FBE for Pixel 2
Includes various minor fixes for building in Android 8 trees with r23+ tag
Update FBE extended header in libtar to version 2 and include the entire
ext4_encryption_policy structure now after translating the policy.
See this post for more details:
https://plus.google.com/u/1/+DeesTroy/posts/i33ygUi7tiu
Change-Id: I2af981e51f459b17fcd895fb8c2d3f6c8200e24b
diff --git a/crypto/ext4crypt/Decrypt.cpp b/crypto/ext4crypt/Decrypt.cpp
index 3b69d46..2dab166 100644
--- a/crypto/ext4crypt/Decrypt.cpp
+++ b/crypto/ext4crypt/Decrypt.cpp
@@ -26,10 +26,50 @@
#include <sys/stat.h>
#include <sys/types.h>
-#include "ext4_crypt.h"
+#ifndef HAVE_LIBKEYUTILS
#include "key_control.h"
+#else
+#include <keyutils.h>
+#endif
+#ifdef HAVE_SYNTH_PWD_SUPPORT
+#include "Weaver1.h"
+#include "cutils/properties.h"
+
+#include <openssl/sha.h>
+#include <openssl/aes.h>
+#include <openssl/evp.h>
+#include <openssl/rand.h>
+
+#include <dirent.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <sys/types.h>
+#include <fstream>
+
+#include <ext4_utils/ext4_crypt.h>
+
+#include <keystore/IKeystoreService.h>
+#include <binder/IPCThreadState.h>
+#include <binder/IServiceManager.h>
+
+#include <keystore/keystore.h>
+#include <keystore/authorization_set.h>
+
+#include <algorithm>
+extern "C" {
+#include "crypto_scrypt.h"
+}
+#else
+#include "ext4_crypt.h"
+#endif //ifdef HAVE_SYNTH_PWD_SUPPORT
+
+#ifdef HAVE_GATEKEEPER1
+#include <android/hardware/gatekeeper/1.0/IGatekeeper.h>
+#else
#include <hardware/gatekeeper.h>
+#endif
#include "HashPassword.h"
#include <android-base/file.h>
@@ -67,7 +107,7 @@
extern "C" bool lookup_ref_tar(const char* policy_type, char* policy) {
if (strncmp(policy_type, "1", 1) != 0) {
- printf("Unexpected version %c\n", policy_type);
+ printf("Unexpected version %c\n", policy_type[0]);
return false;
}
const char* ptr = policy_type + 1; // skip past the version number
@@ -94,6 +134,7 @@
return true;
}
+#ifndef HAVE_GATEKEEPER1
int gatekeeper_device_initialize(gatekeeper_device_t **dev) {
int ret;
const hw_module_t *mod;
@@ -110,29 +151,7 @@
printf("failed to open gatekeeper\n");
return ret;
}
-
-int Get_Password_Type(const userid_t user_id, std::string& filename) {
- 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";
- struct stat st;
- 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;
-}
+#endif //ifndef HAVE_GATEKEEPER1
bool Decrypt_DE() {
if (!e4crypt_initialize_global_de()) { // this deals with the overarching device encryption
@@ -146,6 +165,692 @@
return true;
}
+#ifdef HAVE_SYNTH_PWD_SUPPORT
+// 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<uint8_t>* 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;
+}
+
+// The password data is stored in big endian and has to be swapped on little endian ARM
+template <class T>
+void endianswap(T *objp) {
+ unsigned char *memp = reinterpret_cast<unsigned char*>(objp);
+ std::reverse(memp, memp + sizeof(T));
+}
+
+/* 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);
+ } else {
+ printf("Get_Password_Data salt_len is 0\n");
+ return false;
+ }
+ 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<const uint8_t*>(Password.data()), Password.size(),
+ reinterpret_cast<const uint8_t*>(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 */
+sp<IBinder> getKeystoreBinder() {
+ sp<IServiceManager> sm = defaultServiceManager();
+ return sm->getService(String16("android.security.keystore"));
+}
+
+sp<IBinder> getKeystoreBinderRetry() {
+ printf("Starting keystore...\n");
+ property_set("ctl.start", "keystore");
+ int retry_count = 50;
+ sp<IBinder> 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 1
+#define SYNTHETIC_PASSWORD_PASSWORD_BASED 0
+#define SYNTHETIC_PASSWORD_KEY_PREFIX "USRSKEY_synthetic_password_"
+
+/* 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) {
+ 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;
+
+ 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;
+
+ 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))
+ continue;
+ 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("keystoreid: '%s'\n", keystoreid.c_str());
+ found_subid = true;
+ }
+ }
+ 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);
+ 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) {
+ std::string disk_decryption_secret_key = "";
+
+ std::string keystore_alias_subid;
+ if (!Find_Keystore_Alias_SubID_And_Prep_Files(user_id, keystore_alias_subid)) {
+ printf("failed to scan keystore alias subid and prep keystore files\n");
+ return disk_decryption_secret_key;
+ }
+
+ // First get the keystore service
+ sp<IBinder> binder = getKeystoreBinderRetry();
+ sp<IKeystoreService> service = interface_cast<IKeystoreService>(binder);
+ if (service == NULL) {
+ printf("error: could not connect to keystore service\n");
+ return disk_decryption_secret_key;
+ }
+
+ // 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;
+ }
+ const unsigned char* byteptr = (const unsigned char*)spblob_data.data();
+ if (*byteptr != SYNTHETIC_PASSWORD_VERSION) {
+ printf("SYNTHETIC_PASSWORD_VERSION does not match\n");
+ return disk_decryption_secret_key;
+ }
+ 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
+ /* We're now going to handle decryptSPBlob: https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordCrypto.java#115
+ * Called from https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java#879
+ * This small function ends up being quite a headache. The call to get data from the keystore basically is not needed in TWRP at this time.
+ * The keystore data seems to be the serialized data from an entire class in Java. Specifically I think it represents:
+ * https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/keystore/java/android/security/keystore/AndroidKeyStoreCipherSpiBase.java
+ * or perhaps
+ * https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/keystore/java/android/security/keystore/AndroidKeyStoreAuthenticatedAESCipherSpi.java
+ * but the only things we "need" from this keystore are a user ID and the keyAlias which ends up being USRSKEY_synthetic_password_{handle_str}
+ * the latter of which we already have. We may need to figure out how to get the user ID if we ever support decrypting mulitple users.
+ * There are 2 calls to a Java decrypt funcion that is overloaded. These 2 calls go in completely different directions despite the seemingly
+ * similar use of decrypt() and decrypt parameters. To figure out where things were going, I added logging to:
+ * https://android.googlesource.com/platform/libcore/+/android-8.0.0_r23/ojluni/src/main/java/javax/crypto/Cipher.java#2575
+ * Logger.global.severe("Cipher tryCombinations " + prov.getName() + " - " + prov.getInfo());
+ * To make logging work in libcore, import java.util.logging.Logger; and either set a better logging level or modify the framework to log everything
+ * regardless of logging level. This will give you some strings that you can grep for and find the actual crypto provider in use. In our case there were
+ * 2 different providers in use. The first stage to get the intermediate key used:
+ * https://android.googlesource.com/platform/external/conscrypt/+/android-8.0.0_r23/common/src/main/java/org/conscrypt/OpenSSLProvider.java
+ * which is a pretty straight-forward OpenSSL implementation of AES/GCM/NoPadding. */
+ // 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) {
+ printf("malloc personalized_application_id\n");
+ 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* iv = (const unsigned char*)byteptr; // The IV is the first 12 bytes of the spblob
+ //printf("iv: "); output_hex((const unsigned char*)iv, 12); printf("\n");
+ const unsigned char* cipher_text = (const unsigned char*)byteptr + 12; // The cipher text comes immediately after the IV
+ //printf("cipher_text: "); output_hex((const unsigned char*)cipher_text, spblob_data.size() - 2 - 12); printf("\n");
+ 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, iv);
+ std::vector<unsigned char> intermediate_key;
+ intermediate_key.resize(spblob_data.size() - 2 - 12, '\0');
+ EVP_DecryptUpdate(d_ctx, &intermediate_key[0], &actual_size, cipher_text, spblob_data.size() - 2 - 12);
+ unsigned char tag[AES_BLOCK_SIZE];
+ EVP_CIPHER_CTX_ctrl(d_ctx, EVP_CTRL_GCM_SET_TAG, 16, tag);
+ EVP_DecryptFinal_ex(d_ctx, &intermediate_key[actual_size], &final_size);
+ EVP_CIPHER_CTX_free(d_ctx);
+ free(personalized_application_id);
+ //printf("spblob_data size: %lu actual_size %i, final_size: %i\n", spblob_data.size(), actual_size, final_size);
+ intermediate_key.resize(actual_size + final_size - 16, '\0');// not sure why we have to trim the size by 16 as I don't see where this is done in Java side
+ //printf("intermediate key: "); output_hex((const unsigned char*)intermediate_key.data(), intermediate_key.size()); printf("\n");
+
+ int32_t ret;
+
+ /* We only need a keyAlias which is USRSKEY_synthetic_password_b6f71045af7bd042 which we find and a uid which is -1 or 1000, I forget which
+ * as the key data will be read again by the begin function later via the keystore.
+ * The data is in a hidl_vec format which consists of a type and a value. */
+ /*::keystore::hidl_vec<uint8_t> data;
+ std::string keystoreid = SYNTHETIC_PASSWORD_KEY_PREFIX;
+ keystoreid += handle_str;
+
+ ret = service->get(String16(keystoreid.c_str()), user_id, &data);
+ if (ret < 0) {
+ printf("Could not connect to keystore service %i\n", ret);
+ return disk_decryption_secret_key;
+ } else if (ret != 1 /*android::keystore::ResponseCode::NO_ERROR*//*) {
+ printf("keystore error: (%d)\n", /*responses[ret],*//* ret);
+ return disk_decryption_secret_key;
+ } else {
+ printf("keystore returned: "); output_hex(&data[0], data.size()); printf("\n");
+ }*/
+
+ // Now we'll break up the intermediate key into the IV (first 12 bytes) and the cipher text (the rest of it).
+ std::vector<unsigned char> nonce = intermediate_key;
+ nonce.resize(12);
+ intermediate_key.erase (intermediate_key.begin(),intermediate_key.begin()+12);
+ //printf("nonce: "); output_hex((const unsigned char*)nonce.data(), nonce.size()); printf("\n");
+ //printf("cipher text: "); output_hex((const unsigned char*)intermediate_key.data(), intermediate_key.size()); printf("\n");
+
+ /* Now we will begin the second decrypt call found in
+ * https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordCrypto.java#122
+ * This time 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 */
+ size_t maclen = 128;
+ ::keystore::AuthorizationSetBuilder begin_params;
+ 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, nonce);
+ begin_params.Authorization(::keystore::TAG_MAC_LENGTH, maclen);
+ //keymasterArgs.addEnum(KeymasterDefs.KM_TAG_ALGORITHM, KeymasterDefs.KM_ALGORITHM_AES);
+ //keymasterArgs.addEnum(KeymasterDefs.KM_TAG_BLOCK_MODE, mKeymasterBlockMode);
+ //keymasterArgs.addEnum(KeymasterDefs.KM_TAG_PADDING, mKeymasterPadding);
+ //keymasterArgs.addUnsignedInt(KeymasterDefs.KM_TAG_MAC_LENGTH, mTagLengthBits);
+ ::keystore::hidl_vec<uint8_t> entropy; // No entropy is needed for decrypt
+ entropy.resize(0);
+ std::string keystore_alias = SYNTHETIC_PASSWORD_KEY_PREFIX;
+ keystore_alias += keystore_alias_subid;
+ String16 keystore_alias16(keystore_alias.c_str());
+ ::keystore::KeyPurpose purpose = ::keystore::KeyPurpose::DECRYPT;
+ OperationResult begin_result;
+ // These parameters are mostly driven by the cipher.init call https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r23/services/core/java/com/android/server/locksettings/SyntheticPasswordCrypto.java#63
+ service->begin(binder, keystore_alias16, purpose, true, begin_params.hidl_data(), entropy, -1, &begin_result);
+ ret = begin_result.resultCode;
+ if (ret != 1 /*android::keystore::ResponseCode::NO_ERROR*/) {
+ printf("keystore begin error: (%d)\n", /*responses[ret],*/ ret);
+ return disk_decryption_secret_key;
+ } else {
+ //printf("keystore begin operation successful\n");
+ }
+ ::keystore::hidl_vec<::keystore::KeyParameter> empty_params;
+ empty_params.resize(0);
+ OperationResult update_result;
+ // 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
+ service->update(begin_result.token, empty_params, intermediate_key, &update_result);
+ ret = update_result.resultCode;
+ if (ret != 1 /*android::keystore::ResponseCode::NO_ERROR*/) {
+ printf("keystore update error: (%d)\n", /*responses[ret],*/ ret);
+ return disk_decryption_secret_key;
+ } else {
+ //printf("keystore update operation successful\n");
+ //printf("keystore update returned: "); output_hex(&update_result.data[0], update_result.data.size()); printf("\n"); // this ends up being the synthetic password
+ }
+ // We must use the data in update_data.data before we call finish below or the data will be gone
+ // 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!
+ disk_decryption_secret_key = PersonalizedHash(PERSONALIZATION_FBE_KEY, (const char*)&update_result.data[0], update_result.data.size());
+ //printf("disk_decryption_secret_key: '%s'\n", disk_decryption_secret_key.c_str());
+ ::keystore::hidl_vec<uint8_t> signature;
+ OperationResult finish_result;
+ service->finish(begin_result.token, empty_params, signature, entropy, &finish_result);
+ ret = finish_result.resultCode;
+ if (ret != 1 /*android::keystore::ResponseCode::NO_ERROR*/) {
+ printf("keystore finish error: (%d)\n", /*responses[ret],*/ ret);
+ return disk_decryption_secret_key;
+ } else {
+ //printf("keystore finish operation successful\n");
+ }
+ stop_keystore();
+ return disk_decryption_secret_key;
+}
+
+}}
+
+#define PASSWORD_TOKEN_SIZE 32
+
+bool Free_Return(bool retval, void* weaver_key, void* pwd_salt) {
+ if (weaver_key)
+ free(weaver_key);
+ if (pwd_salt)
+ free(pwd_salt);
+ 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;
+
+ 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.salt);
+ }
+ 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.salt);
+ }
+ //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.salt);
+ }
+ //output_hex(&password_token[0], PASSWORD_TOKEN_SIZE);printf("\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");
+ // Fail over to gatekeeper path for Pixel 1???
+ return Free_Return(retval, weaver_key, pwd.salt);
+ }
+ // 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.salt);
+ }
+ // 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.salt);
+ }
+ // 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.salt);
+ } 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<uint8_t> 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.salt);
+ }
+ //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
+ char application_id[PASSWORD_TOKEN_SIZE + SHA512_DIGEST_LENGTH];
+ 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
+ // 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);
+ if (!secret.size()) {
+ printf("failed to unwrapSyntheticPasswordBlob\n");
+ return Free_Return(retval, weaver_key, pwd.salt);
+ }
+ if (!e4crypt_unlock_user_key(user_id, 0, token.c_str(), secret.c_str())) {
+ printf("e4crypt_unlock_user_key returned fail\n");
+ return Free_Return(retval, weaver_key, pwd.salt);
+ }
+ if (!e4crypt_prepare_user_storage(nullptr, user_id, 0, flags)) {
+ printf("failed to e4crypt_prepare_user_storage\n");
+ return Free_Return(retval, weaver_key, pwd.salt);
+ }
+ printf("Decrypted Successfully!\n");
+ retval = true;
+ return Free_Return(retval, weaver_key, pwd.salt);
+}
+#endif //HAVE_SYNTH_PWD_SUPPORT
+
+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) {
+#ifdef HAVE_SYNTH_PWD_SUPPORT
+ 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
+ return 2; // In TWRP this means pattern
+ else if (pwd.password_type == 2) // In Android this means PIN or password
+ return 1; // In TWRP this means PIN or password
+ return 0; // We'll try the default password
+#else
+ printf("Synthetic password support not present in TWRP\n");
+ return -1;
+#endif
+ }
+ 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;
@@ -167,8 +872,6 @@
flags = FLAG_STORAGE_DE;
else
flags = FLAG_STORAGE_CE;
- gatekeeper_device_t *device;
- ret = gatekeeper_device_initialize(&device);
if (Default_Password) {
if (!e4crypt_unlock_user_key(user_id, 0, "!", "!")) {
printf("e4crypt_unlock_user_key returned fail\n");
@@ -181,8 +884,15 @@
printf("Decrypted Successfully!\n");
return true;
}
- if (ret!=0)
+ if (stat("/data/system_de/0/spblob", &st) == 0) {
+#ifdef HAVE_SYNTH_PWD_SUPPORT
+ printf("Using synthetic password method\n");
+ return Decrypt_User_Synth_Pass(user_id, Password);
+#else
+ printf("Synthetic password support not present in TWRP\n");
return false;
+#endif
+ }
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));
@@ -194,13 +904,51 @@
return false;
}
bool should_reenroll;
- ret = device->verify(device, user_id, 0, (const uint8_t *)handle.c_str(), st.st_size,
+#ifdef HAVE_GATEKEEPER1
+ bool request_reenroll = false;
+ android::sp<android::hardware::gatekeeper::V1_0::IGatekeeper> gk_device;
+ gk_device = ::android::hardware::gatekeeper::V1_0::IGatekeeper::getService();
+ if (gk_device == nullptr)
+ return false;
+ android::hardware::hidl_vec<uint8_t> curPwdHandle;
+ curPwdHandle.setToExternal(const_cast<uint8_t *>((const uint8_t *)handle.c_str()), st.st_size);
+ android::hardware::hidl_vec<uint8_t> enteredPwd;
+ enteredPwd.setToExternal(const_cast<uint8_t *>((const uint8_t *)Password.c_str()), Password.size());
+
+ android::hardware::Return<void> 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<int>(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;
+ }
+#else
+ gatekeeper_device_t *gk_device;
+ ret = gatekeeper_device_initialize(&gk_device);
+ if (ret!=0)
+ return false;
+ ret = gk_device->verify(gk_device, user_id, 0, (const uint8_t *)handle.c_str(), st.st_size,
(const uint8_t *)Password.c_str(), (uint32_t)Password.size(), &auth_token, &auth_token_len,
&should_reenroll);
if (ret !=0) {
printf("failed to verify\n");
return false;
}
+#endif
char token_hex[(auth_token_len*2)+1];
token_hex[(auth_token_len*2)] = 0;
uint32_t i;