1// Copyright (c) 2012 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.
4
5#include "net/cert/cert_verify_proc_openssl.h"
6
7#include <openssl/x509v3.h>
8
9#include <string>
10#include <vector>
11
12#include "base/logging.h"
13#include "base/sha1.h"
14#include "crypto/openssl_util.h"
15#include "crypto/sha2.h"
16#include "net/base/net_errors.h"
17#include "net/cert/asn1_util.h"
18#include "net/cert/cert_status_flags.h"
19#include "net/cert/cert_verifier.h"
20#include "net/cert/cert_verify_result.h"
21#include "net/cert/x509_certificate.h"
22
23namespace net {
24
25namespace {
26
27// Maps X509_STORE_CTX_get_error() return values to our cert status flags.
28CertStatus MapCertErrorToCertStatus(int err) {
29  switch (err) {
30    case X509_V_ERR_SUBJECT_ISSUER_MISMATCH:
31      return CERT_STATUS_COMMON_NAME_INVALID;
32    case X509_V_ERR_CERT_NOT_YET_VALID:
33    case X509_V_ERR_CERT_HAS_EXPIRED:
34    case X509_V_ERR_CRL_NOT_YET_VALID:
35    case X509_V_ERR_CRL_HAS_EXPIRED:
36    case X509_V_ERR_ERROR_IN_CERT_NOT_BEFORE_FIELD:
37    case X509_V_ERR_ERROR_IN_CERT_NOT_AFTER_FIELD:
38    case X509_V_ERR_ERROR_IN_CRL_LAST_UPDATE_FIELD:
39    case X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD:
40      return CERT_STATUS_DATE_INVALID;
41    case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT:
42    case X509_V_ERR_UNABLE_TO_GET_CRL:
43    case X509_V_ERR_INVALID_CA:
44    case X509_V_ERR_UNABLE_TO_GET_CRL_ISSUER:
45    case X509_V_ERR_INVALID_NON_CA:
46    case X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT:
47    case X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN:
48    case X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY:
49      return CERT_STATUS_AUTHORITY_INVALID;
50#if 0
51// TODO(bulach): what should we map to these status?
52      return CERT_STATUS_NO_REVOCATION_MECHANISM;
53      return CERT_STATUS_UNABLE_TO_CHECK_REVOCATION;
54#endif
55    case X509_V_ERR_CERT_REVOKED:
56      return CERT_STATUS_REVOKED;
57    // All these status are mapped to CERT_STATUS_INVALID.
58    case X509_V_ERR_UNABLE_TO_DECRYPT_CERT_SIGNATURE:
59    case X509_V_ERR_UNABLE_TO_DECRYPT_CRL_SIGNATURE:
60    case X509_V_ERR_UNABLE_TO_DECODE_ISSUER_PUBLIC_KEY:
61    case X509_V_ERR_CERT_SIGNATURE_FAILURE:
62    case X509_V_ERR_CRL_SIGNATURE_FAILURE:
63    case X509_V_ERR_OUT_OF_MEM:
64    case X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE:
65    case X509_V_ERR_CERT_CHAIN_TOO_LONG:
66    case X509_V_ERR_PATH_LENGTH_EXCEEDED:
67    case X509_V_ERR_INVALID_PURPOSE:
68    case X509_V_ERR_CERT_UNTRUSTED:
69    case X509_V_ERR_CERT_REJECTED:
70    case X509_V_ERR_AKID_SKID_MISMATCH:
71    case X509_V_ERR_AKID_ISSUER_SERIAL_MISMATCH:
72    case X509_V_ERR_UNHANDLED_CRITICAL_EXTENSION:
73    case X509_V_ERR_KEYUSAGE_NO_CERTSIGN:
74    case X509_V_ERR_KEYUSAGE_NO_CRL_SIGN:
75    case X509_V_ERR_UNHANDLED_CRITICAL_CRL_EXTENSION:
76    case X509_V_ERR_PROXY_PATH_LENGTH_EXCEEDED:
77    case X509_V_ERR_KEYUSAGE_NO_DIGITAL_SIGNATURE:
78    case X509_V_ERR_PROXY_CERTIFICATES_NOT_ALLOWED:
79    case X509_V_ERR_INVALID_EXTENSION:
80    case X509_V_ERR_INVALID_POLICY_EXTENSION:
81    case X509_V_ERR_NO_EXPLICIT_POLICY:
82    case X509_V_ERR_UNNESTED_RESOURCE:
83    case X509_V_ERR_APPLICATION_VERIFICATION:
84      return CERT_STATUS_INVALID;
85    default:
86      NOTREACHED() << "Invalid X509 err " << err;
87      return CERT_STATUS_INVALID;
88  }
89}
90
91// sk_X509_free is a function-style macro, so can't be used as a template
92// param directly.
93void sk_X509_free_fn(STACK_OF(X509)* st) {
94  sk_X509_free(st);
95}
96
97void GetCertChainInfo(X509_STORE_CTX* store_ctx,
98                      CertVerifyResult* verify_result) {
99  STACK_OF(X509)* chain = X509_STORE_CTX_get_chain(store_ctx);
100  X509* verified_cert = NULL;
101  std::vector<X509*> verified_chain;
102  for (int i = 0; i < sk_X509_num(chain); ++i) {
103    X509* cert = sk_X509_value(chain, i);
104    if (i == 0) {
105      verified_cert = cert;
106    } else {
107      verified_chain.push_back(cert);
108    }
109
110    // Only check the algorithm status for certificates that are not in the
111    // trust store.
112    if (i < store_ctx->last_untrusted) {
113      int sig_alg = OBJ_obj2nid(cert->sig_alg->algorithm);
114      if (sig_alg == NID_md2WithRSAEncryption) {
115        verify_result->has_md2 = true;
116      } else if (sig_alg == NID_md4WithRSAEncryption) {
117        verify_result->has_md4 = true;
118      } else if (sig_alg == NID_md5WithRSAEncryption) {
119        verify_result->has_md5 = true;
120      }
121    }
122  }
123
124  if (verified_cert) {
125    verify_result->verified_cert =
126        X509Certificate::CreateFromHandle(verified_cert, verified_chain);
127  }
128}
129
130void AppendPublicKeyHashes(X509_STORE_CTX* store_ctx,
131                           HashValueVector* hashes) {
132  STACK_OF(X509)* chain = X509_STORE_CTX_get_chain(store_ctx);
133  for (int i = 0; i < sk_X509_num(chain); ++i) {
134    X509* cert = sk_X509_value(chain, i);
135
136    std::string der_data;
137    if (!X509Certificate::GetDEREncoded(cert, &der_data))
138      continue;
139
140    base::StringPiece der_bytes(der_data);
141    base::StringPiece spki_bytes;
142    if (!asn1::ExtractSPKIFromDERCert(der_bytes, &spki_bytes))
143      continue;
144
145    HashValue sha1(HASH_VALUE_SHA1);
146    base::SHA1HashBytes(reinterpret_cast<const uint8*>(spki_bytes.data()),
147                        spki_bytes.size(), sha1.data());
148    hashes->push_back(sha1);
149
150    HashValue sha256(HASH_VALUE_SHA256);
151    crypto::SHA256HashString(spki_bytes, sha256.data(), crypto::kSHA256Length);
152    hashes->push_back(sha256);
153  }
154}
155
156}  // namespace
157
158CertVerifyProcOpenSSL::CertVerifyProcOpenSSL() {}
159
160CertVerifyProcOpenSSL::~CertVerifyProcOpenSSL() {}
161
162bool CertVerifyProcOpenSSL::SupportsAdditionalTrustAnchors() const {
163  return false;
164}
165
166int CertVerifyProcOpenSSL::VerifyInternal(
167    X509Certificate* cert,
168    const std::string& hostname,
169    int flags,
170    CRLSet* crl_set,
171    const CertificateList& additional_trust_anchors,
172    CertVerifyResult* verify_result) {
173  crypto::EnsureOpenSSLInit();
174
175  if (!cert->VerifyNameMatch(hostname))
176    verify_result->cert_status |= CERT_STATUS_COMMON_NAME_INVALID;
177
178  crypto::ScopedOpenSSL<X509_STORE_CTX, X509_STORE_CTX_free> ctx(
179      X509_STORE_CTX_new());
180
181  crypto::ScopedOpenSSL<STACK_OF(X509), sk_X509_free_fn> intermediates(
182      sk_X509_new_null());
183  if (!intermediates.get())
184    return ERR_OUT_OF_MEMORY;
185
186  const X509Certificate::OSCertHandles& os_intermediates =
187      cert->GetIntermediateCertificates();
188  for (X509Certificate::OSCertHandles::const_iterator it =
189       os_intermediates.begin(); it != os_intermediates.end(); ++it) {
190    if (!sk_X509_push(intermediates.get(), *it))
191      return ERR_OUT_OF_MEMORY;
192  }
193  if (X509_STORE_CTX_init(ctx.get(), X509Certificate::cert_store(),
194                          cert->os_cert_handle(), intermediates.get()) != 1) {
195    NOTREACHED();
196    return ERR_FAILED;
197  }
198
199  if (X509_verify_cert(ctx.get()) != 1) {
200    int x509_error = X509_STORE_CTX_get_error(ctx.get());
201    CertStatus cert_status = MapCertErrorToCertStatus(x509_error);
202    LOG(ERROR) << "X509 Verification error "
203        << X509_verify_cert_error_string(x509_error)
204        << " : " << x509_error
205        << " : " << X509_STORE_CTX_get_error_depth(ctx.get())
206        << " : " << cert_status;
207    verify_result->cert_status |= cert_status;
208  }
209
210  GetCertChainInfo(ctx.get(), verify_result);
211  AppendPublicKeyHashes(ctx.get(), &verify_result->public_key_hashes);
212  if (IsCertStatusError(verify_result->cert_status))
213    return MapCertStatusToNetError(verify_result->cert_status);
214
215  // Currently we only ues OpenSSL's default root CA paths, so treat all
216  // correctly verified certs as being from a known root.
217  // TODO(joth): if the motivations described in
218  // http://src.chromium.org/viewvc/chrome?view=rev&revision=80778 become an
219  // issue on OpenSSL builds, we will need to embed a hardcoded list of well
220  // known root CAs, as per the _mac and _win versions.
221  verify_result->is_issued_by_known_root = true;
222
223  return OK;
224}
225
226}  // namespace net
227