Initial NSS support for TLS.

This is enough to get a chutney network to bootstrap, though a bunch
of work remains.

src/lib/tls/tortls.c

@@ -4,6 +4,7 @@
 /* See LICENSE for licensing information */
 
 #define TORTLS_PRIVATE
+#define TOR_X509_PRIVATE
 #include "lib/tls/x509.h"
 #include "lib/tls/x509_internal.h"
 #include "lib/tls/tortls.h"
@@ -14,6 +15,8 @@
 #include "lib/crypt_ops/crypto_rsa.h"
 #include "lib/crypt_ops/crypto_rand.h"
 
+#include <time.h>
+
 /** Global TLS contexts. We keep them here because nobody else needs
  * to touch them.
  *
@@ -31,6 +34,26 @@ tor_tls_context_get(int is_server)
   return is_server ? server_tls_context : client_tls_context;
 }
 
+/** Convert an errno (or a WSAerrno on windows) into a TOR_TLS_* error
+ * code. */
+int
+tor_errno_to_tls_error(int e)
+{
+  switch (e) {
+    case SOCK_ERRNO(ECONNRESET): // most common
+      return TOR_TLS_ERROR_CONNRESET;
+    case SOCK_ERRNO(ETIMEDOUT):
+      return TOR_TLS_ERROR_TIMEOUT;
+    case SOCK_ERRNO(EHOSTUNREACH):
+    case SOCK_ERRNO(ENETUNREACH):
+      return TOR_TLS_ERROR_NO_ROUTE;
+    case SOCK_ERRNO(ECONNREFUSED):
+      return TOR_TLS_ERROR_CONNREFUSED; // least common
+    default:
+      return TOR_TLS_ERROR_MISC;
+  }
+}
+
 /** Set *<b>link_cert_out</b> and *<b>id_cert_out</b> to the link certificate
  * and ID certificate that we're currently using for our V3 in-protocol
  * handshake's certificate chain.  If <b>server</b> is true, provide the certs
@@ -334,3 +357,102 @@ tor_tls_is_server(tor_tls_t *tls)
   tor_assert(tls);
   return tls->isServer;
 }
+
+/** Release resources associated with a TLS object.  Does not close the
+ * underlying file descriptor.
+ */
+void
+tor_tls_free_(tor_tls_t *tls)
+{
+  if (!tls)
+    return;
+  tor_assert(tls->ssl);
+  {
+    size_t r,w;
+    tor_tls_get_n_raw_bytes(tls,&r,&w); /* ensure written_by_tls is updated */
+  }
+  tor_tls_impl_free_(tls->ssl);
+  tls->ssl = NULL;
+#ifdef ENABLE_OPENSSL
+  tls->negotiated_callback = NULL;
+#endif
+  if (tls->context)
+    tor_tls_context_decref(tls->context);
+  tor_free(tls->address);
+  tls->magic = 0x99999999;
+  tor_free(tls);
+}
+
+/** If the provided tls connection is authenticated and has a
+ * certificate chain that is currently valid and signed, then set
+ * *<b>identity_key</b> to the identity certificate's key and return
+ * 0.  Else, return -1 and log complaints with log-level <b>severity</b>.
+ */
+int
+tor_tls_verify(int severity, tor_tls_t *tls, crypto_pk_t **identity)
+{
+  tor_x509_cert_impl_t *cert = NULL, *id_cert = NULL;
+  tor_x509_cert_t *peer_x509 = NULL, *id_x509 = NULL;
+  tor_assert(tls);
+  tor_assert(identity);
+  int rv = -1;
+
+  try_to_extract_certs_from_tls(severity, tls, &cert, &id_cert);
+  if (!cert)
+    goto done;
+  if (!id_cert) {
+    log_fn(severity,LD_PROTOCOL,"No distinct identity certificate found");
+    goto done;
+  }
+  peer_x509 = tor_x509_cert_new(cert);
+  id_x509 = tor_x509_cert_new(id_cert);
+  cert = id_cert = NULL; /* Prevent double-free */
+
+  if (! tor_tls_cert_is_valid(severity, peer_x509, id_x509, time(NULL), 0)) {
+    goto done;
+  }
+
+  *identity = tor_tls_cert_get_key(id_x509);
+  rv = 0;
+
+ done:
+  if (cert)
+    tor_x509_cert_impl_free_(cert);
+  if (id_cert)
+    tor_x509_cert_impl_free_(id_cert);
+  tor_x509_cert_free(peer_x509);
+  tor_x509_cert_free(id_x509);
+
+  return rv;
+}
+
+/** Check whether the certificate set on the connection <b>tls</b> is expired
+ * give or take <b>past_tolerance</b> seconds, or not-yet-valid give or take
+ * <b>future_tolerance</b> seconds. Return 0 for valid, -1 for failure.
+ *
+ * NOTE: you should call tor_tls_verify before tor_tls_check_lifetime.
+ */
+int
+tor_tls_check_lifetime(int severity, tor_tls_t *tls,
+                       time_t now,
+                       int past_tolerance, int future_tolerance)
+{
+  tor_x509_cert_t *cert;
+  int r = -1;
+
+  if (!(cert = tor_tls_get_peer_cert(tls)))
+    goto done;
+
+  if (tor_x509_check_cert_lifetime_internal(severity, cert->cert, now,
+                                            past_tolerance,
+                                            future_tolerance) < 0)
+    goto done;
+
+  r = 0;
+ done:
+  tor_x509_cert_free(cert);
+  /* Not expected to get invoked */
+  tls_log_errors(tls, LOG_WARN, LD_NET, "checking certificate lifetime");
+
+  return r;
+}

src/lib/tls/tortls.h

@@ -13,10 +13,25 @@
 
 #include "lib/crypt_ops/crypto_rsa.h"
 #include "lib/testsupport/testsupport.h"
+#include "lib/net/nettypes.h"
 
 /* Opaque structure to hold a TLS connection. */
 typedef struct tor_tls_t tor_tls_t;
 
+#ifdef TORTLS_PRIVATE
+#ifdef ENABLE_OPENSSL
+struct ssl_st;
+struct ssl_ctx_st;
+struct ssl_session_st;
+typedef struct ssl_ctx_st tor_tls_context_impl_t;
+typedef struct ssl_st tor_tls_impl_t;
+#else
+struct PRFileDesc;
+typedef struct PRFileDesc tor_tls_context_impl_t;
+typedef struct PRFileDesc tor_tls_impl_t;
+#endif
+#endif
+
 struct tor_x509_cert_t;
 
 /* Possible return values for most tor_tls_* functions. */
@@ -73,7 +88,7 @@ int tor_tls_context_init(unsigned flags,
 void tor_tls_context_incref(tor_tls_context_t *ctx);
 void tor_tls_context_decref(tor_tls_context_t *ctx);
 tor_tls_context_t *tor_tls_context_get(int is_server);
-tor_tls_t *tor_tls_new(int sock, int is_server);
+tor_tls_t *tor_tls_new(tor_socket_t sock, int is_server);
 void tor_tls_set_logged_address(tor_tls_t *tls, const char *address);
 void tor_tls_set_renegotiate_callback(tor_tls_t *tls,
                                       void (*cb)(tor_tls_t *, void *arg),
@@ -121,13 +136,17 @@ MOCK_DECL(int,tor_tls_export_key_material,(
                      size_t context_len,
                      const char *label));
 
+#ifdef ENABLE_OPENSSL
 /* Log and abort if there are unhandled TLS errors in OpenSSL's error stack.
  */
 #define check_no_tls_errors() check_no_tls_errors_(__FILE__,__LINE__)
-
 void check_no_tls_errors_(const char *fname, int line);
+
 void tor_tls_log_one_error(tor_tls_t *tls, unsigned long err,
                            int severity, int domain, const char *doing);
+#else
+#define check_no_tls_errors() STMT_NIL
+#endif
 
 int tor_tls_get_my_certs(int server,
                          const struct tor_x509_cert_t **link_cert_out,

src/lib/tls/tortls_internal.h

@@ -6,15 +6,11 @@
 #ifndef TORTLS_INTERNAL_H
 #define TORTLS_INTERNAL_H
 
-#ifdef ENABLE_OPENSSL
-struct ssl_st;
-struct ssl_ctx_st;
-struct ssl_session_st;
-#endif
-
 int tor_errno_to_tls_error(int e);
+#ifdef ENABLE_OPENSSL
 int tor_tls_get_error(tor_tls_t *tls, int r, int extra,
                   const char *doing, int severity, int domain);
+#endif
 MOCK_DECL(void, try_to_extract_certs_from_tls,
           (int severity, tor_tls_t *tls,
            tor_x509_cert_impl_t **cert_out,
@@ -31,13 +27,9 @@ int tor_tls_context_init_certificates(tor_tls_context_t *result,
                                       crypto_pk_t *identity,
                                       unsigned key_lifetime,
                                       unsigned flags);
+void tor_tls_impl_free_(tor_tls_impl_t *ssl);
 
-#ifdef ENABLE_OPENSSL
-void tor_tls_context_impl_free(struct ssl_ctx_st *);
-#else
-struct ssl_ctx_st; // XXXX replace
-void tor_tls_context_impl_free(struct ssl_ctx_st *);
-#endif
+void tor_tls_context_impl_free(tor_tls_context_impl_t *);
 
 #ifdef ENABLE_OPENSSL
 tor_tls_t *tor_tls_get_by_ssl(const struct ssl_st *ssl);

src/lib/tls/tortls_nss.c

@@ -12,6 +12,7 @@
 #include "orconfig.h"
 
 #define TORTLS_PRIVATE
+#define TOR_X509_PRIVATE
 
 #ifdef _WIN32 /*wrkard for dtls1.h >= 0.9.8m of "#include <winsock.h>"*/
   #include <winsock2.h>
@@ -22,6 +23,9 @@
 #include "lib/crypt_ops/crypto_rand.h"
 #include "lib/crypt_ops/crypto_dh.h"
 #include "lib/crypt_ops/crypto_util.h"
+#include "lib/crypt_ops/crypto_nss_mgt.h"
+#include "lib/string/printf.h"
+
 #include "lib/tls/x509.h"
 #include "lib/tls/x509_internal.h"
 #include "lib/tls/tortls.h"
@@ -29,26 +33,16 @@
 #include "lib/tls/tortls_internal.h"
 #include "lib/log/util_bug.h"
 
-int
-tor_errno_to_tls_error(int e)
-{
-  (void)e;
-  // XXXX
-  return -1;
-}
-int
-tor_tls_get_error(tor_tls_t *tls, int r, int extra,
-                  const char *doing, int severity, int domain)
-{
-  (void)tls;
-  (void)r;
-  (void)extra;
-  (void)doing;
-  (void)severity;
-  (void)domain;
-  // XXXX
-  return -1;
-}
+#include <prio.h>
+// For access to raw sockets.
+#include <private/pprio.h>
+#include <ssl.h>
+#include <sslt.h>
+#include <sslproto.h>
+#include <certt.h>
+
+static SECStatus always_accept_cert_cb(void *, PRFileDesc *, PRBool, PRBool);
+
 MOCK_IMPL(void,
 try_to_extract_certs_from_tls,(int severity, tor_tls_t *tls,
                                tor_x509_cert_impl_t **cert_out,
@@ -57,14 +51,109 @@ try_to_extract_certs_from_tls,(int severity, tor_tls_t *tls,
   tor_assert(tls);
   tor_assert(cert_out);
   tor_assert(id_cert_out);
-  (void)severity;
-  // XXXX
+  (void) severity;
+
+  *cert_out = *id_cert_out = NULL;
+
+  CERTCertificate *peer = SSL_PeerCertificate(tls->ssl);
+  if (!peer)
+    return;
+  *cert_out = peer; /* Now owns pointer. */
+
+  CERTCertList *chain = SSL_PeerCertificateChain(tls->ssl);
+  CERTCertListNode *c = CERT_LIST_HEAD(chain);
+  for (; !CERT_LIST_END(c, chain); c = CERT_LIST_NEXT(c)) {
+    if (CERT_CompareCerts(c->cert, peer) == PR_FALSE) {
+      *id_cert_out = CERT_DupCertificate(c->cert);
+      break;
+    }
+  }
+  CERT_DestroyCertList(chain);
+}
+
+static bool
+we_like_ssl_cipher(SSLCipherAlgorithm ca)
+{
+  switch (ca) {
+    case ssl_calg_null: return false;
+    case ssl_calg_rc4: return false;
+    case ssl_calg_rc2: return false;
+    case ssl_calg_des: return false;
+    case ssl_calg_3des: return false; /* ???? */
+    case ssl_calg_idea: return false;
+    case ssl_calg_fortezza: return false;
+    case ssl_calg_camellia: return false;
+    case ssl_calg_seed: return false;
+
+    case ssl_calg_aes: return true;
+    case ssl_calg_aes_gcm: return true;
+    case ssl_calg_chacha20: return true;
+    default: return true;
+  }
+}
+static bool
+we_like_ssl_kea(SSLKEAType kt)
+{
+  switch (kt) {
+    case ssl_kea_null: return false;
+    case ssl_kea_rsa: return false; /* ??? */
+    case ssl_kea_fortezza: return false;
+    case ssl_kea_ecdh_psk: return false;
+    case ssl_kea_dh_psk: return false;
+
+    case ssl_kea_dh: return true;
+    case ssl_kea_ecdh: return true;
+    case ssl_kea_tls13_any: return true;
+
+    case ssl_kea_size: return true; /* prevent a warning. */
+    default: return true;
+  }
+}
+
+static bool
+we_like_mac_algorithm(SSLMACAlgorithm ma)
+{
+  switch (ma) {
+    case ssl_mac_null: return false;
+    case ssl_mac_md5: return false;
+    case ssl_hmac_md5: return false;
+
+    case ssl_mac_sha: return true;
+    case ssl_hmac_sha: return true;
+    case ssl_hmac_sha256: return true;
+    case ssl_mac_aead: return true;
+    case ssl_hmac_sha384: return true;
+    default: return true;
+  }
+}
+
+static bool
+we_like_auth_type(SSLAuthType at)
+{
+  switch (at) {
+    case ssl_auth_null: return false;
+    case ssl_auth_rsa_decrypt: return false;
+    case ssl_auth_dsa: return false;
+    case ssl_auth_kea: return false;
+
+    case ssl_auth_ecdsa: return true;
+    case ssl_auth_ecdh_rsa: return true;
+    case ssl_auth_ecdh_ecdsa: return true;
+    case ssl_auth_rsa_sign: return true;
+    case ssl_auth_rsa_pss: return true;
+    case ssl_auth_psk: return true;
+    case ssl_auth_tls13_any: return true;
+
+    case ssl_auth_size: return true; /* prevent a warning. */
+    default: return true;
+  }
 }
 
 tor_tls_context_t *
 tor_tls_context_new(crypto_pk_t *identity,
                     unsigned int key_lifetime, unsigned flags, int is_client)
 {
+  SECStatus s;
   tor_assert(identity);
 
   tor_tls_context_t *ctx = tor_malloc_zero(sizeof(tor_tls_context_t));
@@ -77,7 +166,128 @@ tor_tls_context_new(crypto_pk_t *identity,
     }
   }
 
-  // XXXX write the main body.
+  {
+    /* Create the "model" PRFileDesc that we will use to base others on. */
+    PRFileDesc *tcp = PR_NewTCPSocket();
+    if (!tcp)
+      goto err;
+
+    ctx->ctx = SSL_ImportFD(NULL, tcp);
+    if (!ctx->ctx) {
+      PR_Close(tcp);
+      goto err;
+    }
+  }
+
+  // Configure the certificate.
+  if (!is_client) {
+    s = SSL_ConfigServerCert(ctx->ctx,
+                             ctx->my_link_cert->cert,
+                             (SECKEYPrivateKey *)
+                               crypto_pk_get_nss_privkey(ctx->link_key),
+                             NULL, /* ExtraServerCertData */
+                             0 /* DataLen */);
+    if (s != SECSuccess)
+      goto err;
+  }
+
+  // We need a certificate from the other side.
+  if (is_client) {
+    // XXXX does this do anything?
+    s = SSL_OptionSet(ctx->ctx, SSL_REQUIRE_CERTIFICATE, PR_TRUE);
+    if (s != SECSuccess)
+      goto err;
+  }
+
+  // Always accept other side's cert; we'll check it ourselves in goofy
+  // tor ways.
+  s = SSL_AuthCertificateHook(ctx->ctx, always_accept_cert_cb, NULL);
+
+  // We allow simultaneous read and write.
+  s = SSL_OptionSet(ctx->ctx, SSL_ENABLE_FDX, PR_TRUE);
+  if (s != SECSuccess)
+    goto err;
+  // XXXX SSL_ROLLBACK_DETECTION??
+  // XXXX SSL_ENABLE_ALPN??
+
+  // Force client-mode or server_mode.
+  s = SSL_OptionSet(ctx->ctx,
+                is_client ? SSL_HANDSHAKE_AS_CLIENT : SSL_HANDSHAKE_AS_SERVER,
+                PR_TRUE);
+  if (s != SECSuccess)
+    goto err;
+
+  // Disable everything before TLS 1.0; support everything else.
+  {
+    SSLVersionRange vrange;
+    memset(&vrange, 0, sizeof(vrange));
+    s = SSL_VersionRangeGetSupported(ssl_variant_stream, &vrange);
+    if (s != SECSuccess)
+      goto err;
+    if (vrange.min < SSL_LIBRARY_VERSION_TLS_1_0)
+      vrange.min = SSL_LIBRARY_VERSION_TLS_1_0;
+    s = SSL_VersionRangeSet(ctx->ctx, &vrange);
+    if (s != SECSuccess)
+      goto err;
+  }
+
+  // Only support strong ciphers.
+  {
+    const PRUint16 *ciphers = SSL_GetImplementedCiphers();
+    const PRUint16 n_ciphers = SSL_GetNumImplementedCiphers();
+    PRUint16 i;
+    for (i = 0; i < n_ciphers; ++i) {
+      SSLCipherSuiteInfo info;
+      memset(&info, 0, sizeof(info));
+      s = SSL_GetCipherSuiteInfo(ciphers[i], &info, sizeof(info));
+      if (s != SECSuccess)
+        goto err;
+      if (BUG(info.cipherSuite != ciphers[i]))
+        goto err;
+      int disable = info.effectiveKeyBits < 128 ||
+        info.macBits < 128 ||
+        !we_like_ssl_cipher(info.symCipher) ||
+        !we_like_ssl_kea(info.keaType) ||
+        !we_like_mac_algorithm(info.macAlgorithm) ||
+        !we_like_auth_type(info.authType)/* Requires NSS 3.24 */;
+
+      s = SSL_CipherPrefSet(ctx->ctx, ciphers[i],
+                            disable ? PR_FALSE : PR_TRUE);
+      if (s != SECSuccess)
+        goto err;
+    }
+  }
+
+  // Only use DH and ECDH keys once.
+  s = SSL_OptionSet(ctx->ctx, SSL_REUSE_SERVER_ECDHE_KEY, PR_FALSE);
+  if (s != SECSuccess)
+    goto err;
+
+  // don't cache sessions.
+  s = SSL_OptionSet(ctx->ctx, SSL_NO_CACHE, PR_TRUE);
+  if (s != SECSuccess)
+    goto err;
+
+  // Enable DH.
+  s = SSL_OptionSet(ctx->ctx, SSL_ENABLE_SERVER_DHE, PR_TRUE);
+  if (s != SECSuccess)
+    goto err;
+
+  // Set DH and ECDH groups.
+  SSLNamedGroup groups[] = {
+      ssl_grp_ec_curve25519,
+      ssl_grp_ec_secp256r1,
+      ssl_grp_ec_secp224r1,
+      ssl_grp_ffdhe_2048,
+  };
+  s = SSL_NamedGroupConfig(ctx->ctx, groups, ARRAY_LENGTH(groups));
+  if (s != SECSuccess)
+    goto err;
+
+  // These features are off by default, so we don't need to disable them:
+  //   Session tickets
+  //   Renegotiation
+  //   Compression
 
   goto done;
  err:
@@ -88,11 +298,9 @@ tor_tls_context_new(crypto_pk_t *identity,
 }
 
 void
-tor_tls_context_impl_free(struct ssl_ctx_st *ctx)
+tor_tls_context_impl_free(tor_tls_context_impl_t *ctx)
 {
-  (void)ctx;
-  // XXXX
-  // XXXX openssl type.
+  PR_Close(ctx);
 }
 
 void
@@ -101,33 +309,82 @@ tor_tls_get_state_description(tor_tls_t *tls, char *buf, size_t sz)
   (void)tls;
   (void)buf;
   (void)sz;
-  // XXXX
+  // AFAICT, NSS doesn't expose its internal state.
+  buf[0]=0;
 }
 
 void
 tor_tls_init(void)
 {
-  // XXXX
+  /* We don't have any global setup to do yet, but that will change */
 }
+
 void
 tls_log_errors(tor_tls_t *tls, int severity, int domain,
                const char *doing)
 {
+  /* XXXX This implementation isn't right for NSS -- it logs the last error
+     whether anything actually failed or not. */
+
   (void)tls;
-  (void)severity;
-  (void)domain;
-  (void)doing;
-  // XXXX
+  PRErrorCode code = PORT_GetError();
+
+  const char *string = PORT_ErrorToString(code);
+  const char *name = PORT_ErrorToName(code);
+  char buf[16];
+  if (!string)
+    string = "<unrecognized>";
+  if (!name) {
+    tor_snprintf(buf, sizeof(buf), "%d", code);
+    name = buf;
+  }
+
+  if (doing) {
+    log_fn(severity, domain, "TLS error %s while %s: %s", name, doing, string);
+  } else {
+    log_fn(severity, domain, "TLS error %s: %s", name, string);
+  }
 }
 
 tor_tls_t *
-tor_tls_new(int sock, int is_server)
+tor_tls_new(tor_socket_t sock, int is_server)
 {
   (void)sock;
-  (void)is_server;
-  // XXXX
-  return NULL;
+  tor_tls_context_t *ctx = tor_tls_context_get(is_server);
+
+  PRFileDesc *tcp = PR_ImportTCPSocket(sock);
+  if (!tcp)
+    return NULL;
+
+  PRFileDesc *ssl = SSL_ImportFD(ctx->ctx, tcp);
+  if (!ssl) {
+    PR_Close(tcp);
+    return NULL;
+  }
+
+  tor_tls_t *tls = tor_malloc_zero(sizeof(tor_tls_t));
+  tls->magic = TOR_TLS_MAGIC;
+  tls->context = ctx;
+  tor_tls_context_incref(ctx);
+  tls->ssl = ssl;
+  tls->socket = sock;
+  tls->state = TOR_TLS_ST_HANDSHAKE;
+  tls->isServer = !!is_server;
+
+  if (!is_server) {
+    /* Set a random SNI */
+    char *fake_hostname = crypto_random_hostname(4,25, "www.",".com");
+    SSL_SetURL(tls->ssl, fake_hostname);
+    tor_free(fake_hostname);
+  }
+  SECStatus s = SSL_ResetHandshake(ssl, is_server ? PR_TRUE : PR_FALSE);
+  if (s != SECSuccess) {
+    crypto_nss_log_errors(LOG_WARN, "resetting handshake state");
+  }
+
+  return tls;
 }
+
 void
 tor_tls_set_renegotiate_callback(tor_tls_t *