#include "KeyStorage.h"
#include "Utils.h"
+#include <algorithm>
#include <iomanip>
#include <map>
#include <set>
#include <sstream>
#include <string>
-#include <cutils/properties.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
+#include <limits.h>
#include <openssl/sha.h>
#include <selinux/android.h>
#include <stdio.h>
static constexpr int FLAG_STORAGE_CE = 1 << 1;
namespace {
-const std::string device_key_dir = std::string() + DATA_MNT_POINT + "/unencrypted";
+const std::string device_key_dir = std::string() + DATA_MNT_POINT + e4crypt_unencrypted_folder;
const std::string device_key_path = device_key_dir + "/key";
const std::string device_key_temp = device_key_dir + "/temp";
};
}
-// TODO replace with proper function to test for file encryption
-bool e4crypt_is_native() {
- char value[PROPERTY_VALUE_MAX];
- property_get("ro.crypto.type", value, "none");
- return !strcmp(value, "file");
-}
-
static bool e4crypt_is_emulated() {
return property_get_bool("persist.sys.emulate_fbe", false);
}
return StringPrintf("%s/de/%d", user_key_dir.c_str(), user_id);
}
-static std::string get_ce_key_path(userid_t user_id) {
- return StringPrintf("%s/ce/%d/current", user_key_dir.c_str(), user_id);
+static std::string get_ce_key_directory_path(userid_t user_id) {
+ return StringPrintf("%s/ce/%d", user_key_dir.c_str(), user_id);
+}
+
+// Returns the keys newest first
+static std::vector<std::string> get_ce_key_paths(const std::string& directory_path) {
+ auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(directory_path.c_str()), closedir);
+ if (!dirp) {
+ PLOG(ERROR) << "Unable to open ce key directory: " + directory_path;
+ return std::vector<std::string>();
+ }
+ std::vector<std::string> result;
+ for (;;) {
+ errno = 0;
+ auto const entry = readdir(dirp.get());
+ if (!entry) {
+ if (errno) {
+ PLOG(ERROR) << "Unable to read ce key directory: " + directory_path;
+ return std::vector<std::string>();
+ }
+ break;
+ }
+ if (entry->d_type != DT_DIR || entry->d_name[0] != 'c') {
+ LOG(DEBUG) << "Skipping non-key " << entry->d_name;
+ continue;
+ }
+ result.emplace_back(directory_path + "/" + entry->d_name);
+ }
+ std::sort(result.begin(), result.end());
+ std::reverse(result.begin(), result.end());
+ return result;
+}
+
+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,
+ const std::vector<std::string>& paths) {
+ for (auto const other_path: paths) {
+ if (other_path != to_fix) {
+ android::vold::destroyKey(other_path);
+ }
+ }
+ auto const current_path = get_ce_key_current_path(directory_path);
+ if (to_fix != current_path) {
+ LOG(DEBUG) << "Renaming " << to_fix << " to " << current_path;
+ if (rename(to_fix.c_str(), current_path.c_str()) != 0) {
+ PLOG(WARNING) << "Unable to rename " << to_fix << " to " << current_path;
+ }
+ }
+}
+
+static bool read_and_fixate_user_ce_key(userid_t user_id,
+ const android::vold::KeyAuthentication& auth,
+ std::string *ce_key) {
+ auto const directory_path = get_ce_key_directory_path(user_id);
+ auto const paths = get_ce_key_paths(directory_path);
+ for (auto const ce_key_path: paths) {
+ LOG(DEBUG) << "Trying user CE key " << ce_key_path;
+ if (android::vold::retrieveKey(ce_key_path, auth, ce_key)) {
+ LOG(DEBUG) << "Successfully retrieved key";
+ fixate_user_ce_key(directory_path, ce_key_path, paths);
+ return true;
+ }
+ }
+ LOG(ERROR) << "Failed to find working ce key for user " << user_id;
+ return false;
}
static bool read_and_install_user_ce_key(userid_t user_id,
const android::vold::KeyAuthentication& auth) {
if (s_ce_key_raw_refs.count(user_id) != 0) return true;
- const auto ce_key_path = get_ce_key_path(user_id);
std::string ce_key;
- if (!android::vold::retrieveKey(ce_key_path, auth, &ce_key)) return false;
+ if (!read_and_fixate_user_ce_key(user_id, auth, &ce_key)) return false;
std::string ce_raw_ref;
if (!install_key(ce_key, &ce_raw_ref)) return false;
s_ce_keys[user_id] = ce_key;
// If the key should be created as ephemeral, don't store it.
s_ephemeral_users.insert(user_id);
} else {
+ auto const directory_path = get_ce_key_directory_path(user_id);
+ if (!prepare_dir(directory_path, 0700, AID_ROOT, AID_ROOT)) return false;
+ 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 (!store_key(ce_key_path, user_key_temp,
+ kEmptyAuthentication, ce_key)) return false;
+ fixate_user_ce_key(directory_path, ce_key_path, paths);
+ // Write DE key second; once this is written, all is good.
if (!store_key(get_de_key_path(user_id), user_key_temp,
kEmptyAuthentication, de_key)) return false;
- if (!prepare_dir(user_key_dir + "/ce/" + std::to_string(user_id),
- 0700, AID_ROOT, AID_ROOT)) return false;
- if (!store_key(get_ce_key_path(user_id), user_key_temp,
- kEmptyAuthentication, ce_key)) return false;
}
std::string de_raw_ref;
if (!install_key(de_key, &de_raw_ref)) return false;
if (!prepare_dir(user_key_dir, 0700, AID_ROOT, AID_ROOT)) return false;
if (!prepare_dir(user_key_dir + "/ce", 0700, AID_ROOT, AID_ROOT)) return false;
if (!prepare_dir(user_key_dir + "/de", 0700, AID_ROOT, AID_ROOT)) return false;
- auto de_path = get_de_key_path(0);
- auto ce_path = get_ce_key_path(0);
- if (!path_exists(de_path) || !path_exists(ce_path)) {
- if (path_exists(de_path)) {
- android::vold::destroyKey(de_path); // May be partially created so ignore errors
- }
- if (path_exists(ce_path)) {
- android::vold::destroyKey(ce_path); // May be partially created so ignore errors
- }
+ if (!path_exists(get_de_key_path(0))) {
if (!create_and_install_user_keys(0, false)) return false;
}
// TODO: switch to loading only DE_0 here once framework makes
if (it != s_ephemeral_users.end()) {
s_ephemeral_users.erase(it);
} else {
- success &= android::vold::destroyKey(get_ce_key_path(user_id));
+ for (auto const path: get_ce_key_paths(get_ce_key_directory_path(user_id))) {
+ success &= android::vold::destroyKey(path);
+ }
success &= android::vold::destroyKey(get_de_key_path(user_id));
}
return success;
return true;
}
-bool e4crypt_change_user_key(userid_t user_id, int serial, const char* token_hex,
- const char* old_secret_hex, const char* new_secret_hex) {
- LOG(DEBUG) << "e4crypt_change_user_key " << user_id << " serial=" << serial
+bool e4crypt_add_user_key_auth(userid_t user_id, int serial, const char* token_hex,
+ const char* secret_hex) {
+ LOG(DEBUG) << "e4crypt_add_user_key_auth " << user_id << " serial=" << serial
<< " token_present=" << (strcmp(token_hex, "!") != 0);
if (!e4crypt_is_native()) return true;
if (s_ephemeral_users.count(user_id) != 0) return true;
- std::string token, old_secret, new_secret;
+ std::string token, secret;
if (!parse_hex(token_hex, &token)) return false;
- if (!parse_hex(old_secret_hex, &old_secret)) return false;
- if (!parse_hex(new_secret_hex, &new_secret)) return false;
- auto old_auth = old_secret.empty() ? kEmptyAuthentication
- : android::vold::KeyAuthentication(token, old_secret);
- auto new_auth = new_secret.empty() ? kEmptyAuthentication
- : android::vold::KeyAuthentication(token, new_secret);
+ 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;
}
auto ce_key = it->second;
- auto ce_key_path = get_ce_key_path(user_id);
- std::string trial_key;
- if (!android::vold::retrieveKey(ce_key_path, old_auth, &trial_key)) {
- LOG(WARNING) << "change_user_key wasn't given enough info to reconstruct the key";
- } else if (ce_key != trial_key) {
- LOG(WARNING) << "Reconstructed key != stored key";
- }
- android::vold::destroyKey(ce_key_path);
- if (!store_key(ce_key_path, user_key_temp, new_auth, ce_key)) return false;
+ 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 (!store_key(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;
+ 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;
}
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