/* $OpenBSD: tls.c,v 1.82 2018/11/29 14:24:23 tedu Exp $ */
/*
 * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/socket.h>

#include <errno.h>
#include <limits.h>
#include <pthread.h>
#include <stdlib.h>
#include <unistd.h>

#include <openssl/bio.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/pem.h>
#include <openssl/safestack.h>
#include <openssl/ssl.h>
#include <openssl/x509.h>

#include <tls.h>
#include "tls_internal.h"

static struct tls_config *tls_config_default;

static int tls_init_rv = -1;

static void
tls_do_init(void)
{
#ifndef __VMS
   OPENSSL_init_ssl(OPENSSL_INIT_NO_LOAD_CONFIG, NULL);
#else
   SSL_load_error_strings();
   SSL_library_init();
#endif

   if (BIO_sock_init() != 1)
      return;

   if ((tls_config_default = tls_config_new_internal()) == NULL)
      return;

   tls_config_default->refcount++;

   tls_init_rv = 0;
}

int
tls_init(void)
{
#ifndef __VMS
   static pthread_once_t once = PTHREAD_ONCE_INIT;

   if (pthread_once(&once, tls_do_init) != 0)
      return -1;
#else
   tls_do_init();
#endif

   return tls_init_rv;
}

const char *
tls_error(struct tls *ctx)
{
   return ctx->error.msg;
}

void
tls_error_clear(struct tls_error *error)
{
   free(error->msg);
   error->msg = NULL;
   error->num = 0;
   error->tls = 0;
}

static int
tls_error_vset(struct tls_error *error, int errnum, const char *fmt, va_list ap)
{
   char *errmsg = NULL;
   int rv = -1;

   tls_error_clear(error);

   error->num = errnum;
   error->tls = 1;

   if (vasprintf(&errmsg, fmt, ap) == -1) {
      errmsg = NULL;
      goto err;
   }

   if (errnum == -1) {
      error->msg = errmsg;
      return (0);
   }

   if (asprintf(&error->msg, "%s: %s", errmsg, strerror(errnum)) == -1) {
      error->msg = NULL;
      goto err;
   }
   rv = 0;

 err:
   free(errmsg);

   return (rv);
}

int
tls_error_set(struct tls_error *error, const char *fmt, ...)
{
   va_list ap;
   int errnum, rv;

   errnum = errno;

   va_start(ap, fmt);
   rv = tls_error_vset(error, errnum, fmt, ap);
   va_end(ap);

   return (rv);
}

int
tls_error_setx(struct tls_error *error, const char *fmt, ...)
{
   va_list ap;
   int rv;

   va_start(ap, fmt);
   rv = tls_error_vset(error, -1, fmt, ap);
   va_end(ap);

   return (rv);
}

int
tls_config_set_error(struct tls_config *config, const char *fmt, ...)
{
   va_list ap;
   int errnum, rv;

   errnum = errno;

   va_start(ap, fmt);
   rv = tls_error_vset(&config->error, errnum, fmt, ap);
   va_end(ap);

   return (rv);
}

int
tls_config_set_errorx(struct tls_config *config, const char *fmt, ...)
{
   va_list ap;
   int rv;

   va_start(ap, fmt);
   rv = tls_error_vset(&config->error, -1, fmt, ap);
   va_end(ap);

   return (rv);
}

int
tls_set_error(struct tls *ctx, const char *fmt, ...)
{
   va_list ap;
   int errnum, rv;

   errnum = errno;

   va_start(ap, fmt);
   rv = tls_error_vset(&ctx->error, errnum, fmt, ap);
   va_end(ap);

   return (rv);
}

int
tls_set_errorx(struct tls *ctx, const char *fmt, ...)
{
   va_list ap;
   int rv;

   va_start(ap, fmt);
   rv = tls_error_vset(&ctx->error, -1, fmt, ap);
   va_end(ap);

   return (rv);
}

int
tls_set_ssl_errorx(struct tls *ctx, const char *fmt, ...)
{
   va_list ap;
   int rv;

   /* Only set an error if a more specific one does not already exist. */
   if (ctx->error.tls != 0)
      return (0);

   va_start(ap, fmt);
   rv = tls_error_vset(&ctx->error, -1, fmt, ap);
   va_end(ap);

   return (rv);
}

struct tls_sni_ctx *
tls_sni_ctx_new(void)
{
   return (calloc(1, sizeof(struct tls_sni_ctx)));
}

void
tls_sni_ctx_free(struct tls_sni_ctx *sni_ctx)
{
   if (sni_ctx == NULL)
      return;

   SSL_CTX_free(sni_ctx->ssl_ctx);
   X509_free(sni_ctx->ssl_cert);

   free(sni_ctx);
}

struct tls *
tls_new(void)
{
   struct tls *ctx;

   if ((ctx = calloc(1, sizeof(*ctx))) == NULL)
      return (NULL);

   tls_reset(ctx);

   if (tls_configure(ctx, tls_config_default) == -1) {
      free(ctx);
      return NULL;
   }

   return (ctx);
}

int
tls_configure(struct tls *ctx, struct tls_config *config)
{
   if (config == NULL)
      config = tls_config_default;

   config->refcount++;

   tls_config_free(ctx->config);

   ctx->config = config;
   ctx->keypair = config->keypair;

   if ((ctx->flags & TLS_SERVER) != 0)
      return (tls_configure_server(ctx));

   return (0);
}

int
tls_cert_hash(X509 *cert, char **hash)
{
#ifndef __VMS
        char d[EVP_MAX_MD_SIZE], *dhex = NULL;
        int dlen, rv = -1;
#else
        unsigned char d[EVP_MAX_MD_SIZE];
        char *dhex = NULL;
        unsigned int dlen, rv = -1;
#endif

   free(*hash);
   *hash = NULL;

   if (X509_digest(cert, EVP_sha256(), d, &dlen) != 1)
      goto err;

   if (tls_hex_string(d, dlen, &dhex, NULL) != 0)
      goto err;

   if (asprintf(hash, "SHA256:%s", dhex) == -1) {
      *hash = NULL;
      goto err;
   }

   rv = 0;
 err:
   free(dhex);

   return (rv);
}

int
tls_cert_pubkey_hash(X509 *cert, char **hash)
{
   char d[EVP_MAX_MD_SIZE], *dhex = NULL;
   int dlen, rv = -1;

   free(*hash);
   *hash = NULL;

#ifndef __VMS
   if (X509_pubkey_digest(cert, EVP_sha256(), d, &dlen) != 1)
      goto err;

   if (tls_hex_string(d, dlen, &dhex, NULL) != 0)
      goto err;
#else
   if (X509_pubkey_digest(cert, EVP_sha256(),
                          (unsigned char*)d, (unsigned int*)&dlen) != 1)
      goto err;

   if (tls_hex_string((unsigned char*)d, dlen, &dhex, NULL) != 0)
      goto err;
#endif

   if (asprintf(hash, "SHA256:%s", dhex) == -1) {
      *hash = NULL;
      goto err;
   }

   rv = 0;

 err:
   free(dhex);

   return (rv);
}

int
tls_configure_ssl_keypair(struct tls *ctx, SSL_CTX *ssl_ctx,
    struct tls_keypair *keypair, int required)
{
   EVP_PKEY *pkey = NULL;
   BIO *bio = NULL;

   if (!required &&
       keypair->cert_mem == NULL &&
       keypair->key_mem == NULL)
      return(0);

   if (keypair->cert_mem != NULL) {
      if (keypair->cert_len > INT_MAX) {
         tls_set_errorx(ctx, "certificate too long");
         goto err;
      }

#ifndef __VMS
                if (SSL_CTX_use_certificate_chain_mem(ssl_ctx,
                    keypair->cert_mem, keypair->cert_len) != 1) {
                        tls_set_errorx(ctx, "failed to load certificate");
                        goto err;
                }
#else
                tls_set_errorx(ctx, "failed to load certificate");
                goto err;
#endif
   }

   if (keypair->key_mem != NULL) {
      if (keypair->key_len > INT_MAX) {
         tls_set_errorx(ctx, "key too long");
         goto err;
      }

      if ((bio = BIO_new_mem_buf(keypair->key_mem,
          keypair->key_len)) == NULL) {
         tls_set_errorx(ctx, "failed to create buffer");
         goto err;
      }
      if ((pkey = PEM_read_bio_PrivateKey(bio, NULL, tls_password_cb,
          NULL)) == NULL) {
         tls_set_errorx(ctx, "failed to read private key");
         goto err;
      }

      if (keypair->pubkey_hash != NULL) {
         RSA *rsa;
         /* XXX only RSA for now for relayd privsep */
         if ((rsa = EVP_PKEY_get1_RSA(pkey)) != NULL) {
            RSA_set_ex_data(rsa, 0, keypair->pubkey_hash);
            RSA_free(rsa);
         }
      }

      if (SSL_CTX_use_PrivateKey(ssl_ctx, pkey) != 1) {
         tls_set_errorx(ctx, "failed to load private key");
         goto err;
      }
      BIO_free(bio);
      bio = NULL;
      EVP_PKEY_free(pkey);
      pkey = NULL;
   }

   if (!ctx->config->skip_private_key_check &&
       SSL_CTX_check_private_key(ssl_ctx) != 1) {
      tls_set_errorx(ctx, "private/public key mismatch");
      goto err;
   }

   return (0);

 err:
   EVP_PKEY_free(pkey);
   BIO_free(bio);

   return (1);
}

int
tls_configure_ssl(struct tls *ctx, SSL_CTX *ssl_ctx)
{
   SSL_CTX_set_mode(ssl_ctx, SSL_MODE_ENABLE_PARTIAL_WRITE);
   SSL_CTX_set_mode(ssl_ctx, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);

   SSL_CTX_set_options(ssl_ctx, SSL_OP_NO_SSLv2);
   SSL_CTX_set_options(ssl_ctx, SSL_OP_NO_SSLv3);

   SSL_CTX_clear_options(ssl_ctx, SSL_OP_NO_TLSv1);
   SSL_CTX_clear_options(ssl_ctx, SSL_OP_NO_TLSv1_1);
   SSL_CTX_clear_options(ssl_ctx, SSL_OP_NO_TLSv1_2);

   if ((ctx->config->protocols & TLS_PROTOCOL_TLSv1_0) == 0)
      SSL_CTX_set_options(ssl_ctx, SSL_OP_NO_TLSv1);
   if ((ctx->config->protocols & TLS_PROTOCOL_TLSv1_1) == 0)
      SSL_CTX_set_options(ssl_ctx, SSL_OP_NO_TLSv1_1);
   if ((ctx->config->protocols & TLS_PROTOCOL_TLSv1_2) == 0)
      SSL_CTX_set_options(ssl_ctx, SSL_OP_NO_TLSv1_2);

   if (ctx->config->alpn != NULL) {
#ifndef __VMS
                if (SSL_CTX_set_alpn_protos(ssl_ctx, ctx->config->alpn,
#else
                if (SSL_CTX_set_alpn_protos(ssl_ctx, (const unsigned char*)ctx->config->alpn,
#endif
          ctx->config->alpn_len) != 0) {
         tls_set_errorx(ctx, "failed to set alpn");
         goto err;
      }
   }

   if (ctx->config->ciphers != NULL) {
      if (SSL_CTX_set_cipher_list(ssl_ctx,
          ctx->config->ciphers) != 1) {
         tls_set_errorx(ctx, "failed to set ciphers");
         goto err;
      }
   }

#ifndef __VMS
        if (ctx->config->verify_time == 0) {
                X509_VERIFY_PARAM_set_flags(ssl_ctx->param,
                    X509_V_FLAG_NO_CHECK_TIME);
        }
#else
#ifdef X509_V_FLAG_NO_CHECK_TIME
        if (ctx->config->verify_time == 0) {
#if WCME_OPENSSL_SINCE_110
           X509_VERIFY_PARAM_set_flags(SSL_CTX_get0_param(ssl_ctx),
                                       X509_V_FLAG_NO_CHECK_TIME);
#else
           X509_VERIFY_PARAM_set_flags(ssl_ctx->param,
                                       X509_V_FLAG_NO_CHECK_TIME);
#endif
        }
#endif
#endif

   /* Disable any form of session caching by default */
   SSL_CTX_set_session_cache_mode(ssl_ctx, SSL_SESS_CACHE_OFF);
   SSL_CTX_set_options(ssl_ctx, SSL_OP_NO_TICKET);

   return (0);

 err:
   return (-1);
}

static int
tls_ssl_cert_verify_cb(X509_STORE_CTX *x509_ctx, void *arg)
{
   struct tls *ctx = arg;
   int x509_err;

#ifdef __VMS
   return (1);
#endif

   if (ctx->config->verify_cert == 0)
      return (1);

   if ((X509_verify_cert(x509_ctx)) < 0) {
      tls_set_errorx(ctx, "X509 verify cert failed");
      return (0);
   }

   x509_err = X509_STORE_CTX_get_error(x509_ctx);
   if (x509_err == X509_V_OK)
      return (1);

   tls_set_errorx(ctx, "certificate verification failed: %s",
       X509_verify_cert_error_string(x509_err));

   return (0);
}

int
tls_configure_ssl_verify(struct tls *ctx, SSL_CTX *ssl_ctx, int verify)
{
   size_t ca_len = ctx->config->ca_len;
   char *ca_mem = ctx->config->ca_mem;
   char *crl_mem = ctx->config->crl_mem;
   size_t crl_len = ctx->config->crl_len;
   char *ca_free = NULL;
   STACK_OF(X509_INFO) *xis = NULL;
   X509_STORE *store;
   X509_INFO *xi;
   BIO *bio = NULL;
   int rv = -1;
   int i;

   SSL_CTX_set_verify(ssl_ctx, verify, NULL);
   SSL_CTX_set_cert_verify_callback(ssl_ctx, tls_ssl_cert_verify_cb, ctx);

   if (ctx->config->verify_depth >= 0)
      SSL_CTX_set_verify_depth(ssl_ctx, ctx->config->verify_depth);

   if (ctx->config->verify_cert == 0)
      goto done;

#ifndef __VMS
   /* If no CA has been specified, attempt to load the default. */
   if (ctx->config->ca_mem == NULL && ctx->config->ca_path == NULL) {
      if (tls_config_load_file(&ctx->error, "CA", _PATH_SSL_CA_FILE,
                               &ca_mem, &ca_len) != 0)
         goto err;
      ca_free = ca_mem;
   }
   if (ca_mem != NULL) {
      if (ca_len > INT_MAX) {
         tls_set_errorx(ctx, "ca too long");
         goto err;
      }
      if (SSL_CTX_load_verify_mem(ssl_ctx, ca_mem, ca_len) != 1) {
         tls_set_errorx(ctx, "ssl verify memory setup failure");
         goto err;
      }
   } else if (SSL_CTX_load_verify_locations(ssl_ctx, NULL,
                                            ctx->config->ca_path) != 1) {
      tls_set_errorx(ctx, "ssl verify locations failure");
      goto err;
   }
#else
   /* more of a WCME idiom */
   if (tls_config_load_file(&ctx->error, "CA", "WCME_CACERT",
                            &ca_mem, &ca_len) != 0)
   {
#ifdef WCME_DBG_LIBTLS
      doddbg("tls_configure_ssl_verify(%d) %s failed",
             __LINE__, "WCME_CACERT");
#endif
      goto err;
   }
#ifdef WCME_DBG_LIBTLS
   doddbg ("tls_configure_ssl_verify(%d) %s success",
           __LINE__, "WCME_CACERT");
#endif
   ca_free = ca_mem;
#endif

   if (crl_mem != NULL) {
      if (crl_len > INT_MAX) {
         tls_set_errorx(ctx, "crl too long");
         goto err;
      }
      if ((bio = BIO_new_mem_buf(crl_mem, crl_len)) == NULL) {
         tls_set_errorx(ctx, "failed to create buffer");
         goto err;
      }
      if ((xis = PEM_X509_INFO_read_bio(bio, NULL, tls_password_cb,
          NULL)) == NULL) {
         tls_set_errorx(ctx, "failed to parse crl");
         goto err;
      }
      store = SSL_CTX_get_cert_store(ssl_ctx);
      for (i = 0; i < sk_X509_INFO_num(xis); i++) {
         xi = sk_X509_INFO_value(xis, i);
         if (xi->crl == NULL)
            continue;
         if (!X509_STORE_add_crl(store, xi->crl)) {
            tls_set_error(ctx, "failed to add crl");
            goto err;
         }
         xi->crl = NULL;
      }
#if WCME_OPENSSL_SINCE_110
      X509_VERIFY_PARAM_set_flags(SSL_CTX_get0_param(ssl_ctx),
          X509_V_FLAG_CRL_CHECK | X509_V_FLAG_CRL_CHECK_ALL);
#else
      X509_VERIFY_PARAM_set_flags(store->param,
          X509_V_FLAG_CRL_CHECK | X509_V_FLAG_CRL_CHECK_ALL);
#endif
   }

 done:
   rv = 0;

 err:
   sk_X509_INFO_pop_free(xis, X509_INFO_free);
   BIO_free(bio);
   free(ca_free);

   return (rv);
}

void
tls_free(struct tls *ctx)
{
   if (ctx == NULL)
      return;

   tls_reset(ctx);

   free(ctx);
}

void
tls_reset(struct tls *ctx)
{
   struct tls_sni_ctx *sni, *nsni;

   tls_config_free(ctx->config);
   ctx->config = NULL;

   SSL_CTX_free(ctx->ssl_ctx);
   SSL_free(ctx->ssl_conn);
   X509_free(ctx->ssl_peer_cert);

   ctx->ssl_conn = NULL;
   ctx->ssl_ctx = NULL;
   ctx->ssl_peer_cert = NULL;
   /* X509 objects in chain are freed with the SSL */
   ctx->ssl_peer_chain = NULL;

   ctx->socket = -1;
   ctx->state = 0;

   free(ctx->servername);
   ctx->servername = NULL;

   free(ctx->error.msg);
   ctx->error.msg = NULL;
   ctx->error.num = -1;

   tls_conninfo_free(ctx->conninfo);
   ctx->conninfo = NULL;

   tls_ocsp_free(ctx->ocsp);
   ctx->ocsp = NULL;

   for (sni = ctx->sni_ctx; sni != NULL; sni = nsni) {
      nsni = sni->next;
      tls_sni_ctx_free(sni);
   }
   ctx->sni_ctx = NULL;

   ctx->read_cb = NULL;
   ctx->write_cb = NULL;
   ctx->cb_arg = NULL;
}

int
tls_ssl_error(struct tls *ctx, SSL *ssl_conn, int ssl_ret, const char *prefix)
{
   const char *errstr = "unknown error";
   unsigned long err;
   int ssl_err;

   ssl_err = SSL_get_error(ssl_conn, ssl_ret);
   switch (ssl_err) {
   case SSL_ERROR_NONE:
   case SSL_ERROR_ZERO_RETURN:
      return (0);

   case SSL_ERROR_WANT_READ:
      return (TLS_WANT_POLLIN);

   case SSL_ERROR_WANT_WRITE:
      return (TLS_WANT_POLLOUT);

   case SSL_ERROR_SYSCALL:
      if ((err = ERR_peek_error()) != 0) {
         errstr = ERR_error_string(err, NULL);
      } else if (ssl_ret == 0) {
         if ((ctx->state & TLS_HANDSHAKE_COMPLETE) != 0) {
            ctx->state |= TLS_EOF_NO_CLOSE_NOTIFY;
            return (0);
         }
         errstr = "unexpected EOF";
      } else if (ssl_ret == -1) {
         errstr = strerror(errno);
      }
      tls_set_ssl_errorx(ctx, "%s failed: %s", prefix, errstr);
      return (-1);

   case SSL_ERROR_SSL:
      if ((err = ERR_peek_error()) != 0) {
         errstr = ERR_error_string(err, NULL);
      }
      tls_set_ssl_errorx(ctx, "%s failed: %s", prefix, errstr);
      return (-1);

   case SSL_ERROR_WANT_CONNECT:
   case SSL_ERROR_WANT_ACCEPT:
   case SSL_ERROR_WANT_X509_LOOKUP:
   default:
      tls_set_ssl_errorx(ctx, "%s failed (%i)", prefix, ssl_err);
      return (-1);
   }
}

int
tls_handshake(struct tls *ctx)
{
   int rv = -1;

   tls_error_clear(&ctx->error);

   if ((ctx->flags & (TLS_CLIENT | TLS_SERVER_CONN)) == 0) {
      tls_set_errorx(ctx, "invalid operation for context");
      goto out;
   }

   if ((ctx->state & TLS_HANDSHAKE_COMPLETE) != 0) {
      tls_set_errorx(ctx, "handshake already completed");
      goto out;
   }

   if ((ctx->flags & TLS_CLIENT) != 0)
      rv = tls_handshake_client(ctx);
   else if ((ctx->flags & TLS_SERVER_CONN) != 0)
      rv = tls_handshake_server(ctx);

   if (rv == 0) {
      ctx->ssl_peer_cert = SSL_get_peer_certificate(ctx->ssl_conn);
      ctx->ssl_peer_chain = SSL_get_peer_cert_chain(ctx->ssl_conn);
      if (tls_conninfo_populate(ctx) == -1)
         rv = -1;
      if (ctx->ocsp == NULL)
         ctx->ocsp = tls_ocsp_setup_from_peer(ctx);
   }
 out:
   /* Prevent callers from performing incorrect error handling */
   errno = 0;
   return (rv);
}

ssize_t
tls_read(struct tls *ctx, void *buf, size_t buflen)
{
   ssize_t rv = -1;
   int ssl_ret;

   tls_error_clear(&ctx->error);

   if ((ctx->state & TLS_HANDSHAKE_COMPLETE) == 0) {
      if ((rv = tls_handshake(ctx)) != 0)
         goto out;
   }

   if (buflen > INT_MAX) {
      tls_set_errorx(ctx, "buflen too long");
      goto out;
   }

   ERR_clear_error();
   if ((ssl_ret = SSL_read(ctx->ssl_conn, buf, buflen)) > 0) {
      rv = (ssize_t)ssl_ret;
      goto out;
   }
   rv = (ssize_t)tls_ssl_error(ctx, ctx->ssl_conn, ssl_ret, "read");

 out:
   /* Prevent callers from performing incorrect error handling */
   errno = 0;
   return (rv);
}

ssize_t
tls_write(struct tls *ctx, const void *buf, size_t buflen)
{
   ssize_t rv = -1;
   int ssl_ret;

#ifdef WCME_DBG_LIBTLS
        doddbg ("(tls:%d) tls_write() %d |%s|", __LINE__, buflen, buf);
#endif

   tls_error_clear(&ctx->error);

   if ((ctx->state & TLS_HANDSHAKE_COMPLETE) == 0) {
      if ((rv = tls_handshake(ctx)) != 0)
         goto out;
   }

#ifdef WCME_DBG_LIBTLS
        doddbg ("(tls:%d) tls_write() %d", __LINE__, buflen);
#endif

   if (buflen > INT_MAX) {
      tls_set_errorx(ctx, "buflen too long");
      goto out;
   }

#ifdef WCME_DBG_LIBTLS
        doddbg ("(tls:%d) tls_write() %d", __LINE__, buflen);
#endif

   ERR_clear_error();
   if ((ssl_ret = SSL_write(ctx->ssl_conn, buf, buflen)) > 0) {
      rv = (ssize_t)ssl_ret;
      goto out;
   }
#ifdef WCME_DBG_LIBTLS
        doddbg ("(tls:%d) tls_write() %d", __LINE__, buflen);
#endif
   rv = (ssize_t)tls_ssl_error(ctx, ctx->ssl_conn, ssl_ret, "write");
#ifdef WCME_DBG_LIBTLS
        doddbg ("(tls:%d) tls_write() %d", __LINE__, buflen);
#endif

 out:
#ifdef WCME_DBG_LIBTLS
        doddbg ("(tls:%d) tls_write() %d", __LINE__, buflen);
#endif
   /* Prevent callers from performing incorrect error handling */
   errno = 0;
   return (rv);
}

int
tls_close(struct tls *ctx)
{
   int ssl_ret;
   int rv = 0;

   tls_error_clear(&ctx->error);

   if ((ctx->flags & (TLS_CLIENT | TLS_SERVER_CONN)) == 0) {
      tls_set_errorx(ctx, "invalid operation for context");
      rv = -1;
      goto out;
   }

   if (ctx->state & TLS_SSL_NEEDS_SHUTDOWN) {
      ERR_clear_error();
      ssl_ret = SSL_shutdown(ctx->ssl_conn);
      if (ssl_ret < 0) {
         rv = tls_ssl_error(ctx, ctx->ssl_conn, ssl_ret,
             "shutdown");
         if (rv == TLS_WANT_POLLIN || rv == TLS_WANT_POLLOUT)
            goto out;
      }
      ctx->state &= ~TLS_SSL_NEEDS_SHUTDOWN;
   }

   if (ctx->socket != -1) {
      if (shutdown(ctx->socket, SHUT_RDWR) != 0) {
         if (rv == 0 &&
             errno != ENOTCONN && errno != ECONNRESET) {
            tls_set_error(ctx, "shutdown");
            rv = -1;
         }
      }
      if (close(ctx->socket) != 0) {
         if (rv == 0) {
            tls_set_error(ctx, "close");
            rv = -1;
         }
      }
      ctx->socket = -1;
   }

   if ((ctx->state & TLS_EOF_NO_CLOSE_NOTIFY) != 0) {
      tls_set_errorx(ctx, "EOF without close notify");
      rv = -1;
   }

 out:
   /* Prevent callers from performing incorrect error handling */
   errno = 0;
   return (rv);
}