1/*
2 * Copyright 2012 The Android Open Source Project
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
16 * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY
17 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
18 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
19 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
20 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 *
24 */
25
26#include <UniquePtr.h>
27
28#include <sys/socket.h>
29#include <stdarg.h>
30#include <string.h>
31#include <unistd.h>
32
33#include <openssl/dsa.h>
34#include <openssl/engine.h>
35#include <openssl/ec.h>
36#include <openssl/evp.h>
37#include <openssl/objects.h>
38#include <openssl/rsa.h>
39
40//#define LOG_NDEBUG 0
41#define LOG_TAG "OpenSSL-keystore"
42#include <cutils/log.h>
43
44#include <binder/IServiceManager.h>
45#include <keystore/keystore.h>
46#include <keystore/IKeystoreService.h>
47
48#include "methods.h"
49
50using namespace android;
51
52#define DYNAMIC_ENGINE
53const char* kKeystoreEngineId = "keystore";
54static const char* kKeystoreEngineDesc = "Android keystore engine";
55
56
57/*
58 * ex_data index for keystore's key alias.
59 */
60int rsa_key_handle;
61int dsa_key_handle;
62
63
64/*
65 * Only initialize the *_key_handle once.
66 */
67static pthread_once_t key_handle_control = PTHREAD_ONCE_INIT;
68
69/**
70 * Many OpenSSL APIs take ownership of an argument on success but don't free the argument
71 * on failure. This means we need to tell our scoped pointers when we've transferred ownership,
72 * without triggering a warning by not using the result of release().
73 */
74#define OWNERSHIP_TRANSFERRED(obj) \
75    typeof (obj.release()) _dummy __attribute__((unused)) = obj.release()
76
77
78struct ENGINE_Delete {
79    void operator()(ENGINE* p) const {
80        ENGINE_free(p);
81    }
82};
83typedef UniquePtr<ENGINE, ENGINE_Delete> Unique_ENGINE;
84
85struct EVP_PKEY_Delete {
86    void operator()(EVP_PKEY* p) const {
87        EVP_PKEY_free(p);
88    }
89};
90typedef UniquePtr<EVP_PKEY, EVP_PKEY_Delete> Unique_EVP_PKEY;
91
92/**
93 * Called to initialize RSA's ex_data for the key_id handle. This should
94 * only be called when protected by a lock.
95 */
96static void init_key_handle() {
97    rsa_key_handle = RSA_get_ex_new_index(0, NULL, keyhandle_new, keyhandle_dup, keyhandle_free);
98    dsa_key_handle = DSA_get_ex_new_index(0, NULL, keyhandle_new, keyhandle_dup, keyhandle_free);
99}
100
101static EVP_PKEY* keystore_loadkey(ENGINE* e, const char* key_id, UI_METHOD* ui_method,
102        void* callback_data) {
103#if LOG_NDEBUG
104    (void)ui_method;
105    (void)callback_data;
106#else
107    ALOGV("keystore_loadkey(%p, \"%s\", %p, %p)", e, key_id, ui_method, callback_data);
108#endif
109
110    sp<IServiceManager> sm = defaultServiceManager();
111    sp<IBinder> binder = sm->getService(String16("android.security.keystore"));
112    sp<IKeystoreService> service = interface_cast<IKeystoreService>(binder);
113
114    if (service == NULL) {
115        ALOGE("could not contact keystore");
116        return 0;
117    }
118
119    uint8_t *pubkey = NULL;
120    size_t pubkeyLen;
121    int32_t ret = service->get_pubkey(String16(key_id), &pubkey, &pubkeyLen);
122    if (ret < 0) {
123        ALOGW("could not contact keystore");
124        free(pubkey);
125        return NULL;
126    } else if (ret != 0) {
127        ALOGW("keystore reports error: %d", ret);
128        free(pubkey);
129        return NULL;
130    }
131
132    const unsigned char* tmp = reinterpret_cast<const unsigned char*>(pubkey);
133    Unique_EVP_PKEY pkey(d2i_PUBKEY(NULL, &tmp, pubkeyLen));
134    free(pubkey);
135    if (pkey.get() == NULL) {
136        ALOGW("Cannot convert pubkey");
137        return NULL;
138    }
139
140    switch (EVP_PKEY_type(pkey->type)) {
141    case EVP_PKEY_DSA: {
142        dsa_pkey_setup(e, pkey.get(), key_id);
143        break;
144    }
145    case EVP_PKEY_RSA: {
146        rsa_pkey_setup(e, pkey.get(), key_id);
147        break;
148    }
149    case EVP_PKEY_EC: {
150        ecdsa_pkey_setup(e, pkey.get(), key_id);
151        break;
152    }
153    default:
154        ALOGE("Unsupported key type %d", EVP_PKEY_type(pkey->type));
155        return NULL;
156    }
157
158    return pkey.release();
159}
160
161static const ENGINE_CMD_DEFN keystore_cmd_defns[] = {
162    {0, NULL, NULL, 0}
163};
164
165static int keystore_engine_setup(ENGINE* e) {
166    ALOGV("keystore_engine_setup");
167
168    if (!ENGINE_set_id(e, kKeystoreEngineId)
169            || !ENGINE_set_name(e, kKeystoreEngineDesc)
170            || !ENGINE_set_load_privkey_function(e, keystore_loadkey)
171            || !ENGINE_set_load_pubkey_function(e, keystore_loadkey)
172            || !ENGINE_set_flags(e, 0)
173            || !ENGINE_set_cmd_defns(e, keystore_cmd_defns)) {
174        ALOGE("Could not set up keystore engine");
175        return 0;
176    }
177
178    /* We need a handle in the keys types as well for keygen if it's not already initialized. */
179    pthread_once(&key_handle_control, init_key_handle);
180    if ((rsa_key_handle < 0) || (dsa_key_handle < 0)) {
181        ALOGE("Could not set up ex_data index");
182        return 0;
183    }
184
185    if (!dsa_register(e)) {
186        ALOGE("DSA registration failed");
187        return 0;
188    } else if (!ecdsa_register(e)) {
189        ALOGE("ECDSA registration failed");
190        return 0;
191    } else if (!rsa_register(e)) {
192        ALOGE("RSA registration failed");
193        return 0;
194    }
195
196    return 1;
197}
198
199ENGINE* ENGINE_keystore() {
200    ALOGV("ENGINE_keystore");
201
202    Unique_ENGINE engine(ENGINE_new());
203    if (engine.get() == NULL) {
204        return NULL;
205    }
206
207    if (!keystore_engine_setup(engine.get())) {
208        return NULL;
209    }
210
211    return engine.release();
212}
213
214static int keystore_bind_fn(ENGINE *e, const char *id) {
215    ALOGV("keystore_bind_fn");
216
217    if (!id) {
218        return 0;
219    }
220
221    if (strcmp(id, kKeystoreEngineId)) {
222        return 0;
223    }
224
225    if (!keystore_engine_setup(e)) {
226        return 0;
227    }
228
229    return 1;
230}
231
232extern "C" {
233#undef OPENSSL_EXPORT
234#define OPENSSL_EXPORT extern __attribute__ ((visibility ("default")))
235
236IMPLEMENT_DYNAMIC_CHECK_FN()
237IMPLEMENT_DYNAMIC_BIND_FN(keystore_bind_fn)
238};
239