1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #include "net/android/keystore_openssl.h"
8 #include <openssl/bn.h>
9 #include <openssl/dsa.h>
10 #include <openssl/ec.h>
11 #include <openssl/engine.h>
12 #include <openssl/err.h>
13 #include <openssl/evp.h>
14 #include <openssl/rsa.h>
16 #include "base/android/build_info.h"
17 #include "base/android/jni_android.h"
18 #include "base/android/scoped_java_ref.h"
19 #include "base/basictypes.h"
20 #include "base/lazy_instance.h"
21 #include "base/logging.h"
22 #include "crypto/openssl_util.h"
23 #include "net/android/keystore.h"
24 #include "net/android/legacy_openssl.h"
25 #include "net/ssl/ssl_client_cert_type.h"
27 // IMPORTANT NOTE: The following code will currently only work when used
28 // to implement client certificate support with OpenSSL. That's because
29 // only the signing operations used in this use case are implemented here.
31 // Generally speaking, OpenSSL provides many different ways to sign
32 // digests. This code doesn't support all these cases, only the ones that
33 // are required to sign the digest during the OpenSSL handshake for TLS.
35 // The OpenSSL EVP_PKEY type is a generic wrapper around key pairs.
36 // Internally, it can hold a pointer to a RSA, DSA or ECDSA structure,
37 // which model keypair implementations of each respective crypto
40 // The RSA type has a 'method' field pointer to a vtable-like structure
41 // called a RSA_METHOD. This contains several function pointers that
42 // correspond to operations on RSA keys (e.g. decode/encode with public
43 // key, decode/encode with private key, signing, validation), as well as
46 // For example, the RSA_sign() function will call "method->rsa_sign()" if
47 // method->rsa_sign is not NULL, otherwise, it will perform a regular
48 // signing operation using the other fields in the RSA structure (which
49 // are used to hold the typical modulus / exponent / parameters for the
52 // This source file thus defines a custom RSA_METHOD structure whose
53 // fields point to static methods used to implement the corresponding
54 // RSA operation using platform Android APIs.
56 // However, the platform APIs require a jobject JNI reference to work. It must
57 // be stored in the RSA instance, or made accessible when the custom RSA
58 // methods are called. This is done by storing it in a |KeyExData| structure
59 // that's referenced by the key using |EX_DATA|.
61 using base::android::ScopedJavaGlobalRef;
62 using base::android::ScopedJavaLocalRef;
69 extern const RSA_METHOD android_rsa_method;
70 extern const ECDSA_METHOD android_ecdsa_method;
72 // KeyExData contains the data that is contained in the EX_DATA of the RSA, DSA
73 // and ECDSA objects that are created to wrap Android system keys.
75 // private_key contains a reference to a Java, private-key object.
77 // legacy_rsa, if not NULL, points to an RSA* in the system's OpenSSL (which
78 // might not be ABI compatible with Chromium).
79 AndroidRSA* legacy_rsa;
80 // cached_size contains the "size" of the key. This is the size of the
81 // modulus (in bytes) for RSA, or the group order size for (EC)DSA. This
82 // avoids calling into Java to calculate the size.
86 // ExDataDup is called when one of the RSA, DSA or EC_KEY objects is
87 // duplicated. We don't support this and it should never happen.
88 int ExDataDup(CRYPTO_EX_DATA* to,
89 const CRYPTO_EX_DATA* from,
94 CHECK_EQ((void*)NULL, *from_d);
98 // ExDataFree is called when one of the RSA, DSA or EC_KEY object is freed.
99 void ExDataFree(void* parent,
105 // Ensure the global JNI reference created with this wrapper is
106 // properly destroyed with it.
107 KeyExData *ex_data = reinterpret_cast<KeyExData*>(ptr);
108 if (ex_data != NULL) {
109 ReleaseKey(ex_data->private_key);
114 // BoringSSLEngine is a BoringSSL ENGINE that implements RSA, DSA and ECDSA by
115 // forwarding the requested operations to the Java libraries.
116 class BoringSSLEngine {
119 : rsa_index_(RSA_get_ex_new_index(0 /* argl */,
124 ec_key_index_(EC_KEY_get_ex_new_index(0 /* argl */,
129 engine_(ENGINE_new()) {
130 ENGINE_set_RSA_method(
131 engine_, &android_rsa_method, sizeof(android_rsa_method));
132 ENGINE_set_ECDSA_method(
133 engine_, &android_ecdsa_method, sizeof(android_ecdsa_method));
136 int rsa_ex_index() const { return rsa_index_; }
137 int ec_key_ex_index() const { return ec_key_index_; }
139 const ENGINE* engine() const { return engine_; }
142 const int rsa_index_;
143 const int ec_key_index_;
144 ENGINE* const engine_;
147 base::LazyInstance<BoringSSLEngine>::Leaky global_boringssl_engine =
148 LAZY_INSTANCE_INITIALIZER;
151 // VectorBignumSize returns the number of bytes needed to represent the bignum
152 // given in |v|, i.e. the length of |v| less any leading zero bytes.
153 size_t VectorBignumSize(const std::vector<uint8>& v) {
154 size_t size = v.size();
155 // Ignore any leading zero bytes.
156 for (size_t i = 0; i < v.size() && v[i] == 0; i++) {
162 KeyExData* RsaGetExData(const RSA* rsa) {
163 return reinterpret_cast<KeyExData*>(
164 RSA_get_ex_data(rsa, global_boringssl_engine.Get().rsa_ex_index()));
167 size_t RsaMethodSize(const RSA *rsa) {
168 const KeyExData *ex_data = RsaGetExData(rsa);
169 return ex_data->cached_size;
172 int RsaMethodEncrypt(RSA* rsa,
180 OPENSSL_PUT_ERROR(RSA, encrypt, RSA_R_UNKNOWN_ALGORITHM_TYPE);
184 int RsaMethodSignRaw(RSA* rsa,
191 DCHECK_EQ(RSA_PKCS1_PADDING, padding);
192 if (padding != RSA_PKCS1_PADDING) {
193 // TODO(davidben): If we need to, we can implement RSA_NO_PADDING
194 // by using javax.crypto.Cipher and picking either the
195 // "RSA/ECB/NoPadding" or "RSA/ECB/PKCS1Padding" transformation as
196 // appropriate. I believe support for both of these was added in
197 // the same Android version as the "NONEwithRSA"
198 // java.security.Signature algorithm, so the same version checks
199 // for GetRsaLegacyKey should work.
200 OPENSSL_PUT_ERROR(RSA, sign_raw, RSA_R_UNKNOWN_PADDING_TYPE);
204 // Retrieve private key JNI reference.
205 const KeyExData *ex_data = RsaGetExData(rsa);
206 if (!ex_data || !ex_data->private_key) {
207 LOG(WARNING) << "Null JNI reference passed to RsaMethodPrivEnc!";
208 OPENSSL_PUT_ERROR(RSA, sign_raw, ERR_R_INTERNAL_ERROR);
212 // Pre-4.2 legacy codepath.
213 if (ex_data->legacy_rsa) {
214 int ret = ex_data->legacy_rsa->meth->rsa_priv_enc(
215 in_len, in, out, ex_data->legacy_rsa, ANDROID_RSA_PKCS1_PADDING);
217 LOG(WARNING) << "Could not sign message in RsaMethodPrivEnc!";
218 // System OpenSSL will use a separate error queue, so it is still
219 // necessary to push a new error.
221 // TODO(davidben): It would be good to also clear the system error queue
222 // if there were some way to convince Java to do it. (Without going
223 // through Java, it's difficult to get a handle on a system OpenSSL
224 // function; dlopen loads a second copy.)
225 OPENSSL_PUT_ERROR(RSA, sign_raw, ERR_R_INTERNAL_ERROR);
232 base::StringPiece from_piece(reinterpret_cast<const char*>(in), in_len);
233 std::vector<uint8> result;
234 // For RSA keys, this function behaves as RSA_private_encrypt with
236 if (!RawSignDigestWithPrivateKey(ex_data->private_key, from_piece, &result)) {
237 LOG(WARNING) << "Could not sign message in RsaMethodPrivEnc!";
238 OPENSSL_PUT_ERROR(RSA, sign_raw, ERR_R_INTERNAL_ERROR);
242 size_t expected_size = static_cast<size_t>(RSA_size(rsa));
243 if (result.size() > expected_size) {
244 LOG(ERROR) << "RSA Signature size mismatch, actual: "
245 << result.size() << ", expected <= " << expected_size;
246 OPENSSL_PUT_ERROR(RSA, sign_raw, ERR_R_INTERNAL_ERROR);
250 if (max_out < expected_size) {
251 OPENSSL_PUT_ERROR(RSA, sign_raw, RSA_R_DATA_TOO_LARGE);
255 // Copy result to OpenSSL-provided buffer. RawSignDigestWithPrivateKey
256 // should pad with leading 0s, but if it doesn't, pad the result.
257 size_t zero_pad = expected_size - result.size();
258 memset(out, 0, zero_pad);
259 memcpy(out + zero_pad, &result[0], result.size());
260 *out_len = expected_size;
265 int RsaMethodDecrypt(RSA* rsa,
273 OPENSSL_PUT_ERROR(RSA, decrypt, RSA_R_UNKNOWN_ALGORITHM_TYPE);
277 int RsaMethodVerifyRaw(RSA* rsa,
285 OPENSSL_PUT_ERROR(RSA, verify_raw, RSA_R_UNKNOWN_ALGORITHM_TYPE);
289 const RSA_METHOD android_rsa_method = {
305 NULL /* private_transform */,
307 NULL /* bn_mod_exp */,
312 // Setup an EVP_PKEY to wrap an existing platform RSA PrivateKey object.
313 // |private_key| is the JNI reference (local or global) to the object.
314 // |legacy_rsa|, if non-NULL, is a pointer to the system OpenSSL RSA object
315 // backing |private_key|. This parameter is only used for Android < 4.2 to
316 // implement key operations not exposed by the platform.
317 // Returns a new EVP_PKEY on success, NULL otherwise.
318 // On success, this creates a new global JNI reference to the object
319 // that is owned by and destroyed with the EVP_PKEY. I.e. caller can
320 // free |private_key| after the call.
321 crypto::ScopedEVP_PKEY GetRsaPkeyWrapper(jobject private_key,
322 AndroidRSA* legacy_rsa) {
323 crypto::ScopedRSA rsa(
324 RSA_new_method(global_boringssl_engine.Get().engine()));
326 ScopedJavaGlobalRef<jobject> global_key;
327 global_key.Reset(NULL, private_key);
328 if (global_key.is_null()) {
329 LOG(ERROR) << "Could not create global JNI reference";
330 return crypto::ScopedEVP_PKEY();
333 std::vector<uint8> modulus;
334 if (!GetRSAKeyModulus(private_key, &modulus)) {
335 LOG(ERROR) << "Failed to get private key modulus";
336 return crypto::ScopedEVP_PKEY();
339 KeyExData* ex_data = new KeyExData;
340 ex_data->private_key = global_key.Release();
341 ex_data->legacy_rsa = legacy_rsa;
342 ex_data->cached_size = VectorBignumSize(modulus);
344 rsa.get(), global_boringssl_engine.Get().rsa_ex_index(), ex_data);
346 crypto::ScopedEVP_PKEY pkey(EVP_PKEY_new());
348 !EVP_PKEY_set1_RSA(pkey.get(), rsa.get())) {
349 return crypto::ScopedEVP_PKEY();
354 // On Android < 4.2, the libkeystore.so ENGINE uses CRYPTO_EX_DATA and is not
355 // added to the global engine list. If all references to it are dropped, OpenSSL
356 // will dlclose the module, leaving a dangling function pointer in the RSA
357 // CRYPTO_EX_DATA class. To work around this, leak an extra reference to the
358 // ENGINE we extract in GetRsaLegacyKey.
360 // In 4.2, this change avoids the problem:
361 // https://android.googlesource.com/platform/libcore/+/106a8928fb4249f2f3d4dba1dddbe73ca5cb3d61
363 // https://crbug.com/381465
364 class KeystoreEngineWorkaround {
366 KeystoreEngineWorkaround() {}
368 void LeakEngine(jobject private_key) {
369 if (!engine_.is_null())
371 ScopedJavaLocalRef<jobject> engine =
372 GetOpenSSLEngineForPrivateKey(private_key);
373 if (engine.is_null()) {
377 engine_.Reset(engine);
381 ScopedJavaGlobalRef<jobject> engine_;
384 void LeakEngine(jobject private_key) {
385 static base::LazyInstance<KeystoreEngineWorkaround>::Leaky s_instance =
386 LAZY_INSTANCE_INITIALIZER;
387 s_instance.Get().LeakEngine(private_key);
390 // Setup an EVP_PKEY to wrap an existing platform RSA PrivateKey object
391 // for Android 4.0 to 4.1.x. Must only be used on Android < 4.2.
392 // |private_key| is a JNI reference (local or global) to the object.
393 // |pkey| is the EVP_PKEY to setup as a wrapper.
394 // Returns true on success, false otherwise.
395 crypto::ScopedEVP_PKEY GetRsaLegacyKey(jobject private_key) {
396 AndroidEVP_PKEY* sys_pkey =
397 GetOpenSSLSystemHandleForPrivateKey(private_key);
398 if (sys_pkey != NULL) {
399 if (sys_pkey->type != ANDROID_EVP_PKEY_RSA) {
400 LOG(ERROR) << "Private key has wrong type!";
401 return crypto::ScopedEVP_PKEY();
404 AndroidRSA* sys_rsa = sys_pkey->pkey.rsa;
405 if (sys_rsa->engine) {
406 // |private_key| may not have an engine if the PrivateKey did not come
407 // from the key store, such as in unit tests.
408 if (strcmp(sys_rsa->engine->id, "keystore") == 0) {
409 LeakEngine(private_key);
415 return GetRsaPkeyWrapper(private_key, sys_rsa);
418 // GetOpenSSLSystemHandleForPrivateKey() will fail on Android 4.0.3 and
419 // earlier. However, it is possible to get the key content with
420 // PrivateKey.getEncoded() on these platforms. Note that this method may
421 // return NULL on 4.0.4 and later.
422 std::vector<uint8> encoded;
423 if (!GetPrivateKeyEncodedBytes(private_key, &encoded)) {
424 LOG(ERROR) << "Can't get private key data!";
425 return crypto::ScopedEVP_PKEY();
427 const unsigned char* p =
428 reinterpret_cast<const unsigned char*>(&encoded[0]);
429 int len = static_cast<int>(encoded.size());
430 crypto::ScopedEVP_PKEY pkey(d2i_AutoPrivateKey(NULL, &p, len));
432 LOG(ERROR) << "Can't convert private key data!";
433 return crypto::ScopedEVP_PKEY();
438 // Custom ECDSA_METHOD that uses the platform APIs.
439 // Note that for now, only signing through ECDSA_sign() is really supported.
440 // all other method pointers are either stubs returning errors, or no-ops.
442 jobject EcKeyGetKey(const EC_KEY* ec_key) {
443 KeyExData* ex_data = reinterpret_cast<KeyExData*>(EC_KEY_get_ex_data(
444 ec_key, global_boringssl_engine.Get().ec_key_ex_index()));
445 return ex_data->private_key;
448 size_t EcdsaMethodGroupOrderSize(const EC_KEY* ec_key) {
449 KeyExData* ex_data = reinterpret_cast<KeyExData*>(EC_KEY_get_ex_data(
450 ec_key, global_boringssl_engine.Get().ec_key_ex_index()));
451 return ex_data->cached_size;
454 int EcdsaMethodSign(const uint8_t* digest,
457 unsigned int* sig_len,
459 // Retrieve private key JNI reference.
460 jobject private_key = EcKeyGetKey(ec_key);
462 LOG(WARNING) << "Null JNI reference passed to EcdsaMethodSign!";
465 // Sign message with it through JNI.
466 std::vector<uint8> signature;
467 base::StringPiece digest_sp(reinterpret_cast<const char*>(digest),
469 if (!RawSignDigestWithPrivateKey(private_key, digest_sp, &signature)) {
470 LOG(WARNING) << "Could not sign message in EcdsaMethodSign!";
474 // Note: With ECDSA, the actual signature may be smaller than
476 size_t max_expected_size = ECDSA_size(ec_key);
477 if (signature.size() > max_expected_size) {
478 LOG(ERROR) << "ECDSA Signature size mismatch, actual: "
479 << signature.size() << ", expected <= "
480 << max_expected_size;
484 memcpy(sig, &signature[0], signature.size());
485 *sig_len = signature.size();
489 int EcdsaMethodVerify(const uint8_t* digest,
495 OPENSSL_PUT_ERROR(ECDSA, ECDSA_do_verify, ECDSA_R_NOT_IMPLEMENTED);
499 // Setup an EVP_PKEY to wrap an existing platform PrivateKey object.
500 // |private_key| is the JNI reference (local or global) to the object.
501 // Returns a new EVP_PKEY on success, NULL otherwise.
502 // On success, this creates a global JNI reference to the object that
503 // is owned by and destroyed with the EVP_PKEY. I.e. the caller shall
504 // always free |private_key| after the call.
505 crypto::ScopedEVP_PKEY GetEcdsaPkeyWrapper(jobject private_key) {
506 crypto::ScopedEC_KEY ec_key(
507 EC_KEY_new_method(global_boringssl_engine.Get().engine()));
509 ScopedJavaGlobalRef<jobject> global_key;
510 global_key.Reset(NULL, private_key);
511 if (global_key.is_null()) {
512 LOG(ERROR) << "Can't create global JNI reference";
513 return crypto::ScopedEVP_PKEY();
516 std::vector<uint8> order;
517 if (!GetECKeyOrder(private_key, &order)) {
518 LOG(ERROR) << "Can't extract order parameter from EC private key";
519 return crypto::ScopedEVP_PKEY();
522 KeyExData* ex_data = new KeyExData;
523 ex_data->private_key = global_key.Release();
524 ex_data->legacy_rsa = NULL;
525 ex_data->cached_size = VectorBignumSize(order);
528 ec_key.get(), global_boringssl_engine.Get().ec_key_ex_index(), ex_data);
530 crypto::ScopedEVP_PKEY pkey(EVP_PKEY_new());
532 !EVP_PKEY_set1_EC_KEY(pkey.get(), ec_key.get())) {
533 return crypto::ScopedEVP_PKEY();
538 const ECDSA_METHOD android_ecdsa_method = {
547 EcdsaMethodGroupOrderSize,
555 crypto::ScopedEVP_PKEY GetOpenSSLPrivateKeyWrapper(jobject private_key) {
556 const int kAndroid42ApiLevel = 17;
558 // Create sub key type, depending on private key's algorithm type.
559 PrivateKeyType key_type = GetPrivateKeyType(private_key);
561 case PRIVATE_KEY_TYPE_RSA:
562 // Route around platform bug: if Android < 4.2, then
563 // base::android::RawSignDigestWithPrivateKey() cannot work, so
564 // instead, obtain a raw EVP_PKEY* to the system object
565 // backing this PrivateKey object.
566 if (base::android::BuildInfo::GetInstance()->sdk_int() <
567 kAndroid42ApiLevel) {
568 return GetRsaLegacyKey(private_key);
570 // Running on Android 4.2.
571 return GetRsaPkeyWrapper(private_key, NULL);
573 case PRIVATE_KEY_TYPE_ECDSA:
574 return GetEcdsaPkeyWrapper(private_key);
577 << "GetOpenSSLPrivateKeyWrapper() called with invalid key type";
578 return crypto::ScopedEVP_PKEY();
582 } // namespace android