net/socket/nss_ssl_util.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/socket/nss_ssl_util.h"
   6
   7 #include <nss.h>
   8 #include <secerr.h>
   9 #include <ssl.h>
  10 #include <sslerr.h>
  11 #include <sslproto.h>
  12
  13 #include <string>
  14
  15 #include "base/bind.h"
  16 #include "base/cpu.h"
  17 #include "base/lazy_instance.h"
  18 #include "base/logging.h"
  19 #include "base/memory/singleton.h"
  20 #include "base/threading/thread_restrictions.h"
  21 #include "base/values.h"
  22 #include "build/build_config.h"
  23 #include "crypto/nss_util.h"
  24 #include "net/base/net_errors.h"
  25 #include "net/base/net_log.h"
  26 #include "net/base/nss_memio.h"
  27
  28 #if defined(OS_WIN)
  29 #include "base/win/windows_version.h"
  30 #endif
  31
  32 namespace {
  33
  34 // CiphersRemove takes a zero-terminated array of cipher suite ids in
  35 // |to_remove| and sets every instance of them in |ciphers| to zero. It returns
  36 // true if it found and removed every element of |to_remove|. It assumes that
  37 // there are no duplicates in |ciphers| nor in |to_remove|.
  38 bool CiphersRemove(const uint16* to_remove, uint16* ciphers, size_t num) {
  39   size_t i, found = 0;
  40
  41   for (i = 0; ; i++) {
  42     if (to_remove[i] == 0)
  43       break;
  44
  45     for (size_t j = 0; j < num; j++) {
  46       if (to_remove[i] == ciphers[j]) {
  47         ciphers[j] = 0;
  48         found++;
  49         break;
  50       }
  51     }
  52   }
  53
  54   return found == i;
  55 }
  56
  57 // CiphersCompact takes an array of cipher suite ids in |ciphers|, where some
  58 // entries are zero, and moves the entries so that all the non-zero elements
  59 // are compacted at the end of the array.
  60 void CiphersCompact(uint16* ciphers, size_t num) {
  61   size_t j = num - 1;
  62
  63   for (size_t i = num - 1; i < num; i--) {
  64     if (ciphers[i] == 0)
  65       continue;
  66     ciphers[j--] = ciphers[i];
  67   }
  68 }
  69
  70 // CiphersCopy copies the zero-terminated array |in| to |out|. It returns the
  71 // number of cipher suite ids copied.
  72 size_t CiphersCopy(const uint16* in, uint16* out) {
  73   for (size_t i = 0; ; i++) {
  74     if (in[i] == 0)
  75       return i;
  76     out[i] = in[i];
  77   }
  78 }
  79
  80 }  // anonymous namespace
  81
  82 namespace net {
  83
  84 class NSSSSLInitSingleton {
  85  public:
  86   NSSSSLInitSingleton() : model_fd_(NULL) {
  87     crypto::EnsureNSSInit();
  88
  89     NSS_SetDomesticPolicy();
  90
  91     const PRUint16* const ssl_ciphers = SSL_GetImplementedCiphers();
  92     const PRUint16 num_ciphers = SSL_GetNumImplementedCiphers();
  93
  94     // Disable ECDSA cipher suites on platforms that do not support ECDSA
  95     // signed certificates, as servers may use the presence of such
  96     // ciphersuites as a hint to send an ECDSA certificate.
  97     bool disableECDSA = false;
  98 #if defined(OS_WIN)
  99     if (base::win::GetVersion() < base::win::VERSION_VISTA)
 100       disableECDSA = true;
 101 #endif
 102
 103     // Explicitly enable exactly those ciphers with keys of at least 80 bits
 104     for (int i = 0; i < num_ciphers; i++) {
 105       SSLCipherSuiteInfo info;
 106       if (SSL_GetCipherSuiteInfo(ssl_ciphers[i], &info,
 107                                  sizeof(info)) == SECSuccess) {
 108         bool enabled = info.effectiveKeyBits >= 80;
 109         if (info.authAlgorithm == ssl_auth_ecdsa && disableECDSA)
 110           enabled = false;
 111
 112         // Trim the list of cipher suites in order to keep the size of the
 113         // ClientHello down. DSS, ECDH, CAMELLIA, SEED, ECC+3DES, and
 114         // HMAC-SHA256 cipher suites are disabled.
 115         if (info.symCipher == ssl_calg_camellia ||
 116             info.symCipher == ssl_calg_seed ||
 117             (info.symCipher == ssl_calg_3des && info.keaType != ssl_kea_rsa) ||
 118             info.authAlgorithm == ssl_auth_dsa ||
 119             info.macAlgorithm == ssl_hmac_sha256 ||
 120             info.nonStandard ||
 121             strcmp(info.keaTypeName, "ECDH") == 0) {
 122           enabled = false;
 123         }
 124
 125         if (ssl_ciphers[i] == TLS_DHE_DSS_WITH_AES_128_CBC_SHA) {
 126           // Enabled to allow servers with only a DSA certificate to function.
 127           enabled = true;
 128         }
 129         SSL_CipherPrefSetDefault(ssl_ciphers[i], enabled);
 130       }
 131     }
 132
 133     // Enable SSL.
 134     SSL_OptionSetDefault(SSL_SECURITY, PR_TRUE);
 135
 136     // Calculate the order of ciphers that we'll use for NSS sockets. (Note
 137     // that, even if a cipher is specified in the ordering, it must still be
 138     // enabled in order to be included in a ClientHello.)
 139     //
 140     // Our top preference cipher suites are either forward-secret AES-GCM or
 141     // forward-secret ChaCha20-Poly1305. If the local machine has AES-NI then
 142     // we prefer AES-GCM, otherwise ChaCha20. The remainder of the cipher suite
 143     // preference is inheriented from NSS. */
 144     static const uint16 chacha_ciphers[] = {
 145       TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305,
 146       TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305,
 147       0,
 148     };
 149     static const uint16 aes_gcm_ciphers[] = {
 150       TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
 151       TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
 152       TLS_DHE_RSA_WITH_AES_128_GCM_SHA256,
 153       0,
 154     };
 155     scoped_ptr<uint16[]> ciphers(new uint16[num_ciphers]);
 156     memcpy(ciphers.get(), ssl_ciphers, sizeof(uint16)*num_ciphers);
 157
 158     if (CiphersRemove(chacha_ciphers, ciphers.get(), num_ciphers) &&
 159         CiphersRemove(aes_gcm_ciphers, ciphers.get(), num_ciphers)) {
 160       CiphersCompact(ciphers.get(), num_ciphers);
 161
 162       const uint16* preference_ciphers = chacha_ciphers;
 163       const uint16* other_ciphers = aes_gcm_ciphers;
 164       base::CPU cpu;
 165
 166       if (cpu.has_aesni() && cpu.has_avx()) {
 167         preference_ciphers = aes_gcm_ciphers;
 168         other_ciphers = chacha_ciphers;
 169       }
 170       unsigned i = CiphersCopy(preference_ciphers, ciphers.get());
 171       CiphersCopy(other_ciphers, &ciphers[i]);
 172
 173       if ((model_fd_ = memio_CreateIOLayer(1, 1)) == NULL ||
 174           SSL_ImportFD(NULL, model_fd_) == NULL ||
 175           SECSuccess !=
 176               SSL_CipherOrderSet(model_fd_, ciphers.get(), num_ciphers)) {
 177         NOTREACHED();
 178         if (model_fd_) {
 179           PR_Close(model_fd_);
 180           model_fd_ = NULL;
 181         }
 182       }
 183     }
 184
 185     // All other SSL options are set per-session by SSLClientSocket and
 186     // SSLServerSocket.
 187   }
 188
 189   PRFileDesc* GetModelSocket() {
 190     return model_fd_;
 191   }
 192
 193   ~NSSSSLInitSingleton() {
 194     // Have to clear the cache, or NSS_Shutdown fails with SEC_ERROR_BUSY.
 195     SSL_ClearSessionCache();
 196     if (model_fd_)
 197       PR_Close(model_fd_);
 198   }
 199
 200  private:
 201   PRFileDesc* model_fd_;
 202 };
 203
 204 static base::LazyInstance<NSSSSLInitSingleton>::Leaky g_nss_ssl_init_singleton =
 205     LAZY_INSTANCE_INITIALIZER;
 206
 207 // Initialize the NSS SSL library if it isn't already initialized.  This must
 208 // be called before any other NSS SSL functions.  This function is
 209 // thread-safe, and the NSS SSL library will only ever be initialized once.
 210 // The NSS SSL library will be properly shut down on program exit.
 211 void EnsureNSSSSLInit() {
 212   // Initializing SSL causes us to do blocking IO.
 213   // Temporarily allow it until we fix
 214   //   http://code.google.com/p/chromium/issues/detail?id=59847
 215   base::ThreadRestrictions::ScopedAllowIO allow_io;
 216
 217   g_nss_ssl_init_singleton.Get();
 218 }
 219
 220 PRFileDesc* GetNSSModelSocket() {
 221   return g_nss_ssl_init_singleton.Get().GetModelSocket();
 222 }
 223
 224 // Map a Chromium net error code to an NSS error code.
 225 // See _MD_unix_map_default_error in the NSS source
 226 // tree for inspiration.
 227 PRErrorCode MapErrorToNSS(int result) {
 228   if (result >=0)
 229     return result;
 230
 231   switch (result) {
 232     case ERR_IO_PENDING:
 233       return PR_WOULD_BLOCK_ERROR;
 234     case ERR_ACCESS_DENIED:
 235     case ERR_NETWORK_ACCESS_DENIED:
 236       // For connect, this could be mapped to PR_ADDRESS_NOT_SUPPORTED_ERROR.
 237       return PR_NO_ACCESS_RIGHTS_ERROR;
 238     case ERR_NOT_IMPLEMENTED:
 239       return PR_NOT_IMPLEMENTED_ERROR;
 240     case ERR_SOCKET_NOT_CONNECTED:
 241       return PR_NOT_CONNECTED_ERROR;
 242     case ERR_INTERNET_DISCONNECTED:  // Equivalent to ENETDOWN.
 243       return PR_NETWORK_UNREACHABLE_ERROR;  // Best approximation.
 244     case ERR_CONNECTION_TIMED_OUT:
 245     case ERR_TIMED_OUT:
 246       return PR_IO_TIMEOUT_ERROR;
 247     case ERR_CONNECTION_RESET:
 248       return PR_CONNECT_RESET_ERROR;
 249     case ERR_CONNECTION_ABORTED:
 250       return PR_CONNECT_ABORTED_ERROR;
 251     case ERR_CONNECTION_REFUSED:
 252       return PR_CONNECT_REFUSED_ERROR;
 253     case ERR_ADDRESS_UNREACHABLE:
 254       return PR_HOST_UNREACHABLE_ERROR;  // Also PR_NETWORK_UNREACHABLE_ERROR.
 255     case ERR_ADDRESS_INVALID:
 256       return PR_ADDRESS_NOT_AVAILABLE_ERROR;
 257     case ERR_NAME_NOT_RESOLVED:
 258       return PR_DIRECTORY_LOOKUP_ERROR;
 259     default:
 260       LOG(WARNING) << "MapErrorToNSS " << result
 261                    << " mapped to PR_UNKNOWN_ERROR";
 262       return PR_UNKNOWN_ERROR;
 263   }
 264 }
 265
 266 // The default error mapping function.
 267 // Maps an NSS error code to a network error code.
 268 int MapNSSError(PRErrorCode err) {
 269   // TODO(port): fill this out as we learn what's important
 270   switch (err) {
 271     case PR_WOULD_BLOCK_ERROR:
 272       return ERR_IO_PENDING;
 273     case PR_ADDRESS_NOT_SUPPORTED_ERROR:  // For connect.
 274     case PR_NO_ACCESS_RIGHTS_ERROR:
 275       return ERR_ACCESS_DENIED;
 276     case PR_IO_TIMEOUT_ERROR:
 277       return ERR_TIMED_OUT;
 278     case PR_CONNECT_RESET_ERROR:
 279       return ERR_CONNECTION_RESET;
 280     case PR_CONNECT_ABORTED_ERROR:
 281       return ERR_CONNECTION_ABORTED;
 282     case PR_CONNECT_REFUSED_ERROR:
 283       return ERR_CONNECTION_REFUSED;
 284     case PR_NOT_CONNECTED_ERROR:
 285       return ERR_SOCKET_NOT_CONNECTED;
 286     case PR_HOST_UNREACHABLE_ERROR:
 287     case PR_NETWORK_UNREACHABLE_ERROR:
 288       return ERR_ADDRESS_UNREACHABLE;
 289     case PR_ADDRESS_NOT_AVAILABLE_ERROR:
 290       return ERR_ADDRESS_INVALID;
 291     case PR_INVALID_ARGUMENT_ERROR:
 292       return ERR_INVALID_ARGUMENT;
 293     case PR_END_OF_FILE_ERROR:
 294       return ERR_CONNECTION_CLOSED;
 295     case PR_NOT_IMPLEMENTED_ERROR:
 296       return ERR_NOT_IMPLEMENTED;
 297
 298     case SEC_ERROR_LIBRARY_FAILURE:
 299       return ERR_UNEXPECTED;
 300     case SEC_ERROR_INVALID_ARGS:
 301       return ERR_INVALID_ARGUMENT;
 302     case SEC_ERROR_NO_MEMORY:
 303       return ERR_OUT_OF_MEMORY;
 304     case SEC_ERROR_NO_KEY:
 305       return ERR_SSL_CLIENT_AUTH_CERT_NO_PRIVATE_KEY;
 306     case SEC_ERROR_INVALID_KEY:
 307     case SSL_ERROR_SIGN_HASHES_FAILURE:
 308       LOG(ERROR) << "ERR_SSL_CLIENT_AUTH_SIGNATURE_FAILED: NSS error " << err
 309                  << ", OS error " << PR_GetOSError();
 310       return ERR_SSL_CLIENT_AUTH_SIGNATURE_FAILED;
 311     // A handshake (initial or renegotiation) may fail because some signature
 312     // (for example, the signature in the ServerKeyExchange message for an
 313     // ephemeral Diffie-Hellman cipher suite) is invalid.
 314     case SEC_ERROR_BAD_SIGNATURE:
 315       return ERR_SSL_PROTOCOL_ERROR;
 316
 317     case SSL_ERROR_SSL_DISABLED:
 318       return ERR_NO_SSL_VERSIONS_ENABLED;
 319     case SSL_ERROR_NO_CYPHER_OVERLAP:
 320     case SSL_ERROR_PROTOCOL_VERSION_ALERT:
 321     case SSL_ERROR_UNSUPPORTED_VERSION:
 322       return ERR_SSL_VERSION_OR_CIPHER_MISMATCH;
 323     case SSL_ERROR_HANDSHAKE_FAILURE_ALERT:
 324     case SSL_ERROR_HANDSHAKE_UNEXPECTED_ALERT:
 325     case SSL_ERROR_ILLEGAL_PARAMETER_ALERT:
 326       return ERR_SSL_PROTOCOL_ERROR;
 327     case SSL_ERROR_DECOMPRESSION_FAILURE_ALERT:
 328       return ERR_SSL_DECOMPRESSION_FAILURE_ALERT;
 329     case SSL_ERROR_BAD_MAC_ALERT:
 330       return ERR_SSL_BAD_RECORD_MAC_ALERT;
 331     case SSL_ERROR_DECRYPT_ERROR_ALERT:
 332       return ERR_SSL_DECRYPT_ERROR_ALERT;
 333     case SSL_ERROR_UNRECOGNIZED_NAME_ALERT:
 334       return ERR_SSL_UNRECOGNIZED_NAME_ALERT;
 335     case SSL_ERROR_UNSAFE_NEGOTIATION:
 336       return ERR_SSL_UNSAFE_NEGOTIATION;
 337     case SSL_ERROR_WEAK_SERVER_EPHEMERAL_DH_KEY:
 338       return ERR_SSL_WEAK_SERVER_EPHEMERAL_DH_KEY;
 339     case SSL_ERROR_HANDSHAKE_NOT_COMPLETED:
 340       return ERR_SSL_HANDSHAKE_NOT_COMPLETED;
 341     case SEC_ERROR_BAD_KEY:
 342     case SSL_ERROR_EXTRACT_PUBLIC_KEY_FAILURE:
 343     // TODO(wtc): the following errors may also occur in contexts unrelated
 344     // to the peer's public key.  We should add new error codes for them, or
 345     // map them to ERR_SSL_BAD_PEER_PUBLIC_KEY only in the right context.
 346     // General unsupported/unknown key algorithm error.
 347     case SEC_ERROR_UNSUPPORTED_KEYALG:
 348     // General DER decoding errors.
 349     case SEC_ERROR_BAD_DER:
 350     case SEC_ERROR_EXTRA_INPUT:
 351       return ERR_SSL_BAD_PEER_PUBLIC_KEY;
 352     // During renegotiation, the server presented a different certificate than
 353     // was used earlier.
 354     case SSL_ERROR_WRONG_CERTIFICATE:
 355       return ERR_SSL_SERVER_CERT_CHANGED;
 356     case SSL_ERROR_INAPPROPRIATE_FALLBACK_ALERT:
 357       return ERR_SSL_INAPPROPRIATE_FALLBACK;
 358
 359     default: {
 360       const char* err_name = PR_ErrorToName(err);
 361       if (err_name == NULL)
 362         err_name = "";
 363       if (IS_SSL_ERROR(err)) {
 364         LOG(WARNING) << "Unknown SSL error " << err << " (" << err_name << ")"
 365                      << " mapped to net::ERR_SSL_PROTOCOL_ERROR";
 366         return ERR_SSL_PROTOCOL_ERROR;
 367       }
 368       LOG(WARNING) << "Unknown error " << err << " (" << err_name << ")"
 369                    << " mapped to net::ERR_FAILED";
 370       return ERR_FAILED;
 371     }
 372   }
 373 }
 374
 375 // Returns parameters to attach to the NetLog when we receive an error in
 376 // response to a call to an NSS function.  Used instead of
 377 // NetLogSSLErrorCallback with events of type TYPE_SSL_NSS_ERROR.
 378 base::Value* NetLogSSLFailedNSSFunctionCallback(
 379     const char* function,
 380     const char* param,
 381     int ssl_lib_error,
 382     NetLog::LogLevel /* log_level */) {
 383   base::DictionaryValue* dict = new base::DictionaryValue();
 384   dict->SetString("function", function);
 385   if (param[0] != '\0')
 386     dict->SetString("param", param);
 387   dict->SetInteger("ssl_lib_error", ssl_lib_error);
 388   return dict;
 389 }
 390
 391 void LogFailedNSSFunction(const BoundNetLog& net_log,
 392                           const char* function,
 393                           const char* param) {
 394   DCHECK(function);
 395   DCHECK(param);
 396   net_log.AddEvent(
 397       NetLog::TYPE_SSL_NSS_ERROR,
 398       base::Bind(&NetLogSSLFailedNSSFunctionCallback,
 399                  function, param, PR_GetError()));
 400 }
 401
 402 }  // namespace net