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 //#define LOG_NDEBUG 0
29 #define LOG_TAG "OpenSSL-keystore-rsa"
30 #include <cutils/log.h>
31
32 #include <binder/IServiceManager.h>
33 #include <keystore/IKeystoreService.h>
34
35 #include <openssl/rsa.h>
36 #include <openssl/engine.h>
37
38 #include "methods.h"
39
40
41 using namespace android;
42
43
keystore_rsa_priv_enc(int flen,const unsigned char * from,unsigned char * to,RSA * rsa,int padding)44 int keystore_rsa_priv_enc(int flen, const unsigned char* from, unsigned char* to, RSA* rsa,
45 int padding) {
46 ALOGV("keystore_rsa_priv_enc(%d, %p, %p, %p, %d)", flen, from, to, rsa, padding);
47
48 int num = RSA_size(rsa);
49 UniquePtr<uint8_t> padded(new uint8_t[num]);
50 if (padded.get() == NULL) {
51 ALOGE("could not allocate padded signature");
52 return 0;
53 }
54
55 switch (padding) {
56 case RSA_PKCS1_PADDING:
57 if (!RSA_padding_add_PKCS1_type_1(padded.get(), num, from, flen)) {
58 return 0;
59 }
60 break;
61 case RSA_X931_PADDING:
62 if (!RSA_padding_add_X931(padded.get(), num, from, flen)) {
63 return 0;
64 }
65 break;
66 case RSA_NO_PADDING:
67 if (!RSA_padding_add_none(padded.get(), num, from, flen)) {
68 return 0;
69 }
70 break;
71 default:
72 ALOGE("Unknown padding type: %d", padding);
73 return 0;
74 }
75
76 uint8_t* key_id = reinterpret_cast<uint8_t*>(RSA_get_ex_data(rsa, rsa_key_handle));
77 if (key_id == NULL) {
78 ALOGE("key had no key_id!");
79 return 0;
80 }
81
82 sp<IServiceManager> sm = defaultServiceManager();
83 sp<IBinder> binder = sm->getService(String16("android.security.keystore"));
84 sp<IKeystoreService> service = interface_cast<IKeystoreService>(binder);
85
86 if (service == NULL) {
87 ALOGE("could not contact keystore");
88 return 0;
89 }
90
91 uint8_t* reply = NULL;
92 size_t replyLen;
93 int32_t ret = service->sign(String16(reinterpret_cast<const char*>(key_id)), padded.get(),
94 num, &reply, &replyLen);
95 if (ret < 0) {
96 ALOGW("There was an error during signing: could not connect");
97 free(reply);
98 return 0;
99 } else if (ret != 0) {
100 ALOGW("Error during signing from keystore: %d", ret);
101 free(reply);
102 return 0;
103 } else if (replyLen <= 0) {
104 ALOGW("No valid signature returned");
105 return 0;
106 }
107
108 memcpy(to, reply, replyLen);
109 free(reply);
110
111 ALOGV("rsa=%p keystore_rsa_priv_enc => returning %p len %llu", rsa, to,
112 (unsigned long long) replyLen);
113 return static_cast<int>(replyLen);
114 }
115
keystore_rsa_priv_dec(int flen,const unsigned char * from,unsigned char * to,RSA * rsa,int padding)116 int keystore_rsa_priv_dec(int flen, const unsigned char* from, unsigned char* to, RSA* rsa,
117 int padding) {
118 ALOGV("keystore_rsa_priv_dec(%d, %p, %p, %p, %d)", flen, from, to, rsa, padding);
119
120 uint8_t* key_id = reinterpret_cast<uint8_t*>(RSA_get_ex_data(rsa, rsa_key_handle));
121 if (key_id == NULL) {
122 ALOGE("key had no key_id!");
123 return 0;
124 }
125
126 sp<IServiceManager> sm = defaultServiceManager();
127 sp<IBinder> binder = sm->getService(String16("android.security.keystore"));
128 sp<IKeystoreService> service = interface_cast<IKeystoreService>(binder);
129
130 if (service == NULL) {
131 ALOGE("could not contact keystore");
132 return 0;
133 }
134
135 int num = RSA_size(rsa);
136
137 uint8_t* reply = NULL;
138 size_t replyLen;
139 int32_t ret = service->sign(String16(reinterpret_cast<const char*>(key_id)), from,
140 flen, &reply, &replyLen);
141 if (ret < 0) {
142 ALOGW("There was an error during rsa_mod_exp: could not connect");
143 return 0;
144 } else if (ret != 0) {
145 ALOGW("Error during sign from keystore: %d", ret);
146 return 0;
147 } else if (replyLen <= 0) {
148 ALOGW("No valid signature returned");
149 return 0;
150 }
151
152 /* Trim off the top zero if it's there */
153 uint8_t* alignedReply;
154 if (*reply == 0x00) {
155 alignedReply = reply + 1;
156 replyLen--;
157 } else {
158 alignedReply = reply;
159 }
160
161 int outSize;
162 switch (padding) {
163 case RSA_PKCS1_PADDING:
164 outSize = RSA_padding_check_PKCS1_type_2(to, num, alignedReply, replyLen, num);
165 break;
166 case RSA_X931_PADDING:
167 outSize = RSA_padding_check_X931(to, num, alignedReply, replyLen, num);
168 break;
169 case RSA_NO_PADDING:
170 outSize = RSA_padding_check_none(to, num, alignedReply, replyLen, num);
171 break;
172 default:
173 ALOGE("Unknown padding type: %d", padding);
174 outSize = -1;
175 break;
176 }
177
178 free(reply);
179
180 ALOGV("rsa=%p keystore_rsa_priv_dec => returning %p len %d", rsa, to, outSize);
181 return outSize;
182 }
183
184 static RSA_METHOD keystore_rsa_meth = {
185 kKeystoreEngineId,
186 NULL, /* rsa_pub_enc (wrap) */
187 NULL, /* rsa_pub_dec (verification) */
188 keystore_rsa_priv_enc, /* rsa_priv_enc (signing) */
189 keystore_rsa_priv_dec, /* rsa_priv_dec (unwrap) */
190 NULL, /* rsa_mod_exp */
191 NULL, /* bn_mod_exp */
192 NULL, /* init */
193 NULL, /* finish */
194 RSA_FLAG_EXT_PKEY | RSA_FLAG_NO_BLINDING, /* flags */
195 NULL, /* app_data */
196 NULL, /* rsa_sign */
197 NULL, /* rsa_verify */
198 NULL, /* rsa_keygen */
199 };
200
register_rsa_methods()201 static int register_rsa_methods() {
202 const RSA_METHOD* rsa_meth = RSA_PKCS1_SSLeay();
203
204 keystore_rsa_meth.rsa_pub_enc = rsa_meth->rsa_pub_enc;
205 keystore_rsa_meth.rsa_pub_dec = rsa_meth->rsa_pub_dec;
206 keystore_rsa_meth.rsa_mod_exp = rsa_meth->rsa_mod_exp;
207 keystore_rsa_meth.bn_mod_exp = rsa_meth->bn_mod_exp;
208
209 return 1;
210 }
211
rsa_pkey_setup(ENGINE * e,EVP_PKEY * pkey,const char * key_id)212 int rsa_pkey_setup(ENGINE *e, EVP_PKEY *pkey, const char *key_id) {
213 Unique_RSA rsa(EVP_PKEY_get1_RSA(pkey));
214 if (!RSA_set_ex_data(rsa.get(), rsa_key_handle, reinterpret_cast<void*>(strdup(key_id)))) {
215 ALOGW("Could not set ex_data for loaded RSA key");
216 return 0;
217 }
218
219 RSA_set_method(rsa.get(), &keystore_rsa_meth);
220 RSA_blinding_off(rsa.get());
221
222 /*
223 * "RSA_set_ENGINE()" should probably be an OpenSSL API. Since it isn't,
224 * and EVP_PKEY_free() calls ENGINE_finish(), we need to call ENGINE_init()
225 * here.
226 */
227 ENGINE_init(e);
228 rsa->engine = e;
229 rsa->flags |= RSA_FLAG_EXT_PKEY;
230
231 return 1;
232 }
233
rsa_register(ENGINE * e)234 int rsa_register(ENGINE* e) {
235 if (!ENGINE_set_RSA(e, &keystore_rsa_meth)
236 || !register_rsa_methods()) {
237 ALOGE("Could not set up keystore RSA methods");
238 return 0;
239 }
240
241 return 1;
242 }
243