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android / platform / system / security / e5f3a444f692f2d61d54783021551bb82c56e507 / . / keystore / keystore.cpp
blob: ffd8b5cbf541d65a1389446d29850643c757ce52 [file] [log] [blame]
/*
* Copyright (C) 2009 The Android Open Source 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.
*/
//#define LOG_NDEBUG 0
#define LOG_TAG "keystore"
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>
#include <signal.h>
#include <errno.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <assert.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <arpa/inet.h>
#include <openssl/aes.h>
#include <openssl/bio.h>
#include <openssl/evp.h>
#include <openssl/md5.h>
#include <openssl/pem.h>
#include <hardware/keymaster0.h>
#include <keymaster/soft_keymaster_device.h>
#include <keymaster/soft_keymaster_logger.h>
#include <keymaster/softkeymaster.h>
#include <UniquePtr.h>
#include <utils/String8.h>
#include <utils/Vector.h>
#include <keystore/IKeystoreService.h>
#include <binder/IPCThreadState.h>
#include <binder/IServiceManager.h>
#include <cutils/log.h>
#include <cutils/sockets.h>
#include <private/android_filesystem_config.h>
#include <keystore/keystore.h>
#include <selinux/android.h>
#include <sstream>
#include "auth_token_table.h"
#include "defaults.h"
#include "keystore_keymaster_enforcement.h"
#include "operation.h"
/* KeyStore is a secured storage for key-value pairs. In this implementation,
* each file stores one key-value pair. Keys are encoded in file names, and
* values are encrypted with checksums. The encryption key is protected by a
* user-defined password. To keep things simple, buffers are always larger than
* the maximum space we needed, so boundary checks on buffers are omitted. */
#define KEY_SIZE ((NAME_MAX - 15) / 2)
#define VALUE_SIZE 32768
#define PASSWORD_SIZE VALUE_SIZE
using keymaster::SoftKeymasterDevice;
struct BIGNUM_Delete {
void operator()(BIGNUM* p) const {
BN_free(p);
}
};
typedef UniquePtr<BIGNUM, BIGNUM_Delete> Unique_BIGNUM;
struct BIO_Delete {
void operator()(BIO* p) const {
BIO_free(p);
}
};
typedef UniquePtr<BIO, BIO_Delete> Unique_BIO;
struct EVP_PKEY_Delete {
void operator()(EVP_PKEY* p) const {
EVP_PKEY_free(p);
}
};
typedef UniquePtr<EVP_PKEY, EVP_PKEY_Delete> Unique_EVP_PKEY;
struct PKCS8_PRIV_KEY_INFO_Delete {
void operator()(PKCS8_PRIV_KEY_INFO* p) const {
PKCS8_PRIV_KEY_INFO_free(p);
}
};
typedef UniquePtr<PKCS8_PRIV_KEY_INFO, PKCS8_PRIV_KEY_INFO_Delete> Unique_PKCS8_PRIV_KEY_INFO;
static int keymaster0_device_initialize(const hw_module_t* mod, keymaster1_device_t** dev) {
assert(mod->module_api_version < KEYMASTER_MODULE_API_VERSION_1_0);
ALOGI("Found keymaster0 module %s, version %x", mod->name, mod->module_api_version);
UniquePtr<SoftKeymasterDevice> soft_keymaster(new SoftKeymasterDevice);
keymaster0_device_t* km0_device = NULL;
keymaster_error_t error = KM_ERROR_OK;
int rc = keymaster0_open(mod, &km0_device);
if (rc) {
ALOGE("Error opening keystore keymaster0 device.");
goto err;
}
if (km0_device->flags & KEYMASTER_SOFTWARE_ONLY) {
ALOGI("Keymaster0 module is software-only. Using SoftKeymasterDevice instead.");
km0_device->common.close(&km0_device->common);
km0_device = NULL;
// SoftKeymasterDevice will be deleted by keymaster_device_release()
*dev = soft_keymaster.release()->keymaster_device();
return 0;
}
ALOGE("Wrapping keymaster0 module %s with SoftKeymasterDevice", mod->name);
error = soft_keymaster->SetHardwareDevice(km0_device);
km0_device = NULL; // SoftKeymasterDevice has taken ownership.
if (error != KM_ERROR_OK) {
ALOGE("Got error %d from SetHardwareDevice", error);
rc = error;
goto err;
}
// SoftKeymasterDevice will be deleted by keymaster_device_release()
*dev = soft_keymaster.release()->keymaster_device();
return 0;
err:
if (km0_device)
km0_device->common.close(&km0_device->common);
*dev = NULL;
return rc;
}
static int keymaster1_device_initialize(const hw_module_t* mod, keymaster1_device_t** dev) {
assert(mod->module_api_version >= KEYMASTER_MODULE_API_VERSION_1_0);
ALOGI("Found keymaster1 module %s, version %x", mod->name, mod->module_api_version);
UniquePtr<SoftKeymasterDevice> soft_keymaster(new SoftKeymasterDevice);
keymaster1_device_t* km1_device = NULL;
keymaster_error_t error = KM_ERROR_OK;
int rc = keymaster1_open(mod, &km1_device);
if (rc) {
ALOGE("Error %d opening keystore keymaster1 device", rc);
goto err;
}
error = soft_keymaster->SetHardwareDevice(km1_device);
km1_device = NULL; // SoftKeymasterDevice has taken ownership.
if (error != KM_ERROR_OK) {
ALOGE("Got error %d from SetHardwareDevice", error);
rc = error;
goto err;
}
if (!soft_keymaster->Keymaster1DeviceIsGood()) {
ALOGI("Keymaster1 module is incomplete, using SoftKeymasterDevice wrapper");
// SoftKeymasterDevice will be deleted by keymaster_device_release()
*dev = soft_keymaster.release()->keymaster_device();
return 0;
} else {
ALOGI("Keymaster1 module is good, destroying wrapper and re-opening");
soft_keymaster.reset(NULL);
rc = keymaster1_open(mod, &km1_device);
if (rc) {
ALOGE("Error %d re-opening keystore keymaster1 device.", rc);
goto err;
}
*dev = km1_device;
return 0;
}
err:
if (km1_device)
km1_device->common.close(&km1_device->common);
*dev = NULL;
return rc;
}
static int keymaster_device_initialize(keymaster1_device_t** dev) {
const hw_module_t* mod;
int rc = hw_get_module_by_class(KEYSTORE_HARDWARE_MODULE_ID, NULL, &mod);
if (rc) {
ALOGI("Could not find any keystore module, using software-only implementation.");
// SoftKeymasterDevice will be deleted by keymaster_device_release()
*dev = (new SoftKeymasterDevice)->keymaster_device();
return 0;
}
if (mod->module_api_version < KEYMASTER_MODULE_API_VERSION_1_0) {
return keymaster0_device_initialize(mod, dev);
} else {
return keymaster1_device_initialize(mod, dev);
}
}
// softkeymaster_logger appears not to be used in keystore, but it installs itself as the
// logger used by SoftKeymasterDevice.
static keymaster::SoftKeymasterLogger softkeymaster_logger;
static int fallback_keymaster_device_initialize(keymaster1_device_t** dev) {
*dev = (new SoftKeymasterDevice)->keymaster_device();
// SoftKeymasterDevice will be deleted by keymaster_device_release()
return 0;
}
static void keymaster_device_release(keymaster1_device_t* dev) {
dev->common.close(&dev->common);
}
static void add_legacy_key_authorizations(int keyType, std::vector<keymaster_key_param_t>* params) {
params->push_back(keymaster_param_enum(KM_TAG_PURPOSE, KM_PURPOSE_SIGN));
params->push_back(keymaster_param_enum(KM_TAG_PURPOSE, KM_PURPOSE_VERIFY));
params->push_back(keymaster_param_enum(KM_TAG_PURPOSE, KM_PURPOSE_ENCRYPT));
params->push_back(keymaster_param_enum(KM_TAG_PURPOSE, KM_PURPOSE_DECRYPT));
params->push_back(keymaster_param_enum(KM_TAG_PADDING, KM_PAD_NONE));
if (keyType == EVP_PKEY_RSA) {
params->push_back(keymaster_param_enum(KM_TAG_PADDING, KM_PAD_RSA_PKCS1_1_5_SIGN));
params->push_back(keymaster_param_enum(KM_TAG_PADDING, KM_PAD_RSA_PKCS1_1_5_ENCRYPT));
params->push_back(keymaster_param_enum(KM_TAG_PADDING, KM_PAD_RSA_PSS));
params->push_back(keymaster_param_enum(KM_TAG_PADDING, KM_PAD_RSA_OAEP));
}
params->push_back(keymaster_param_enum(KM_TAG_DIGEST, KM_DIGEST_NONE));
params->push_back(keymaster_param_enum(KM_TAG_DIGEST, KM_DIGEST_MD5));
params->push_back(keymaster_param_enum(KM_TAG_DIGEST, KM_DIGEST_SHA1));
params->push_back(keymaster_param_enum(KM_TAG_DIGEST, KM_DIGEST_SHA_2_224));
params->push_back(keymaster_param_enum(KM_TAG_DIGEST, KM_DIGEST_SHA_2_256));
params->push_back(keymaster_param_enum(KM_TAG_DIGEST, KM_DIGEST_SHA_2_384));
params->push_back(keymaster_param_enum(KM_TAG_DIGEST, KM_DIGEST_SHA_2_512));
params->push_back(keymaster_param_bool(KM_TAG_ALL_USERS));
params->push_back(keymaster_param_bool(KM_TAG_NO_AUTH_REQUIRED));
params->push_back(keymaster_param_date(KM_TAG_ORIGINATION_EXPIRE_DATETIME, LLONG_MAX));
params->push_back(keymaster_param_date(KM_TAG_USAGE_EXPIRE_DATETIME, LLONG_MAX));
params->push_back(keymaster_param_date(KM_TAG_ACTIVE_DATETIME, 0));
uint64_t now = keymaster::java_time(time(NULL));
params->push_back(keymaster_param_date(KM_TAG_CREATION_DATETIME, now));
}
/***************
* PERMISSIONS *
***************/
/* Here are the permissions, actions, users, and the main function. */
typedef enum {
P_GET_STATE = 1 << 0,
P_GET = 1 << 1,
P_INSERT = 1 << 2,
P_DELETE = 1 << 3,
P_EXIST = 1 << 4,
P_LIST = 1 << 5,
P_RESET = 1 << 6,
P_PASSWORD = 1 << 7,
P_LOCK = 1 << 8,
P_UNLOCK = 1 << 9,
P_IS_EMPTY = 1 << 10,
P_SIGN = 1 << 11,
P_VERIFY = 1 << 12,
P_GRANT = 1 << 13,
P_DUPLICATE = 1 << 14,
P_CLEAR_UID = 1 << 15,
P_ADD_AUTH = 1 << 16,
P_USER_CHANGED = 1 << 17,
} perm_t;
static struct user_euid {
uid_t uid;
uid_t euid;
} user_euids[] = {
{AID_VPN, AID_SYSTEM},
{AID_WIFI, AID_SYSTEM},
{AID_ROOT, AID_SYSTEM},
};
/* perm_labels associcated with keystore_key SELinux class verbs. */
const char *perm_labels[] = {
"get_state",
"get",
"insert",
"delete",
"exist",
"list",
"reset",
"password",
"lock",
"unlock",
"is_empty",
"sign",
"verify",
"grant",
"duplicate",
"clear_uid",
"add_auth",
"user_changed",
};
static struct user_perm {
uid_t uid;
perm_t perms;
} user_perms[] = {
{AID_SYSTEM, static_cast<perm_t>((uint32_t)(~0)) },
{AID_VPN, static_cast<perm_t>(P_GET | P_SIGN | P_VERIFY) },
{AID_WIFI, static_cast<perm_t>(P_GET | P_SIGN | P_VERIFY) },
{AID_ROOT, static_cast<perm_t>(P_GET) },
};
static const perm_t DEFAULT_PERMS = static_cast<perm_t>(P_GET_STATE | P_GET | P_INSERT | P_DELETE
| P_EXIST | P_LIST | P_SIGN | P_VERIFY);
struct audit_data {
pid_t pid;
uid_t uid;
};
static char *tctx;
static int ks_is_selinux_enabled;
static const char *get_perm_label(perm_t perm) {
unsigned int index = ffs(perm);
if (index > 0 && index <= (sizeof(perm_labels) / sizeof(perm_labels[0]))) {
return perm_labels[index - 1];
} else {
ALOGE("Keystore: Failed to retrieve permission label.\n");
abort();
}
}
/**
* Returns the app ID (in the Android multi-user sense) for the current
* UNIX UID.
*/
static uid_t get_app_id(uid_t uid) {
return uid % AID_USER;
}
/**
* Returns the user ID (in the Android multi-user sense) for the current
* UNIX UID.
*/
static uid_t get_user_id(uid_t uid) {
return uid / AID_USER;
}
static int audit_callback(void *data, security_class_t /* cls */, char *buf, size_t len)
{
struct audit_data *ad = reinterpret_cast<struct audit_data *>(data);
if (!ad) {
ALOGE("No keystore audit data");
return 0;
}
snprintf(buf, len, "pid=%d uid=%d", ad->pid, ad->uid);
return 0;
}
static bool keystore_selinux_check_access(uid_t uid, perm_t perm, pid_t spid) {
if (!ks_is_selinux_enabled) {
return true;
}
audit_data ad;
char *sctx = NULL;
const char *selinux_class = "keystore_key";
const char *str_perm = get_perm_label(perm);
if (!str_perm) {
return false;
}
if (getpidcon(spid, &sctx) != 0) {
ALOGE("SELinux: Failed to get source pid context.\n");
return false;
}
ad.pid = spid;
ad.uid = uid;
bool allowed = selinux_check_access(sctx, tctx, selinux_class, str_perm,
reinterpret_cast<void *>(&ad)) == 0;
freecon(sctx);
return allowed;
}
static bool has_permission(uid_t uid, perm_t perm, pid_t spid) {
// All system users are equivalent for multi-user support.
if (get_app_id(uid) == AID_SYSTEM) {
uid = AID_SYSTEM;
}
for (size_t i = 0; i < sizeof(user_perms)/sizeof(user_perms[0]); i++) {
struct user_perm user = user_perms[i];
if (user.uid == uid) {
return (user.perms & perm) &&
keystore_selinux_check_access(uid, perm, spid);
}
}
return (DEFAULT_PERMS & perm) &&
keystore_selinux_check_access(uid, perm, spid);
}
/**
* Returns the UID that the callingUid should act as. This is here for
* legacy support of the WiFi and VPN systems and should be removed
* when WiFi can operate in its own namespace.
*/
static uid_t get_keystore_euid(uid_t uid) {
for (size_t i = 0; i < sizeof(user_euids)/sizeof(user_euids[0]); i++) {
struct user_euid user = user_euids[i];
if (user.uid == uid) {
return user.euid;
}
}
return uid;
}
/**
* Returns true if the callingUid is allowed to interact in the targetUid's
* namespace.
*/
static bool is_granted_to(uid_t callingUid, uid_t targetUid) {
if (callingUid == targetUid) {
return true;
}
for (size_t i = 0; i < sizeof(user_euids)/sizeof(user_euids[0]); i++) {
struct user_euid user = user_euids[i];
if (user.euid == callingUid && user.uid == targetUid) {
return true;
}
}
return false;
}
/* Here is the encoding of keys. This is necessary in order to allow arbitrary
* characters in keys. Characters in [0-~] are not encoded. Others are encoded
* into two bytes. The first byte is one of [+-.] which represents the first
* two bits of the character. The second byte encodes the rest of the bits into
* [0-o]. Therefore in the worst case the length of a key gets doubled. Note
* that Base64 cannot be used here due to the need of prefix match on keys. */
static size_t encode_key_length(const android::String8& keyName) {
const uint8_t* in = reinterpret_cast<const uint8_t*>(keyName.string());
size_t length = keyName.length();
for (int i = length; i > 0; --i, ++in) {
if (*in < '0' || *in > '~') {
++length;
}
}
return length;
}
static int encode_key(char* out, const android::String8& keyName) {
const uint8_t* in = reinterpret_cast<const uint8_t*>(keyName.string());
size_t length = keyName.length();
for (int i = length; i > 0; --i, ++in, ++out) {
if (*in < '0' || *in > '~') {
*out = '+' + (*in >> 6);
*++out = '0' + (*in & 0x3F);
++length;
} else {
*out = *in;
}
}
*out = '\0';
return length;
}
/*
* Converts from the "escaped" format on disk to actual name.
* This will be smaller than the input string.
*
* Characters that should combine with the next at the end will be truncated.
*/
static size_t decode_key_length(const char* in, size_t length) {
size_t outLength = 0;
for (const char* end = in + length; in < end; in++) {
/* This combines with the next character. */
if (*in < '0' || *in > '~') {
continue;
}
outLength++;
}
return outLength;
}
static void decode_key(char* out, const char* in, size_t length) {
for (const char* end = in + length; in < end; in++) {
if (*in < '0' || *in > '~') {
/* Truncate combining characters at the end. */
if (in + 1 >= end) {
break;
}
*out = (*in++ - '+') << 6;
*out++ |= (*in - '0') & 0x3F;
} else {
*out++ = *in;
}
}
*out = '\0';
}
static size_t readFully(int fd, uint8_t* data, size_t size) {
size_t remaining = size;
while (remaining > 0) {
ssize_t n = TEMP_FAILURE_RETRY(read(fd, data, remaining));
if (n <= 0) {
return size - remaining;
}
data += n;
remaining -= n;
}
return size;
}
static size_t writeFully(int fd, uint8_t* data, size_t size) {
size_t remaining = size;
while (remaining > 0) {
ssize_t n = TEMP_FAILURE_RETRY(write(fd, data, remaining));
if (n < 0) {
ALOGW("write failed: %s", strerror(errno));
return size - remaining;
}
data += n;
remaining -= n;
}
return size;
}
class Entropy {
public:
Entropy() : mRandom(-1) {}
~Entropy() {
if (mRandom >= 0) {
close(mRandom);
}
}
bool open() {
const char* randomDevice = "/dev/urandom";
mRandom = TEMP_FAILURE_RETRY(::open(randomDevice, O_RDONLY));
if (mRandom < 0) {
ALOGE("open: %s: %s", randomDevice, strerror(errno));
return false;
}
return true;
}
bool generate_random_data(uint8_t* data, size_t size) const {
return (readFully(mRandom, data, size) == size);
}
private:
int mRandom;
};
/* Here is the file format. There are two parts in blob.value, the secret and
* the description. The secret is stored in ciphertext, and its original size
* can be found in blob.length. The description is stored after the secret in
* plaintext, and its size is specified in blob.info. The total size of the two
* parts must be no more than VALUE_SIZE bytes. The first field is the version,
* the second is the blob's type, and the third byte is flags. Fields other
* than blob.info, blob.length, and blob.value are modified by encryptBlob()
* and decryptBlob(). Thus they should not be accessed from outside. */
/* ** Note to future implementors of encryption: **
* Currently this is the construction:
* metadata || Enc(MD5(data) || data)
*
* This should be the construction used for encrypting if re-implementing:
*
* Derive independent keys for encryption and MAC:
* Kenc = AES_encrypt(masterKey, "Encrypt")
* Kmac = AES_encrypt(masterKey, "MAC")
*
* Store this:
* metadata || AES_CTR_encrypt(Kenc, rand_IV, data) ||
* HMAC(Kmac, metadata || Enc(data))
*/
struct __attribute__((packed)) blob {
uint8_t version;
uint8_t type;
uint8_t flags;
uint8_t info;
uint8_t vector[AES_BLOCK_SIZE];
uint8_t encrypted[0]; // Marks offset to encrypted data.
uint8_t digest[MD5_DIGEST_LENGTH];
uint8_t digested[0]; // Marks offset to digested data.
int32_t length; // in network byte order when encrypted
uint8_t value[VALUE_SIZE + AES_BLOCK_SIZE];
};
typedef enum {
TYPE_ANY = 0, // meta type that matches anything
TYPE_GENERIC = 1,
TYPE_MASTER_KEY = 2,
TYPE_KEY_PAIR = 3,
TYPE_KEYMASTER_10 = 4,
} BlobType;
static const uint8_t CURRENT_BLOB_VERSION = 2;
class Blob {
public:
Blob(const uint8_t* value, size_t valueLength, const uint8_t* info, uint8_t infoLength,
BlobType type) {
memset(&mBlob, 0, sizeof(mBlob));
if (valueLength > VALUE_SIZE) {
valueLength = VALUE_SIZE;
ALOGW("Provided blob length too large");
}
if (infoLength + valueLength > VALUE_SIZE) {
infoLength = VALUE_SIZE - valueLength;
ALOGW("Provided info length too large");
}
mBlob.length = valueLength;
memcpy(mBlob.value, value, valueLength);
mBlob.info = infoLength;
memcpy(mBlob.value + valueLength, info, infoLength);
mBlob.version = CURRENT_BLOB_VERSION;
mBlob.type = uint8_t(type);
if (type == TYPE_MASTER_KEY) {
mBlob.flags = KEYSTORE_FLAG_ENCRYPTED;
} else {
mBlob.flags = KEYSTORE_FLAG_NONE;
}
}
Blob(blob b) {
mBlob = b;
}
Blob() {
memset(&mBlob, 0, sizeof(mBlob));
}
const uint8_t* getValue() const {
return mBlob.value;
}
int32_t getLength() const {
return mBlob.length;
}
const uint8_t* getInfo() const {
return mBlob.value + mBlob.length;
}
uint8_t getInfoLength() const {
return mBlob.info;
}
uint8_t getVersion() const {
return mBlob.version;
}
bool isEncrypted() const {
if (mBlob.version < 2) {
return true;
}
return mBlob.flags & KEYSTORE_FLAG_ENCRYPTED;
}
void setEncrypted(bool encrypted) {
if (encrypted) {
mBlob.flags |= KEYSTORE_FLAG_ENCRYPTED;
} else {
mBlob.flags &= ~KEYSTORE_FLAG_ENCRYPTED;
}
}
bool isFallback() const {
return mBlob.flags & KEYSTORE_FLAG_FALLBACK;
}
void setFallback(bool fallback) {
if (fallback) {
mBlob.flags |= KEYSTORE_FLAG_FALLBACK;
} else {
mBlob.flags &= ~KEYSTORE_FLAG_FALLBACK;
}
}
void setVersion(uint8_t version) {
mBlob.version = version;
}
BlobType getType() const {
return BlobType(mBlob.type);
}
void setType(BlobType type) {
mBlob.type = uint8_t(type);
}
ResponseCode writeBlob(const char* filename, AES_KEY *aes_key, State state, Entropy* entropy) {
ALOGV("writing blob %s", filename);
if (isEncrypted()) {
if (state != STATE_NO_ERROR) {
ALOGD("couldn't insert encrypted blob while not unlocked");
return LOCKED;
}
if (!entropy->generate_random_data(mBlob.vector, AES_BLOCK_SIZE)) {
ALOGW("Could not read random data for: %s", filename);
return SYSTEM_ERROR;
}
}
// data includes the value and the value's length
size_t dataLength = mBlob.length + sizeof(mBlob.length);
// pad data to the AES_BLOCK_SIZE
size_t digestedLength = ((dataLength + AES_BLOCK_SIZE - 1)
/ AES_BLOCK_SIZE * AES_BLOCK_SIZE);
// encrypted data includes the digest value
size_t encryptedLength = digestedLength + MD5_DIGEST_LENGTH;
// move info after space for padding
memmove(&mBlob.encrypted[encryptedLength], &mBlob.value[mBlob.length], mBlob.info);
// zero padding area
memset(mBlob.value + mBlob.length, 0, digestedLength - dataLength);
mBlob.length = htonl(mBlob.length);
if (isEncrypted()) {
MD5(mBlob.digested, digestedLength, mBlob.digest);
uint8_t vector[AES_BLOCK_SIZE];
memcpy(vector, mBlob.vector, AES_BLOCK_SIZE);
AES_cbc_encrypt(mBlob.encrypted, mBlob.encrypted, encryptedLength,
aes_key, vector, AES_ENCRYPT);
}
size_t headerLength = (mBlob.encrypted - (uint8_t*) &mBlob);
size_t fileLength = encryptedLength + headerLength + mBlob.info;
const char* tmpFileName = ".tmp";
int out = TEMP_FAILURE_RETRY(open(tmpFileName,
O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR));
if (out < 0) {
ALOGW("could not open file: %s: %s", tmpFileName, strerror(errno));
return SYSTEM_ERROR;
}
size_t writtenBytes = writeFully(out, (uint8_t*) &mBlob, fileLength);
if (close(out) != 0) {
return SYSTEM_ERROR;
}
if (writtenBytes != fileLength) {
ALOGW("blob not fully written %zu != %zu", writtenBytes, fileLength);
unlink(tmpFileName);
return SYSTEM_ERROR;
}
if (rename(tmpFileName, filename) == -1) {
ALOGW("could not rename blob to %s: %s", filename, strerror(errno));
return SYSTEM_ERROR;
}
return NO_ERROR;
}
ResponseCode readBlob(const char* filename, AES_KEY *aes_key, State state) {
ALOGV("reading blob %s", filename);
int in = TEMP_FAILURE_RETRY(open(filename, O_RDONLY));
if (in < 0) {
return (errno == ENOENT) ? KEY_NOT_FOUND : SYSTEM_ERROR;
}
// fileLength may be less than sizeof(mBlob) since the in
// memory version has extra padding to tolerate rounding up to
// the AES_BLOCK_SIZE
size_t fileLength = readFully(in, (uint8_t*) &mBlob, sizeof(mBlob));
if (close(in) != 0) {
return SYSTEM_ERROR;
}
if (fileLength == 0) {
return VALUE_CORRUPTED;
}
if (isEncrypted() && (state != STATE_NO_ERROR)) {
return LOCKED;
}
size_t headerLength = (mBlob.encrypted - (uint8_t*) &mBlob);
if (fileLength < headerLength) {
return VALUE_CORRUPTED;
}
ssize_t encryptedLength = fileLength - (headerLength + mBlob.info);
if (encryptedLength < 0) {
return VALUE_CORRUPTED;
}
ssize_t digestedLength;
if (isEncrypted()) {
if (encryptedLength % AES_BLOCK_SIZE != 0) {
return VALUE_CORRUPTED;
}
AES_cbc_encrypt(mBlob.encrypted, mBlob.encrypted, encryptedLength, aes_key,
mBlob.vector, AES_DECRYPT);
digestedLength = encryptedLength - MD5_DIGEST_LENGTH;
uint8_t computedDigest[MD5_DIGEST_LENGTH];
MD5(mBlob.digested, digestedLength, computedDigest);
if (memcmp(mBlob.digest, computedDigest, MD5_DIGEST_LENGTH) != 0) {
return VALUE_CORRUPTED;
}
} else {
digestedLength = encryptedLength;
}
ssize_t maxValueLength = digestedLength - sizeof(mBlob.length);
mBlob.length = ntohl(mBlob.length);
if (mBlob.length < 0 || mBlob.length > maxValueLength) {
return VALUE_CORRUPTED;
}
if (mBlob.info != 0) {
// move info from after padding to after data
memmove(&mBlob.value[mBlob.length], &mBlob.value[maxValueLength], mBlob.info);
}
return ::NO_ERROR;
}
private:
struct blob mBlob;
};
class UserState {
public:
UserState(uid_t userId) : mUserId(userId), mRetry(MAX_RETRY) {
asprintf(&mUserDir, "user_%u", mUserId);
asprintf(&mMasterKeyFile, "%s/.masterkey", mUserDir);
}
~UserState() {
free(mUserDir);
free(mMasterKeyFile);
}
bool initialize() {
if ((mkdir(mUserDir, S_IRUSR | S_IWUSR | S_IXUSR) < 0) && (errno != EEXIST)) {
ALOGE("Could not create directory '%s'", mUserDir);
return false;
}
if (access(mMasterKeyFile, R_OK) == 0) {
setState(STATE_LOCKED);
} else {
setState(STATE_UNINITIALIZED);
}
return true;
}
uid_t getUserId() const {
return mUserId;
}
const char* getUserDirName() const {
return mUserDir;
}
const char* getMasterKeyFileName() const {
return mMasterKeyFile;
}
void setState(State state) {
mState = state;
if (mState == STATE_NO_ERROR || mState == STATE_UNINITIALIZED) {
mRetry = MAX_RETRY;
}
}
State getState() const {
return mState;
}
int8_t getRetry() const {
return mRetry;
}
void zeroizeMasterKeysInMemory() {
memset(mMasterKey, 0, sizeof(mMasterKey));
memset(mSalt, 0, sizeof(mSalt));
memset(&mMasterKeyEncryption, 0, sizeof(mMasterKeyEncryption));
memset(&mMasterKeyDecryption, 0, sizeof(mMasterKeyDecryption));
}
bool deleteMasterKey() {
setState(STATE_UNINITIALIZED);
zeroizeMasterKeysInMemory();
return unlink(mMasterKeyFile) == 0 || errno == ENOENT;
}
ResponseCode initialize(const android::String8& pw, Entropy* entropy) {
if (!generateMasterKey(entropy)) {
return SYSTEM_ERROR;
}
ResponseCode response = writeMasterKey(pw, entropy);
if (response != NO_ERROR) {
return response;
}
setupMasterKeys();
return ::NO_ERROR;
}
ResponseCode copyMasterKey(UserState* src) {
if (mState != STATE_UNINITIALIZED) {
return ::SYSTEM_ERROR;
}
if (src->getState() != STATE_NO_ERROR) {
return ::SYSTEM_ERROR;
}
memcpy(mMasterKey, src->mMasterKey, MASTER_KEY_SIZE_BYTES);
setupMasterKeys();
return copyMasterKeyFile(src);
}
ResponseCode copyMasterKeyFile(UserState* src) {
/* Copy the master key file to the new user.
* Unfortunately we don't have the src user's password so we cannot
* generate a new file with a new salt.
*/
int in = TEMP_FAILURE_RETRY(open(src->getMasterKeyFileName(), O_RDONLY));
if (in < 0) {
return ::SYSTEM_ERROR;
}
blob rawBlob;
size_t length = readFully(in, (uint8_t*) &rawBlob, sizeof(rawBlob));
if (close(in) != 0) {
return ::SYSTEM_ERROR;
}
int out = TEMP_FAILURE_RETRY(open(mMasterKeyFile,
O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR));
if (out < 0) {
return ::SYSTEM_ERROR;
}
size_t outLength = writeFully(out, (uint8_t*) &rawBlob, length);
if (close(out) != 0) {
return ::SYSTEM_ERROR;
}
if (outLength != length) {
ALOGW("blob not fully written %zu != %zu", outLength, length);
unlink(mMasterKeyFile);
return ::SYSTEM_ERROR;
}
return ::NO_ERROR;
}
ResponseCode writeMasterKey(const android::String8& pw, Entropy* entropy) {
uint8_t passwordKey[MASTER_KEY_SIZE_BYTES];
generateKeyFromPassword(passwordKey, MASTER_KEY_SIZE_BYTES, pw, mSalt);
AES_KEY passwordAesKey;
AES_set_encrypt_key(passwordKey, MASTER_KEY_SIZE_BITS, &passwordAesKey);
Blob masterKeyBlob(mMasterKey, sizeof(mMasterKey), mSalt, sizeof(mSalt), TYPE_MASTER_KEY);
return masterKeyBlob.writeBlob(mMasterKeyFile, &passwordAesKey, STATE_NO_ERROR, entropy);
}
ResponseCode readMasterKey(const android::String8& pw, Entropy* entropy) {
int in = TEMP_FAILURE_RETRY(open(mMasterKeyFile, O_RDONLY));
if (in < 0) {
return SYSTEM_ERROR;
}
// we read the raw blob to just to get the salt to generate
// the AES key, then we create the Blob to use with decryptBlob
blob rawBlob;
size_t length = readFully(in, (uint8_t*) &rawBlob, sizeof(rawBlob));
if (close(in) != 0) {
return SYSTEM_ERROR;
}
// find salt at EOF if present, otherwise we have an old file
uint8_t* salt;
if (length > SALT_SIZE && rawBlob.info == SALT_SIZE) {
salt = (uint8_t*) &rawBlob + length - SALT_SIZE;
} else {
salt = NULL;
}
uint8_t passwordKey[MASTER_KEY_SIZE_BYTES];
generateKeyFromPassword(passwordKey, MASTER_KEY_SIZE_BYTES, pw, salt);
AES_KEY passwordAesKey;
AES_set_decrypt_key(passwordKey, MASTER_KEY_SIZE_BITS, &passwordAesKey);
Blob masterKeyBlob(rawBlob);
ResponseCode response = masterKeyBlob.readBlob(mMasterKeyFile, &passwordAesKey,
STATE_NO_ERROR);
if (response == SYSTEM_ERROR) {
return response;
}
if (response == NO_ERROR && masterKeyBlob.getLength() == MASTER_KEY_SIZE_BYTES) {
// if salt was missing, generate one and write a new master key file with the salt.
if (salt == NULL) {
if (!generateSalt(entropy)) {
return SYSTEM_ERROR;
}
response = writeMasterKey(pw, entropy);
}
if (response == NO_ERROR) {
memcpy(mMasterKey, masterKeyBlob.getValue(), MASTER_KEY_SIZE_BYTES);
setupMasterKeys();
}
return response;
}
if (mRetry <= 0) {
reset();
return UNINITIALIZED;
}
--mRetry;
switch (mRetry) {
case 0: return WRONG_PASSWORD_0;
case 1: return WRONG_PASSWORD_1;
case 2: return WRONG_PASSWORD_2;
case 3: return WRONG_PASSWORD_3;
default: return WRONG_PASSWORD_3;
}
}
AES_KEY* getEncryptionKey() {
return &mMasterKeyEncryption;
}
AES_KEY* getDecryptionKey() {
return &mMasterKeyDecryption;
}
bool reset() {
DIR* dir = opendir(getUserDirName());
if (!dir) {
// If the directory doesn't exist then nothing to do.
if (errno == ENOENT) {
return true;
}
ALOGW("couldn't open user directory: %s", strerror(errno));
return false;
}
struct dirent* file;
while ((file = readdir(dir)) != NULL) {
// skip . and ..
if (!strcmp(".", file->d_name) || !strcmp("..", file->d_name)) {
continue;
}
unlinkat(dirfd(dir), file->d_name, 0);
}
closedir(dir);
return true;
}
private:
static const int MASTER_KEY_SIZE_BYTES = 16;
static const int MASTER_KEY_SIZE_BITS = MASTER_KEY_SIZE_BYTES * 8;
static const int MAX_RETRY = 4;
static const size_t SALT_SIZE = 16;
void generateKeyFromPassword(uint8_t* key, ssize_t keySize, const android::String8& pw,
uint8_t* salt) {
size_t saltSize;
if (salt != NULL) {
saltSize = SALT_SIZE;
} else {
// pre-gingerbread used this hardwired salt, readMasterKey will rewrite these when found
salt = (uint8_t*) "keystore";
// sizeof = 9, not strlen = 8
saltSize = sizeof("keystore");
}
PKCS5_PBKDF2_HMAC_SHA1(reinterpret_cast<const char*>(pw.string()), pw.length(), salt,
saltSize, 8192, keySize, key);
}
bool generateSalt(Entropy* entropy) {
return entropy->generate_random_data(mSalt, sizeof(mSalt));
}
bool generateMasterKey(Entropy* entropy) {
if (!entropy->generate_random_data(mMasterKey, sizeof(mMasterKey))) {
return false;
}
if (!generateSalt(entropy)) {
return false;
}
return true;
}
void setupMasterKeys() {
AES_set_encrypt_key(mMasterKey, MASTER_KEY_SIZE_BITS, &mMasterKeyEncryption);
AES_set_decrypt_key(mMasterKey, MASTER_KEY_SIZE_BITS, &mMasterKeyDecryption);
setState(STATE_NO_ERROR);
}
uid_t mUserId;
char* mUserDir;
char* mMasterKeyFile;
State mState;
int8_t mRetry;
uint8_t mMasterKey[MASTER_KEY_SIZE_BYTES];
uint8_t mSalt[SALT_SIZE];
AES_KEY mMasterKeyEncryption;
AES_KEY mMasterKeyDecryption;
};
typedef struct {
uint32_t uid;
const uint8_t* filename;
} grant_t;
class KeyStore {
public:
KeyStore(Entropy* entropy, keymaster1_device_t* device, keymaster1_device_t* fallback)
: mEntropy(entropy)
, mDevice(device)
, mFallbackDevice(fallback)
{
memset(&mMetaData, '\0', sizeof(mMetaData));
}
~KeyStore() {
for (android::Vector<grant_t*>::iterator it(mGrants.begin());
it != mGrants.end(); it++) {
delete *it;
}
mGrants.clear();
for (android::Vector<UserState*>::iterator it(mMasterKeys.begin());
it != mMasterKeys.end(); it++) {
delete *it;
}
mMasterKeys.clear();
}
/**
* Depending on the hardware keymaster version is this may return a
* keymaster0_device_t* cast to a keymaster1_device_t*. All methods from
* keymaster0 are safe to call, calls to keymaster1_device_t methods should
* be guarded by a check on the device's version.
*/
keymaster1_device_t *getDevice() const {
return mDevice;
}
keymaster1_device_t *getFallbackDevice() const {
return mFallbackDevice;
}
keymaster1_device_t *getDeviceForBlob(const Blob& blob) const {
return blob.isFallback() ? mFallbackDevice: mDevice;
}
ResponseCode initialize() {
readMetaData();
if (upgradeKeystore()) {
writeMetaData();
}
return ::NO_ERROR;
}
State getState(uid_t userId) {
return getUserState(userId)->getState();
}
ResponseCode initializeUser(const android::String8& pw, uid_t userId) {
UserState* userState = getUserState(userId);
return userState->initialize(pw, mEntropy);
}
ResponseCode copyMasterKey(uid_t srcUser, uid_t dstUser) {
UserState *userState = getUserState(dstUser);
UserState *initState = getUserState(srcUser);
return userState->copyMasterKey(initState);
}
ResponseCode writeMasterKey(const android::String8& pw, uid_t userId) {
UserState* userState = getUserState(userId);
return userState->writeMasterKey(pw, mEntropy);
}
ResponseCode readMasterKey(const android::String8& pw, uid_t userId) {
UserState* userState = getUserState(userId);
return userState->readMasterKey(pw, mEntropy);
}
android::String8 getKeyName(const android::String8& keyName) {
char encoded[encode_key_length(keyName) + 1]; // add 1 for null char
encode_key(encoded, keyName);
return android::String8(encoded);
}
android::String8 getKeyNameForUid(const android::String8& keyName, uid_t uid) {
char encoded[encode_key_length(keyName) + 1]; // add 1 for null char
encode_key(encoded, keyName);
return android::String8::format("%u_%s", uid, encoded);
}
android::String8 getKeyNameForUidWithDir(const android::String8& keyName, uid_t uid) {
char encoded[encode_key_length(keyName) + 1]; // add 1 for null char
encode_key(encoded, keyName);
return android::String8::format("%s/%u_%s", getUserStateByUid(uid)->getUserDirName(), uid,
encoded);
}
/*
* Delete entries owned by userId. If keepUnencryptedEntries is true
* then only encrypted entries will be removed, otherwise all entries will
* be removed.
*/
void resetUser(uid_t userId, bool keepUnenryptedEntries) {
android::String8 prefix("");
android::Vector<android::String16> aliases;
UserState* userState = getUserState(userId);
if (list(prefix, &aliases, userId) != ::NO_ERROR) {
return;
}
for (uint32_t i = 0; i < aliases.size(); i++) {
android::String8 filename(aliases[i]);
filename = android::String8::format("%s/%s", userState->getUserDirName(),
getKeyName(filename).string());
bool shouldDelete = true;
if (keepUnenryptedEntries) {
Blob blob;
ResponseCode rc = get(filename, &blob, ::TYPE_ANY, userId);
/* get can fail if the blob is encrypted and the state is
* not unlocked, only skip deleting blobs that were loaded and
* who are not encrypted. If there are blobs we fail to read for
* other reasons err on the safe side and delete them since we
* can't tell if they're encrypted.
*/
shouldDelete = !(rc == ::NO_ERROR && !blob.isEncrypted());
}
if (shouldDelete) {
del(filename, ::TYPE_ANY, userId);
}
}
if (!userState->deleteMasterKey()) {
ALOGE("Failed to delete user %d's master key", userId);
}
if (!keepUnenryptedEntries) {
if(!userState->reset()) {
ALOGE("Failed to remove user %d's directory", userId);
}
}
}
bool isEmpty(uid_t userId) const {
const UserState* userState = getUserState(userId);
if (userState == NULL) {
return true;
}
DIR* dir = opendir(userState->getUserDirName());
if (!dir) {
return true;
}
bool result = true;
struct dirent* file;
while ((file = readdir(dir)) != NULL) {
// We only care about files.
if (file->d_type != DT_REG) {
continue;
}
// Skip anything that starts with a "."
if (file->d_name[0] == '.') {
continue;
}
result = false;
break;
}
closedir(dir);
return result;
}
void lock(uid_t userId) {
UserState* userState = getUserState(userId);
userState->zeroizeMasterKeysInMemory();
userState->setState(STATE_LOCKED);
}
ResponseCode get(const char* filename, Blob* keyBlob, const BlobType type, uid_t userId) {
UserState* userState = getUserState(userId);
ResponseCode rc = keyBlob->readBlob(filename, userState->getDecryptionKey(),
userState->getState());
if (rc != NO_ERROR) {
return rc;
}
const uint8_t version = keyBlob->getVersion();
if (version < CURRENT_BLOB_VERSION) {
/* If we upgrade the key, we need to write it to disk again. Then
* it must be read it again since the blob is encrypted each time
* it's written.
*/
if (upgradeBlob(filename, keyBlob, version, type, userId)) {
if ((rc = this->put(filename, keyBlob, userId)) != NO_ERROR
|| (rc = keyBlob->readBlob(filename, userState->getDecryptionKey(),
userState->getState())) != NO_ERROR) {
return rc;
}
}
}
/*
* This will upgrade software-backed keys to hardware-backed keys when
* the HAL for the device supports the newer key types.
*/
if (rc == NO_ERROR && type == TYPE_KEY_PAIR
&& mDevice->common.module->module_api_version >= KEYMASTER_MODULE_API_VERSION_0_2
&& keyBlob->isFallback()) {
ResponseCode imported = importKey(keyBlob->getValue(), keyBlob->getLength(), filename,
userId, keyBlob->isEncrypted() ? KEYSTORE_FLAG_ENCRYPTED : KEYSTORE_FLAG_NONE);
// The HAL allowed the import, reget the key to have the "fresh"
// version.
if (imported == NO_ERROR) {
rc = get(filename, keyBlob, TYPE_KEY_PAIR, userId);
}
}
// Keymaster 0.3 keys are valid keymaster 1.0 keys, so silently upgrade.
if (keyBlob->getType() == TYPE_KEY_PAIR) {
keyBlob->setType(TYPE_KEYMASTER_10);
rc = this->put(filename, keyBlob, userId);
}
if (type != TYPE_ANY && keyBlob->getType() != type) {
ALOGW("key found but type doesn't match: %d vs %d", keyBlob->getType(), type);
return KEY_NOT_FOUND;
}
return rc;
}
ResponseCode put(const char* filename, Blob* keyBlob, uid_t userId) {
UserState* userState = getUserState(userId);
return keyBlob->writeBlob(filename, userState->getEncryptionKey(), userState->getState(),
mEntropy);
}
ResponseCode del(const char *filename, const BlobType type, uid_t userId) {
Blob keyBlob;
ResponseCode rc = get(filename, &keyBlob, type, userId);
if (rc == ::VALUE_CORRUPTED) {
// The file is corrupt, the best we can do is rm it.
return (unlink(filename) && errno != ENOENT) ? ::SYSTEM_ERROR : ::NO_ERROR;
}
if (rc != ::NO_ERROR) {
return rc;
}
if (keyBlob.getType() == ::TYPE_KEY_PAIR) {
// A device doesn't have to implement delete_key.
if (mDevice->delete_key != NULL && !keyBlob.isFallback()) {
keymaster_key_blob_t blob = {keyBlob.getValue(),
static_cast<size_t>(keyBlob.getLength())};
if (mDevice->delete_key(mDevice, &blob)) {
rc = ::SYSTEM_ERROR;
}
}
}
if (keyBlob.getType() == ::TYPE_KEYMASTER_10) {
keymaster1_device_t* dev = getDeviceForBlob(keyBlob);
if (dev->delete_key) {
keymaster_key_blob_t blob;
blob.key_material = keyBlob.getValue();
blob.key_material_size = keyBlob.getLength();
dev->delete_key(dev, &blob);
}
}
if (rc != ::NO_ERROR) {
return rc;
}
return (unlink(filename) && errno != ENOENT) ? ::SYSTEM_ERROR : ::NO_ERROR;
}
ResponseCode list(const android::String8& prefix, android::Vector<android::String16> *matches,
uid_t userId) {
UserState* userState = getUserState(userId);
size_t n = prefix.length();
DIR* dir = opendir(userState->getUserDirName());
if (!dir) {
ALOGW("can't open directory for user: %s", strerror(errno));
return ::SYSTEM_ERROR;
}
struct dirent* file;
while ((file = readdir(dir)) != NULL) {
// We only care about files.
if (file->d_type != DT_REG) {
continue;
}
// Skip anything that starts with a "."
if (file->d_name[0] == '.') {
continue;
}
if (!strncmp(prefix.string(), file->d_name, n)) {
const char* p = &file->d_name[n];
size_t plen = strlen(p);
size_t extra = decode_key_length(p, plen);
char *match = (char*) malloc(extra + 1);
if (match != NULL) {
decode_key(match, p, plen);
matches->push(android::String16(match, extra));
free(match);
} else {
ALOGW("could not allocate match of size %zd", extra);
}
}
}
closedir(dir);
return ::NO_ERROR;
}
void addGrant(const char* filename, uid_t granteeUid) {
const grant_t* existing = getGrant(filename, granteeUid);
if (existing == NULL) {
grant_t* grant = new grant_t;
grant->uid = granteeUid;
grant->filename = reinterpret_cast<const uint8_t*>(strdup(filename));
mGrants.add(grant);
}
}
bool removeGrant(const char* filename, uid_t granteeUid) {
for (android::Vector<grant_t*>::iterator it(mGrants.begin());
it != mGrants.end(); it++) {
grant_t* grant = *it;
if (grant->uid == granteeUid
&& !strcmp(reinterpret_cast<const char*>(grant->filename), filename)) {
mGrants.erase(it);
return true;
}
}
return false;
}
bool hasGrant(const char* filename, const uid_t uid) const {
return getGrant(filename, uid) != NULL;
}
ResponseCode importKey(const uint8_t* key, size_t keyLen, const char* filename, uid_t userId,
int32_t flags) {
Unique_PKCS8_PRIV_KEY_INFO pkcs8(d2i_PKCS8_PRIV_KEY_INFO(NULL, &key, keyLen));
if (!pkcs8.get()) {
return ::SYSTEM_ERROR;
}
Unique_EVP_PKEY pkey(EVP_PKCS82PKEY(pkcs8.get()));
if (!pkey.get()) {
return ::SYSTEM_ERROR;
}
int type = EVP_PKEY_type(pkey->type);
android::KeymasterArguments params;
add_legacy_key_authorizations(type, &params.params);
switch (type) {
case EVP_PKEY_RSA:
params.params.push_back(keymaster_param_enum(KM_TAG_ALGORITHM, KM_ALGORITHM_RSA));
break;
case EVP_PKEY_EC:
params.params.push_back(keymaster_param_enum(KM_TAG_ALGORITHM,
KM_ALGORITHM_EC));
break;
default:
ALOGW("Unsupported key type %d", type);
return ::SYSTEM_ERROR;
}
std::vector<keymaster_key_param_t> opParams(params.params);
const keymaster_key_param_set_t inParams = {opParams.data(), opParams.size()};
keymaster_blob_t input = {key, keyLen};
keymaster_key_blob_t blob = {nullptr, 0};
bool isFallback = false;
keymaster_error_t error = mDevice->import_key(mDevice, &inParams, KM_KEY_FORMAT_PKCS8,
&input, &blob, NULL /* characteristics */);
if (error != KM_ERROR_OK){
ALOGE("Keymaster error %d importing key pair, falling back", error);
/*
* There should be no way to get here. Fallback shouldn't ever really happen
* because the main device may be many (SW, KM0/SW hybrid, KM1/SW hybrid), but it must
* provide full support of the API. In any case, we'll do the fallback just for
* consistency... and I suppose to cover for broken HW implementations.
*/
error = mFallbackDevice->import_key(mFallbackDevice, &inParams, KM_KEY_FORMAT_PKCS8,
&input, &blob, NULL /* characteristics */);
isFallback = true;
if (error) {
ALOGE("Keymaster error while importing key pair with fallback: %d", error);
return SYSTEM_ERROR;
}
}
Blob keyBlob(blob.key_material, blob.key_material_size, NULL, 0, TYPE_KEYMASTER_10);
free(const_cast<uint8_t*>(blob.key_material));
keyBlob.setEncrypted(flags & KEYSTORE_FLAG_ENCRYPTED);
keyBlob.setFallback(isFallback);
return put(filename, &keyBlob, userId);
}
bool isHardwareBacked(const android::String16& keyType) const {
if (mDevice == NULL) {
ALOGW("can't get keymaster device");
return false;
}
if (sRSAKeyType == keyType) {
return (mDevice->flags & KEYMASTER_SOFTWARE_ONLY) == 0;
} else {
return (mDevice->flags & KEYMASTER_SOFTWARE_ONLY) == 0
&& (mDevice->common.module->module_api_version
>= KEYMASTER_MODULE_API_VERSION_0_2);
}
}
ResponseCode getKeyForName(Blob* keyBlob, const android::String8& keyName, const uid_t uid,
const BlobType type) {
android::String8 filepath8(getKeyNameForUidWithDir(keyName, uid));
uid_t userId = get_user_id(uid);
ResponseCode responseCode = get(filepath8.string(), keyBlob, type, userId);
if (responseCode == NO_ERROR) {
return responseCode;
}
// If this is one of the legacy UID->UID mappings, use it.
uid_t euid = get_keystore_euid(uid);
if (euid != uid) {
filepath8 = getKeyNameForUidWithDir(keyName, euid);
responseCode = get(filepath8.string(), keyBlob, type, userId);
if (responseCode == NO_ERROR) {
return responseCode;
}
}
// They might be using a granted key.
android::String8 filename8 = getKeyName(keyName);
char* end;
strtoul(filename8.string(), &end, 10);
if (end[0] != '_' || end[1] == 0) {
return KEY_NOT_FOUND;
}
filepath8 = android::String8::format("%s/%s", getUserState(userId)->getUserDirName(),
filename8.string());
if (!hasGrant(filepath8.string(), uid)) {
return responseCode;
}
// It is a granted key. Try to load it.
return get(filepath8.string(), keyBlob, type, userId);
}
/**
* Returns any existing UserState or creates it if it doesn't exist.
*/
UserState* getUserState(uid_t userId) {
for (android::Vector<UserState*>::iterator it(mMasterKeys.begin());
it != mMasterKeys.end(); it++) {
UserState* state = *it;
if (state->getUserId() == userId) {
return state;
}
}
UserState* userState = new UserState(userId);
if (!userState->initialize()) {
/* There's not much we can do if initialization fails. Trying to
* unlock the keystore for that user will fail as well, so any
* subsequent request for this user will just return SYSTEM_ERROR.
*/
ALOGE("User initialization failed for %u; subsuquent operations will fail", userId);
}
mMasterKeys.add(userState);
return userState;
}
/**
* Returns any existing UserState or creates it if it doesn't exist.
*/
UserState* getUserStateByUid(uid_t uid) {
uid_t userId = get_user_id(uid);
return getUserState(userId);
}
/**
* Returns NULL if the UserState doesn't already exist.
*/
const UserState* getUserState(uid_t userId) const {
for (android::Vector<UserState*>::const_iterator it(mMasterKeys.begin());
it != mMasterKeys.end(); it++) {
UserState* state = *it;
if (state->getUserId() == userId) {
return state;
}
}
return NULL;
}
/**
* Returns NULL if the UserState doesn't already exist.
*/
const UserState* getUserStateByUid(uid_t uid) const {
uid_t userId = get_user_id(uid);
return getUserState(userId);
}
private:
static const char* sOldMasterKey;
static const char* sMetaDataFile;
static const android::String16 sRSAKeyType;
Entropy* mEntropy;
keymaster1_device_t* mDevice;
keymaster1_device_t* mFallbackDevice;
android::Vector<UserState*> mMasterKeys;
android::Vector<grant_t*> mGrants;
typedef struct {
uint32_t version;
} keystore_metadata_t;
keystore_metadata_t mMetaData;
const grant_t* getGrant(const char* filename, uid_t uid) const {
for (android::Vector<grant_t*>::const_iterator it(mGrants.begin());
it != mGrants.end(); it++) {
grant_t* grant = *it;
if (grant->uid == uid
&& !strcmp(reinterpret_cast<const char*>(grant->filename), filename)) {
return grant;
}
}
return NULL;
}
/**
* Upgrade code. This will upgrade the key from the current version
* to whatever is newest.
*/
bool upgradeBlob(const char* filename, Blob* blob, const uint8_t oldVersion,
const BlobType type, uid_t uid) {
bool updated = false;
uint8_t version = oldVersion;
/* From V0 -> V1: All old types were unknown */
if (version == 0) {
ALOGV("upgrading to version 1 and setting type %d", type);
blob->setType(type);
if (type == TYPE_KEY_PAIR) {
importBlobAsKey(blob, filename, uid);
}
version = 1;
updated = true;
}
/* From V1 -> V2: All old keys were encrypted */
if (version == 1) {
ALOGV("upgrading to version 2");
blob->setEncrypted(true);
version = 2;
updated = true;
}
/*
* If we've updated, set the key blob to the right version
* and write it.
*/
if (updated) {
ALOGV("updated and writing file %s", filename);
blob->setVersion(version);
}
return updated;
}
/**
* Takes a blob that is an PEM-encoded RSA key as a byte array and
* converts it to a DER-encoded PKCS#8 for import into a keymaster.
* Then it overwrites the original blob with the new blob
* format that is returned from the keymaster.
*/
ResponseCode importBlobAsKey(Blob* blob, const char* filename, uid_t uid) {
// We won't even write to the blob directly with this BIO, so const_cast is okay.
Unique_BIO b(BIO_new_mem_buf(const_cast<uint8_t*>(blob->getValue()), blob->getLength()));
if (b.get() == NULL) {
ALOGE("Problem instantiating BIO");
return SYSTEM_ERROR;
}
Unique_EVP_PKEY pkey(PEM_read_bio_PrivateKey(b.get(), NULL, NULL, NULL));
if (pkey.get() == NULL) {
ALOGE("Couldn't read old PEM file");
return SYSTEM_ERROR;
}
Unique_PKCS8_PRIV_KEY_INFO pkcs8(EVP_PKEY2PKCS8(pkey.get()));
int len = i2d_PKCS8_PRIV_KEY_INFO(pkcs8.get(), NULL);
if (len < 0) {
ALOGE("Couldn't measure PKCS#8 length");
return SYSTEM_ERROR;
}
UniquePtr<unsigned char[]> pkcs8key(new unsigned char[len]);
uint8_t* tmp = pkcs8key.get();
if (i2d_PKCS8_PRIV_KEY_INFO(pkcs8.get(), &tmp) != len) {
ALOGE("Couldn't convert to PKCS#8");
return SYSTEM_ERROR;
}
ResponseCode rc = importKey(pkcs8key.get(), len, filename, get_user_id(uid),
blob->isEncrypted() ? KEYSTORE_FLAG_ENCRYPTED : KEYSTORE_FLAG_NONE);
if (rc != NO_ERROR) {
return rc;
}
return get(filename, blob, TYPE_KEY_PAIR, uid);
}
void readMetaData() {
int in = TEMP_FAILURE_RETRY(open(sMetaDataFile, O_RDONLY));
if (in < 0) {
return;
}
size_t fileLength = readFully(in, (uint8_t*) &mMetaData, sizeof(mMetaData));
if (fileLength != sizeof(mMetaData)) {
ALOGI("Metadata file is %zd bytes (%zd experted); upgrade?", fileLength,
sizeof(mMetaData));
}
close(in);
}
void writeMetaData() {
const char* tmpFileName = ".metadata.tmp";
int out = TEMP_FAILURE_RETRY(open(tmpFileName,
O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR));
if (out < 0) {
ALOGE("couldn't write metadata file: %s", strerror(errno));
return;
}
size_t fileLength = writeFully(out, (uint8_t*) &mMetaData, sizeof(mMetaData));
if (fileLength != sizeof(mMetaData)) {
ALOGI("Could only write %zd bytes to metadata file (%zd expected)", fileLength,
sizeof(mMetaData));
}
close(out);
rename(tmpFileName, sMetaDataFile);
}
bool upgradeKeystore() {
bool upgraded = false;
if (mMetaData.version == 0) {
UserState* userState = getUserStateByUid(0);
// Initialize first so the directory is made.
userState->initialize();
// Migrate the old .masterkey file to user 0.
if (access(sOldMasterKey, R_OK) == 0) {
if (rename(sOldMasterKey, userState->getMasterKeyFileName()) < 0) {
ALOGE("couldn't migrate old masterkey: %s", strerror(errno));
return false;
}
}
// Initialize again in case we had a key.
userState->initialize();
// Try to migrate existing keys.
DIR* dir = opendir(".");
if (!dir) {
// Give up now; maybe we can upgrade later.
ALOGE("couldn't open keystore's directory; something is wrong");
return false;
}
struct dirent* file;
while ((file = readdir(dir)) != NULL) {
// We only care about files.
if (file->d_type != DT_REG) {
continue;
}
// Skip anything that starts with a "."
if (file->d_name[0] == '.') {
continue;
}
// Find the current file's user.
char* end;
unsigned long thisUid = strtoul(file->d_name, &end, 10);
if (end[0] != '_' || end[1] == 0) {
continue;
}
UserState* otherUser = getUserStateByUid(thisUid);
if (otherUser->getUserId() != 0) {
unlinkat(dirfd(dir), file->d_name, 0);
}
// Rename the file into user directory.
DIR* otherdir = opendir(otherUser->getUserDirName());
if (otherdir == NULL) {
ALOGW("couldn't open user directory for rename");
continue;
}
if (renameat(dirfd(dir), file->d_name, dirfd(otherdir), file->d_name) < 0) {
ALOGW("couldn't rename blob: %s: %s", file->d_name, strerror(errno));
}
closedir(otherdir);
}
closedir(dir);
mMetaData.version = 1;
upgraded = true;
}
return upgraded;
}
};
const char* KeyStore::sOldMasterKey = ".masterkey";
const char* KeyStore::sMetaDataFile = ".metadata";
const android::String16 KeyStore::sRSAKeyType("RSA");
namespace android {
class KeyStoreProxy : public BnKeystoreService, public IBinder::DeathRecipient {
public:
KeyStoreProxy(KeyStore* keyStore)
: mKeyStore(keyStore),
mOperationMap(this)
{
}
void binderDied(const wp<IBinder>& who) {
auto operations = mOperationMap.getOperationsForToken(who.unsafe_get());
for (auto token: operations) {
abort(token);
}
}
int32_t getState(int32_t userId) {
if (!checkBinderPermission(P_GET_STATE)) {
return ::PERMISSION_DENIED;
}
return mKeyStore->getState(userId);
}
int32_t get(const String16& name, uint8_t** item, size_t* itemLength) {
if (!checkBinderPermission(P_GET)) {
return ::PERMISSION_DENIED;
}
uid_t callingUid = IPCThreadState::self()->getCallingUid();
String8 name8(name);
Blob keyBlob;
ResponseCode responseCode = mKeyStore->getKeyForName(&keyBlob, name8, callingUid,
TYPE_GENERIC);
if (responseCode != ::NO_ERROR) {
*item = NULL;
*itemLength = 0;
return responseCode;
}
*item = (uint8_t*) malloc(keyBlob.getLength());
memcpy(*item, keyBlob.getValue(), keyBlob.getLength());
*itemLength = keyBlob.getLength();
return ::NO_ERROR;
}
int32_t insert(const String16& name, const uint8_t* item, size_t itemLength, int targetUid,
int32_t flags) {
targetUid = getEffectiveUid(targetUid);
int32_t result = checkBinderPermissionAndKeystoreState(P_INSERT, targetUid,
flags & KEYSTORE_FLAG_ENCRYPTED);
if (result != ::NO_ERROR) {
return result;
}
String8 name8(name);
String8 filename(mKeyStore->getKeyNameForUidWithDir(name8, targetUid));
Blob keyBlob(item, itemLength, NULL, 0, ::TYPE_GENERIC);
keyBlob.setEncrypted(flags & KEYSTORE_FLAG_ENCRYPTED);
return mKeyStore->put(filename.string(), &keyBlob, get_user_id(targetUid));
}
int32_t del(const String16& name, int targetUid) {
targetUid = getEffectiveUid(targetUid);
if (!checkBinderPermission(P_DELETE, targetUid)) {
return ::PERMISSION_DENIED;
}
String8 name8(name);
String8 filename(mKeyStore->getKeyNameForUidWithDir(name8, targetUid));
return mKeyStore->del(filename.string(), ::TYPE_ANY, get_user_id(targetUid));
}
int32_t exist(const String16& name, int targetUid) {
targetUid = getEffectiveUid(targetUid);
if (!checkBinderPermission(P_EXIST, targetUid)) {
return ::PERMISSION_DENIED;
}
String8 name8(name);
String8 filename(mKeyStore->getKeyNameForUidWithDir(name8, targetUid));
if (access(filename.string(), R_OK) == -1) {
return (errno != ENOENT) ? ::SYSTEM_ERROR : ::KEY_NOT_FOUND;
}
return ::NO_ERROR;
}
int32_t list(const String16& prefix, int targetUid, Vector<String16>* matches) {
targetUid = getEffectiveUid(targetUid);
if (!checkBinderPermission(P_LIST, targetUid)) {
return ::PERMISSION_DENIED;
}
const String8 prefix8(prefix);
String8 filename(mKeyStore->getKeyNameForUid(prefix8, targetUid));
if (mKeyStore->list(filename, matches, get_user_id(targetUid)) != ::NO_ERROR) {
return ::SYSTEM_ERROR;
}
return ::NO_ERROR;
}
int32_t reset() {
if (!checkBinderPermission(P_RESET)) {
return ::PERMISSION_DENIED;
}
uid_t callingUid = IPCThreadState::self()->getCallingUid();
mKeyStore->resetUser(get_user_id(callingUid), false);
return ::NO_ERROR;
}
int32_t onUserPasswordChanged(int32_t userId, const String16& password) {
if (!checkBinderPermission(P_PASSWORD)) {
return ::PERMISSION_DENIED;
}
const String8 password8(password);
// Flush the auth token table to prevent stale tokens from sticking
// around.
mAuthTokenTable.Clear();
if (password.size() == 0) {
ALOGI("Secure lockscreen for user %d removed, deleting encrypted entries", userId);
mKeyStore->resetUser(userId, true);
return ::NO_ERROR;
} else {
switch (mKeyStore->getState(userId)) {
case ::STATE_UNINITIALIZED: {
// generate master key, encrypt with password, write to file,
// initialize mMasterKey*.
return mKeyStore->initializeUser(password8, userId);
}
case ::STATE_NO_ERROR: {
// rewrite master key with new password.
return mKeyStore->writeMasterKey(password8, userId);
}
case ::STATE_LOCKED: {
ALOGE("Changing user %d's password while locked, clearing old encryption",
userId);
mKeyStore->resetUser(userId, true);
return mKeyStore->initializeUser(password8, userId);
}
}
return ::SYSTEM_ERROR;
}
}
int32_t onUserAdded(int32_t userId, int32_t parentId) {
if (!checkBinderPermission(P_USER_CHANGED)) {
return ::PERMISSION_DENIED;
}
// Sanity check that the new user has an empty keystore.
if (!mKeyStore->isEmpty(userId)) {
ALOGW("New user %d's keystore not empty. Clearing old entries.", userId);
}
// Unconditionally clear the keystore, just to be safe.
mKeyStore->resetUser(userId, false);
if (parentId != -1) {
// This profile must share the same master key password as the parent
// profile. Because the password of the parent profile is not known
// here, the best we can do is copy the parent's master key and master
// key file. This makes this profile use the same master key as the
// parent profile, forever.
return mKeyStore->copyMasterKey(parentId, userId);
} else {
return ::NO_ERROR;
}
}
int32_t onUserRemoved(int32_t userId) {
if (!checkBinderPermission(P_USER_CHANGED)) {
return ::PERMISSION_DENIED;
}
mKeyStore->resetUser(userId, false);
return ::NO_ERROR;
}
int32_t lock(int32_t userId) {
if (!checkBinderPermission(P_LOCK)) {
return ::PERMISSION_DENIED;
}
State state = mKeyStore->getState(userId);
if (state != ::STATE_NO_ERROR) {
ALOGD("calling lock in state: %d", state);
return state;
}
mKeyStore->lock(userId);
return ::NO_ERROR;
}
int32_t unlock(int32_t userId, const String16& pw) {
if (!checkBinderPermission(P_UNLOCK)) {
return ::PERMISSION_DENIED;
}
State state = mKeyStore->getState(userId);
if (state != ::STATE_LOCKED) {
switch (state) {
case ::STATE_NO_ERROR:
ALOGI("calling unlock when already unlocked, ignoring.");
break;
case ::STATE_UNINITIALIZED:
ALOGE("unlock called on uninitialized keystore.");
break;
default:
ALOGE("unlock called on keystore in unknown state: %d", state);
break;
}
return state;
}
const String8 password8(pw);
// read master key, decrypt with password, initialize mMasterKey*.
return mKeyStore->readMasterKey(password8, userId);
}
bool isEmpty(int32_t userId) {
if (!checkBinderPermission(P_IS_EMPTY)) {
return false;
}
return mKeyStore->isEmpty(userId);
}
int32_t generate(const String16& name, int32_t targetUid, int32_t keyType, int32_t keySize,
int32_t flags, Vector<sp<KeystoreArg> >* args) {
targetUid = getEffectiveUid(targetUid);
int32_t result = checkBinderPermissionAndKeystoreState(P_INSERT, targetUid,
flags & KEYSTORE_FLAG_ENCRYPTED);
if (result != ::NO_ERROR) {
return result;
}
KeymasterArguments params;
add_legacy_key_authorizations(keyType, &params.params);
switch (keyType) {
case EVP_PKEY_EC: {
params.params.push_back(keymaster_param_enum(KM_TAG_ALGORITHM, KM_ALGORITHM_EC));
if (keySize == -1) {
keySize = EC_DEFAULT_KEY_SIZE;
} else if (keySize < EC_MIN_KEY_SIZE || keySize > EC_MAX_KEY_SIZE) {
ALOGI("invalid key size %d", keySize);
return ::SYSTEM_ERROR;
}
params.params.push_back(keymaster_param_int(KM_TAG_KEY_SIZE, keySize));
break;
}
case EVP_PKEY_RSA: {
params.params.push_back(keymaster_param_enum(KM_TAG_ALGORITHM, KM_ALGORITHM_RSA));
if (keySize == -1) {
keySize = RSA_DEFAULT_KEY_SIZE;
} else if (keySize < RSA_MIN_KEY_SIZE || keySize > RSA_MAX_KEY_SIZE) {
ALOGI("invalid key size %d", keySize);
return ::SYSTEM_ERROR;
}
params.params.push_back(keymaster_param_int(KM_TAG_KEY_SIZE, keySize));
unsigned long exponent = RSA_DEFAULT_EXPONENT;
if (args->size() > 1) {
ALOGI("invalid number of arguments: %zu", args->size());
return ::SYSTEM_ERROR;
} else if (args->size() == 1) {
sp<KeystoreArg> expArg = args->itemAt(0);
if (expArg != NULL) {
Unique_BIGNUM pubExpBn(
BN_bin2bn(reinterpret_cast<const unsigned char*>(expArg->data()),
expArg->size(), NULL));
if (pubExpBn.get() == NULL) {
ALOGI("Could not convert public exponent to BN");
return ::SYSTEM_ERROR;
}
exponent = BN_get_word(pubExpBn.get());
if (exponent == 0xFFFFFFFFL) {
ALOGW("cannot represent public exponent as a long value");
return ::SYSTEM_ERROR;
}
} else {
ALOGW("public exponent not read");
return ::SYSTEM_ERROR;
}
}
params.params.push_back(keymaster_param_long(KM_TAG_RSA_PUBLIC_EXPONENT,
exponent));
break;
}
default: {
ALOGW("Unsupported key type %d", keyType);
return ::SYSTEM_ERROR;
}
}
int32_t rc = generateKey(name, params, NULL, 0, targetUid, flags,
/*outCharacteristics*/ NULL);
if (rc != ::NO_ERROR) {
ALOGW("generate failed: %d", rc);
}
return translateResultToLegacyResult(rc);
}
int32_t import(const String16& name, const uint8_t* data, size_t length, int targetUid,
int32_t flags) {
const uint8_t* ptr = data;
Unique_PKCS8_PRIV_KEY_INFO pkcs8(d2i_PKCS8_PRIV_KEY_INFO(NULL, &ptr, length));
if (!pkcs8.get()) {
return ::SYSTEM_ERROR;
}
Unique_EVP_PKEY pkey(EVP_PKCS82PKEY(pkcs8.get()));
if (!pkey.get()) {
return ::SYSTEM_ERROR;
}
int type = EVP_PKEY_type(pkey->type);
KeymasterArguments params;
add_legacy_key_authorizations(type, &params.params);
switch (type) {
case EVP_PKEY_RSA:
params.params.push_back(keymaster_param_enum(KM_TAG_ALGORITHM, KM_ALGORITHM_RSA));
break;
case EVP_PKEY_EC:
params.params.push_back(keymaster_param_enum(KM_TAG_ALGORITHM,
KM_ALGORITHM_EC));
break;
default:
ALOGW("Unsupported key type %d", type);
return ::SYSTEM_ERROR;
}
int32_t rc = importKey(name, params, KM_KEY_FORMAT_PKCS8, data, length, targetUid, flags,
/*outCharacteristics*/ NULL);
if (rc != ::NO_ERROR) {
ALOGW("importKey failed: %d", rc);
}
return translateResultToLegacyResult(rc);
}
int32_t sign(const String16& name, const uint8_t* data, size_t length, uint8_t** out,
size_t* outLength) {
if (!checkBinderPermission(P_SIGN)) {
return ::PERMISSION_DENIED;
}
return doLegacySignVerify(name, data, length, out, outLength, NULL, 0, KM_PURPOSE_SIGN);
}
int32_t verify(const String16& name, const uint8_t* data, size_t dataLength,
const uint8_t* signature, size_t signatureLength) {
if (!checkBinderPermission(P_VERIFY)) {
return ::PERMISSION_DENIED;
}
return doLegacySignVerify(name, data, dataLength, NULL, NULL, signature, signatureLength,
KM_PURPOSE_VERIFY);
}
/*
* TODO: The abstraction between things stored in hardware and regular blobs
* of data stored on the filesystem should be moved down to keystore itself.
* Unfortunately the Java code that calls this has naming conventions that it
* knows about. Ideally keystore shouldn't be used to store random blobs of
* data.
*
* Until that happens, it's necessary to have a separate "get_pubkey" and
* "del_key" since the Java code doesn't really communicate what it's
* intentions are.
*/
int32_t get_pubkey(const String16& name, uint8_t** pubkey, size_t* pubkeyLength) {
ExportResult result;
exportKey(name, KM_KEY_FORMAT_X509, NULL, NULL, &result);
if (result.resultCode != ::NO_ERROR) {
ALOGW("export failed: %d", result.resultCode);
return translateResultToLegacyResult(result.resultCode);
}
*pubkey = result.exportData.release();
*pubkeyLength = result.dataLength;
return ::NO_ERROR;
}
int32_t grant(const String16& name, int32_t granteeUid) {
uid_t callingUid = IPCThreadState::self()->getCallingUid();
int32_t result = checkBinderPermissionAndKeystoreState(P_GRANT);
if (result != ::NO_ERROR) {
return result;
}
String8 name8(name);
String8 filename(mKeyStore->getKeyNameForUidWithDir(name8, callingUid));
if (access(filename.string(), R_OK) == -1) {
return (errno != ENOENT) ? ::SYSTEM_ERROR : ::KEY_NOT_FOUND;
}
mKeyStore->addGrant(filename.string(), granteeUid);
return ::NO_ERROR;
}
int32_t ungrant(const String16& name, int32_t granteeUid) {
uid_t callingUid = IPCThreadState::self()->getCallingUid();
int32_t result = checkBinderPermissionAndKeystoreState(P_GRANT);
if (result != ::NO_ERROR) {
return result;
}
String8 name8(name);
String8 filename(mKeyStore->getKeyNameForUidWithDir(name8, callingUid));
if (access(filename.string(), R_OK) == -1) {
return (errno != ENOENT) ? ::SYSTEM_ERROR : ::KEY_NOT_FOUND;
}
return mKeyStore->removeGrant(filename.string(), granteeUid) ? ::NO_ERROR : ::KEY_NOT_FOUND;
}
int64_t getmtime(const String16& name) {
uid_t callingUid = IPCThreadState::self()->getCallingUid();
if (!checkBinderPermission(P_GET)) {
ALOGW("permission denied for %d: getmtime", callingUid);
return -1L;
}
String8 name8(name);
String8 filename(mKeyStore->getKeyNameForUidWithDir(name8, callingUid));
if (access(filename.string(), R_OK) == -1) {
ALOGW("could not access %s for getmtime", filename.string());
return -1L;
}
int fd = TEMP_FAILURE_RETRY(open(filename.string(), O_NOFOLLOW, O_RDONLY));
if (fd < 0) {
ALOGW("could not open %s for getmtime", filename.string());
return -1L;
}
struct stat s;
int ret = fstat(fd, &s);
close(fd);
if (ret == -1) {
ALOGW("could not stat %s for getmtime", filename.string());
return -1L;
}
return static_cast<int64_t>(s.st_mtime);
}
int32_t duplicate(const String16& srcKey, int32_t srcUid, const String16& destKey,
int32_t destUid) {
uid_t callingUid = IPCThreadState::self()->getCallingUid();
pid_t spid = IPCThreadState::self()->getCallingPid();
if (!has_permission(callingUid, P_DUPLICATE, spid)) {
ALOGW("permission denied for %d: duplicate", callingUid);
return -1L;
}
State state = mKeyStore->getState(get_user_id(callingUid));
if (!isKeystoreUnlocked(state)) {
ALOGD("calling duplicate in state: %d", state);
return state;
}
if (srcUid == -1 || static_cast<uid_t>(srcUid) == callingUid) {
srcUid = callingUid;
} else if (!is_granted_to(callingUid, srcUid)) {
ALOGD("migrate not granted from source: %d -> %d", callingUid, srcUid);
return ::PERMISSION_DENIED;
}
if (destUid == -1) {
destUid = callingUid;
}
if (srcUid != destUid) {
if (static_cast<uid_t>(srcUid) != callingUid) {
ALOGD("can only duplicate from caller to other or to same uid: "
"calling=%d, srcUid=%d, destUid=%d", callingUid, srcUid, destUid);
return ::PERMISSION_DENIED;
}
if (!is_granted_to(callingUid, destUid)) {
ALOGD("duplicate not granted to dest: %d -> %d", callingUid, destUid);
return ::PERMISSION_DENIED;
}
}
String8 source8(srcKey);
String8 sourceFile(mKeyStore->getKeyNameForUidWithDir(source8, srcUid));
String8 target8(destKey);
String8 targetFile(mKeyStore->getKeyNameForUidWithDir(target8, destUid));
if (access(targetFile.string(), W_OK) != -1 || errno != ENOENT) {
ALOGD("destination already exists: %s", targetFile.string());
return ::SYSTEM_ERROR;
}
Blob keyBlob;
ResponseCode responseCode = mKeyStore->get(sourceFile.string(), &keyBlob, TYPE_ANY,
get_user_id(srcUid));
if (responseCode != ::NO_ERROR) {
return responseCode;
}
return mKeyStore->put(targetFile.string(), &keyBlob, get_user_id(destUid));
}
int32_t is_hardware_backed(const String16& keyType) {
return mKeyStore->isHardwareBacked(keyType) ? 1 : 0;
}
int32_t clear_uid(int64_t targetUid64) {
uid_t targetUid = getEffectiveUid(targetUid64);
if (!checkBinderPermissionSelfOrSystem(P_CLEAR_UID, targetUid)) {
return ::PERMISSION_DENIED;
}
String8 prefix = String8::format("%u_", targetUid);
Vector<String16> aliases;
if (mKeyStore->list(prefix, &aliases, get_user_id(targetUid)) != ::NO_ERROR) {
return ::SYSTEM_ERROR;
}
for (uint32_t i = 0; i < aliases.size(); i++) {
String8 name8(aliases[i]);
String8 filename(mKeyStore->getKeyNameForUidWithDir(name8, targetUid));
mKeyStore->del(filename.string(), ::TYPE_ANY, get_user_id(targetUid));
}
return ::NO_ERROR;
}
int32_t addRngEntropy(const uint8_t* data, size_t dataLength) {
const keymaster1_device_t* device = mKeyStore->getDevice();
const keymaster1_device_t* fallback = mKeyStore->getFallbackDevice();
int32_t devResult = KM_ERROR_UNIMPLEMENTED;
int32_t fallbackResult = KM_ERROR_UNIMPLEMENTED;
if (device->common.module->module_api_version >= KEYMASTER_MODULE_API_VERSION_1_0 &&
device->add_rng_entropy != NULL) {
devResult = device->add_rng_entropy(device, data, dataLength);
}
if (fallback->add_rng_entropy) {
fallbackResult = fallback->add_rng_entropy(fallback, data, dataLength);
}
if (devResult) {
return devResult;
}
if (fallbackResult) {
return fallbackResult;
}
return ::NO_ERROR;
}
int32_t generateKey(const String16& name, const KeymasterArguments& params,
const uint8_t* entropy, size_t entropyLength, int uid, int flags,
KeyCharacteristics* outCharacteristics) {
uid = getEffectiveUid(uid);
int rc = checkBinderPermissionAndKeystoreState(P_INSERT, uid,
flags & KEYSTORE_FLAG_ENCRYPTED);
if (rc != ::NO_ERROR) {
return rc;
}
rc = KM_ERROR_UNIMPLEMENTED;
bool isFallback = false;
keymaster_key_blob_t blob;
keymaster_key_characteristics_t *out = NULL;
const keymaster1_device_t* device = mKeyStore->getDevice();
const keymaster1_device_t* fallback = mKeyStore->getFallbackDevice();
std::vector<keymaster_key_param_t> opParams(params.params);
const keymaster_key_param_set_t inParams = {opParams.data(), opParams.size()};
if (device == NULL) {
return ::SYSTEM_ERROR;
}
// TODO: Seed from Linux RNG before this.
if (device->common.module->module_api_version >= KEYMASTER_MODULE_API_VERSION_1_0 &&
device->generate_key != NULL) {
if (!entropy) {
rc = KM_ERROR_OK;
} else if (device->add_rng_entropy) {
rc = device->add_rng_entropy(device, entropy, entropyLength);
} else {
rc = KM_ERROR_UNIMPLEMENTED;
}
if (rc == KM_ERROR_OK) {
rc = device->generate_key(device, &inParams, &blob, &out);
}
}
// If the HW device didn't support generate_key or generate_key failed
// fall back to the software implementation.
if (rc && fallback->generate_key != NULL) {
ALOGW("Primary keymaster device failed to generate key, falling back to SW.");
isFallback = true;
if (!entropy) {
rc = KM_ERROR_OK;
} else if (fallback->add_rng_entropy) {
rc = fallback->add_rng_entropy(fallback, entropy, entropyLength);
} else {
rc = KM_ERROR_UNIMPLEMENTED;
}
if (rc == KM_ERROR_OK) {
rc = fallback->generate_key(fallback, &inParams, &blob, &out);
}
}
if (out) {
if (outCharacteristics) {
outCharacteristics->characteristics = *out;
} else {
keymaster_free_characteristics(out);
}
free(out);
}
if (rc) {
return rc;
}
String8 name8(name);
String8 filename(mKeyStore->getKeyNameForUidWithDir(name8, uid));
Blob keyBlob(blob.key_material, blob.key_material_size, NULL, 0, ::TYPE_KEYMASTER_10);
keyBlob.setFallback(isFallback);
keyBlob.setEncrypted(flags & KEYSTORE_FLAG_ENCRYPTED);
free(const_cast<uint8_t*>(blob.key_material));
return mKeyStore->put(filename.string(), &keyBlob, get_user_id(uid));
}
int32_t getKeyCharacteristics(const String16& name,
const keymaster_blob_t* clientId,
const keymaster_blob_t* appData,
KeyCharacteristics* outCharacteristics) {
if (!outCharacteristics) {
return KM_ERROR_UNEXPECTED_NULL_POINTER;
}
uid_t callingUid = IPCThreadState::self()->getCallingUid();
Blob keyBlob;
String8 name8(name);
int rc;
ResponseCode responseCode = mKeyStore->getKeyForName(&keyBlob, name8, callingUid,
TYPE_KEYMASTER_10);
if (responseCode != ::NO_ERROR) {
return responseCode;
}
keymaster_key_blob_t key;
key.key_material_size = keyBlob.getLength();
key.key_material = keyBlob.getValue();
keymaster1_device_t* dev = mKeyStore->getDeviceForBlob(keyBlob);
keymaster_key_characteristics_t *out = NULL;
if (!dev->get_key_characteristics) {
ALOGW("device does not implement get_key_characteristics");
return KM_ERROR_UNIMPLEMENTED;
}
rc = dev->get_key_characteristics(dev, &key, clientId, appData, &out);
if (out) {
outCharacteristics->characteristics = *out;
free(out);
}
return rc ? rc : ::NO_ERROR;
}
int32_t importKey(const String16& name, const KeymasterArguments& params,
keymaster_key_format_t format, const uint8_t *keyData,
size_t keyLength, int uid, int flags,
KeyCharacteristics* outCharacteristics) {
uid = getEffectiveUid(uid);
int rc = checkBinderPermissionAndKeystoreState(P_INSERT, uid,
flags & KEYSTORE_FLAG_ENCRYPTED);
if (rc != ::NO_ERROR) {
return rc;
}
rc = KM_ERROR_UNIMPLEMENTED;
bool isFallback = false;
keymaster_key_blob_t blob;
keymaster_key_characteristics_t *out = NULL;
const keymaster1_device_t* device = mKeyStore->getDevice();
const keymaster1_device_t* fallback = mKeyStore->getFallbackDevice();
std::vector<keymaster_key_param_t> opParams(params.params);
const keymaster_key_param_set_t inParams = {opParams.data(), opParams.size()};
const keymaster_blob_t input = {keyData, keyLength};
if (device == NULL) {
return ::SYSTEM_ERROR;
}
if (device->common.module->module_api_version >= KEYMASTER_MODULE_API_VERSION_1_0 &&
device->import_key != NULL) {
rc = device->import_key(device, &inParams, format,&input, &blob, &out);
}
if (rc && fallback->import_key != NULL) {
ALOGW("Primary keymaster device failed to import key, falling back to SW.");
isFallback = true;
rc = fallback->import_key(fallback, &inParams, format, &input, &blob, &out);
}
if (out) {
if (outCharacteristics) {
outCharacteristics->characteristics = *out;
} else {
keymaster_free_characteristics(out);
}
free(out);
}
if (rc) {
return rc;
}
String8 name8(name);
String8 filename(mKeyStore->getKeyNameForUidWithDir(name8, uid));
Blob keyBlob(blob.key_material, blob.key_material_size, NULL, 0, ::TYPE_KEYMASTER_10);
keyBlob.setFallback(isFallback);
keyBlob.setEncrypted(flags & KEYSTORE_FLAG_ENCRYPTED);
free((void*) blob.key_material);
return mKeyStore->put(filename.string(), &keyBlob, get_user_id(uid));
}
void exportKey(const String16& name, keymaster_key_format_t format,
const keymaster_blob_t* clientId,
const keymaster_blob_t* appData, ExportResult* result) {
uid_t callingUid = IPCThreadState::self()->getCallingUid();
Blob keyBlob;
String8 name8(name);
int rc;
ResponseCode responseCode = mKeyStore->getKeyForName(&keyBlob, name8, callingUid,
TYPE_KEYMASTER_10);
if (responseCode != ::NO_ERROR) {
result->resultCode = responseCode;
return;
}
keymaster_key_blob_t key;
key.key_material_size = keyBlob.getLength();
key.key_material = keyBlob.getValue();
keymaster1_device_t* dev = mKeyStore->getDeviceForBlob(keyBlob);
if (!dev->export_key) {
result->resultCode = KM_ERROR_UNIMPLEMENTED;
return;
}
keymaster_blob_t output = {NULL, 0};
rc = dev->export_key(dev, format, &key, clientId, appData, &output);
result->exportData.reset(const_cast<uint8_t*>(output.data));
result->dataLength = output.data_length;
result->resultCode = rc ? rc : ::NO_ERROR;
}
void begin(const sp<IBinder>& appToken, const String16& name, keymaster_purpose_t purpose,
bool pruneable, const KeymasterArguments& params, const uint8_t* entropy,
size_t entropyLength, OperationResult* result) {
uid_t callingUid = IPCThreadState::self()->getCallingUid();
if (!pruneable && get_app_id(callingUid) != AID_SYSTEM) {
ALOGE("Non-system uid %d trying to start non-pruneable operation", callingUid);
result->resultCode = ::PERMISSION_DENIED;
return;
}
if (!checkAllowedOperationParams(params.params)) {
result->resultCode = KM_ERROR_INVALID_ARGUMENT;
return;
}
Blob keyBlob;
String8 name8(name);
ResponseCode responseCode = mKeyStore->getKeyForName(&keyBlob, name8, callingUid,
TYPE_KEYMASTER_10);
if (responseCode != ::NO_ERROR) {
result->resultCode = responseCode;
return;
}
keymaster_key_blob_t key;
key.key_material_size = keyBlob.getLength();
key.key_material = keyBlob.getValue();
keymaster_operation_handle_t handle;
keymaster1_device_t* dev = mKeyStore->getDeviceForBlob(keyBlob);
keymaster_error_t err = KM_ERROR_UNIMPLEMENTED;
std::vector<keymaster_key_param_t> opParams(params.params);
Unique_keymaster_key_characteristics characteristics;
characteristics.reset(new keymaster_key_characteristics_t);
err = getOperationCharacteristics(key, dev, opParams, characteristics.get());
if (err) {
result->resultCode = err;
return;
}
const hw_auth_token_t* authToken = NULL;
int32_t authResult = getAuthToken(characteristics.get(), 0, purpose, &authToken,
/*failOnTokenMissing*/ false);
// If per-operation auth is needed we need to begin the operation and
// the client will need to authorize that operation before calling
// update. Any other auth issues stop here.
if (authResult != ::NO_ERROR && authResult != ::OP_AUTH_NEEDED) {
result->resultCode = authResult;
return;
}
addAuthToParams(&opParams, authToken);
// Add entropy to the device first.
if (entropy) {
if (dev->add_rng_entropy) {
err = dev->add_rng_entropy(dev, entropy, entropyLength);
} else {
err = KM_ERROR_UNIMPLEMENTED;
}
if (err) {
result->resultCode = err;
return;
}
}
keymaster_key_param_set_t inParams = {opParams.data(), opParams.size()};
// Create a keyid for this key.
keymaster::km_id_t keyid;
if (!enforcement_policy.CreateKeyId(key, &keyid)) {
ALOGE("Failed to create a key ID for authorization checking.");
result->resultCode = KM_ERROR_UNKNOWN_ERROR;
return;
}
// Check that all key authorization policy requirements are met.
keymaster::AuthorizationSet key_auths(characteristics->hw_enforced);
key_auths.push_back(characteristics->sw_enforced);
keymaster::AuthorizationSet operation_params(inParams);
err = enforcement_policy.AuthorizeOperation(purpose, keyid, key_auths, operation_params,
0 /* op_handle */,
true /* is_begin_operation */);
if (err) {
result->resultCode = err;
return;
}
keymaster_key_param_set_t outParams = {NULL, 0};
err = dev->begin(dev, purpose, &key, &inParams, &outParams, &handle);
// If there are too many operations abort the oldest operation that was
// started as pruneable and try again.
while (err == KM_ERROR_TOO_MANY_OPERATIONS && mOperationMap.hasPruneableOperation()) {
sp<IBinder> oldest = mOperationMap.getOldestPruneableOperation();
ALOGD("Ran out of operation handles, trying to prune %p", oldest.get());
// We mostly ignore errors from abort() below because all we care about is whether at
// least one pruneable operation has been removed.
size_t op_count_before = mOperationMap.getPruneableOperationCount();
int abort_error = abort(oldest);
size_t op_count_after = mOperationMap.getPruneableOperationCount();
if (op_count_after >= op_count_before) {
// Failed to create space for a new operation. Bail to avoid an infinite loop.
ALOGE("Failed to remove pruneable operation %p, error: %d",
oldest.get(), abort_error);
break;
}
err = dev->begin(dev, purpose, &key, &inParams, &outParams, &handle);
}
if (err) {
result->resultCode = err;
return;
}
sp<IBinder> operationToken = mOperationMap.addOperation(handle, keyid, purpose, dev,
appToken, characteristics.release(),
pruneable);
if (authToken) {
mOperationMap.setOperationAuthToken(operationToken, authToken);
}
// Return the authentication lookup result. If this is a per operation
// auth'd key then the resultCode will be ::OP_AUTH_NEEDED and the
// application should get an auth token using the handle before the
// first call to update, which will fail if keystore hasn't received the
// auth token.
result->resultCode = authResult;
result->token = operationToken;
result->handle = handle;
if (outParams.params) {
result->outParams.params.assign(outParams.params, outParams.params + outParams.length);
free(outParams.params);
}
}
void update(const sp<IBinder>& token, const KeymasterArguments& params, const uint8_t* data,
size_t dataLength, OperationResult* result) {
if (!checkAllowedOperationParams(params.params)) {
result->resultCode = KM_ERROR_INVALID_ARGUMENT;
return;
}
const keymaster1_device_t* dev;
keymaster_operation_handle_t handle;
keymaster_purpose_t purpose;
keymaster::km_id_t keyid;
const keymaster_key_characteristics_t* characteristics;
if (!mOperationMap.getOperation(token, &handle, &keyid, &purpose, &dev, &characteristics)) {
result->resultCode = KM_ERROR_INVALID_OPERATION_HANDLE;
return;
}
std::vector<keymaster_key_param_t> opParams(params.params);
int32_t authResult = addOperationAuthTokenIfNeeded(token, &opParams);
if (authResult != ::NO_ERROR) {
result->resultCode = authResult;
return;
}
keymaster_key_param_set_t inParams = {opParams.data(), opParams.size()};
keymaster_blob_t input = {data, dataLength};
size_t consumed = 0;
keymaster_blob_t output = {NULL, 0};
keymaster_key_param_set_t outParams = {NULL, 0};
// Check that all key authorization policy requirements are met.
keymaster::AuthorizationSet key_auths(characteristics->hw_enforced);
key_auths.push_back(characteristics->sw_enforced);
keymaster::AuthorizationSet operation_params(inParams);
result->resultCode =
enforcement_policy.AuthorizeOperation(purpose, keyid, key_auths,
operation_params, handle,
false /* is_begin_operation */);
if (result->resultCode) {
return;
}
keymaster_error_t err = dev->update(dev, handle, &inParams, &input, &consumed, &outParams,
&output);
result->data.reset(const_cast<uint8_t*>(output.data));
result->dataLength = output.data_length;
result->inputConsumed = consumed;
result->resultCode = err ? (int32_t) err : ::NO_ERROR;
if (outParams.params) {
result->outParams.params.assign(outParams.params, outParams.params + outParams.length);
free(outParams.params);
}
}
void finish(const sp<IBinder>& token, const KeymasterArguments& params,
const uint8_t* signature, size_t signatureLength,
const uint8_t* entropy, size_t entropyLength, OperationResult* result) {
if (!checkAllowedOperationParams(params.params)) {
result->resultCode = KM_ERROR_INVALID_ARGUMENT;
return;
}
const keymaster1_device_t* dev;
keymaster_operation_handle_t handle;
keymaster_purpose_t purpose;
keymaster::km_id_t keyid;
const keymaster_key_characteristics_t* characteristics;
if (!mOperationMap.getOperation(token, &handle, &keyid, &purpose, &dev, &characteristics)) {
result->resultCode = KM_ERROR_INVALID_OPERATION_HANDLE;
return;
}
std::vector<keymaster_key_param_t> opParams(params.params);
int32_t authResult = addOperationAuthTokenIfNeeded(token, &opParams);
if (authResult != ::NO_ERROR) {
result->resultCode = authResult;
return;
}
keymaster_error_t err;
if (entropy) {
if (dev->add_rng_entropy) {
err = dev->add_rng_entropy(dev, entropy, entropyLength);
} else {
err = KM_ERROR_UNIMPLEMENTED;
}
if (err) {
result->resultCode = err;
return;
}
}
keymaster_key_param_set_t inParams = {opParams.data(), opParams.size()};
keymaster_blob_t input = {signature, signatureLength};
keymaster_blob_t output = {NULL, 0};
keymaster_key_param_set_t outParams = {NULL, 0};
// Check that all key authorization policy requirements are met.
keymaster::AuthorizationSet key_auths(characteristics->hw_enforced);
key_auths.push_back(characteristics->sw_enforced);
keymaster::AuthorizationSet operation_params(inParams);
err = enforcement_policy.AuthorizeOperation(purpose, keyid, key_auths, operation_params,
handle, false /* is_begin_operation */);
if (err) {
result->resultCode = err;
return;
}
err = dev->finish(dev, handle, &inParams, &input, &outParams, &output);
// Remove the operation regardless of the result
mOperationMap.removeOperation(token);
mAuthTokenTable.MarkCompleted(handle);
result->data.reset(const_cast<uint8_t*>(output.data));
result->dataLength = output.data_length;
result->resultCode = err ? (int32_t) err : ::NO_ERROR;
if (outParams.params) {
result->outParams.params.assign(outParams.params, outParams.params + outParams.length);
free(outParams.params);
}
}
int32_t abort(const sp<IBinder>& token) {
const keymaster1_device_t* dev;
keymaster_operation_handle_t handle;
keymaster_purpose_t purpose;
keymaster::km_id_t keyid;
if (!mOperationMap.getOperation(token, &handle, &keyid, &purpose, &dev, NULL)) {
return KM_ERROR_INVALID_OPERATION_HANDLE;
}
mOperationMap.removeOperation(token);
int32_t rc;
if (!dev->abort) {
rc = KM_ERROR_UNIMPLEMENTED;
} else {
rc = dev->abort(dev, handle);
}
mAuthTokenTable.MarkCompleted(handle);
if (rc) {
return rc;
}
return ::NO_ERROR;
}
bool isOperationAuthorized(const sp<IBinder>& token) {
const keymaster1_device_t* dev;
keymaster_operation_handle_t handle;
const keymaster_key_characteristics_t* characteristics;
keymaster_purpose_t purpose;
keymaster::km_id_t keyid;
if (!mOperationMap.getOperation(token, &handle, &keyid, &purpose, &dev, &characteristics)) {
return false;
}
const hw_auth_token_t* authToken = NULL;
mOperationMap.getOperationAuthToken(token, &authToken);
std::vector<keymaster_key_param_t> ignored;
int32_t authResult = addOperationAuthTokenIfNeeded(token, &ignored);
return authResult == ::NO_ERROR;
}
int32_t addAuthToken(const uint8_t* token, size_t length) {
if (!checkBinderPermission(P_ADD_AUTH)) {
ALOGW("addAuthToken: permission denied for %d",
IPCThreadState::self()->getCallingUid());
return ::PERMISSION_DENIED;
}
if (length != sizeof(hw_auth_token_t)) {
return KM_ERROR_INVALID_ARGUMENT;
}
hw_auth_token_t* authToken = new hw_auth_token_t;
memcpy(reinterpret_cast<void*>(authToken), token, sizeof(hw_auth_token_t));
// The table takes ownership of authToken.
mAuthTokenTable.AddAuthenticationToken(authToken);
return ::NO_ERROR;
}
private:
static const int32_t UID_SELF = -1;
/**
* Get the effective target uid for a binder operation that takes an
* optional uid as the target.
*/
inline uid_t getEffectiveUid(int32_t targetUid) {
if (targetUid == UID_SELF) {
return IPCThreadState::self()->getCallingUid();
}
return static_cast<uid_t>(targetUid);
}
/**
* Check if the caller of the current binder method has the required
* permission and if acting on other uids the grants to do so.
*/
inline bool checkBinderPermission(perm_t permission, int32_t targetUid = UID_SELF) {
uid_t callingUid = IPCThreadState::self()->getCallingUid();
pid_t spid = IPCThreadState::self()->getCallingPid();
if (!has_permission(callingUid, permission, spid)) {
ALOGW("permission %s denied for %d", get_perm_label(permission), callingUid);
return false;
}
if (!is_granted_to(callingUid, getEffectiveUid(targetUid))) {
ALOGW("uid %d not granted to act for %d", callingUid, targetUid);
return false;
}
return true;
}
/**
* Check if the caller of the current binder method has the required
* permission and the target uid is the caller or the caller is system.
*/
inline bool checkBinderPermissionSelfOrSystem(perm_t permission, int32_t targetUid) {
uid_t callingUid = IPCThreadState::self()->getCallingUid();
pid_t spid = IPCThreadState::self()->getCallingPid();
if (!has_permission(callingUid, permission, spid)) {
ALOGW("permission %s denied for %d", get_perm_label(permission), callingUid);
return false;
}
return getEffectiveUid(targetUid) == callingUid || callingUid == AID_SYSTEM;
}
/**
* Check if the caller of the current binder method has the required
* permission or the target of the operation is the caller's uid. This is
* for operation where the permission is only for cross-uid activity and all
* uids are allowed to act on their own (ie: clearing all entries for a
* given uid).
*/
inline bool checkBinderPermissionOrSelfTarget(perm_t permission, int32_t targetUid) {
uid_t callingUid = IPCThreadState::self()->getCallingUid();
if (getEffectiveUid(targetUid) == callingUid) {
return true;
} else {
return checkBinderPermission(permission, targetUid);
}
}
/**
* Helper method to check that the caller has the required permission as
* well as the keystore is in the unlocked state if checkUnlocked is true.
*
* Returns NO_ERROR on success, PERMISSION_DENIED on a permission error and
* otherwise the state of keystore when not unlocked and checkUnlocked is
* true.
*/
inline int32_t checkBinderPermissionAndKeystoreState(perm_t permission, int32_t targetUid = -1,
bool checkUnlocked = true) {
if (!checkBinderPermission(permission, targetUid)) {
return ::PERMISSION_DENIED;
}
State state = mKeyStore->getState(get_user_id(getEffectiveUid(targetUid)));
if (checkUnlocked && !isKeystoreUnlocked(state)) {
return state;
}
return ::NO_ERROR;
}
inline bool isKeystoreUnlocked(State state) {
switch (state) {
case ::STATE_NO_ERROR:
return true;
case ::STATE_UNINITIALIZED:
case ::STATE_LOCKED:
return false;
}
return false;
}
bool isKeyTypeSupported(const keymaster1_device_t* device, keymaster_keypair_t keyType) {
const int32_t device_api = device->common.module->module_api_version;
if (device_api == KEYMASTER_MODULE_API_VERSION_0_2) {
switch (keyType) {
case TYPE_RSA:
case TYPE_DSA:
case TYPE_EC:
return true;
default:
return false;
}
} else if (device_api >= KEYMASTER_MODULE_API_VERSION_0_3) {
switch (keyType) {
case TYPE_RSA:
return true;
case TYPE_DSA:
return device->flags & KEYMASTER_SUPPORTS_DSA;
case TYPE_EC:
return device->flags & KEYMASTER_SUPPORTS_EC;
default:
return false;
}
} else {
return keyType == TYPE_RSA;
}
}
/**
* Check that all keymaster_key_param_t's provided by the application are
* allowed. Any parameter that keystore adds itself should be disallowed here.
*/
bool checkAllowedOperationParams(const std::vector<keymaster_key_param_t>& params) {
for (auto param: params) {
switch (param.tag) {
case KM_TAG_AUTH_TOKEN:
return false;
default:
break;
}
}
return true;
}
keymaster_error_t getOperationCharacteristics(const keymaster_key_blob_t& key,
const keymaster1_device_t* dev,
const std::vector<keymaster_key_param_t>& params,
keymaster_key_characteristics_t* out) {
UniquePtr<keymaster_blob_t> appId;
UniquePtr<keymaster_blob_t> appData;
for (auto param : params) {
if (param.tag == KM_TAG_APPLICATION_ID) {
appId.reset(new keymaster_blob_t);
appId->data = param.blob.data;
appId->data_length = param.blob.data_length;
} else if (param.tag == KM_TAG_APPLICATION_DATA) {
appData.reset(new keymaster_blob_t);
appData->data = param.blob.data;
appData->data_length = param.blob.data_length;
}
}
keymaster_key_characteristics_t* result = NULL;
if (!dev->get_key_characteristics) {
return KM_ERROR_UNIMPLEMENTED;
}
keymaster_error_t error = dev->get_key_characteristics(dev, &key, appId.get(),
appData.get(), &result);
if (result) {
*out = *result;
free(result);
}
return error;
}
/**
* Get the auth token for this operation from the auth token table.
*
* Returns ::NO_ERROR if the auth token was set or none was required.
* ::OP_AUTH_NEEDED if it is a per op authorization, no
* authorization token exists for that operation and
* failOnTokenMissing is false.
* KM_ERROR_KEY_USER_NOT_AUTHENTICATED if there is no valid auth
* token for the operation
*/
int32_t getAuthToken(const keymaster_key_characteristics_t* characteristics,
keymaster_operation_handle_t handle,
keymaster_purpose_t purpose,
const hw_auth_token_t** authToken,
bool failOnTokenMissing = true) {
std::vector<keymaster_key_param_t> allCharacteristics;
for (size_t i = 0; i < characteristics->sw_enforced.length; i++) {
allCharacteristics.push_back(characteristics->sw_enforced.params[i]);
}
for (size_t i = 0; i < characteristics->hw_enforced.length; i++) {
allCharacteristics.push_back(characteristics->hw_enforced.params[i]);
}
keymaster::AuthTokenTable::Error err = mAuthTokenTable.FindAuthorization(
allCharacteristics.data(), allCharacteristics.size(), purpose, handle, authToken);
switch (err) {
case keymaster::AuthTokenTable::OK:
case keymaster::AuthTokenTable::AUTH_NOT_REQUIRED:
return ::NO_ERROR;
case keymaster::AuthTokenTable::AUTH_TOKEN_NOT_FOUND:
case keymaster::AuthTokenTable::AUTH_TOKEN_EXPIRED:
case keymaster::AuthTokenTable::AUTH_TOKEN_WRONG_SID:
return KM_ERROR_KEY_USER_NOT_AUTHENTICATED;
case keymaster::AuthTokenTable::OP_HANDLE_REQUIRED:
return failOnTokenMissing ? (int32_t) KM_ERROR_KEY_USER_NOT_AUTHENTICATED :
(int32_t) ::OP_AUTH_NEEDED;
default:
ALOGE("Unexpected FindAuthorization return value %d", err);
return KM_ERROR_INVALID_ARGUMENT;
}
}
inline void addAuthToParams(std::vector<keymaster_key_param_t>* params,
const hw_auth_token_t* token) {
if (token) {
params->push_back(keymaster_param_blob(KM_TAG_AUTH_TOKEN,
reinterpret_cast<const uint8_t*>(token),
sizeof(hw_auth_token_t)));
}
}
/**
* Add the auth token for the operation to the param list if the operation
* requires authorization. Uses the cached result in the OperationMap if available
* otherwise gets the token from the AuthTokenTable and caches the result.
*
* Returns ::NO_ERROR if the auth token was added or not needed.
* KM_ERROR_KEY_USER_NOT_AUTHENTICATED if the operation is not
* authenticated.
* KM_ERROR_INVALID_OPERATION_HANDLE if token is not a valid
* operation token.
*/
int32_t addOperationAuthTokenIfNeeded(sp<IBinder> token,
std::vector<keymaster_key_param_t>* params) {
const hw_auth_token_t* authToken = NULL;
mOperationMap.getOperationAuthToken(token, &authToken);
if (!authToken) {
const keymaster1_device_t* dev;
keymaster_operation_handle_t handle;
const keymaster_key_characteristics_t* characteristics = NULL;
keymaster_purpose_t purpose;
keymaster::km_id_t keyid;
if (!mOperationMap.getOperation(token, &handle, &keyid, &purpose, &dev,
&characteristics)) {
return KM_ERROR_INVALID_OPERATION_HANDLE;
}
int32_t result = getAuthToken(characteristics, handle, purpose, &authToken);
if (result != ::NO_ERROR) {
return result;
}
if (authToken) {
mOperationMap.setOperationAuthToken(token, authToken);
}
}
addAuthToParams(params, authToken);
return ::NO_ERROR;
}
/**
* Translate a result value to a legacy return value. All keystore errors are
* preserved and keymaster errors become SYSTEM_ERRORs
*/
inline int32_t translateResultToLegacyResult(int32_t result) {
if (result > 0) {
return result;
}
return ::SYSTEM_ERROR;
}
keymaster_key_param_t* getKeyAlgorithm(keymaster_key_characteristics_t* characteristics) {
for (size_t i = 0; i < characteristics->hw_enforced.length; i++) {
if (characteristics->hw_enforced.params[i].tag == KM_TAG_ALGORITHM) {
return &characteristics->hw_enforced.params[i];
}
}
for (size_t i = 0; i < characteristics->sw_enforced.length; i++) {
if (characteristics->sw_enforced.params[i].tag == KM_TAG_ALGORITHM) {
return &characteristics->sw_enforced.params[i];
}
}
return NULL;
}
void addLegacyBeginParams(const String16& name, std::vector<keymaster_key_param_t>& params) {
// All legacy keys are DIGEST_NONE/PAD_NONE.
params.push_back(keymaster_param_enum(KM_TAG_DIGEST, KM_DIGEST_NONE));
params.push_back(keymaster_param_enum(KM_TAG_PADDING, KM_PAD_NONE));
// Look up the algorithm of the key.
KeyCharacteristics characteristics;
int32_t rc = getKeyCharacteristics(name, NULL, NULL, &characteristics);
if (rc != ::NO_ERROR) {
ALOGE("Failed to get key characteristics");
return;
}
keymaster_key_param_t* algorithm = getKeyAlgorithm(&characteristics.characteristics);
if (!algorithm) {
ALOGE("getKeyCharacteristics did not include KM_TAG_ALGORITHM");
return;
}
params.push_back(*algorithm);
}
int32_t doLegacySignVerify(const String16& name, const uint8_t* data, size_t length,
uint8_t** out, size_t* outLength, const uint8_t* signature,
size_t signatureLength, keymaster_purpose_t purpose) {
std::basic_stringstream<uint8_t> outBuffer;
OperationResult result;
KeymasterArguments inArgs;
addLegacyBeginParams(name, inArgs.params);
sp<IBinder> appToken(new BBinder);
sp<IBinder> token;
begin(appToken, name, purpose, true, inArgs, NULL, 0, &result);
if (result.resultCode != ResponseCode::NO_ERROR) {
if (result.resultCode == ::KEY_NOT_FOUND) {
ALOGW("Key not found");
} else {
ALOGW("Error in begin: %d", result.resultCode);
}
return translateResultToLegacyResult(result.resultCode);
}
inArgs.params.clear();
token = result.token;
size_t consumed = 0;
size_t lastConsumed = 0;
do {
update(token, inArgs, data + consumed, length - consumed, &result);
if (result.resultCode != ResponseCode::NO_ERROR) {
ALOGW("Error in update: %d", result.resultCode);
return translateResultToLegacyResult(result.resultCode);
}
if (out) {
outBuffer.write(result.data.get(), result.dataLength);
}
lastConsumed = result.inputConsumed;
consumed += lastConsumed;
} while (consumed < length && lastConsumed > 0);
if (consumed != length) {
ALOGW("Not all data consumed. Consumed %zu of %zu", consumed, length);
return ::SYSTEM_ERROR;
}
finish(token, inArgs, signature, signatureLength, NULL, 0, &result);
if (result.resultCode != ResponseCode::NO_ERROR) {
ALOGW("Error in finish: %d", result.resultCode);
return translateResultToLegacyResult(result.resultCode);
}
if (out) {
outBuffer.write(result.data.get(), result.dataLength);
}
if (out) {
auto buf = outBuffer.str();
*out = new uint8_t[buf.size()];
memcpy(*out, buf.c_str(), buf.size());
*outLength = buf.size();
}
return ::NO_ERROR;
}
::KeyStore* mKeyStore;
OperationMap mOperationMap;
keymaster::AuthTokenTable mAuthTokenTable;
KeystoreKeymasterEnforcement enforcement_policy;
};
}; // namespace android
int main(int argc, char* argv[]) {
if (argc < 2) {
ALOGE("A directory must be specified!");
return 1;
}
if (chdir(argv[1]) == -1) {
ALOGE("chdir: %s: %s", argv[1], strerror(errno));
return 1;
}
Entropy entropy;
if (!entropy.open()) {
return 1;
}
keymaster1_device_t* dev;
if (keymaster_device_initialize(&dev)) {
ALOGE("keystore keymaster could not be initialized; exiting");
return 1;
}
keymaster1_device_t* fallback;
if (fallback_keymaster_device_initialize(&fallback)) {
ALOGE("software keymaster could not be initialized; exiting");
return 1;
}
ks_is_selinux_enabled = is_selinux_enabled();
if (ks_is_selinux_enabled) {
union selinux_callback cb;
cb.func_audit = audit_callback;
selinux_set_callback(SELINUX_CB_AUDIT, cb);
cb.func_log = selinux_log_callback;
selinux_set_callback(SELINUX_CB_LOG, cb);
if (getcon(&tctx) != 0) {
ALOGE("SELinux: Could not acquire target context. Aborting keystore.\n");
return -1;
}
} else {
ALOGI("SELinux: Keystore SELinux is disabled.\n");
}
KeyStore keyStore(&entropy, dev, fallback);
keyStore.initialize();
android::sp<android::IServiceManager> sm = android::defaultServiceManager();
android::sp<android::KeyStoreProxy> proxy = new android::KeyStoreProxy(&keyStore);
android::status_t ret = sm->addService(android::String16("android.security.keystore"), proxy);
if (ret != android::OK) {
ALOGE("Couldn't register binder service!");
return -1;
}
/*
* We're the only thread in existence, so we're just going to process
* Binder transaction as a single-threaded program.
*/
android::IPCThreadState::self()->joinThreadPool();
keymaster_device_release(dev);
return 1;
}