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Add support for multi-user decryption

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* Add CLI support using the command "twrp decrypt <PASSWORD> [USER ID]"
* Add GUI support using the menu Advanced --> Decrypt User

Change-Id: Id2681bc2b1012a0571417f7a6e0b980b1b25c61c
(cherry picked from commit 5a79f67a1b1bd1bcadeca0a4896a871646652534)
This commit is contained in:
Noah Jacobson
2019-04-28 00:10:07 -04:00
committed by bigbiff
parent 784073e9fe
commit 0b25b1d79b
18 changed files with 640 additions and 655 deletions
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440
crypto/ext4crypt/Ext4CryptPie.cpp
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@@ -110,9 +110,9 @@ static bool e4crypt_is_emulated() {
return property_get_bool("persist.sys.emulate_fbe", false);
}
static const char* escape_empty(const std::string& value) {
/*static const char* escape_empty(const std::string& value) {
return value.empty() ? "null" : value.c_str();
}
}*/
static std::string get_de_key_path(userid_t user_id) {
return StringPrintf("%s/de/%d", user_key_dir.c_str(), user_id);
@@ -155,23 +155,6 @@ static std::string get_ce_key_current_path(const std::string& directory_path) {
return directory_path + "/current";
}
/*static bool get_ce_key_new_path(const std::string& directory_path,
const std::vector<std::string>& paths,
std::string *ce_key_path) {
if (paths.empty()) {
*ce_key_path = get_ce_key_current_path(directory_path);
return true;
}
for (unsigned int i = 0; i < UINT_MAX; i++) {
auto const candidate = StringPrintf("%s/cx%010u", directory_path.c_str(), i);
if (paths[0] < candidate) {
*ce_key_path = candidate;
return true;
}
}
return false;
}*/
// Discard all keys but the named one; rename it to canonical name.
// No point in acting on errors in this; ignore them.
static void fixate_user_ce_key(const std::string& directory_path, const std::string &to_fix,
@@ -259,15 +242,6 @@ static bool prepare_dir(const std::string& dir, mode_t mode, uid_t uid, gid_t gi
return true;
}
/*static bool destroy_dir(const std::string& dir) {
LOG(DEBUG) << "Destroying: " << dir;
if (rmdir(dir.c_str()) != 0 && errno != ENOENT) {
PLOG(ERROR) << "Failed to destroy " << dir;
return false;
}
return true;
}*/
// NB this assumes that there is only one thread listening for crypt commands, because
// it creates keys in a fixed location.
static bool create_and_install_user_keys(userid_t user_id, bool create_ephemeral) {
@@ -327,13 +301,6 @@ static void get_data_file_encryption_modes(PolicyKeyRef* key_ref) {
android::base::GetProperty("fbe.filenames", "aes-256-heh");
}
static bool ensure_policy(const PolicyKeyRef& key_ref, const std::string& path) {
return true;
/*return e4crypt_policy_ensure(path.c_str(), key_ref.key_raw_ref.data(),
key_ref.key_raw_ref.size(), key_ref.contents_mode.c_str(),
key_ref.filenames_mode.c_str()) == 0;*/
}
static bool is_numeric(const char* name) {
for (const char* p = name; *p != '\0'; p++) {
if (!isdigit(*p)) return false;
@@ -379,6 +346,9 @@ static bool load_all_de_keys() {
if (!android::vold::installKey(key, &raw_ref)) return false;
s_de_key_raw_refs[user_id] = raw_ref;
LOG(DEBUG) << "Installed de key for user " << user_id << std::endl;
std::string user_prop = "twrp.user." + std::to_string(user_id) + ".decrypt";
property_set(user_prop.c_str(), "0");
}
}
// ext4enc:TODO: go through all DE directories, ensure that all user dirs have the
@@ -435,13 +405,6 @@ bool e4crypt_init_user0() {
// explicit calls to install DE keys for secondary users
if (!load_all_de_keys()) return false;
}
// We can only safely prepare DE storage here, since CE keys are probably
// entangled with user credentials. The framework will always prepare CE
// storage once CE keys are installed.
if (!e4crypt_prepare_user_storage("", 0, 0, /*android::os::IVold::*/STORAGE_FLAG_DE)) {
LOG(ERROR) << "Failed to prepare user 0 storage" << std::endl;
return false;
}
// If this is a non-FBE device that recently left an emulated mode,
// restore user data directories to known-good state.
@@ -452,92 +415,6 @@ bool e4crypt_init_user0() {
return true;
}
/*bool e4crypt_vold_create_user_key(userid_t user_id, int serial, bool ephemeral) {
LOG(DEBUG) << "TWRP NOT e4crypt_vold_create_user_key for " << user_id << " serial " << serial;
return true;
if (!e4crypt_is_native()) {
return true;
}
// FIXME test for existence of key that is not loaded yet
if (s_ce_key_raw_refs.count(user_id) != 0) {
LOG(ERROR) << "Already exists, can't e4crypt_vold_create_user_key for " << user_id
<< " serial " << serial;
// FIXME should we fail the command?
return true;
}
if (!create_and_install_user_keys(user_id, ephemeral)) {
return false;
}
return true;
}
static void drop_caches() {
// Clean any dirty pages (otherwise they won't be dropped).
sync();
// Drop inode and page caches.
if (!WriteStringToFile("3", "/proc/sys/vm/drop_caches")) {
PLOG(ERROR) << "Failed to drop caches during key eviction";
}
}
static bool evict_ce_key(userid_t user_id) {
LOG(ERROR) << "TWRP NOT evict_ce_key\n";
return true;
s_ce_keys.erase(user_id);
bool success = true;
std::string raw_ref;
// If we haven't loaded the CE key, no need to evict it.
if (lookup_key_ref(s_ce_key_raw_refs, user_id, &raw_ref)) {
success &= android::vold::evictKey(raw_ref);
drop_caches();
}
s_ce_key_raw_refs.erase(user_id);
return success;
}
bool e4crypt_destroy_user_key(userid_t user_id) {
LOG(DEBUG) << "NOT e4crypt_destroy_user_key(" << user_id << ")";
return true;
if (!e4crypt_is_native()) {
return true;
}
bool success = true;
std::string raw_ref;
success &= evict_ce_key(user_id);
success &= lookup_key_ref(s_de_key_raw_refs, user_id, &raw_ref)
&& android::vold::evictKey(raw_ref);
s_de_key_raw_refs.erase(user_id);
auto it = s_ephemeral_users.find(user_id);
if (it != s_ephemeral_users.end()) {
s_ephemeral_users.erase(it);
} else {
for (auto const path: get_ce_key_paths(get_ce_key_directory_path(user_id))) {
success &= android::vold::destroyKey(path);
}
auto de_key_path = get_de_key_path(user_id);
if (android::vold::pathExists(de_key_path)) {
success &= android::vold::destroyKey(de_key_path);
} else {
LOG(INFO) << "Not present so not erasing: " << de_key_path;
}
}
return success;
}
static bool emulated_lock(const std::string& path) {
if (chmod(path.c_str(), 0000) != 0) {
PLOG(ERROR) << "Failed to chmod " << path;
return false;
}
#if EMULATED_USES_SELINUX
if (setfilecon(path.c_str(), "u:object_r:storage_stub_file:s0") != 0) {
PLOG(WARNING) << "Failed to setfilecon " << path;
return false;
}
#endif
return true;
}*/
static bool emulated_unlock(const std::string& path, mode_t mode) {
if (chmod(path.c_str(), mode) != 0) {
PLOG(ERROR) << "Failed to chmod " << path << std::endl;
@@ -566,92 +443,6 @@ static bool parse_hex(const std::string& hex, std::string* result) {
return true;
}
static std::string volkey_path(const std::string& misc_path, const std::string& volume_uuid) {
return misc_path + "/vold/volume_keys/" + volume_uuid + "/default";
}
static std::string volume_secdiscardable_path(const std::string& volume_uuid) {
return systemwide_volume_key_dir + "/" + volume_uuid + "/secdiscardable";
}
static bool read_or_create_volkey(const std::string& misc_path, const std::string& volume_uuid,
PolicyKeyRef* key_ref) {
auto secdiscardable_path = volume_secdiscardable_path(volume_uuid);
std::string secdiscardable_hash;
bool wrapped_key_supported = false;
if (android::vold::pathExists(secdiscardable_path)) {
if (!android::vold::readSecdiscardable(secdiscardable_path, &secdiscardable_hash))
return false;
} else {
if (fs_mkdirs(secdiscardable_path.c_str(), 0700) != 0) {
PLOG(ERROR) << "Creating directories for: " << secdiscardable_path << std::endl;
return false;
}
if (!android::vold::createSecdiscardable(secdiscardable_path, &secdiscardable_hash))
return false;
}
auto key_path = volkey_path(misc_path, volume_uuid);
if (fs_mkdirs(key_path.c_str(), 0700) != 0) {
PLOG(ERROR) << "Creating directories for: " << key_path << std::endl;
return false;
}
android::vold::KeyAuthentication auth("", secdiscardable_hash);
wrapped_key_supported = is_wrapped_key_supported_external();
if (!android::vold::retrieveAndInstallKey(true, auth, key_path, key_path + "_tmp",
&key_ref->key_raw_ref, wrapped_key_supported))
return false;
key_ref->contents_mode =
android::base::GetProperty("ro.crypto.volume.contents_mode", "aes-256-xts");
key_ref->filenames_mode =
android::base::GetProperty("ro.crypto.volume.filenames_mode", "aes-256-heh");
return true;
}
/*static bool destroy_volkey(const std::string& misc_path, const std::string& volume_uuid) {
auto path = volkey_path(misc_path, volume_uuid);
if (!android::vold::pathExists(path)) return true;
return android::vold::destroyKey(path);
}
bool e4crypt_add_user_key_auth(userid_t user_id, int serial, const std::string& token_hex,
const std::string& secret_hex) {
LOG(DEBUG) << "e4crypt_add_user_key_auth " << user_id << " serial=" << serial
<< " token_present=" << (token_hex != "!");
if (!e4crypt_is_native()) return true;
if (s_ephemeral_users.count(user_id) != 0) return true;
std::string token, secret;
if (!parse_hex(token_hex, &token)) return false;
if (!parse_hex(secret_hex, &secret)) return false;
auto auth = secret.empty() ? kEmptyAuthentication
: android::vold::KeyAuthentication(token, secret);
auto it = s_ce_keys.find(user_id);
if (it == s_ce_keys.end()) {
LOG(ERROR) << "Key not loaded into memory, can't change for user " << user_id;
return false;
}
const auto &ce_key = it->second;
auto const directory_path = get_ce_key_directory_path(user_id);
auto const paths = get_ce_key_paths(directory_path);
std::string ce_key_path;
if (!get_ce_key_new_path(directory_path, paths, &ce_key_path)) return false;
if (!android::vold::storeKeyAtomically(ce_key_path, user_key_temp, auth, ce_key)) return false;
return true;
}
bool e4crypt_fixate_newest_user_key_auth(userid_t user_id) {
LOG(DEBUG) << "e4crypt_fixate_newest_user_key_auth " << user_id;
if (!e4crypt_is_native()) return true;
if (s_ephemeral_users.count(user_id) != 0) return true;
auto const directory_path = get_ce_key_directory_path(user_id);
auto const paths = get_ce_key_paths(directory_path);
if (paths.empty()) {
LOG(ERROR) << "No ce keys present, cannot fixate for user " << user_id;
return false;
}
fixate_user_ce_key(directory_path, paths[0], paths);
return true;
}*/
// TODO: rename to 'install' for consistency, and take flags to know which keys to install
bool e4crypt_unlock_user_key(userid_t user_id, int serial, const std::string& token_hex,
const std::string& secret_hex) {
@@ -684,224 +475,3 @@ bool e4crypt_unlock_user_key(userid_t user_id, int serial, const std::string& to
}
return true;
}
// TODO: rename to 'evict' for consistency
/*bool e4crypt_lock_user_key(userid_t user_id) {
LOG(DEBUG) << "TWRP NOTe4crypt_lock_user_key " << user_id;
return true;
if (e4crypt_is_native()) {
return evict_ce_key(user_id);
} else if (e4crypt_is_emulated()) {
// When in emulation mode, we just use chmod
if (!emulated_lock(android::vold::BuildDataSystemCePath(user_id)) ||
!emulated_lock(android::vold::BuildDataMiscCePath(user_id)) ||
!emulated_lock(android::vold::BuildDataMediaCePath("", user_id)) ||
!emulated_lock(android::vold::BuildDataUserCePath("", user_id))) {
LOG(ERROR) << "Failed to lock user " << user_id;
return false;
}
}
return true;
}*/
static bool prepare_subdirs(const std::string& action, const std::string& volume_uuid,
userid_t user_id, int flags) {
LOG(ERROR) << "not actually forking for vold_prepare_subdirs\n";
return true;
/*if (0 != android::vold::ForkExecvp(
std::vector<std::string>{prepare_subdirs_path, action, volume_uuid,
std::to_string(user_id), std::to_string(flags)})) {
LOG(ERROR) << "vold_prepare_subdirs failed";
return false;
}
return true;*/
}
bool e4crypt_prepare_user_storage(const std::string& volume_uuid, userid_t user_id, int serial,
int flags) {
LOG(DEBUG) << "e4crypt_prepare_user_storage for volume " << escape_empty(volume_uuid)
<< ", user " << user_id << ", serial " << serial << ", flags " << flags << std::endl;
if (flags & /*android::os::IVold::*/STORAGE_FLAG_DE) {
// DE_sys key
auto system_legacy_path = android::vold::BuildDataSystemLegacyPath(user_id);
auto misc_legacy_path = android::vold::BuildDataMiscLegacyPath(user_id);
auto profiles_de_path = android::vold::BuildDataProfilesDePath(user_id);
// DE_n key
auto system_de_path = android::vold::BuildDataSystemDePath(user_id);
auto misc_de_path = android::vold::BuildDataMiscDePath(user_id);
auto vendor_de_path = android::vold::BuildDataVendorDePath(user_id);
auto user_de_path = android::vold::BuildDataUserDePath(nullptr, user_id);
if (volume_uuid.empty()) {
if (!prepare_dir(system_legacy_path, 0700, AID_SYSTEM, AID_SYSTEM)) return false;
#if MANAGE_MISC_DIRS
if (!prepare_dir(misc_legacy_path, 0750, multiuser_get_uid(user_id, AID_SYSTEM),
multiuser_get_uid(user_id, AID_EVERYBODY))) return false;
#endif
if (!prepare_dir(profiles_de_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false;
if (!prepare_dir(system_de_path, 0770, AID_SYSTEM, AID_SYSTEM)) return false;
if (!prepare_dir(misc_de_path, 01771, AID_SYSTEM, AID_MISC)) return false;
if (!prepare_dir(vendor_de_path, 0771, AID_ROOT, AID_ROOT)) return false;
}
if (!prepare_dir(user_de_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false;
if (e4crypt_is_native()) {
PolicyKeyRef de_ref;
if (volume_uuid.empty()) {
if (!lookup_key_ref(s_de_key_raw_refs, user_id, &de_ref.key_raw_ref)) return false;
get_data_file_encryption_modes(&de_ref);
if (!ensure_policy(de_ref, system_de_path)) return false;
if (!ensure_policy(de_ref, misc_de_path)) return false;
if (!ensure_policy(de_ref, vendor_de_path)) return false;
} else {
if (!read_or_create_volkey(misc_de_path, nullptr, &de_ref)) return false;
}
if (!ensure_policy(de_ref, user_de_path)) return false;
}
}
if (flags & /*android::os::IVold::*/STORAGE_FLAG_CE) {
// CE_n key
auto system_ce_path = android::vold::BuildDataSystemCePath(user_id);
auto misc_ce_path = android::vold::BuildDataMiscCePath(user_id);
auto vendor_ce_path = android::vold::BuildDataVendorCePath(user_id);
auto media_ce_path = android::vold::BuildDataMediaCePath(nullptr, user_id);
auto user_ce_path = android::vold::BuildDataUserCePath(nullptr, user_id);
if (volume_uuid.empty()) {
if (!prepare_dir(system_ce_path, 0770, AID_SYSTEM, AID_SYSTEM)) return false;
if (!prepare_dir(misc_ce_path, 01771, AID_SYSTEM, AID_MISC)) return false;
if (!prepare_dir(vendor_ce_path, 0771, AID_ROOT, AID_ROOT)) return false;
}
if (!prepare_dir(media_ce_path, 0770, AID_MEDIA_RW, AID_MEDIA_RW)) return false;
if (!prepare_dir(user_ce_path, 0771, AID_SYSTEM, AID_SYSTEM)) return false;
if (e4crypt_is_native()) {
PolicyKeyRef ce_ref;
if (volume_uuid.empty()) {
if (!lookup_key_ref(s_ce_key_raw_refs, user_id, &ce_ref.key_raw_ref)) return false;
get_data_file_encryption_modes(&ce_ref);
if (!ensure_policy(ce_ref, system_ce_path)) return false;
if (!ensure_policy(ce_ref, misc_ce_path)) return false;
if (!ensure_policy(ce_ref, vendor_ce_path)) return false;
} else {
if (!read_or_create_volkey(misc_ce_path, nullptr, &ce_ref)) return false;
}
if (!ensure_policy(ce_ref, media_ce_path)) return false;
if (!ensure_policy(ce_ref, user_ce_path)) return false;
}
if (volume_uuid.empty()) {
// Now that credentials have been installed, we can run restorecon
// over these paths
// NOTE: these paths need to be kept in sync with libselinux
//android::vold::RestoreconRecursive(system_ce_path);
//android::vold::RestoreconRecursive(misc_ce_path);
}
}
if (!prepare_subdirs("prepare", volume_uuid, user_id, flags)) return false;
return true;
}
/*bool e4crypt_destroy_user_storage(const std::string& volume_uuid, userid_t user_id, int flags) {
LOG(DEBUG) << "TWRP NOT e4crypt_destroy_user_storage for volume " << escape_empty(volume_uuid)
<< ", user " << user_id << ", flags " << flags;
bool res = true;
return res;
res &= prepare_subdirs("destroy", volume_uuid, user_id, flags);
if (flags & android::os::IVold::STORAGE_FLAG_CE) {
// CE_n key
auto system_ce_path = android::vold::BuildDataSystemCePath(user_id);
auto misc_ce_path = android::vold::BuildDataMiscCePath(user_id);
auto vendor_ce_path = android::vold::BuildDataVendorCePath(user_id);
auto media_ce_path = android::vold::BuildDataMediaCePath(nullptr, user_id);
auto user_ce_path = android::vold::BuildDataUserCePath(nullptr, user_id);
res &= destroy_dir(media_ce_path);
res &= destroy_dir(user_ce_path);
if (volume_uuid.empty()) {
res &= destroy_dir(system_ce_path);
res &= destroy_dir(misc_ce_path);
res &= destroy_dir(vendor_ce_path);
} else {
if (e4crypt_is_native()) {
res &= destroy_volkey(misc_ce_path, volume_uuid);
}
}
}
if (flags & android::os::IVold::STORAGE_FLAG_DE) {
// DE_sys key
auto system_legacy_path = android::vold::BuildDataSystemLegacyPath(user_id);
auto misc_legacy_path = android::vold::BuildDataMiscLegacyPath(user_id);
auto profiles_de_path = android::vold::BuildDataProfilesDePath(user_id);
// DE_n key
auto system_de_path = android::vold::BuildDataSystemDePath(user_id);
auto misc_de_path = android::vold::BuildDataMiscDePath(user_id);
auto vendor_de_path = android::vold::BuildDataVendorDePath(user_id);
auto user_de_path = android::vold::BuildDataUserDePath(nullptr, user_id);
res &= destroy_dir(user_de_path);
if (volume_uuid.empty()) {
res &= destroy_dir(system_legacy_path);
#if MANAGE_MISC_DIRS
res &= destroy_dir(misc_legacy_path);
#endif
res &= destroy_dir(profiles_de_path);
res &= destroy_dir(system_de_path);
res &= destroy_dir(misc_de_path);
res &= destroy_dir(vendor_de_path);
} else {
if (e4crypt_is_native()) {
res &= destroy_volkey(misc_de_path, volume_uuid);
}
}
}
return res;
}
static bool destroy_volume_keys(const std::string& directory_path, const std::string& volume_uuid) {
LOG(ERROR) << "TWRP NOT destroy_volume_keys\n";
return true;
auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(directory_path.c_str()), closedir);
if (!dirp) {
PLOG(ERROR) << "Unable to open directory: " + directory_path;
return false;
}
bool res = true;
for (;;) {
errno = 0;
auto const entry = readdir(dirp.get());
if (!entry) {
if (errno) {
PLOG(ERROR) << "Unable to read directory: " + directory_path;
return false;
}
break;
}
if (entry->d_type != DT_DIR || entry->d_name[0] == '.') {
LOG(DEBUG) << "Skipping non-user " << entry->d_name;
continue;
}
res &= destroy_volkey(directory_path + "/" + entry->d_name, volume_uuid);
}
return res;
}
bool e4crypt_destroy_volume_keys(const std::string& volume_uuid) {
bool res = true;
LOG(DEBUG) << "TWRP NOT e4crypt_destroy_volume_keys for volume " << escape_empty(volume_uuid);
/*return res;
auto secdiscardable_path = volume_secdiscardable_path(volume_uuid);
res &= android::vold::runSecdiscardSingle(secdiscardable_path);
res &= destroy_volume_keys("/data/misc_ce", volume_uuid);
res &= destroy_volume_keys("/data/misc_de", volume_uuid);
return res;
}*/