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1 /*
2  *
3  * Copyright 2018 gRPC authors.
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at
8  *
9  *     http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  *
17  */
18 
19 #include <grpc/support/port_platform.h>
20 
21 #include "src/core/lib/security/security_connector/ssl/ssl_security_connector.h"
22 
23 #include <stdbool.h>
24 
25 #include "absl/strings/str_cat.h"
26 #include "absl/strings/str_format.h"
27 #include "absl/strings/string_view.h"
28 
29 #include <grpc/support/alloc.h>
30 #include <grpc/support/log.h>
31 
32 #include "src/core/ext/transport/chttp2/alpn/alpn.h"
33 #include "src/core/lib/channel/handshaker.h"
34 #include "src/core/lib/gpr/string.h"
35 #include "src/core/lib/gprpp/host_port.h"
36 #include "src/core/lib/gprpp/ref_counted_ptr.h"
37 #include "src/core/lib/gprpp/sync.h"
38 #include "src/core/lib/security/context/security_context.h"
39 #include "src/core/lib/security/credentials/credentials.h"
40 #include "src/core/lib/security/credentials/ssl/ssl_credentials.h"
41 #include "src/core/lib/security/security_connector/load_system_roots.h"
42 #include "src/core/lib/security/security_connector/ssl_utils.h"
43 #include "src/core/lib/security/transport/security_handshaker.h"
44 #include "src/core/tsi/ssl_transport_security.h"
45 #include "src/core/tsi/transport_security.h"
46 
47 namespace {
ssl_check_peer(const char * peer_name,const tsi_peer * peer,grpc_core::RefCountedPtr<grpc_auth_context> * auth_context)48 grpc_error* ssl_check_peer(
49     const char* peer_name, const tsi_peer* peer,
50     grpc_core::RefCountedPtr<grpc_auth_context>* auth_context) {
51   grpc_error* error = grpc_ssl_check_alpn(peer);
52   if (error != GRPC_ERROR_NONE) {
53     return error;
54   }
55   /* Check the peer name if specified. */
56   if (peer_name != nullptr && !grpc_ssl_host_matches_name(peer, peer_name)) {
57     return GRPC_ERROR_CREATE_FROM_COPIED_STRING(
58         absl::StrCat("Peer name ", peer_name, " is not in peer certificate")
59             .c_str());
60   }
61   *auth_context =
62       grpc_ssl_peer_to_auth_context(peer, GRPC_SSL_TRANSPORT_SECURITY_TYPE);
63   return GRPC_ERROR_NONE;
64 }
65 
66 class grpc_ssl_channel_security_connector final
67     : public grpc_channel_security_connector {
68  public:
grpc_ssl_channel_security_connector(grpc_core::RefCountedPtr<grpc_channel_credentials> channel_creds,grpc_core::RefCountedPtr<grpc_call_credentials> request_metadata_creds,const grpc_ssl_config * config,const char * target_name,const char * overridden_target_name)69   grpc_ssl_channel_security_connector(
70       grpc_core::RefCountedPtr<grpc_channel_credentials> channel_creds,
71       grpc_core::RefCountedPtr<grpc_call_credentials> request_metadata_creds,
72       const grpc_ssl_config* config, const char* target_name,
73       const char* overridden_target_name)
74       : grpc_channel_security_connector(GRPC_SSL_URL_SCHEME,
75                                         std::move(channel_creds),
76                                         std::move(request_metadata_creds)),
77         overridden_target_name_(
78             overridden_target_name == nullptr ? "" : overridden_target_name),
79         verify_options_(&config->verify_options) {
80     absl::string_view host;
81     absl::string_view port;
82     grpc_core::SplitHostPort(target_name, &host, &port);
83     target_name_ = std::string(host);
84   }
85 
~grpc_ssl_channel_security_connector()86   ~grpc_ssl_channel_security_connector() override {
87     tsi_ssl_client_handshaker_factory_unref(client_handshaker_factory_);
88   }
89 
InitializeHandshakerFactory(const grpc_ssl_config * config,const char * pem_root_certs,const tsi_ssl_root_certs_store * root_store,tsi_ssl_session_cache * ssl_session_cache)90   grpc_security_status InitializeHandshakerFactory(
91       const grpc_ssl_config* config, const char* pem_root_certs,
92       const tsi_ssl_root_certs_store* root_store,
93       tsi_ssl_session_cache* ssl_session_cache) {
94     bool has_key_cert_pair =
95         config->pem_key_cert_pair != nullptr &&
96         config->pem_key_cert_pair->private_key != nullptr &&
97         config->pem_key_cert_pair->cert_chain != nullptr;
98     tsi_ssl_client_handshaker_options options;
99     GPR_DEBUG_ASSERT(pem_root_certs != nullptr);
100     options.pem_root_certs = pem_root_certs;
101     options.root_store = root_store;
102     options.alpn_protocols =
103         grpc_fill_alpn_protocol_strings(&options.num_alpn_protocols);
104     if (has_key_cert_pair) {
105       options.pem_key_cert_pair = config->pem_key_cert_pair;
106     }
107     options.cipher_suites = grpc_get_ssl_cipher_suites();
108     options.session_cache = ssl_session_cache;
109     options.min_tls_version = grpc_get_tsi_tls_version(config->min_tls_version);
110     options.max_tls_version = grpc_get_tsi_tls_version(config->max_tls_version);
111     const tsi_result result =
112         tsi_create_ssl_client_handshaker_factory_with_options(
113             &options, &client_handshaker_factory_);
114     gpr_free(options.alpn_protocols);
115     if (result != TSI_OK) {
116       gpr_log(GPR_ERROR, "Handshaker factory creation failed with %s.",
117               tsi_result_to_string(result));
118       return GRPC_SECURITY_ERROR;
119     }
120     return GRPC_SECURITY_OK;
121   }
122 
add_handshakers(const grpc_channel_args * args,grpc_pollset_set *,grpc_core::HandshakeManager * handshake_mgr)123   void add_handshakers(const grpc_channel_args* args,
124                        grpc_pollset_set* /*interested_parties*/,
125                        grpc_core::HandshakeManager* handshake_mgr) override {
126     // Instantiate TSI handshaker.
127     tsi_handshaker* tsi_hs = nullptr;
128     tsi_result result = tsi_ssl_client_handshaker_factory_create_handshaker(
129         client_handshaker_factory_,
130         overridden_target_name_.empty() ? target_name_.c_str()
131                                         : overridden_target_name_.c_str(),
132         &tsi_hs);
133     if (result != TSI_OK) {
134       gpr_log(GPR_ERROR, "Handshaker creation failed with error %s.",
135               tsi_result_to_string(result));
136       return;
137     }
138     // Create handshakers.
139     handshake_mgr->Add(grpc_core::SecurityHandshakerCreate(tsi_hs, this, args));
140   }
141 
check_peer(tsi_peer peer,grpc_endpoint *,grpc_core::RefCountedPtr<grpc_auth_context> * auth_context,grpc_closure * on_peer_checked)142   void check_peer(tsi_peer peer, grpc_endpoint* /*ep*/,
143                   grpc_core::RefCountedPtr<grpc_auth_context>* auth_context,
144                   grpc_closure* on_peer_checked) override {
145     const char* target_name = overridden_target_name_.empty()
146                                   ? target_name_.c_str()
147                                   : overridden_target_name_.c_str();
148     grpc_error* error = ssl_check_peer(target_name, &peer, auth_context);
149     if (error == GRPC_ERROR_NONE &&
150         verify_options_->verify_peer_callback != nullptr) {
151       const tsi_peer_property* p =
152           tsi_peer_get_property_by_name(&peer, TSI_X509_PEM_CERT_PROPERTY);
153       if (p == nullptr) {
154         error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
155             "Cannot check peer: missing pem cert property.");
156       } else {
157         char* peer_pem = static_cast<char*>(gpr_malloc(p->value.length + 1));
158         memcpy(peer_pem, p->value.data, p->value.length);
159         peer_pem[p->value.length] = '\0';
160         int callback_status = verify_options_->verify_peer_callback(
161             target_name, peer_pem,
162             verify_options_->verify_peer_callback_userdata);
163         gpr_free(peer_pem);
164         if (callback_status) {
165           error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(
166               absl::StrFormat("Verify peer callback returned a failure (%d)",
167                               callback_status)
168                   .c_str());
169         }
170       }
171     }
172     grpc_core::ExecCtx::Run(DEBUG_LOCATION, on_peer_checked, error);
173     tsi_peer_destruct(&peer);
174   }
175 
cmp(const grpc_security_connector * other_sc) const176   int cmp(const grpc_security_connector* other_sc) const override {
177     auto* other =
178         reinterpret_cast<const grpc_ssl_channel_security_connector*>(other_sc);
179     int c = channel_security_connector_cmp(other);
180     if (c != 0) return c;
181     c = target_name_.compare(other->target_name_);
182     if (c != 0) return c;
183     return overridden_target_name_.compare(other->overridden_target_name_);
184   }
185 
check_call_host(absl::string_view host,grpc_auth_context * auth_context,grpc_closure *,grpc_error ** error)186   bool check_call_host(absl::string_view host, grpc_auth_context* auth_context,
187                        grpc_closure* /*on_call_host_checked*/,
188                        grpc_error** error) override {
189     return grpc_ssl_check_call_host(host, target_name_.c_str(),
190                                     overridden_target_name_.c_str(),
191                                     auth_context, error);
192   }
193 
cancel_check_call_host(grpc_closure *,grpc_error * error)194   void cancel_check_call_host(grpc_closure* /*on_call_host_checked*/,
195                               grpc_error* error) override {
196     GRPC_ERROR_UNREF(error);
197   }
198 
199  private:
200   tsi_ssl_client_handshaker_factory* client_handshaker_factory_;
201   std::string target_name_;
202   std::string overridden_target_name_;
203   const verify_peer_options* verify_options_;
204 };
205 
206 class grpc_ssl_server_security_connector
207     : public grpc_server_security_connector {
208  public:
grpc_ssl_server_security_connector(grpc_core::RefCountedPtr<grpc_server_credentials> server_creds)209   explicit grpc_ssl_server_security_connector(
210       grpc_core::RefCountedPtr<grpc_server_credentials> server_creds)
211       : grpc_server_security_connector(GRPC_SSL_URL_SCHEME,
212                                        std::move(server_creds)) {}
213 
~grpc_ssl_server_security_connector()214   ~grpc_ssl_server_security_connector() override {
215     tsi_ssl_server_handshaker_factory_unref(server_handshaker_factory_);
216   }
217 
has_cert_config_fetcher() const218   bool has_cert_config_fetcher() const {
219     return static_cast<const grpc_ssl_server_credentials*>(server_creds())
220         ->has_cert_config_fetcher();
221   }
222 
server_handshaker_factory() const223   const tsi_ssl_server_handshaker_factory* server_handshaker_factory() const {
224     return server_handshaker_factory_;
225   }
226 
InitializeHandshakerFactory()227   grpc_security_status InitializeHandshakerFactory() {
228     if (has_cert_config_fetcher()) {
229       // Load initial credentials from certificate_config_fetcher:
230       if (!try_fetch_ssl_server_credentials()) {
231         gpr_log(GPR_ERROR,
232                 "Failed loading SSL server credentials from fetcher.");
233         return GRPC_SECURITY_ERROR;
234       }
235     } else {
236       auto* server_credentials =
237           static_cast<const grpc_ssl_server_credentials*>(server_creds());
238       size_t num_alpn_protocols = 0;
239       const char** alpn_protocol_strings =
240           grpc_fill_alpn_protocol_strings(&num_alpn_protocols);
241       tsi_ssl_server_handshaker_options options;
242       options.pem_key_cert_pairs =
243           server_credentials->config().pem_key_cert_pairs;
244       options.num_key_cert_pairs =
245           server_credentials->config().num_key_cert_pairs;
246       options.pem_client_root_certs =
247           server_credentials->config().pem_root_certs;
248       options.client_certificate_request =
249           grpc_get_tsi_client_certificate_request_type(
250               server_credentials->config().client_certificate_request);
251       options.cipher_suites = grpc_get_ssl_cipher_suites();
252       options.alpn_protocols = alpn_protocol_strings;
253       options.num_alpn_protocols = static_cast<uint16_t>(num_alpn_protocols);
254       options.min_tls_version = grpc_get_tsi_tls_version(
255           server_credentials->config().min_tls_version);
256       options.max_tls_version = grpc_get_tsi_tls_version(
257           server_credentials->config().max_tls_version);
258       const tsi_result result =
259           tsi_create_ssl_server_handshaker_factory_with_options(
260               &options, &server_handshaker_factory_);
261       gpr_free(alpn_protocol_strings);
262       if (result != TSI_OK) {
263         gpr_log(GPR_ERROR, "Handshaker factory creation failed with %s.",
264                 tsi_result_to_string(result));
265         return GRPC_SECURITY_ERROR;
266       }
267     }
268     return GRPC_SECURITY_OK;
269   }
270 
add_handshakers(const grpc_channel_args * args,grpc_pollset_set *,grpc_core::HandshakeManager * handshake_mgr)271   void add_handshakers(const grpc_channel_args* args,
272                        grpc_pollset_set* /*interested_parties*/,
273                        grpc_core::HandshakeManager* handshake_mgr) override {
274     // Instantiate TSI handshaker.
275     try_fetch_ssl_server_credentials();
276     tsi_handshaker* tsi_hs = nullptr;
277     tsi_result result = tsi_ssl_server_handshaker_factory_create_handshaker(
278         server_handshaker_factory_, &tsi_hs);
279     if (result != TSI_OK) {
280       gpr_log(GPR_ERROR, "Handshaker creation failed with error %s.",
281               tsi_result_to_string(result));
282       return;
283     }
284     // Create handshakers.
285     handshake_mgr->Add(grpc_core::SecurityHandshakerCreate(tsi_hs, this, args));
286   }
287 
check_peer(tsi_peer peer,grpc_endpoint *,grpc_core::RefCountedPtr<grpc_auth_context> * auth_context,grpc_closure * on_peer_checked)288   void check_peer(tsi_peer peer, grpc_endpoint* /*ep*/,
289                   grpc_core::RefCountedPtr<grpc_auth_context>* auth_context,
290                   grpc_closure* on_peer_checked) override {
291     grpc_error* error = ssl_check_peer(nullptr, &peer, auth_context);
292     tsi_peer_destruct(&peer);
293     grpc_core::ExecCtx::Run(DEBUG_LOCATION, on_peer_checked, error);
294   }
295 
cmp(const grpc_security_connector * other) const296   int cmp(const grpc_security_connector* other) const override {
297     return server_security_connector_cmp(
298         static_cast<const grpc_server_security_connector*>(other));
299   }
300 
301  private:
302   /* Attempts to fetch the server certificate config if a callback is available.
303    * Current certificate config will continue to be used if the callback returns
304    * an error. Returns true if new credentials were successfully loaded. */
try_fetch_ssl_server_credentials()305   bool try_fetch_ssl_server_credentials() {
306     grpc_ssl_server_certificate_config* certificate_config = nullptr;
307     bool status;
308     if (!has_cert_config_fetcher()) return false;
309 
310     grpc_core::MutexLock lock(&mu_);
311     grpc_ssl_server_credentials* server_creds =
312         static_cast<grpc_ssl_server_credentials*>(this->mutable_server_creds());
313     grpc_ssl_certificate_config_reload_status cb_result =
314         server_creds->FetchCertConfig(&certificate_config);
315     if (cb_result == GRPC_SSL_CERTIFICATE_CONFIG_RELOAD_UNCHANGED) {
316       gpr_log(GPR_DEBUG, "No change in SSL server credentials.");
317       status = false;
318     } else if (cb_result == GRPC_SSL_CERTIFICATE_CONFIG_RELOAD_NEW) {
319       status = try_replace_server_handshaker_factory(certificate_config);
320     } else {
321       // Log error, continue using previously-loaded credentials.
322       gpr_log(GPR_ERROR,
323               "Failed fetching new server credentials, continuing to "
324               "use previously-loaded credentials.");
325       status = false;
326     }
327 
328     if (certificate_config != nullptr) {
329       grpc_ssl_server_certificate_config_destroy(certificate_config);
330     }
331     return status;
332   }
333 
334   /* Attempts to replace the server_handshaker_factory with a new factory using
335    * the provided grpc_ssl_server_certificate_config. Should new factory
336    * creation fail, the existing factory will not be replaced. Returns true on
337    * success (new factory created). */
try_replace_server_handshaker_factory(const grpc_ssl_server_certificate_config * config)338   bool try_replace_server_handshaker_factory(
339       const grpc_ssl_server_certificate_config* config) {
340     if (config == nullptr) {
341       gpr_log(GPR_ERROR,
342               "Server certificate config callback returned invalid (NULL) "
343               "config.");
344       return false;
345     }
346     gpr_log(GPR_DEBUG, "Using new server certificate config (%p).", config);
347 
348     size_t num_alpn_protocols = 0;
349     const char** alpn_protocol_strings =
350         grpc_fill_alpn_protocol_strings(&num_alpn_protocols);
351     tsi_ssl_server_handshaker_factory* new_handshaker_factory = nullptr;
352     const grpc_ssl_server_credentials* server_creds =
353         static_cast<const grpc_ssl_server_credentials*>(this->server_creds());
354     GPR_DEBUG_ASSERT(config->pem_root_certs != nullptr);
355     tsi_ssl_server_handshaker_options options;
356     options.pem_key_cert_pairs = grpc_convert_grpc_to_tsi_cert_pairs(
357         config->pem_key_cert_pairs, config->num_key_cert_pairs);
358     options.num_key_cert_pairs = config->num_key_cert_pairs;
359     options.pem_client_root_certs = config->pem_root_certs;
360     options.client_certificate_request =
361         grpc_get_tsi_client_certificate_request_type(
362             server_creds->config().client_certificate_request);
363     options.cipher_suites = grpc_get_ssl_cipher_suites();
364     options.alpn_protocols = alpn_protocol_strings;
365     options.num_alpn_protocols = static_cast<uint16_t>(num_alpn_protocols);
366     tsi_result result = tsi_create_ssl_server_handshaker_factory_with_options(
367         &options, &new_handshaker_factory);
368     grpc_tsi_ssl_pem_key_cert_pairs_destroy(
369         const_cast<tsi_ssl_pem_key_cert_pair*>(options.pem_key_cert_pairs),
370         options.num_key_cert_pairs);
371     gpr_free(alpn_protocol_strings);
372 
373     if (result != TSI_OK) {
374       gpr_log(GPR_ERROR, "Handshaker factory creation failed with %s.",
375               tsi_result_to_string(result));
376       return false;
377     }
378     set_server_handshaker_factory(new_handshaker_factory);
379     return true;
380   }
381 
set_server_handshaker_factory(tsi_ssl_server_handshaker_factory * new_factory)382   void set_server_handshaker_factory(
383       tsi_ssl_server_handshaker_factory* new_factory) {
384     if (server_handshaker_factory_) {
385       tsi_ssl_server_handshaker_factory_unref(server_handshaker_factory_);
386     }
387     server_handshaker_factory_ = new_factory;
388   }
389 
390   grpc_core::Mutex mu_;
391   tsi_ssl_server_handshaker_factory* server_handshaker_factory_ = nullptr;
392 };
393 }  // namespace
394 
395 grpc_core::RefCountedPtr<grpc_channel_security_connector>
grpc_ssl_channel_security_connector_create(grpc_core::RefCountedPtr<grpc_channel_credentials> channel_creds,grpc_core::RefCountedPtr<grpc_call_credentials> request_metadata_creds,const grpc_ssl_config * config,const char * target_name,const char * overridden_target_name,tsi_ssl_session_cache * ssl_session_cache)396 grpc_ssl_channel_security_connector_create(
397     grpc_core::RefCountedPtr<grpc_channel_credentials> channel_creds,
398     grpc_core::RefCountedPtr<grpc_call_credentials> request_metadata_creds,
399     const grpc_ssl_config* config, const char* target_name,
400     const char* overridden_target_name,
401     tsi_ssl_session_cache* ssl_session_cache) {
402   if (config == nullptr || target_name == nullptr) {
403     gpr_log(GPR_ERROR, "An ssl channel needs a config and a target name.");
404     return nullptr;
405   }
406 
407   const char* pem_root_certs;
408   const tsi_ssl_root_certs_store* root_store;
409   if (config->pem_root_certs == nullptr) {
410     // Use default root certificates.
411     pem_root_certs = grpc_core::DefaultSslRootStore::GetPemRootCerts();
412     if (pem_root_certs == nullptr) {
413       gpr_log(GPR_ERROR, "Could not get default pem root certs.");
414       return nullptr;
415     }
416     root_store = grpc_core::DefaultSslRootStore::GetRootStore();
417   } else {
418     pem_root_certs = config->pem_root_certs;
419     root_store = nullptr;
420   }
421 
422   grpc_core::RefCountedPtr<grpc_ssl_channel_security_connector> c =
423       grpc_core::MakeRefCounted<grpc_ssl_channel_security_connector>(
424           std::move(channel_creds), std::move(request_metadata_creds), config,
425           target_name, overridden_target_name);
426   const grpc_security_status result = c->InitializeHandshakerFactory(
427       config, pem_root_certs, root_store, ssl_session_cache);
428   if (result != GRPC_SECURITY_OK) {
429     return nullptr;
430   }
431   return c;
432 }
433 
434 grpc_core::RefCountedPtr<grpc_server_security_connector>
grpc_ssl_server_security_connector_create(grpc_core::RefCountedPtr<grpc_server_credentials> server_credentials)435 grpc_ssl_server_security_connector_create(
436     grpc_core::RefCountedPtr<grpc_server_credentials> server_credentials) {
437   GPR_ASSERT(server_credentials != nullptr);
438   grpc_core::RefCountedPtr<grpc_ssl_server_security_connector> c =
439       grpc_core::MakeRefCounted<grpc_ssl_server_security_connector>(
440           std::move(server_credentials));
441   const grpc_security_status retval = c->InitializeHandshakerFactory();
442   if (retval != GRPC_SECURITY_OK) {
443     return nullptr;
444   }
445   return c;
446 }
447