gtls.c

          case GNUTLS_X509_CRLREASON_PRIVILEGEWITHDRAWN:
            crl_reason = "privilege withdrawn";
            break;

          case GNUTLS_X509_CRLREASON_AACOMPROMISE:
            crl_reason = "AA compromised";
            break;
        }

        failf(data, "Server certificate was revoked: %s", crl_reason);
        break;
      }

      default:
      case GNUTLS_OCSP_CERT_UNKNOWN:
        failf(data, "Server certificate status is unknown");
        break;
      }

      gnutls_ocsp_resp_deinit(ocsp_resp);

      return CURLE_SSL_INVALIDCERTSTATUS;
    }
    else
      infof(data, "\t server certificate status verification OK\n");
  }
  else
    infof(data, "\t server certificate status verification SKIPPED\n");
#endif

  /* initialize an X.509 certificate structure. */
  gnutls_x509_crt_init(&x509_cert);

  if(chainp)
    /* convert the given DER or PEM encoded Certificate to the native
       gnutls_x509_crt_t format */
    gnutls_x509_crt_import(x509_cert, chainp, GNUTLS_X509_FMT_DER);

  if(data->set.ssl.issuercert) {
    gnutls_x509_crt_init(&x509_issuer);
    issuerp = load_file(data->set.ssl.issuercert);
    gnutls_x509_crt_import(x509_issuer, &issuerp, GNUTLS_X509_FMT_PEM);
    rc = gnutls_x509_crt_check_issuer(x509_cert, x509_issuer);
    gnutls_x509_crt_deinit(x509_issuer);
    unload_file(issuerp);
    if(rc <= 0) {
      failf(data, "server certificate issuer check failed (IssuerCert: %s)",
            data->set.ssl.issuercert?data->set.ssl.issuercert:"none");
      gnutls_x509_crt_deinit(x509_cert);
      return CURLE_SSL_ISSUER_ERROR;
    }
    infof(data, "\t server certificate issuer check OK (Issuer Cert: %s)\n",
          data->set.ssl.issuercert?data->set.ssl.issuercert:"none");
  }

  size=sizeof(certbuf);
  rc = gnutls_x509_crt_get_dn_by_oid(x509_cert, GNUTLS_OID_X520_COMMON_NAME,
                                     0, /* the first and only one */
                                     FALSE,
                                     certbuf,
                                     &size);
  if(rc) {
    infof(data, "error fetching CN from cert:%s\n",
          gnutls_strerror(rc));
  }

  /* This function will check if the given certificate's subject matches the
     given hostname. This is a basic implementation of the matching described
     in RFC2818 (HTTPS), which takes into account wildcards, and the subject
     alternative name PKIX extension. Returns non zero on success, and zero on
     failure. */
  rc = gnutls_x509_crt_check_hostname(x509_cert, conn->host.name);
#if GNUTLS_VERSION_NUMBER < 0x030306
  /* Before 3.3.6, gnutls_x509_crt_check_hostname() didn't check IP
     addresses. */
  if(!rc) {
#ifdef ENABLE_IPV6
    #define use_addr in6_addr
#else
    #define use_addr in_addr
#endif
    unsigned char addrbuf[sizeof(struct use_addr)];
    unsigned char certaddr[sizeof(struct use_addr)];
    size_t addrlen = 0, certaddrlen;
    int i;
    int ret = 0;

    if(Curl_inet_pton(AF_INET, conn->host.name, addrbuf) > 0)
      addrlen = 4;
#ifdef ENABLE_IPV6
    else if(Curl_inet_pton(AF_INET6, conn->host.name, addrbuf) > 0)
      addrlen = 16;
#endif

    if(addrlen) {
      for(i=0; ; i++) {
        certaddrlen = sizeof(certaddr);
        ret = gnutls_x509_crt_get_subject_alt_name(x509_cert, i, certaddr,
                                                   &certaddrlen, NULL);
        /* If this happens, it wasn't an IP address. */
        if(ret == GNUTLS_E_SHORT_MEMORY_BUFFER)
          continue;
        if(ret < 0)
          break;
        if(ret != GNUTLS_SAN_IPADDRESS)
          continue;
        if(certaddrlen == addrlen && !memcmp(addrbuf, certaddr, addrlen)) {
          rc = 1;
          break;
        }
      }
    }
  }
#endif
  if(!rc) {
    if(data->set.ssl.verifyhost) {
      failf(data, "SSL: certificate subject name (%s) does not match "
            "target host name '%s'", certbuf, conn->host.dispname);
      gnutls_x509_crt_deinit(x509_cert);
      return CURLE_PEER_FAILED_VERIFICATION;
    }
    else
      infof(data, "\t common name: %s (does not match '%s')\n",
            certbuf, conn->host.dispname);
  }
  else
    infof(data, "\t common name: %s (matched)\n", certbuf);

  /* Check for time-based validity */
  certclock = gnutls_x509_crt_get_expiration_time(x509_cert);

  if(certclock == (time_t)-1) {
    if(data->set.ssl.verifypeer) {
      failf(data, "server cert expiration date verify failed");
      gnutls_x509_crt_deinit(x509_cert);
      return CURLE_SSL_CONNECT_ERROR;
    }
    else
      infof(data, "\t server certificate expiration date verify FAILED\n");
  }
  else {
    if(certclock < time(NULL)) {
      if(data->set.ssl.verifypeer) {
        failf(data, "server certificate expiration date has passed.");
        gnutls_x509_crt_deinit(x509_cert);
        return CURLE_PEER_FAILED_VERIFICATION;
      }
      else
        infof(data, "\t server certificate expiration date FAILED\n");
    }
    else
      infof(data, "\t server certificate expiration date OK\n");
  }

  certclock = gnutls_x509_crt_get_activation_time(x509_cert);

  if(certclock == (time_t)-1) {
    if(data->set.ssl.verifypeer) {
      failf(data, "server cert activation date verify failed");
      gnutls_x509_crt_deinit(x509_cert);
      return CURLE_SSL_CONNECT_ERROR;
    }
    else
      infof(data, "\t server certificate activation date verify FAILED\n");
  }
  else {
    if(certclock > time(NULL)) {
      if(data->set.ssl.verifypeer) {
        failf(data, "server certificate not activated yet.");
        gnutls_x509_crt_deinit(x509_cert);
        return CURLE_PEER_FAILED_VERIFICATION;
      }
      else
        infof(data, "\t server certificate activation date FAILED\n");
    }
    else
      infof(data, "\t server certificate activation date OK\n");
  }

  ptr = data->set.str[STRING_SSL_PINNEDPUBLICKEY];
  if(ptr) {
    result = pkp_pin_peer_pubkey(data, x509_cert, ptr);
    if(result != CURLE_OK) {
      failf(data, "SSL: public key does not match pinned public key!");
      gnutls_x509_crt_deinit(x509_cert);
      return result;
    }
  }

  /* Show:

  - subject
  - start date
  - expire date
  - common name
  - issuer

  */

  /* public key algorithm's parameters */
  algo = gnutls_x509_crt_get_pk_algorithm(x509_cert, &bits);
  infof(data, "\t certificate public key: %s\n",
        gnutls_pk_algorithm_get_name(algo));

  /* version of the X.509 certificate. */
  infof(data, "\t certificate version: #%d\n",
        gnutls_x509_crt_get_version(x509_cert));


  size = sizeof(certbuf);
  gnutls_x509_crt_get_dn(x509_cert, certbuf, &size);
  infof(data, "\t subject: %s\n", certbuf);

  certclock = gnutls_x509_crt_get_activation_time(x509_cert);
  showtime(data, "start date", certclock);

  certclock = gnutls_x509_crt_get_expiration_time(x509_cert);
  showtime(data, "expire date", certclock);

  size = sizeof(certbuf);
  gnutls_x509_crt_get_issuer_dn(x509_cert, certbuf, &size);
  infof(data, "\t issuer: %s\n", certbuf);

  gnutls_x509_crt_deinit(x509_cert);

  /* compression algorithm (if any) */
  ptr = gnutls_compression_get_name(gnutls_compression_get(session));
  /* the *_get_name() says "NULL" if GNUTLS_COMP_NULL is returned */
  infof(data, "\t compression: %s\n", ptr);

#ifdef HAS_ALPN
  if(data->set.ssl_enable_alpn) {
    rc = gnutls_alpn_get_selected_protocol(session, &proto);
    if(rc == 0) {
      infof(data, "ALPN, server accepted to use %.*s\n", proto.size,
          proto.data);

#ifdef USE_NGHTTP2
      if(proto.size == NGHTTP2_PROTO_VERSION_ID_LEN &&
         !memcmp(NGHTTP2_PROTO_VERSION_ID, proto.data,
                 NGHTTP2_PROTO_VERSION_ID_LEN)) {
        conn->negnpn = CURL_HTTP_VERSION_2_0;
      }
      else
#endif
      if(proto.size == ALPN_HTTP_1_1_LENGTH &&
         !memcmp(ALPN_HTTP_1_1, proto.data, ALPN_HTTP_1_1_LENGTH)) {
        conn->negnpn = CURL_HTTP_VERSION_1_1;
      }
    }
    else
      infof(data, "ALPN, server did not agree to a protocol\n");
  }
#endif

  conn->ssl[sockindex].state = ssl_connection_complete;
  conn->recv[sockindex] = gtls_recv;
  conn->send[sockindex] = gtls_send;

  {
    /* we always unconditionally get the session id here, as even if we
       already got it from the cache and asked to use it in the connection, it
       might've been rejected and then a new one is in use now and we need to
       detect that. */
    void *connect_sessionid;
    size_t connect_idsize = 0;

    /* get the session ID data size */
    gnutls_session_get_data(session, NULL, &connect_idsize);
    connect_sessionid = malloc(connect_idsize); /* get a buffer for it */

    if(connect_sessionid) {
      /* extract session ID to the allocated buffer */
      gnutls_session_get_data(session, connect_sessionid, &connect_idsize);

      incache = !(Curl_ssl_getsessionid(conn, &ssl_sessionid, NULL));
      if(incache) {
        /* there was one before in the cache, so instead of risking that the
           previous one was rejected, we just kill that and store the new */
        Curl_ssl_delsessionid(conn, ssl_sessionid);
      }

      /* store this session id */
      result = Curl_ssl_addsessionid(conn, connect_sessionid, connect_idsize);
      if(result) {
        free(connect_sessionid);
        result = CURLE_OUT_OF_MEMORY;
      }
    }
    else
      result = CURLE_OUT_OF_MEMORY;
  }

  return result;
}


/*
 * This function is called after the TCP connect has completed. Setup the TLS
 * layer and do all necessary magic.
 */
/* We use connssl->connecting_state to keep track of the connection status;
   there are three states: 'ssl_connect_1' (not started yet or complete),
   'ssl_connect_2_reading' (waiting for data from server), and
   'ssl_connect_2_writing' (waiting to be able to write).
 */
static CURLcode
gtls_connect_common(struct connectdata *conn,
                    int sockindex,
                    bool nonblocking,
                    bool *done)
{
  int rc;
  struct ssl_connect_data *connssl = &conn->ssl[sockindex];

  /* Initiate the connection, if not already done */
  if(ssl_connect_1==connssl->connecting_state) {
    rc = gtls_connect_step1 (conn, sockindex);
    if(rc)
      return rc;
  }

  rc = handshake(conn, sockindex, TRUE, nonblocking);
  if(rc)
    /* handshake() sets its own error message with failf() */
    return rc;

  /* Finish connecting once the handshake is done */
  if(ssl_connect_1==connssl->connecting_state) {
    rc = gtls_connect_step3(conn, sockindex);
    if(rc)
      return rc;
  }

  *done = ssl_connect_1==connssl->connecting_state;

  return CURLE_OK;
}

CURLcode
Curl_gtls_connect_nonblocking(struct connectdata *conn,
                              int sockindex,
                              bool *done)
{
  return gtls_connect_common(conn, sockindex, TRUE, done);
}

CURLcode
Curl_gtls_connect(struct connectdata *conn,
                  int sockindex)

{
  CURLcode result;
  bool done = FALSE;

  result = gtls_connect_common(conn, sockindex, FALSE, &done);
  if(result)
    return result;

  DEBUGASSERT(done);

  return CURLE_OK;
}

static ssize_t gtls_send(struct connectdata *conn,
                         int sockindex,
                         const void *mem,
                         size_t len,
                         CURLcode *curlcode)
{
  ssize_t rc = gnutls_record_send(conn->ssl[sockindex].session, mem, len);

  if(rc < 0 ) {
    *curlcode = (rc == GNUTLS_E_AGAIN)
      ? CURLE_AGAIN
      : CURLE_SEND_ERROR;

    rc = -1;
  }

  return rc;
}

static void close_one(struct connectdata *conn,
                      int idx)
{
  if(conn->ssl[idx].session) {
    gnutls_bye(conn->ssl[idx].session, GNUTLS_SHUT_RDWR);
    gnutls_deinit(conn->ssl[idx].session);
    conn->ssl[idx].session = NULL;
  }
  if(conn->ssl[idx].cred) {
    gnutls_certificate_free_credentials(conn->ssl[idx].cred);
    conn->ssl[idx].cred = NULL;
  }
#ifdef USE_TLS_SRP
  if(conn->ssl[idx].srp_client_cred) {
    gnutls_srp_free_client_credentials(conn->ssl[idx].srp_client_cred);
    conn->ssl[idx].srp_client_cred = NULL;
  }
#endif
}

void Curl_gtls_close(struct connectdata *conn, int sockindex)
{
  close_one(conn, sockindex);
}

/*
 * This function is called to shut down the SSL layer but keep the
 * socket open (CCC - Clear Command Channel)
 */
int Curl_gtls_shutdown(struct connectdata *conn, int sockindex)
{
  ssize_t result;
  int retval = 0;
  struct SessionHandle *data = conn->data;
  int done = 0;
  char buf[120];

  /* This has only been tested on the proftpd server, and the mod_tls code
     sends a close notify alert without waiting for a close notify alert in
     response. Thus we wait for a close notify alert from the server, but
     we do not send one. Let's hope other servers do the same... */

  if(data->set.ftp_ccc == CURLFTPSSL_CCC_ACTIVE)
      gnutls_bye(conn->ssl[sockindex].session, GNUTLS_SHUT_WR);

  if(conn->ssl[sockindex].session) {
    while(!done) {
      int what = Curl_socket_ready(conn->sock[sockindex],
                                   CURL_SOCKET_BAD, SSL_SHUTDOWN_TIMEOUT);
      if(what > 0) {
        /* Something to read, let's do it and hope that it is the close
           notify alert from the server */
        result = gnutls_record_recv(conn->ssl[sockindex].session,
                                    buf, sizeof(buf));
        switch(result) {
        case 0:
          /* This is the expected response. There was no data but only
             the close notify alert */
          done = 1;
          break;
        case GNUTLS_E_AGAIN:
        case GNUTLS_E_INTERRUPTED:
          infof(data, "GNUTLS_E_AGAIN || GNUTLS_E_INTERRUPTED\n");
          break;
        default:
          retval = -1;
          done = 1;
          break;
        }
      }
      else if(0 == what) {
        /* timeout */
        failf(data, "SSL shutdown timeout");
        done = 1;
        break;
      }
      else {
        /* anything that gets here is fatally bad */
        failf(data, "select/poll on SSL socket, errno: %d", SOCKERRNO);
        retval = -1;
        done = 1;
      }
    }
    gnutls_deinit(conn->ssl[sockindex].session);
  }
  gnutls_certificate_free_credentials(conn->ssl[sockindex].cred);

#ifdef USE_TLS_SRP
  if(data->set.ssl.authtype == CURL_TLSAUTH_SRP
     && data->set.ssl.username != NULL)
    gnutls_srp_free_client_credentials(conn->ssl[sockindex].srp_client_cred);
#endif

  conn->ssl[sockindex].cred = NULL;
  conn->ssl[sockindex].session = NULL;

  return retval;
}

static ssize_t gtls_recv(struct connectdata *conn, /* connection data */
                         int num,                  /* socketindex */
                         char *buf,                /* store read data here */
                         size_t buffersize,        /* max amount to read */
                         CURLcode *curlcode)
{
  ssize_t ret;

  ret = gnutls_record_recv(conn->ssl[num].session, buf, buffersize);
  if((ret == GNUTLS_E_AGAIN) || (ret == GNUTLS_E_INTERRUPTED)) {
    *curlcode = CURLE_AGAIN;
    return -1;
  }

  if(ret == GNUTLS_E_REHANDSHAKE) {
    /* BLOCKING call, this is bad but a work-around for now. Fixing this "the
       proper way" takes a whole lot of work. */
    CURLcode result = handshake(conn, num, FALSE, FALSE);
    if(result)
      /* handshake() writes error message on its own */
      *curlcode = result;
    else
      *curlcode = CURLE_AGAIN; /* then return as if this was a wouldblock */
    return -1;
  }

  if(ret < 0) {
    failf(conn->data, "GnuTLS recv error (%d): %s",
          (int)ret, gnutls_strerror((int)ret));
    *curlcode = CURLE_RECV_ERROR;
    return -1;
  }

  return ret;
}

void Curl_gtls_session_free(void *ptr)
{
  free(ptr);
}

size_t Curl_gtls_version(char *buffer, size_t size)
{
  return snprintf(buffer, size, "GnuTLS/%s", gnutls_check_version(NULL));
}

#ifndef USE_GNUTLS_NETTLE
static int Curl_gtls_seed(struct SessionHandle *data)
{
  /* we have the "SSL is seeded" boolean static to prevent multiple
     time-consuming seedings in vain */
  static bool ssl_seeded = FALSE;

  /* Quickly add a bit of entropy */
  gcry_fast_random_poll();

  if(!ssl_seeded || data->set.str[STRING_SSL_RANDOM_FILE] ||
     data->set.str[STRING_SSL_EGDSOCKET]) {

    /* TODO: to a good job seeding the RNG
       This may involve the gcry_control function and these options:
       GCRYCTL_SET_RANDOM_SEED_FILE
       GCRYCTL_SET_RNDEGD_SOCKET
    */
    ssl_seeded = TRUE;
  }
  return 0;
}
#endif

/* data might be NULL! */
int Curl_gtls_random(struct SessionHandle *data,
                     unsigned char *entropy,
                     size_t length)
{
#if defined(USE_GNUTLS_NETTLE)
  (void)data;
  gnutls_rnd(GNUTLS_RND_RANDOM, entropy, length);
#elif defined(USE_GNUTLS)
  if(data)
    Curl_gtls_seed(data); /* Initiate the seed if not already done */
  gcry_randomize(entropy, length, GCRY_STRONG_RANDOM);
#endif
  return 0;
}

void Curl_gtls_md5sum(unsigned char *tmp, /* input */
                      size_t tmplen,
                      unsigned char *md5sum, /* output */
                      size_t md5len)
{
#if defined(USE_GNUTLS_NETTLE)
  struct md5_ctx MD5pw;
  md5_init(&MD5pw);
  md5_update(&MD5pw, (unsigned int)tmplen, tmp);
  md5_digest(&MD5pw, (unsigned int)md5len, md5sum);
#elif defined(USE_GNUTLS)
  gcry_md_hd_t MD5pw;
  gcry_md_open(&MD5pw, GCRY_MD_MD5, 0);
  gcry_md_write(MD5pw, tmp, tmplen);
  memcpy(md5sum, gcry_md_read (MD5pw, 0), md5len);
  gcry_md_close(MD5pw);
#endif
}

void Curl_gtls_sha256sum(const unsigned char *tmp, /* input */
                      size_t tmplen,
                      unsigned char *sha256sum, /* output */
                      size_t sha256len)
{
#if defined(USE_GNUTLS_NETTLE)
  struct sha256_ctx SHA256pw;
  sha256_init(&SHA256pw);
  sha256_update(&SHA256pw, (unsigned int)tmplen, tmp);
  sha256_digest(&SHA256pw, (unsigned int)sha256len, sha256sum);
#elif defined(USE_GNUTLS)
  gcry_md_hd_t SHA256pw;
  gcry_md_open(&SHA256pw, GCRY_MD_SHA256, 0);
  gcry_md_write(SHA256pw, tmp, tmplen);
  memcpy(sha256sum, gcry_md_read (SHA256pw, 0), sha256len);
  gcry_md_close(SHA256pw);
#endif
}

bool Curl_gtls_cert_status_request(void)
{
#ifdef HAS_OCSP
  return TRUE;
#else
  return FALSE;
#endif
}

#endif /* USE_GNUTLS */