1 /*
2 * Copyright 2013 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 //#define LOG_NDEBUG 0
29 #define LOG_TAG "OpenSSL-keystore-ecdsa"
30 #include <cutils/log.h>
31
32 #include <binder/IServiceManager.h>
33 #include <keystore/IKeystoreService.h>
34
35 #include <openssl/ecdsa.h>
36 #include <openssl/engine.h>
37
38 // TODO replace this with real OpenSSL API when it exists
39 #include "crypto/ec/ec_lcl.h"
40 #include "crypto/ecdsa/ecs_locl.h"
41
42 #include "methods.h"
43
44
45 using namespace android;
46
47 struct ECDSA_SIG_Delete {
operator ()ECDSA_SIG_Delete48 void operator()(ECDSA_SIG* p) const {
49 ECDSA_SIG_free(p);
50 }
51 };
52 typedef UniquePtr<ECDSA_SIG, struct ECDSA_SIG_Delete> Unique_ECDSA_SIG;
53
keystore_ecdsa_do_sign(const unsigned char * dgst,int dlen,const BIGNUM *,const BIGNUM *,EC_KEY * eckey)54 static ECDSA_SIG* keystore_ecdsa_do_sign(const unsigned char *dgst, int dlen,
55 const BIGNUM*, const BIGNUM*, EC_KEY *eckey) {
56 ALOGV("keystore_ecdsa_do_sign(%p, %d, %p)", dgst, dlen, eckey);
57
58 uint8_t* key_id = reinterpret_cast<uint8_t*>(EC_KEY_get_key_method_data(eckey,
59 ex_data_dup, ex_data_free, ex_data_clear_free));
60 if (key_id == NULL) {
61 ALOGE("key had no key_id!");
62 return 0;
63 }
64
65 sp<IServiceManager> sm = defaultServiceManager();
66 sp<IBinder> binder = sm->getService(String16("android.security.keystore"));
67 sp<IKeystoreService> service = interface_cast<IKeystoreService>(binder);
68
69 if (service == NULL) {
70 ALOGE("could not contact keystore");
71 return 0;
72 }
73
74 int num = ECDSA_size(eckey);
75
76 uint8_t* reply = NULL;
77 size_t replyLen;
78 int32_t ret = service->sign(String16(reinterpret_cast<const char*>(key_id)), dgst,
79 dlen, &reply, &replyLen);
80 if (ret < 0) {
81 ALOGW("There was an error during dsa_do_sign: could not connect");
82 return 0;
83 } else if (ret != 0) {
84 ALOGW("Error during sign from keystore: %d", ret);
85 return 0;
86 } else if (replyLen <= 0) {
87 ALOGW("No valid signature returned");
88 return 0;
89 } else if (replyLen > (size_t) num) {
90 ALOGW("Signature is too large");
91 return 0;
92 }
93
94 Unique_ECDSA_SIG ecdsa_sig(d2i_ECDSA_SIG(NULL,
95 const_cast<const unsigned char**>(reinterpret_cast<unsigned char**>(&reply)),
96 replyLen));
97 if (ecdsa_sig.get() == NULL) {
98 ALOGW("conversion from DER to ECDSA_SIG failed");
99 return 0;
100 }
101
102 ALOGV("keystore_ecdsa_do_sign(%p, %d, %p) => returning %p len %zu", dgst, dlen, eckey,
103 ecdsa_sig.get(), replyLen);
104 return ecdsa_sig.release();
105 }
106
107 static ECDSA_METHOD keystore_ecdsa_meth = {
108 kKeystoreEngineId, /* name */
109 keystore_ecdsa_do_sign, /* ecdsa_do_sign */
110 NULL, /* ecdsa_sign_setup */
111 NULL, /* ecdsa_do_verify */
112 0, /* flags */
113 NULL, /* app_data */
114 };
115
register_ecdsa_methods()116 static int register_ecdsa_methods() {
117 const ECDSA_METHOD* ecdsa_meth = ECDSA_OpenSSL();
118
119 keystore_ecdsa_meth.ecdsa_do_verify = ecdsa_meth->ecdsa_do_verify;
120
121 return 1;
122 }
123
ecdsa_pkey_setup(ENGINE * e,EVP_PKEY * pkey,const char * key_id)124 int ecdsa_pkey_setup(ENGINE *e, EVP_PKEY *pkey, const char *key_id) {
125 Unique_EC_KEY eckey(EVP_PKEY_get1_EC_KEY(pkey));
126 void* oldData = EC_KEY_insert_key_method_data(eckey.get(),
127 reinterpret_cast<void*>(strdup(key_id)), ex_data_dup, ex_data_free,
128 ex_data_clear_free);
129 if (oldData != NULL) {
130 free(oldData);
131 }
132
133 ECDSA_set_method(eckey.get(), &keystore_ecdsa_meth);
134
135 /*
136 * "ECDSA_set_ENGINE()" should probably be an OpenSSL API. Since it isn't,
137 * and EC_KEY_free() calls ENGINE_finish(), we need to call ENGINE_init()
138 * here.
139 */
140 ECDSA_DATA *ecdsa = ecdsa_check(eckey.get());
141 ENGINE_init(e);
142 ecdsa->engine = e;
143
144 return 1;
145 }
146
ecdsa_register(ENGINE * e)147 int ecdsa_register(ENGINE* e) {
148 if (!ENGINE_set_ECDSA(e, &keystore_ecdsa_meth)
149 || !register_ecdsa_methods()) {
150 ALOGE("Could not set up keystore ECDSA methods");
151 return 0;
152 }
153
154 return 1;
155 }
156