net/cert/x509_util_openssl.cc

   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/x509_util_openssl.h"
   6
   7 #include <openssl/asn1.h>
   8 #include <openssl/mem.h>
   9
  10 #include <algorithm>
  11
  12 #include "base/lazy_instance.h"
  13 #include "base/logging.h"
  14 #include "base/strings/string_piece.h"
  15 #include "base/strings/string_util.h"
  16 #include "crypto/ec_private_key.h"
  17 #include "crypto/openssl_util.h"
  18 #include "crypto/rsa_private_key.h"
  19 #include "crypto/scoped_openssl_types.h"
  20 #include "net/cert/x509_cert_types.h"
  21 #include "net/cert/x509_util.h"
  22 #include "net/ssl/scoped_openssl_types.h"
  23
  24 namespace net {
  25
  26 namespace {
  27
  28 using ScopedASN1_INTEGER =
  29     crypto::ScopedOpenSSL<ASN1_INTEGER, ASN1_INTEGER_free>;
  30 using ScopedASN1_OCTET_STRING =
  31     crypto::ScopedOpenSSL<ASN1_OCTET_STRING, ASN1_OCTET_STRING_free>;
  32 using ScopedASN1_STRING = crypto::ScopedOpenSSL<ASN1_STRING, ASN1_STRING_free>;
  33 using ScopedASN1_TIME = crypto::ScopedOpenSSL<ASN1_TIME, ASN1_TIME_free>;
  34 using ScopedX509_EXTENSION =
  35     crypto::ScopedOpenSSL<X509_EXTENSION, X509_EXTENSION_free>;
  36 using ScopedX509_NAME = crypto::ScopedOpenSSL<X509_NAME, X509_NAME_free>;
  37
  38 const EVP_MD* ToEVP(x509_util::DigestAlgorithm alg) {
  39   switch (alg) {
  40     case x509_util::DIGEST_SHA1:
  41       return EVP_sha1();
  42     case x509_util::DIGEST_SHA256:
  43       return EVP_sha256();
  44   }
  45   return NULL;
  46 }
  47
  48 }  // namespace
  49
  50 namespace x509_util {
  51
  52 namespace {
  53
  54 X509* CreateCertificate(EVP_PKEY* key,
  55                         DigestAlgorithm alg,
  56                         const std::string& common_name,
  57                         uint32_t serial_number,
  58                         base::Time not_valid_before,
  59                         base::Time not_valid_after) {
  60   // Put the serial number into an OpenSSL-friendly object.
  61   ScopedASN1_INTEGER asn1_serial(ASN1_INTEGER_new());
  62   if (!asn1_serial.get() ||
  63       !ASN1_INTEGER_set(asn1_serial.get(), static_cast<long>(serial_number))) {
  64     LOG(ERROR) << "Invalid serial number " << serial_number;
  65     return NULL;
  66   }
  67
  68   // Do the same for the time stamps.
  69   ScopedASN1_TIME asn1_not_before_time(
  70       ASN1_TIME_set(NULL, not_valid_before.ToTimeT()));
  71   if (!asn1_not_before_time.get()) {
  72     LOG(ERROR) << "Invalid not_valid_before time: "
  73                << not_valid_before.ToTimeT();
  74     return NULL;
  75   }
  76
  77   ScopedASN1_TIME asn1_not_after_time(
  78       ASN1_TIME_set(NULL, not_valid_after.ToTimeT()));
  79   if (!asn1_not_after_time.get()) {
  80     LOG(ERROR) << "Invalid not_valid_after time: " << not_valid_after.ToTimeT();
  81     return NULL;
  82   }
  83
  84   // Because |common_name| only contains a common name and starts with 'CN=',
  85   // there is no need for a full RFC 2253 parser here. Do some sanity checks
  86   // though.
  87   static const char kCommonNamePrefix[] = "CN=";
  88   const size_t kCommonNamePrefixLen = sizeof(kCommonNamePrefix) - 1;
  89   if (common_name.size() < kCommonNamePrefixLen ||
  90       strncmp(common_name.c_str(), kCommonNamePrefix, kCommonNamePrefixLen)) {
  91     LOG(ERROR) << "Common name must begin with " << kCommonNamePrefix;
  92     return NULL;
  93   }
  94   if (common_name.size() > INT_MAX) {
  95     LOG(ERROR) << "Common name too long";
  96     return NULL;
  97   }
  98   unsigned char* common_name_str =
  99       reinterpret_cast<unsigned char*>(const_cast<char*>(common_name.data())) +
 100       kCommonNamePrefixLen;
 101   int common_name_len =
 102       static_cast<int>(common_name.size() - kCommonNamePrefixLen);
 103
 104   ScopedX509_NAME name(X509_NAME_new());
 105   if (!name.get() || !X509_NAME_add_entry_by_NID(name.get(),
 106                                                  NID_commonName,
 107                                                  MBSTRING_ASC,
 108                                                  common_name_str,
 109                                                  common_name_len,
 110                                                  -1,
 111                                                  0)) {
 112     LOG(ERROR) << "Can't parse common name: " << common_name.c_str();
 113     return NULL;
 114   }
 115
 116   // Now create certificate and populate it.
 117   ScopedX509 cert(X509_new());
 118   if (!cert.get() || !X509_set_version(cert.get(), 2L) /* i.e. version 3 */ ||
 119       !X509_set_pubkey(cert.get(), key) ||
 120       !X509_set_serialNumber(cert.get(), asn1_serial.get()) ||
 121       !X509_set_notBefore(cert.get(), asn1_not_before_time.get()) ||
 122       !X509_set_notAfter(cert.get(), asn1_not_after_time.get()) ||
 123       !X509_set_subject_name(cert.get(), name.get()) ||
 124       !X509_set_issuer_name(cert.get(), name.get())) {
 125     LOG(ERROR) << "Could not create certificate";
 126     return NULL;
 127   }
 128
 129   return cert.release();
 130 }
 131
 132 // DER-encodes |x509|. On success, returns true and writes the
 133 // encoding to |*out_der|.
 134 bool DerEncodeCert(X509* x509, std::string* out_der) {
 135   int len = i2d_X509(x509, NULL);
 136   if (len < 0)
 137     return false;
 138
 139   uint8_t* ptr = reinterpret_cast<uint8_t*>(base::WriteInto(out_der, len + 1));
 140   if (i2d_X509(x509, &ptr) < 0) {
 141     NOTREACHED();
 142     out_der->clear();
 143     return false;
 144   }
 145   return true;
 146 }
 147
 148 bool SignAndDerEncodeCert(X509* cert,
 149                           EVP_PKEY* key,
 150                           DigestAlgorithm alg,
 151                           std::string* der_encoded) {
 152   // Get the message digest algorithm
 153   const EVP_MD* md = ToEVP(alg);
 154   if (!md) {
 155     LOG(ERROR) << "Unrecognized hash algorithm.";
 156     return false;
 157   }
 158
 159   // Sign it with the private key.
 160   if (!X509_sign(cert, key, md)) {
 161     LOG(ERROR) << "Could not sign certificate with key.";
 162     return false;
 163   }
 164
 165   // Convert it into a DER-encoded string copied to |der_encoded|.
 166   return DerEncodeCert(cert, der_encoded);
 167 }
 168
 169 struct DERCache {
 170   std::string data;
 171 };
 172
 173 void DERCache_free(void* parent, void* ptr, CRYPTO_EX_DATA* ad, int idx,
 174                    long argl, void* argp) {
 175   DERCache* der_cache = static_cast<DERCache*>(ptr);
 176   delete der_cache;
 177 }
 178
 179 class DERCacheInitSingleton {
 180  public:
 181   DERCacheInitSingleton() {
 182     crypto::EnsureOpenSSLInit();
 183     der_cache_ex_index_ = X509_get_ex_new_index(0, 0, 0, 0, DERCache_free);
 184     DCHECK_NE(-1, der_cache_ex_index_);
 185   }
 186
 187   int der_cache_ex_index() const { return der_cache_ex_index_; }
 188
 189  private:
 190   int der_cache_ex_index_;
 191
 192   DISALLOW_COPY_AND_ASSIGN(DERCacheInitSingleton);
 193 };
 194
 195 base::LazyInstance<DERCacheInitSingleton>::Leaky g_der_cache_singleton =
 196     LAZY_INSTANCE_INITIALIZER;
 197
 198 }  // namespace
 199
 200 bool IsSupportedValidityRange(base::Time not_valid_before,
 201                               base::Time not_valid_after) {
 202   if (not_valid_before > not_valid_after)
 203     return false;
 204
 205   // The validity field of a certificate can only encode years 1-9999.
 206
 207   // Compute the base::Time values corresponding to Jan 1st,0001 and
 208   // Jan 1st, 10000 respectively. Done by using the pre-computed numbers
 209   // of days between these dates and the Unix epoch, i.e. Jan 1st, 1970,
 210   // using the following Python script:
 211   //
 212   //     from datetime import date as D
 213   //     print (D(1970,1,1)-D(1,1,1))        # -> 719162 days
 214   //     print (D(9999,12,31)-D(1970,1,1))   # -> 2932896 days
 215   //
 216   // Note: This ignores leap seconds, but should be enough in practice.
 217   //
 218   const int64_t kDaysFromYear0001ToUnixEpoch = 719162;
 219   const int64_t kDaysFromUnixEpochToYear10000 = 2932896 + 1;
 220   const base::Time kEpoch = base::Time::UnixEpoch();
 221   const base::Time kYear0001 = kEpoch -
 222       base::TimeDelta::FromDays(kDaysFromYear0001ToUnixEpoch);
 223   const base::Time kYear10000 = kEpoch +
 224       base::TimeDelta::FromDays(kDaysFromUnixEpochToYear10000);
 225
 226   if (not_valid_before < kYear0001 || not_valid_before >= kYear10000 ||
 227       not_valid_after < kYear0001 || not_valid_after >= kYear10000)
 228     return false;
 229
 230   return true;
 231 }
 232
 233 bool CreateSelfSignedCert(crypto::RSAPrivateKey* key,
 234                           DigestAlgorithm alg,
 235                           const std::string& common_name,
 236                           uint32_t serial_number,
 237                           base::Time not_valid_before,
 238                           base::Time not_valid_after,
 239                           std::string* der_encoded) {
 240   crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
 241   ScopedX509 cert(CreateCertificate(key->key(),
 242                                     alg,
 243                                     common_name,
 244                                     serial_number,
 245                                     not_valid_before,
 246                                     not_valid_after));
 247   if (!cert.get())
 248     return false;
 249
 250   return SignAndDerEncodeCert(cert.get(), key->key(), alg, der_encoded);
 251 }
 252
 253 bool ParsePrincipalKeyAndValue(X509_NAME_ENTRY* entry,
 254                                std::string* key,
 255                                std::string* value) {
 256   if (key) {
 257     ASN1_OBJECT* object = X509_NAME_ENTRY_get_object(entry);
 258     key->assign(OBJ_nid2sn(OBJ_obj2nid(object)));
 259   }
 260
 261   ASN1_STRING* data = X509_NAME_ENTRY_get_data(entry);
 262   if (!data)
 263     return false;
 264
 265   unsigned char* buf = NULL;
 266   int len = ASN1_STRING_to_UTF8(&buf, data);
 267   if (len <= 0)
 268     return false;
 269
 270   value->assign(reinterpret_cast<const char*>(buf), len);
 271   OPENSSL_free(buf);
 272   return true;
 273 }
 274
 275 bool ParsePrincipalKeyAndValueByIndex(X509_NAME* name,
 276                                       int index,
 277                                       std::string* key,
 278                                       std::string* value) {
 279   X509_NAME_ENTRY* entry = X509_NAME_get_entry(name, index);
 280   if (!entry)
 281     return false;
 282
 283   return ParsePrincipalKeyAndValue(entry, key, value);
 284 }
 285
 286 bool ParsePrincipalValueByIndex(X509_NAME* name,
 287                                 int index,
 288                                 std::string* value) {
 289   return ParsePrincipalKeyAndValueByIndex(name, index, NULL, value);
 290 }
 291
 292 bool ParsePrincipalValueByNID(X509_NAME* name, int nid, std::string* value) {
 293   int index = X509_NAME_get_index_by_NID(name, nid, -1);
 294   if (index < 0)
 295     return false;
 296
 297   return ParsePrincipalValueByIndex(name, index, value);
 298 }
 299
 300 bool ParseDate(ASN1_TIME* x509_time, base::Time* time) {
 301   if (!x509_time ||
 302       (x509_time->type != V_ASN1_UTCTIME &&
 303        x509_time->type != V_ASN1_GENERALIZEDTIME))
 304     return false;
 305
 306   base::StringPiece str_date(reinterpret_cast<const char*>(x509_time->data),
 307                              x509_time->length);
 308
 309   CertDateFormat format = x509_time->type == V_ASN1_UTCTIME ?
 310       CERT_DATE_FORMAT_UTC_TIME : CERT_DATE_FORMAT_GENERALIZED_TIME;
 311   return ParseCertificateDate(str_date, format, time);
 312 }
 313
 314 // Returns true if |der_cache| points to valid data, false otherwise.
 315 // (note: the DER-encoded data in |der_cache| is owned by |cert|, callers should
 316 // not free it).
 317 bool GetDER(X509* x509, base::StringPiece* der_cache) {
 318   int x509_der_cache_index =
 319       g_der_cache_singleton.Get().der_cache_ex_index();
 320
 321   // Re-encoding the DER data via i2d_X509 is an expensive operation,
 322   // but it's necessary for comparing two certificates. Re-encode at
 323   // most once per certificate and cache the data within the X509 cert
 324   // using X509_set_ex_data.
 325   DERCache* internal_cache = static_cast<DERCache*>(
 326       X509_get_ex_data(x509, x509_der_cache_index));
 327   if (!internal_cache) {
 328     scoped_ptr<DERCache> new_cache(new DERCache);
 329     if (!DerEncodeCert(x509, &new_cache->data))
 330       return false;
 331     internal_cache = new_cache.get();
 332     X509_set_ex_data(x509, x509_der_cache_index, new_cache.release());
 333   }
 334   *der_cache = base::StringPiece(internal_cache->data);
 335   return true;
 336 }
 337
 338 }  // namespace x509_util
 339
 340 }  // namespace net