758 // First we read the password data which contains scrypt parameters if (!Get_Password_Data(spblob_path, handle_str, &pwd)) { printf("Failed to Get_Password_Data\n"); return Free_Return(retval, weaver_key, &pwd); } // printf("pwd N %i R %i P %i salt ", pwd.scryptN, pwd.scryptR, pwd.scryptP); output_hex((char*)pwd.salt, pwd.salt_len); printf("\n"); unsigned char password_token[PASSWORD_TOKEN_SIZE]; // printf("Password: '%s'\n", Password.c_str()); // The password token is the password scrypted with the parameters from the password data file if (!Get_Password_Token(&pwd, Password, &password_token[0])) { printf("Failed to Get_Password_Token\n"); return Free_Return(retval, weaver_key, &pwd); } // output_hex(&password_token[0], PASSWORD_TOKEN_SIZE);printf("\n"); if (Is_Weaver(spblob_path, handle_str)) { printf("using weaver\n"); // BEGIN PIXEL 2 WEAVER // Get the weaver data from the .weaver file which tells us which slot to use when we ask weaver for the escrowed key // https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#768 weaver_data_struct wd; if (!Get_Weaver_Data(spblob_path, handle_str, &wd)) { printf("Failed to get weaver data\n"); return Free_Return(retval, weaver_key, &pwd); } // The weaver key is the the password token prefixed with "weaver-key" padded to 128 with nulls with the password token appended then SHA512 // https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#1059 weaver_key = PersonalizedHashBinary(PERSONALISATION_WEAVER_KEY, (char*)&password_token[0], PASSWORD_TOKEN_SIZE); if (!weaver_key) { printf("malloc error getting weaver_key\n"); return Free_Return(retval, weaver_key, &pwd); } // Now we start driving weaverVerify: https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#343 // Called from https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#776 android::vold::Weaver weaver; if (!weaver) { printf("Failed to get weaver service\n"); return Free_Return(retval, weaver_key, &pwd); } // Get the key size from weaver service uint32_t weaver_key_size = 0; if (!weaver.GetKeySize(&weaver_key_size)) { printf("Failed to get weaver key size\n"); return Free_Return(retval, weaver_key, &pwd); } else { printf("weaver key size is %u\n", weaver_key_size); } // printf("weaver key: "); output_hex((unsigned char*)weaver_key, weaver_key_size); printf("\n"); // Send the slot from the .weaver file, the computed weaver key, and get the escrowed key data std::vector weaver_payload; // TODO: we should return more information about the status including time delays before the next retry if (!weaver.WeaverVerify(wd.slot, weaver_key, &weaver_payload)) { printf("failed to weaver verify\n"); return Free_Return(retval, weaver_key, &pwd); } // printf("weaver payload: "); output_hex(&weaver_payload); printf("\n"); // Done with weaverVerify // Now we will compute the application ID // https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#964 // Called from https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#780 // The escrowed weaver key data is prefixed with "weaver-pwd" padded to 128 with nulls with the weaver payload appended then SHA512 void* weaver_secret = PersonalizedHashBinary(PERSONALISATION_WEAVER_PASSWORD, (const char*)weaver_payload.data(), weaver_payload.size()); // printf("weaver secret: "); output_hex((unsigned char*)weaver_secret, SHA512_DIGEST_LENGTH); printf("\n"); // The application ID is the password token and weaver secret appended to each other memcpy((void*)&application_id[0], (void*)&password_token[0], PASSWORD_TOKEN_SIZE); memcpy((void*)&application_id[PASSWORD_TOKEN_SIZE], weaver_secret, SHA512_DIGEST_LENGTH); // printf("application ID: "); output_hex((unsigned char*)application_id, PASSWORD_TOKEN_SIZE + SHA512_DIGEST_LENGTH); printf("\n"); // END PIXEL 2 WEAVER } else { printf("using secdis\n"); std::string secdis_data; if (!Get_Secdis(spblob_path, handle_str, secdis_data)) { printf("Failed to get secdis data\n"); return Free_Return(retval, weaver_key, &pwd); } void* secdiscardable = PersonalizedHashBinary(PERSONALISATION_SECDISCARDABLE, (char*)secdis_data.data(), secdis_data.size()); if (!secdiscardable) { printf("malloc error getting secdiscardable\n"); return Free_Return(retval, weaver_key, &pwd); } memcpy((void*)&application_id[0], (void*)&password_token[0], PASSWORD_TOKEN_SIZE); memcpy((void*)&application_id[PASSWORD_TOKEN_SIZE], secdiscardable, SHA512_DIGEST_LENGTH); int ret = -1; bool request_reenroll = false; android::sp gk_device; gk_device = ::android::hardware::gatekeeper::V1_0::IGatekeeper::getService(); if (gk_device == nullptr) { printf("failed to get gatekeeper service\n"); return Free_Return(retval, weaver_key, &pwd); } if (pwd.handle_len <= 0) { printf("no password handle supplied\n"); return Free_Return(retval, weaver_key, &pwd); } android::hardware::hidl_vec pwd_handle_hidl; pwd_handle_hidl.setToExternal(const_cast((const uint8_t *)pwd.password_handle), pwd.handle_len); void* gk_pwd_token = PersonalizedHashBinary(PERSONALIZATION_USER_GK_AUTH, (char*)&password_token[0], PASSWORD_TOKEN_SIZE); if (!gk_pwd_token) { printf("malloc error getting gatekeeper_key\n"); return Free_Return(retval, weaver_key, &pwd); } android::hardware::hidl_vec gk_pwd_token_hidl; gk_pwd_token_hidl.setToExternal(const_cast((const uint8_t *)gk_pwd_token), SHA512_DIGEST_LENGTH); android::hardware::Return hwRet = gk_device->verify(fakeUid(user_id), 0 /* challange */, pwd_handle_hidl, gk_pwd_token_hidl, [&ret, &request_reenroll, &auth_token_len] (const android::hardware::gatekeeper::V1_0::GatekeeperResponse &rsp) { ret = static_cast(rsp.code); // propagate errors if (rsp.code >= android::hardware::gatekeeper::V1_0::GatekeeperStatusCode::STATUS_OK) { auth_token_len = rsp.data.size(); request_reenroll = (rsp.code == android::hardware::gatekeeper::V1_0::GatekeeperStatusCode::STATUS_REENROLL); ret = 0; // all success states are reported as 0 // The keystore refuses to allow the root user to supply auth tokens, so we write the auth token to a file here and later // run a separate service that runs as the system user to add the auth token. We wait for the auth token file to be // deleted by the keymaster_auth service and check for a /auth_error file in case of errors. We quit after a while seconds if // the /auth_token file never gets deleted. unlink("/auth_token"); FILE* auth_file = fopen("/auth_token","wb"); if (auth_file != NULL) { fwrite(rsp.data.data(), sizeof(uint8_t), rsp.data.size(), auth_file); fclose(auth_file); } else { printf("failed to open /auth_token for writing\n"); ret = -2; } } else if (rsp.code == android::hardware::gatekeeper::V1_0::GatekeeperStatusCode::ERROR_RETRY_TIMEOUT && rsp.timeout > 0) { ret = rsp.timeout; } } ); free(gk_pwd_token); if (!hwRet.isOk() || ret != 0) { printf("gatekeeper verification failed\n"); return Free_Return(retval, weaver_key, &pwd); } } // Now we will handle https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#816 // Plus we will include the last bit that computes the disk decrypt key found in: // https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#153 secret = android::keystore::unwrapSyntheticPasswordBlob(spblob_path, handle_str, user_id, (const void*)&application_id[0], PASSWORD_TOKEN_SIZE + SHA512_DIGEST_LENGTH, auth_token_len); if (!secret.size()) { printf("failed to unwrapSyntheticPasswordBlob\n"); return Free_Return(retval, weaver_key, &pwd); } if (!fscrypt_unlock_user_key(user_id, 0, token.c_str(), secret.c_str())) { printf("fscrypt_unlock_user_key returned fail\n"); return Free_Return(retval, weaver_key, &pwd); } if (!fscrypt_prepare_user_storage("", user_id, 0, flags)) { printf("failed to fscrypt_prepare_user_storage\n"); return Free_Return(retval, weaver_key, &pwd); } printf("User %i Decrypted Successfully!\n", user_id); retval = true; return Free_Return(retval, weaver_key, &pwd); } int Get_Password_Type(const userid_t user_id, std::string& filename) { struct stat st; char spblob_path_char[PATH_MAX]; sprintf(spblob_path_char, "/data/system_de/%d/spblob/", user_id); if (stat(spblob_path_char, &st) == 0) { printf("Using synthetic password method\n"); std::string spblob_path = spblob_path_char; std::string handle_str; if (!Find_Handle(spblob_path, handle_str)) { printf("Error getting handle\n"); return 0; } printf("Handle is '%s'\n", handle_str.c_str()); password_data_struct pwd; if (!Get_Password_Data(spblob_path, handle_str, &pwd)) { printf("Failed to Get_Password_Data\n"); return 0; } if (pwd.password_type == 1) { // In Android this means pattern printf("password type: pattern\n"); return 2; // In TWRP this means pattern } // In Android <11 type 2 is PIN or password // In Android 11 type 3 is PIN and type 4 is password else if (pwd.password_type > 1) { printf("password type: pin\n"); return 1; // In TWRP this means PIN or password } printf("using default password\n"); return 0; // We'll try the default password } std::string path; if (user_id == 0) { path = "/data/system/"; } else { char user_id_str[5]; sprintf(user_id_str, "%i", user_id); path = "/data/system/users/"; path += user_id_str; path += "/"; } filename = path + "gatekeeper.password.key"; if (stat(filename.c_str(), &st) == 0 && st.st_size > 0) return 1; filename = path + "gatekeeper.pattern.key"; if (stat(filename.c_str(), &st) == 0 && st.st_size > 0) return 2; printf("Unable to locate gatekeeper password file '%s'\n", filename.c_str()); filename = ""; return 0; } bool Decrypt_User(const userid_t user_id, const std::string& Password) { uint8_t *auth_token; uint32_t auth_token_len; int ret; struct stat st; if (user_id > 9999) { printf("user_id is too big\n"); return false; } std::string filename; bool Default_Password = (Password == "!"); if (Get_Password_Type(user_id, filename) == 0 && !Default_Password) { printf("Unknown password type\n"); return false; } int flags = FLAG_STORAGE_DE; if (user_id == 0) flags = FLAG_STORAGE_DE; else flags = FLAG_STORAGE_CE; if (Default_Password) { if (!fscrypt_unlock_user_key(user_id, 0, "!", "!")) { printf("unlock_user_key returned fail\n"); return false; } if (!fscrypt_prepare_user_storage("", user_id, 0, flags)) { printf("failed to fscrypt_prepare_user_storage\n"); return false; } printf("User %i Decrypted Successfully!\n", user_id); return true; } if (stat("/data/system_de/0/spblob", &st) == 0) { printf("Using synthetic password method\n"); return Decrypt_User_Synth_Pass(user_id, Password); } // printf("password filename is '%s'\n", filename.c_str()); if (stat(filename.c_str(), &st) != 0) { printf("error stat'ing key file: %s\n", strerror(errno)); return false; } std::string handle; if (!android::base::ReadFileToString(filename, &handle)) { printf("Failed to read '%s'\n", filename.c_str()); return false; } bool should_reenroll; bool request_reenroll = false; android::sp gk_device; gk_device = ::android::hardware::gatekeeper::V1_0::IGatekeeper::getService(); if (gk_device == nullptr) return false; android::hardware::hidl_vec curPwdHandle; curPwdHandle.setToExternal(const_cast((const uint8_t *)handle.c_str()), st.st_size); android::hardware::hidl_vec enteredPwd; enteredPwd.setToExternal(const_cast((const uint8_t *)Password.c_str()), Password.size()); android::hardware::Return hwRet = gk_device->verify(user_id, 0 /* challange */, curPwdHandle, enteredPwd, [&ret, &request_reenroll, &auth_token, &auth_token_len] (const android::hardware::gatekeeper::V1_0::GatekeeperResponse &rsp) { ret = static_cast(rsp.code); // propagate errors if (rsp.code >= android::hardware::gatekeeper::V1_0::GatekeeperStatusCode::STATUS_OK) { auth_token = new uint8_t[rsp.data.size()]; auth_token_len = rsp.data.size(); memcpy(auth_token, rsp.data.data(), auth_token_len); request_reenroll = (rsp.code == android::hardware::gatekeeper::V1_0::GatekeeperStatusCode::STATUS_REENROLL); ret = 0; // all success states are reported as 0 } else if (rsp.code == android::hardware::gatekeeper::V1_0::GatekeeperStatusCode::ERROR_RETRY_TIMEOUT && rsp.timeout > 0) { ret = rsp.timeout; } } ); if (!hwRet.isOk()) { return false; } char token_hex[(auth_token_len*2)+1]; token_hex[(auth_token_len*2)] = 0; uint32_t i; for (i=0;i