1 // Copyright 2016 The Chromium Authors
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 //     https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #include "path_builder.h"
16 
17 #include <cstdint>
18 
19 #include <openssl/pool.h>
20 #include "cert_issuer_source_static.h"
21 #include "common_cert_errors.h"
22 #include "crl.h"
23 #include "encode_values.h"
24 #include "input.h"
25 #include "parse_certificate.h"
26 #include "parsed_certificate.h"
27 #include "simple_path_builder_delegate.h"
28 #include "trust_store_in_memory.h"
29 #include "verify_certificate_chain.h"
30 
31 #include "nist_pkits_unittest.h"
32 
33 constexpr int64_t kOneYear = 60 * 60 * 24 * 365;
34 
35 BSSL_NAMESPACE_BEGIN
36 
37 namespace {
38 
39 class CrlCheckingPathBuilderDelegate : public SimplePathBuilderDelegate {
40  public:
CrlCheckingPathBuilderDelegate(const std::vector<std::string> & der_crls,int64_t verify_time,int64_t max_age,size_t min_rsa_modulus_length_bits,DigestPolicy digest_policy)41   CrlCheckingPathBuilderDelegate(const std::vector<std::string> &der_crls,
42                                  int64_t verify_time, int64_t max_age,
43                                  size_t min_rsa_modulus_length_bits,
44                                  DigestPolicy digest_policy)
45       : SimplePathBuilderDelegate(min_rsa_modulus_length_bits, digest_policy),
46         der_crls_(der_crls),
47         verify_time_(verify_time),
48         max_age_(max_age) {}
49 
CheckPathAfterVerification(const CertPathBuilder & path_builder,CertPathBuilderResultPath * path)50   void CheckPathAfterVerification(const CertPathBuilder &path_builder,
51                                   CertPathBuilderResultPath *path) override {
52     SimplePathBuilderDelegate::CheckPathAfterVerification(path_builder, path);
53 
54     if (!path->IsValid()) {
55       return;
56     }
57 
58     // It would be preferable if this test could use
59     // CheckValidatedChainRevocation somehow, but that only supports getting
60     // CRLs by http distributionPoints. So this just settles for writing a
61     // little bit of wrapper code to test CheckCRL directly.
62     const ParsedCertificateList &certs = path->certs;
63     for (size_t reverse_i = 0; reverse_i < certs.size(); ++reverse_i) {
64       size_t i = certs.size() - reverse_i - 1;
65 
66       // Trust anchors bypass OCSP/CRL revocation checks. (The only way to
67       // revoke trust anchors is via CRLSet or the built-in SPKI block list).
68       if (reverse_i == 0 && path->last_cert_trust.IsTrustAnchor()) {
69         continue;
70       }
71 
72       // RFC 5280 6.3.3.  [If the CRL was not specified in a distribution
73       //                  point], assume a DP with both the reasons and the
74       //                  cRLIssuer fields omitted and a distribution point
75       //                  name of the certificate issuer.
76       // Since this implementation only supports URI names in distribution
77       // points, this means a default-initialized ParsedDistributionPoint is
78       // sufficient.
79       ParsedDistributionPoint fake_cert_dp;
80       const ParsedDistributionPoint *cert_dp = &fake_cert_dp;
81 
82       // If the target cert does have a distribution point, use it.
83       std::vector<ParsedDistributionPoint> distribution_points;
84       ParsedExtension crl_dp_extension;
85       if (certs[i]->GetExtension(der::Input(kCrlDistributionPointsOid),
86                                  &crl_dp_extension)) {
87         ASSERT_TRUE(ParseCrlDistributionPoints(crl_dp_extension.value,
88                                                &distribution_points));
89         // TODO(mattm): some test cases (some of the 4.14.* onlySomeReasons
90         // tests)) have two CRLs and two distribution points, one point
91         // corresponding to each CRL.  Should select the matching point for
92         // each CRL.  (Doesn't matter currently since we don't support
93         // reasons.)
94 
95         // Look for a DistributionPoint without reasons.
96         for (const auto &dp : distribution_points) {
97           if (!dp.reasons) {
98             cert_dp = &dp;
99             break;
100           }
101         }
102         // If there were only DistributionPoints with reasons, just use the
103         // first one.
104         if (cert_dp == &fake_cert_dp && !distribution_points.empty()) {
105           cert_dp = &distribution_points[0];
106         }
107       }
108 
109       bool cert_good = false;
110 
111       for (const auto &der_crl : der_crls_) {
112         CRLRevocationStatus crl_status =
113             CheckCRL(der_crl, certs, i, *cert_dp, verify_time_, max_age_);
114         if (crl_status == CRLRevocationStatus::REVOKED) {
115           path->errors.GetErrorsForCert(i)->AddError(
116               cert_errors::kCertificateRevoked);
117           return;
118         }
119         if (crl_status == CRLRevocationStatus::GOOD) {
120           cert_good = true;
121           break;
122         }
123       }
124       if (!cert_good) {
125         // PKITS tests assume hard-fail revocation checking.
126         // From PKITS 4.4: "When running the tests in this section, the
127         // application should be configured in such a way that the
128         // certification path is not accepted unless valid, up-to-date
129         // revocation data is available for every certificate in the path."
130         path->errors.GetErrorsForCert(i)->AddError(
131             cert_errors::kUnableToCheckRevocation);
132       }
133     }
134   }
135 
136  private:
137   std::vector<std::string> der_crls_;
138   int64_t verify_time_;
139   int64_t max_age_;
140 };
141 
142 class PathBuilderPkitsTestDelegate {
143  public:
RunTest(std::vector<std::string> cert_ders,std::vector<std::string> crl_ders,const PkitsTestInfo & orig_info)144   static void RunTest(std::vector<std::string> cert_ders,
145                       std::vector<std::string> crl_ders,
146                       const PkitsTestInfo &orig_info) {
147     PkitsTestInfo info = orig_info;
148 
149     ASSERT_FALSE(cert_ders.empty());
150     ParsedCertificateList certs;
151     for (const std::string &der : cert_ders) {
152       CertErrors errors;
153       ASSERT_TRUE(ParsedCertificate::CreateAndAddToVector(
154           bssl::UniquePtr<CRYPTO_BUFFER>(
155               CRYPTO_BUFFER_new(reinterpret_cast<const uint8_t *>(der.data()),
156                                 der.size(), nullptr)),
157           {}, &certs, &errors))
158           << errors.ToDebugString();
159     }
160     // First entry in the PKITS chain is the trust anchor.
161     // TODO(mattm): test with all possible trust anchors in the trust store?
162     TrustStoreInMemory trust_store;
163 
164     trust_store.AddTrustAnchor(certs[0]);
165 
166     // TODO(mattm): test with other irrelevant certs in cert_issuer_sources?
167     CertIssuerSourceStatic cert_issuer_source;
168     for (size_t i = 1; i < cert_ders.size() - 1; ++i) {
169       cert_issuer_source.AddCert(certs[i]);
170     }
171 
172     std::shared_ptr<const ParsedCertificate> target_cert(certs.back());
173 
174     int64_t verify_time;
175     ASSERT_TRUE(der::GeneralizedTimeToPosixTime(info.time, &verify_time));
176     CrlCheckingPathBuilderDelegate path_builder_delegate(
177         crl_ders, verify_time, /*max_age=*/kOneYear * 2, 1024,
178         SimplePathBuilderDelegate::DigestPolicy::kWeakAllowSha1);
179 
180     std::string_view test_number = info.test_number;
181     if (test_number == "4.4.19" || test_number == "4.5.3" ||
182         test_number == "4.5.4" || test_number == "4.5.6") {
183       // 4.4.19 - fails since CRL is signed by a certificate that is not part
184       //          of the verified chain, which is not supported.
185       // 4.5.3 - fails since non-URI distribution point names are not supported
186       // 4.5.4, 4.5.6 - fails since CRL is signed by a certificate that is not
187       //                part of verified chain, and also non-URI distribution
188       //                point names not supported
189       info.should_validate = false;
190     } else if (test_number == "4.14.1" || test_number == "4.14.4" ||
191                test_number == "4.14.5" || test_number == "4.14.7" ||
192                test_number == "4.14.18" || test_number == "4.14.19" ||
193                test_number == "4.14.22" || test_number == "4.14.24" ||
194                test_number == "4.14.25" || test_number == "4.14.28" ||
195                test_number == "4.14.29" || test_number == "4.14.30" ||
196                test_number == "4.14.33") {
197       // 4.14 tests:
198       // .1 - fails since non-URI distribution point names not supported
199       // .2, .3 - fails since non-URI distribution point names not supported
200       //          (but test is expected to fail for other reason)
201       // .4, .5 - fails since non-URI distribution point names not supported,
202       //          also uses nameRelativeToCRLIssuer which is not supported
203       // .6 - fails since non-URI distribution point names not supported, also
204       //      uses nameRelativeToCRLIssuer which is not supported (but test is
205       //      expected to fail for other reason)
206       // .7 - fails since relative distributionPointName not supported
207       // .8, .9 - fails since relative distributionPointName not supported (but
208       //          test is expected to fail for other reason)
209       // .10, .11, .12, .13, .14, .27, .35 - PASS
210       // .15, .16, .17, .20, .21 - fails since onlySomeReasons is not supported
211       //                           (but test is expected to fail for other
212       //                           reason)
213       // .18, .19 - fails since onlySomeReasons is not supported
214       // .22, .24, .25, .28, .29, .30, .33 - fails since indirect CRLs are not
215       //                                     supported
216       // .23, .26, .31, .32, .34 - fails since indirect CRLs are not supported
217       //                           (but test is expected to fail for other
218       //                           reason)
219       info.should_validate = false;
220     } else if (test_number == "4.15.1" || test_number == "4.15.5") {
221       // 4.15 tests:
222       // .1 - fails due to unhandled critical deltaCRLIndicator extension
223       // .2, .3, .6, .7, .8, .9, .10 - PASS since expected cert status is
224       //                               reflected in base CRL and delta CRL is
225       //                               ignored
226       // .5 - fails, cert status is "on hold" in base CRL but the delta CRL
227       //      which removes the cert from CRL is ignored
228       info.should_validate = false;
229     } else if (test_number == "4.15.4") {
230       // 4.15.4 - Invalid delta-CRL Test4 has the target cert marked revoked in
231       // a delta-CRL. Since delta-CRLs are not supported, the chain validates
232       // successfully.
233       info.should_validate = true;
234     }
235 
236     CertPathBuilder path_builder(
237         std::move(target_cert), &trust_store, &path_builder_delegate, info.time,
238         KeyPurpose::ANY_EKU, info.initial_explicit_policy,
239         info.initial_policy_set, info.initial_policy_mapping_inhibit,
240         info.initial_inhibit_any_policy);
241     path_builder.AddCertIssuerSource(&cert_issuer_source);
242 
243     CertPathBuilder::Result result = path_builder.Run();
244 
245     if (info.should_validate != result.HasValidPath()) {
246       testing::Message msg;
247       for (size_t i = 0; i < result.paths.size(); ++i) {
248         const bssl::CertPathBuilderResultPath *result_path =
249             result.paths[i].get();
250         msg << "path " << i << " errors:\n"
251             << result_path->errors.ToDebugString(result_path->certs) << "\n";
252       }
253       ASSERT_EQ(info.should_validate, result.HasValidPath()) << msg;
254     }
255 
256     if (result.HasValidPath()) {
257       EXPECT_EQ(info.user_constrained_policy_set,
258                 result.GetBestValidPath()->user_constrained_policy_set);
259     }
260   }
261 };
262 
263 }  // namespace
264 
265 INSTANTIATE_TYPED_TEST_SUITE_P(PathBuilder, PkitsTest01SignatureVerification,
266                                PathBuilderPkitsTestDelegate);
267 INSTANTIATE_TYPED_TEST_SUITE_P(PathBuilder, PkitsTest02ValidityPeriods,
268                                PathBuilderPkitsTestDelegate);
269 INSTANTIATE_TYPED_TEST_SUITE_P(PathBuilder, PkitsTest03VerifyingNameChaining,
270                                PathBuilderPkitsTestDelegate);
271 INSTANTIATE_TYPED_TEST_SUITE_P(PathBuilder,
272                                PkitsTest04BasicCertificateRevocationTests,
273                                PathBuilderPkitsTestDelegate);
274 INSTANTIATE_TYPED_TEST_SUITE_P(
275     PathBuilder, PkitsTest05VerifyingPathswithSelfIssuedCertificates,
276     PathBuilderPkitsTestDelegate);
277 INSTANTIATE_TYPED_TEST_SUITE_P(PathBuilder,
278                                PkitsTest06VerifyingBasicConstraints,
279                                PathBuilderPkitsTestDelegate);
280 INSTANTIATE_TYPED_TEST_SUITE_P(PathBuilder, PkitsTest07KeyUsage,
281                                PathBuilderPkitsTestDelegate);
282 INSTANTIATE_TYPED_TEST_SUITE_P(PathBuilder, PkitsTest08CertificatePolicies,
283                                PathBuilderPkitsTestDelegate);
284 INSTANTIATE_TYPED_TEST_SUITE_P(PathBuilder, PkitsTest09RequireExplicitPolicy,
285                                PathBuilderPkitsTestDelegate);
286 INSTANTIATE_TYPED_TEST_SUITE_P(PathBuilder, PkitsTest10PolicyMappings,
287                                PathBuilderPkitsTestDelegate);
288 INSTANTIATE_TYPED_TEST_SUITE_P(PathBuilder, PkitsTest11InhibitPolicyMapping,
289                                PathBuilderPkitsTestDelegate);
290 INSTANTIATE_TYPED_TEST_SUITE_P(PathBuilder, PkitsTest12InhibitAnyPolicy,
291                                PathBuilderPkitsTestDelegate);
292 INSTANTIATE_TYPED_TEST_SUITE_P(PathBuilder, PkitsTest13NameConstraints,
293                                PathBuilderPkitsTestDelegate);
294 INSTANTIATE_TYPED_TEST_SUITE_P(PathBuilder, PkitsTest14DistributionPoints,
295                                PathBuilderPkitsTestDelegate);
296 INSTANTIATE_TYPED_TEST_SUITE_P(PathBuilder, PkitsTest15DeltaCRLs,
297                                PathBuilderPkitsTestDelegate);
298 INSTANTIATE_TYPED_TEST_SUITE_P(PathBuilder,
299                                PkitsTest16PrivateCertificateExtensions,
300                                PathBuilderPkitsTestDelegate);
301 
302 BSSL_NAMESPACE_END
303