--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/curl/lib/vtls/sectransp.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,3277 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 2012 - 2017, Nick Zitzmann, <nickzman@gmail.com>.
+ * Copyright (C) 2012 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+
+/*
+ * Source file for all iOS and macOS SecureTransport-specific code for the
+ * TLS/SSL layer. No code but vtls.c should ever call or use these functions.
+ */
+
+#include "curl_setup.h"
+
+#include "urldata.h" /* for the Curl_easy definition */
+#include "curl_base64.h"
+#include "strtok.h"
+#include "multiif.h"
+
+#ifdef USE_SECTRANSP
+
+#ifdef __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wtautological-pointer-compare"
+#endif /* __clang__ */
+
+#include <limits.h>
+
+#include <Security/Security.h>
+/* For some reason, when building for iOS, the omnibus header above does
+ * not include SecureTransport.h as of iOS SDK 5.1. */
+#include <Security/SecureTransport.h>
+#include <CoreFoundation/CoreFoundation.h>
+#include <CommonCrypto/CommonDigest.h>
+
+/* The Security framework has changed greatly between iOS and different macOS
+   versions, and we will try to support as many of them as we can (back to
+   Leopard and iOS 5) by using macros and weak-linking.
+
+   In general, you want to build this using the most recent OS SDK, since some
+   features require curl to be built against the latest SDK. TLS 1.1 and 1.2
+   support, for instance, require the macOS 10.8 SDK or later. TLS 1.3
+   requires the macOS 10.13 or iOS 11 SDK or later. */
+#if (TARGET_OS_MAC && !(TARGET_OS_EMBEDDED || TARGET_OS_IPHONE))
+
+#if MAC_OS_X_VERSION_MAX_ALLOWED < 1050
+#error "The Secure Transport back-end requires Leopard or later."
+#endif /* MAC_OS_X_VERSION_MAX_ALLOWED < 1050 */
+
+#define CURL_BUILD_IOS 0
+#define CURL_BUILD_IOS_7 0
+#define CURL_BUILD_IOS_9 0
+#define CURL_BUILD_IOS_11 0
+#define CURL_BUILD_MAC 1
+/* This is the maximum API level we are allowed to use when building: */
+#define CURL_BUILD_MAC_10_5 MAC_OS_X_VERSION_MAX_ALLOWED >= 1050
+#define CURL_BUILD_MAC_10_6 MAC_OS_X_VERSION_MAX_ALLOWED >= 1060
+#define CURL_BUILD_MAC_10_7 MAC_OS_X_VERSION_MAX_ALLOWED >= 1070
+#define CURL_BUILD_MAC_10_8 MAC_OS_X_VERSION_MAX_ALLOWED >= 1080
+#define CURL_BUILD_MAC_10_9 MAC_OS_X_VERSION_MAX_ALLOWED >= 1090
+#define CURL_BUILD_MAC_10_11 MAC_OS_X_VERSION_MAX_ALLOWED >= 101100
+#define CURL_BUILD_MAC_10_13 MAC_OS_X_VERSION_MAX_ALLOWED >= 101300
+/* These macros mean "the following code is present to allow runtime backward
+   compatibility with at least this cat or earlier":
+   (You set this at build-time using the compiler command line option
+   "-mmacos-version-min.") */
+#define CURL_SUPPORT_MAC_10_5 MAC_OS_X_VERSION_MIN_REQUIRED <= 1050
+#define CURL_SUPPORT_MAC_10_6 MAC_OS_X_VERSION_MIN_REQUIRED <= 1060
+#define CURL_SUPPORT_MAC_10_7 MAC_OS_X_VERSION_MIN_REQUIRED <= 1070
+#define CURL_SUPPORT_MAC_10_8 MAC_OS_X_VERSION_MIN_REQUIRED <= 1080
+#define CURL_SUPPORT_MAC_10_9 MAC_OS_X_VERSION_MIN_REQUIRED <= 1090
+
+#elif TARGET_OS_EMBEDDED || TARGET_OS_IPHONE
+#define CURL_BUILD_IOS 1
+#define CURL_BUILD_IOS_7 __IPHONE_OS_VERSION_MAX_ALLOWED >= 70000
+#define CURL_BUILD_IOS_9 __IPHONE_OS_VERSION_MAX_ALLOWED >= 90000
+#define CURL_BUILD_IOS_11 __IPHONE_OS_VERSION_MAX_ALLOWED >= 110000
+#define CURL_BUILD_MAC 0
+#define CURL_BUILD_MAC_10_5 0
+#define CURL_BUILD_MAC_10_6 0
+#define CURL_BUILD_MAC_10_7 0
+#define CURL_BUILD_MAC_10_8 0
+#define CURL_BUILD_MAC_10_9 0
+#define CURL_BUILD_MAC_10_11 0
+#define CURL_BUILD_MAC_10_13 0
+#define CURL_SUPPORT_MAC_10_5 0
+#define CURL_SUPPORT_MAC_10_6 0
+#define CURL_SUPPORT_MAC_10_7 0
+#define CURL_SUPPORT_MAC_10_8 0
+#define CURL_SUPPORT_MAC_10_9 0
+
+#else
+#error "The Secure Transport back-end requires iOS or macOS."
+#endif /* (TARGET_OS_MAC && !(TARGET_OS_EMBEDDED || TARGET_OS_IPHONE)) */
+
+#if CURL_BUILD_MAC
+#include <sys/sysctl.h>
+#endif /* CURL_BUILD_MAC */
+
+#include "urldata.h"
+#include "sendf.h"
+#include "inet_pton.h"
+#include "connect.h"
+#include "select.h"
+#include "vtls.h"
+#include "sectransp.h"
+#include "curl_printf.h"
+#include "strdup.h"
+
+#include "curl_memory.h"
+/* The last #include file should be: */
+#include "memdebug.h"
+
+/* From MacTypes.h (which we can't include because it isn't present in iOS: */
+#define ioErr -36
+#define paramErr -50
+
+struct ssl_backend_data {
+  SSLContextRef ssl_ctx;
+  curl_socket_t ssl_sockfd;
+  bool ssl_direction; /* true if writing, false if reading */
+  size_t ssl_write_buffered_length;
+};
+
+#define BACKEND connssl->backend
+
+/* pinned public key support tests */
+
+/* version 1 supports macOS 10.12+ and iOS 10+ */
+#if ((TARGET_OS_IPHONE && __IPHONE_OS_VERSION_MIN_REQUIRED >= 100000) || \
+    (!TARGET_OS_IPHONE && __MAC_OS_X_VERSION_MIN_REQUIRED  >= 101200))
+#define SECTRANSP_PINNEDPUBKEY_V1 1
+#endif
+
+/* version 2 supports MacOSX 10.7+ */
+#if (!TARGET_OS_IPHONE && __MAC_OS_X_VERSION_MIN_REQUIRED >= 1070)
+#define SECTRANSP_PINNEDPUBKEY_V2 1
+#endif
+
+#if defined(SECTRANSP_PINNEDPUBKEY_V1) || defined(SECTRANSP_PINNEDPUBKEY_V2)
+/* this backend supports CURLOPT_PINNEDPUBLICKEY */
+#define SECTRANSP_PINNEDPUBKEY 1
+#endif /* SECTRANSP_PINNEDPUBKEY */
+
+#ifdef SECTRANSP_PINNEDPUBKEY
+/* both new and old APIs return rsa keys missing the spki header (not DER) */
+static const unsigned char rsa4096SpkiHeader[] = {
+                                       0x30, 0x82, 0x02, 0x22, 0x30, 0x0d,
+                                       0x06, 0x09, 0x2a, 0x86, 0x48, 0x86,
+                                       0xf7, 0x0d, 0x01, 0x01, 0x01, 0x05,
+                                       0x00, 0x03, 0x82, 0x02, 0x0f, 0x00};
+
+static const unsigned char rsa2048SpkiHeader[] = {
+                                       0x30, 0x82, 0x01, 0x22, 0x30, 0x0d,
+                                       0x06, 0x09, 0x2a, 0x86, 0x48, 0x86,
+                                       0xf7, 0x0d, 0x01, 0x01, 0x01, 0x05,
+                                       0x00, 0x03, 0x82, 0x01, 0x0f, 0x00};
+#ifdef SECTRANSP_PINNEDPUBKEY_V1
+/* the *new* version doesn't return DER encoded ecdsa certs like the old... */
+static const unsigned char ecDsaSecp256r1SpkiHeader[] = {
+                                       0x30, 0x59, 0x30, 0x13, 0x06, 0x07,
+                                       0x2a, 0x86, 0x48, 0xce, 0x3d, 0x02,
+                                       0x01, 0x06, 0x08, 0x2a, 0x86, 0x48,
+                                       0xce, 0x3d, 0x03, 0x01, 0x07, 0x03,
+                                       0x42, 0x00};
+
+static const unsigned char ecDsaSecp384r1SpkiHeader[] = {
+                                       0x30, 0x76, 0x30, 0x10, 0x06, 0x07,
+                                       0x2a, 0x86, 0x48, 0xce, 0x3d, 0x02,
+                                       0x01, 0x06, 0x05, 0x2b, 0x81, 0x04,
+                                       0x00, 0x22, 0x03, 0x62, 0x00};
+#endif /* SECTRANSP_PINNEDPUBKEY_V1 */
+#endif /* SECTRANSP_PINNEDPUBKEY */
+
+/* The following two functions were ripped from Apple sample code,
+ * with some modifications: */
+static OSStatus SocketRead(SSLConnectionRef connection,
+                           void *data,          /* owned by
+                                                 * caller, data
+                                                 * RETURNED */
+                           size_t *dataLength)  /* IN/OUT */
+{
+  size_t bytesToGo = *dataLength;
+  size_t initLen = bytesToGo;
+  UInt8 *currData = (UInt8 *)data;
+  /*int sock = *(int *)connection;*/
+  struct ssl_connect_data *connssl = (struct ssl_connect_data *)connection;
+  int sock = BACKEND->ssl_sockfd;
+  OSStatus rtn = noErr;
+  size_t bytesRead;
+  ssize_t rrtn;
+  int theErr;
+
+  *dataLength = 0;
+
+  for(;;) {
+    bytesRead = 0;
+    rrtn = read(sock, currData, bytesToGo);
+    if(rrtn <= 0) {
+      /* this is guesswork... */
+      theErr = errno;
+      if(rrtn == 0) { /* EOF = server hung up */
+        /* the framework will turn this into errSSLClosedNoNotify */
+        rtn = errSSLClosedGraceful;
+      }
+      else /* do the switch */
+        switch(theErr) {
+          case ENOENT:
+            /* connection closed */
+            rtn = errSSLClosedGraceful;
+            break;
+          case ECONNRESET:
+            rtn = errSSLClosedAbort;
+            break;
+          case EAGAIN:
+            rtn = errSSLWouldBlock;
+            BACKEND->ssl_direction = false;
+            break;
+          default:
+            rtn = ioErr;
+            break;
+        }
+      break;
+    }
+    else {
+      bytesRead = rrtn;
+    }
+    bytesToGo -= bytesRead;
+    currData  += bytesRead;
+
+    if(bytesToGo == 0) {
+      /* filled buffer with incoming data, done */
+      break;
+    }
+  }
+  *dataLength = initLen - bytesToGo;
+
+  return rtn;
+}
+
+static OSStatus SocketWrite(SSLConnectionRef connection,
+                            const void *data,
+                            size_t *dataLength)  /* IN/OUT */
+{
+  size_t bytesSent = 0;
+  /*int sock = *(int *)connection;*/
+  struct ssl_connect_data *connssl = (struct ssl_connect_data *)connection;
+  int sock = BACKEND->ssl_sockfd;
+  ssize_t length;
+  size_t dataLen = *dataLength;
+  const UInt8 *dataPtr = (UInt8 *)data;
+  OSStatus ortn;
+  int theErr;
+
+  *dataLength = 0;
+
+  do {
+    length = write(sock,
+                   (char *)dataPtr + bytesSent,
+                   dataLen - bytesSent);
+  } while((length > 0) &&
+           ( (bytesSent += length) < dataLen) );
+
+  if(length <= 0) {
+    theErr = errno;
+    if(theErr == EAGAIN) {
+      ortn = errSSLWouldBlock;
+      BACKEND->ssl_direction = true;
+    }
+    else {
+      ortn = ioErr;
+    }
+  }
+  else {
+    ortn = noErr;
+  }
+  *dataLength = bytesSent;
+  return ortn;
+}
+
+#ifndef CURL_DISABLE_VERBOSE_STRINGS
+CF_INLINE const char *SSLCipherNameForNumber(SSLCipherSuite cipher)
+{
+  switch(cipher) {
+    /* SSL version 3.0 */
+    case SSL_RSA_WITH_NULL_MD5:
+      return "SSL_RSA_WITH_NULL_MD5";
+      break;
+    case SSL_RSA_WITH_NULL_SHA:
+      return "SSL_RSA_WITH_NULL_SHA";
+      break;
+    case SSL_RSA_EXPORT_WITH_RC4_40_MD5:
+      return "SSL_RSA_EXPORT_WITH_RC4_40_MD5";
+      break;
+    case SSL_RSA_WITH_RC4_128_MD5:
+      return "SSL_RSA_WITH_RC4_128_MD5";
+      break;
+    case SSL_RSA_WITH_RC4_128_SHA:
+      return "SSL_RSA_WITH_RC4_128_SHA";
+      break;
+    case SSL_RSA_EXPORT_WITH_RC2_CBC_40_MD5:
+      return "SSL_RSA_EXPORT_WITH_RC2_CBC_40_MD5";
+      break;
+    case SSL_RSA_WITH_IDEA_CBC_SHA:
+      return "SSL_RSA_WITH_IDEA_CBC_SHA";
+      break;
+    case SSL_RSA_EXPORT_WITH_DES40_CBC_SHA:
+      return "SSL_RSA_EXPORT_WITH_DES40_CBC_SHA";
+      break;
+    case SSL_RSA_WITH_DES_CBC_SHA:
+      return "SSL_RSA_WITH_DES_CBC_SHA";
+      break;
+    case SSL_RSA_WITH_3DES_EDE_CBC_SHA:
+      return "SSL_RSA_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case SSL_DH_DSS_EXPORT_WITH_DES40_CBC_SHA:
+      return "SSL_DH_DSS_EXPORT_WITH_DES40_CBC_SHA";
+      break;
+    case SSL_DH_DSS_WITH_DES_CBC_SHA:
+      return "SSL_DH_DSS_WITH_DES_CBC_SHA";
+      break;
+    case SSL_DH_DSS_WITH_3DES_EDE_CBC_SHA:
+      return "SSL_DH_DSS_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case SSL_DH_RSA_EXPORT_WITH_DES40_CBC_SHA:
+      return "SSL_DH_RSA_EXPORT_WITH_DES40_CBC_SHA";
+      break;
+    case SSL_DH_RSA_WITH_DES_CBC_SHA:
+      return "SSL_DH_RSA_WITH_DES_CBC_SHA";
+      break;
+    case SSL_DH_RSA_WITH_3DES_EDE_CBC_SHA:
+      return "SSL_DH_RSA_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case SSL_DHE_DSS_EXPORT_WITH_DES40_CBC_SHA:
+      return "SSL_DHE_DSS_EXPORT_WITH_DES40_CBC_SHA";
+      break;
+    case SSL_DHE_DSS_WITH_DES_CBC_SHA:
+      return "SSL_DHE_DSS_WITH_DES_CBC_SHA";
+      break;
+    case SSL_DHE_DSS_WITH_3DES_EDE_CBC_SHA:
+      return "SSL_DHE_DSS_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case SSL_DHE_RSA_EXPORT_WITH_DES40_CBC_SHA:
+      return "SSL_DHE_RSA_EXPORT_WITH_DES40_CBC_SHA";
+      break;
+    case SSL_DHE_RSA_WITH_DES_CBC_SHA:
+      return "SSL_DHE_RSA_WITH_DES_CBC_SHA";
+      break;
+    case SSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA:
+      return "SSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case SSL_DH_anon_EXPORT_WITH_RC4_40_MD5:
+      return "SSL_DH_anon_EXPORT_WITH_RC4_40_MD5";
+      break;
+    case SSL_DH_anon_WITH_RC4_128_MD5:
+      return "SSL_DH_anon_WITH_RC4_128_MD5";
+      break;
+    case SSL_DH_anon_EXPORT_WITH_DES40_CBC_SHA:
+      return "SSL_DH_anon_EXPORT_WITH_DES40_CBC_SHA";
+      break;
+    case SSL_DH_anon_WITH_DES_CBC_SHA:
+      return "SSL_DH_anon_WITH_DES_CBC_SHA";
+      break;
+    case SSL_DH_anon_WITH_3DES_EDE_CBC_SHA:
+      return "SSL_DH_anon_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case SSL_FORTEZZA_DMS_WITH_NULL_SHA:
+      return "SSL_FORTEZZA_DMS_WITH_NULL_SHA";
+      break;
+    case SSL_FORTEZZA_DMS_WITH_FORTEZZA_CBC_SHA:
+      return "SSL_FORTEZZA_DMS_WITH_FORTEZZA_CBC_SHA";
+      break;
+    /* TLS 1.0 with AES (RFC 3268)
+       (Apparently these are used in SSLv3 implementations as well.) */
+    case TLS_RSA_WITH_AES_128_CBC_SHA:
+      return "TLS_RSA_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_DH_DSS_WITH_AES_128_CBC_SHA:
+      return "TLS_DH_DSS_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_DH_RSA_WITH_AES_128_CBC_SHA:
+      return "TLS_DH_RSA_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_DHE_DSS_WITH_AES_128_CBC_SHA:
+      return "TLS_DHE_DSS_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_DHE_RSA_WITH_AES_128_CBC_SHA:
+      return "TLS_DHE_RSA_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_DH_anon_WITH_AES_128_CBC_SHA:
+      return "TLS_DH_anon_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_RSA_WITH_AES_256_CBC_SHA:
+      return "TLS_RSA_WITH_AES_256_CBC_SHA";
+      break;
+    case TLS_DH_DSS_WITH_AES_256_CBC_SHA:
+      return "TLS_DH_DSS_WITH_AES_256_CBC_SHA";
+      break;
+    case TLS_DH_RSA_WITH_AES_256_CBC_SHA:
+      return "TLS_DH_RSA_WITH_AES_256_CBC_SHA";
+      break;
+    case TLS_DHE_DSS_WITH_AES_256_CBC_SHA:
+      return "TLS_DHE_DSS_WITH_AES_256_CBC_SHA";
+      break;
+    case TLS_DHE_RSA_WITH_AES_256_CBC_SHA:
+      return "TLS_DHE_RSA_WITH_AES_256_CBC_SHA";
+      break;
+    case TLS_DH_anon_WITH_AES_256_CBC_SHA:
+      return "TLS_DH_anon_WITH_AES_256_CBC_SHA";
+      break;
+    /* SSL version 2.0 */
+    case SSL_RSA_WITH_RC2_CBC_MD5:
+      return "SSL_RSA_WITH_RC2_CBC_MD5";
+      break;
+    case SSL_RSA_WITH_IDEA_CBC_MD5:
+      return "SSL_RSA_WITH_IDEA_CBC_MD5";
+      break;
+    case SSL_RSA_WITH_DES_CBC_MD5:
+      return "SSL_RSA_WITH_DES_CBC_MD5";
+      break;
+    case SSL_RSA_WITH_3DES_EDE_CBC_MD5:
+      return "SSL_RSA_WITH_3DES_EDE_CBC_MD5";
+      break;
+  }
+  return "SSL_NULL_WITH_NULL_NULL";
+}
+
+CF_INLINE const char *TLSCipherNameForNumber(SSLCipherSuite cipher)
+{
+  switch(cipher) {
+    /* TLS 1.0 with AES (RFC 3268) */
+    case TLS_RSA_WITH_AES_128_CBC_SHA:
+      return "TLS_RSA_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_DH_DSS_WITH_AES_128_CBC_SHA:
+      return "TLS_DH_DSS_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_DH_RSA_WITH_AES_128_CBC_SHA:
+      return "TLS_DH_RSA_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_DHE_DSS_WITH_AES_128_CBC_SHA:
+      return "TLS_DHE_DSS_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_DHE_RSA_WITH_AES_128_CBC_SHA:
+      return "TLS_DHE_RSA_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_DH_anon_WITH_AES_128_CBC_SHA:
+      return "TLS_DH_anon_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_RSA_WITH_AES_256_CBC_SHA:
+      return "TLS_RSA_WITH_AES_256_CBC_SHA";
+      break;
+    case TLS_DH_DSS_WITH_AES_256_CBC_SHA:
+      return "TLS_DH_DSS_WITH_AES_256_CBC_SHA";
+      break;
+    case TLS_DH_RSA_WITH_AES_256_CBC_SHA:
+      return "TLS_DH_RSA_WITH_AES_256_CBC_SHA";
+      break;
+    case TLS_DHE_DSS_WITH_AES_256_CBC_SHA:
+      return "TLS_DHE_DSS_WITH_AES_256_CBC_SHA";
+      break;
+    case TLS_DHE_RSA_WITH_AES_256_CBC_SHA:
+      return "TLS_DHE_RSA_WITH_AES_256_CBC_SHA";
+      break;
+    case TLS_DH_anon_WITH_AES_256_CBC_SHA:
+      return "TLS_DH_anon_WITH_AES_256_CBC_SHA";
+      break;
+#if CURL_BUILD_MAC_10_6 || CURL_BUILD_IOS
+    /* TLS 1.0 with ECDSA (RFC 4492) */
+    case TLS_ECDH_ECDSA_WITH_NULL_SHA:
+      return "TLS_ECDH_ECDSA_WITH_NULL_SHA";
+      break;
+    case TLS_ECDH_ECDSA_WITH_RC4_128_SHA:
+      return "TLS_ECDH_ECDSA_WITH_RC4_128_SHA";
+      break;
+    case TLS_ECDH_ECDSA_WITH_3DES_EDE_CBC_SHA:
+      return "TLS_ECDH_ECDSA_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA:
+      return "TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA:
+      return "TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA";
+      break;
+    case TLS_ECDHE_ECDSA_WITH_NULL_SHA:
+      return "TLS_ECDHE_ECDSA_WITH_NULL_SHA";
+      break;
+    case TLS_ECDHE_ECDSA_WITH_RC4_128_SHA:
+      return "TLS_ECDHE_ECDSA_WITH_RC4_128_SHA";
+      break;
+    case TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA:
+      return "TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA:
+      return "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA:
+      return "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA";
+      break;
+    case TLS_ECDH_RSA_WITH_NULL_SHA:
+      return "TLS_ECDH_RSA_WITH_NULL_SHA";
+      break;
+    case TLS_ECDH_RSA_WITH_RC4_128_SHA:
+      return "TLS_ECDH_RSA_WITH_RC4_128_SHA";
+      break;
+    case TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA:
+      return "TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case TLS_ECDH_RSA_WITH_AES_128_CBC_SHA:
+      return "TLS_ECDH_RSA_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_ECDH_RSA_WITH_AES_256_CBC_SHA:
+      return "TLS_ECDH_RSA_WITH_AES_256_CBC_SHA";
+      break;
+    case TLS_ECDHE_RSA_WITH_NULL_SHA:
+      return "TLS_ECDHE_RSA_WITH_NULL_SHA";
+      break;
+    case TLS_ECDHE_RSA_WITH_RC4_128_SHA:
+      return "TLS_ECDHE_RSA_WITH_RC4_128_SHA";
+      break;
+    case TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA:
+      return "TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA:
+      return "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA:
+      return "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA";
+      break;
+    case TLS_ECDH_anon_WITH_NULL_SHA:
+      return "TLS_ECDH_anon_WITH_NULL_SHA";
+      break;
+    case TLS_ECDH_anon_WITH_RC4_128_SHA:
+      return "TLS_ECDH_anon_WITH_RC4_128_SHA";
+      break;
+    case TLS_ECDH_anon_WITH_3DES_EDE_CBC_SHA:
+      return "TLS_ECDH_anon_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case TLS_ECDH_anon_WITH_AES_128_CBC_SHA:
+      return "TLS_ECDH_anon_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_ECDH_anon_WITH_AES_256_CBC_SHA:
+      return "TLS_ECDH_anon_WITH_AES_256_CBC_SHA";
+      break;
+#endif /* CURL_BUILD_MAC_10_6 || CURL_BUILD_IOS */
+#if CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS
+    /* TLS 1.2 (RFC 5246) */
+    case TLS_RSA_WITH_NULL_MD5:
+      return "TLS_RSA_WITH_NULL_MD5";
+      break;
+    case TLS_RSA_WITH_NULL_SHA:
+      return "TLS_RSA_WITH_NULL_SHA";
+      break;
+    case TLS_RSA_WITH_RC4_128_MD5:
+      return "TLS_RSA_WITH_RC4_128_MD5";
+      break;
+    case TLS_RSA_WITH_RC4_128_SHA:
+      return "TLS_RSA_WITH_RC4_128_SHA";
+      break;
+    case TLS_RSA_WITH_3DES_EDE_CBC_SHA:
+      return "TLS_RSA_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case TLS_RSA_WITH_NULL_SHA256:
+      return "TLS_RSA_WITH_NULL_SHA256";
+      break;
+    case TLS_RSA_WITH_AES_128_CBC_SHA256:
+      return "TLS_RSA_WITH_AES_128_CBC_SHA256";
+      break;
+    case TLS_RSA_WITH_AES_256_CBC_SHA256:
+      return "TLS_RSA_WITH_AES_256_CBC_SHA256";
+      break;
+    case TLS_DH_DSS_WITH_3DES_EDE_CBC_SHA:
+      return "TLS_DH_DSS_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case TLS_DH_RSA_WITH_3DES_EDE_CBC_SHA:
+      return "TLS_DH_RSA_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA:
+      return "TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA:
+      return "TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case TLS_DH_DSS_WITH_AES_128_CBC_SHA256:
+      return "TLS_DH_DSS_WITH_AES_128_CBC_SHA256";
+      break;
+    case TLS_DH_RSA_WITH_AES_128_CBC_SHA256:
+      return "TLS_DH_RSA_WITH_AES_128_CBC_SHA256";
+      break;
+    case TLS_DHE_DSS_WITH_AES_128_CBC_SHA256:
+      return "TLS_DHE_DSS_WITH_AES_128_CBC_SHA256";
+      break;
+    case TLS_DHE_RSA_WITH_AES_128_CBC_SHA256:
+      return "TLS_DHE_RSA_WITH_AES_128_CBC_SHA256";
+      break;
+    case TLS_DH_DSS_WITH_AES_256_CBC_SHA256:
+      return "TLS_DH_DSS_WITH_AES_256_CBC_SHA256";
+      break;
+    case TLS_DH_RSA_WITH_AES_256_CBC_SHA256:
+      return "TLS_DH_RSA_WITH_AES_256_CBC_SHA256";
+      break;
+    case TLS_DHE_DSS_WITH_AES_256_CBC_SHA256:
+      return "TLS_DHE_DSS_WITH_AES_256_CBC_SHA256";
+      break;
+    case TLS_DHE_RSA_WITH_AES_256_CBC_SHA256:
+      return "TLS_DHE_RSA_WITH_AES_256_CBC_SHA256";
+      break;
+    case TLS_DH_anon_WITH_RC4_128_MD5:
+      return "TLS_DH_anon_WITH_RC4_128_MD5";
+      break;
+    case TLS_DH_anon_WITH_3DES_EDE_CBC_SHA:
+      return "TLS_DH_anon_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case TLS_DH_anon_WITH_AES_128_CBC_SHA256:
+      return "TLS_DH_anon_WITH_AES_128_CBC_SHA256";
+      break;
+    case TLS_DH_anon_WITH_AES_256_CBC_SHA256:
+      return "TLS_DH_anon_WITH_AES_256_CBC_SHA256";
+      break;
+    /* TLS 1.2 with AES GCM (RFC 5288) */
+    case TLS_RSA_WITH_AES_128_GCM_SHA256:
+      return "TLS_RSA_WITH_AES_128_GCM_SHA256";
+      break;
+    case TLS_RSA_WITH_AES_256_GCM_SHA384:
+      return "TLS_RSA_WITH_AES_256_GCM_SHA384";
+      break;
+    case TLS_DHE_RSA_WITH_AES_128_GCM_SHA256:
+      return "TLS_DHE_RSA_WITH_AES_128_GCM_SHA256";
+      break;
+    case TLS_DHE_RSA_WITH_AES_256_GCM_SHA384:
+      return "TLS_DHE_RSA_WITH_AES_256_GCM_SHA384";
+      break;
+    case TLS_DH_RSA_WITH_AES_128_GCM_SHA256:
+      return "TLS_DH_RSA_WITH_AES_128_GCM_SHA256";
+      break;
+    case TLS_DH_RSA_WITH_AES_256_GCM_SHA384:
+      return "TLS_DH_RSA_WITH_AES_256_GCM_SHA384";
+      break;
+    case TLS_DHE_DSS_WITH_AES_128_GCM_SHA256:
+      return "TLS_DHE_DSS_WITH_AES_128_GCM_SHA256";
+      break;
+    case TLS_DHE_DSS_WITH_AES_256_GCM_SHA384:
+      return "TLS_DHE_DSS_WITH_AES_256_GCM_SHA384";
+      break;
+    case TLS_DH_DSS_WITH_AES_128_GCM_SHA256:
+      return "TLS_DH_DSS_WITH_AES_128_GCM_SHA256";
+      break;
+    case TLS_DH_DSS_WITH_AES_256_GCM_SHA384:
+      return "TLS_DH_DSS_WITH_AES_256_GCM_SHA384";
+      break;
+    case TLS_DH_anon_WITH_AES_128_GCM_SHA256:
+      return "TLS_DH_anon_WITH_AES_128_GCM_SHA256";
+      break;
+    case TLS_DH_anon_WITH_AES_256_GCM_SHA384:
+      return "TLS_DH_anon_WITH_AES_256_GCM_SHA384";
+      break;
+    /* TLS 1.2 with elliptic curve ciphers (RFC 5289) */
+    case TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256:
+      return "TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256";
+      break;
+    case TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384:
+      return "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384";
+      break;
+    case TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA256:
+      return "TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA256";
+      break;
+    case TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA384:
+      return "TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA384";
+      break;
+    case TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256:
+      return "TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256";
+      break;
+    case TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384:
+      return "TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384";
+      break;
+    case TLS_ECDH_RSA_WITH_AES_128_CBC_SHA256:
+      return "TLS_ECDH_RSA_WITH_AES_128_CBC_SHA256";
+      break;
+    case TLS_ECDH_RSA_WITH_AES_256_CBC_SHA384:
+      return "TLS_ECDH_RSA_WITH_AES_256_CBC_SHA384";
+      break;
+    case TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256:
+      return "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256";
+      break;
+    case TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384:
+      return "TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384";
+      break;
+    case TLS_ECDH_ECDSA_WITH_AES_128_GCM_SHA256:
+      return "TLS_ECDH_ECDSA_WITH_AES_128_GCM_SHA256";
+      break;
+    case TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384:
+      return "TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384";
+      break;
+    case TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256:
+      return "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256";
+      break;
+    case TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384:
+      return "TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384";
+      break;
+    case TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256:
+      return "TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256";
+      break;
+    case TLS_ECDH_RSA_WITH_AES_256_GCM_SHA384:
+      return "TLS_ECDH_RSA_WITH_AES_256_GCM_SHA384";
+      break;
+    case TLS_EMPTY_RENEGOTIATION_INFO_SCSV:
+      return "TLS_EMPTY_RENEGOTIATION_INFO_SCSV";
+      break;
+#else
+    case SSL_RSA_WITH_NULL_MD5:
+      return "TLS_RSA_WITH_NULL_MD5";
+      break;
+    case SSL_RSA_WITH_NULL_SHA:
+      return "TLS_RSA_WITH_NULL_SHA";
+      break;
+    case SSL_RSA_WITH_RC4_128_MD5:
+      return "TLS_RSA_WITH_RC4_128_MD5";
+      break;
+    case SSL_RSA_WITH_RC4_128_SHA:
+      return "TLS_RSA_WITH_RC4_128_SHA";
+      break;
+    case SSL_RSA_WITH_3DES_EDE_CBC_SHA:
+      return "TLS_RSA_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case SSL_DH_anon_WITH_RC4_128_MD5:
+      return "TLS_DH_anon_WITH_RC4_128_MD5";
+      break;
+    case SSL_DH_anon_WITH_3DES_EDE_CBC_SHA:
+      return "TLS_DH_anon_WITH_3DES_EDE_CBC_SHA";
+      break;
+#endif /* CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS */
+#if CURL_BUILD_MAC_10_9 || CURL_BUILD_IOS_7
+    /* TLS PSK (RFC 4279): */
+    case TLS_PSK_WITH_RC4_128_SHA:
+      return "TLS_PSK_WITH_RC4_128_SHA";
+      break;
+    case TLS_PSK_WITH_3DES_EDE_CBC_SHA:
+      return "TLS_PSK_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case TLS_PSK_WITH_AES_128_CBC_SHA:
+      return "TLS_PSK_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_PSK_WITH_AES_256_CBC_SHA:
+      return "TLS_PSK_WITH_AES_256_CBC_SHA";
+      break;
+    case TLS_DHE_PSK_WITH_RC4_128_SHA:
+      return "TLS_DHE_PSK_WITH_RC4_128_SHA";
+      break;
+    case TLS_DHE_PSK_WITH_3DES_EDE_CBC_SHA:
+      return "TLS_DHE_PSK_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case TLS_DHE_PSK_WITH_AES_128_CBC_SHA:
+      return "TLS_DHE_PSK_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_DHE_PSK_WITH_AES_256_CBC_SHA:
+      return "TLS_DHE_PSK_WITH_AES_256_CBC_SHA";
+      break;
+    case TLS_RSA_PSK_WITH_RC4_128_SHA:
+      return "TLS_RSA_PSK_WITH_RC4_128_SHA";
+      break;
+    case TLS_RSA_PSK_WITH_3DES_EDE_CBC_SHA:
+      return "TLS_RSA_PSK_WITH_3DES_EDE_CBC_SHA";
+      break;
+    case TLS_RSA_PSK_WITH_AES_128_CBC_SHA:
+      return "TLS_RSA_PSK_WITH_AES_128_CBC_SHA";
+      break;
+    case TLS_RSA_PSK_WITH_AES_256_CBC_SHA:
+      return "TLS_RSA_PSK_WITH_AES_256_CBC_SHA";
+      break;
+    /* More TLS PSK (RFC 4785): */
+    case TLS_PSK_WITH_NULL_SHA:
+      return "TLS_PSK_WITH_NULL_SHA";
+      break;
+    case TLS_DHE_PSK_WITH_NULL_SHA:
+      return "TLS_DHE_PSK_WITH_NULL_SHA";
+      break;
+    case TLS_RSA_PSK_WITH_NULL_SHA:
+      return "TLS_RSA_PSK_WITH_NULL_SHA";
+      break;
+    /* Even more TLS PSK (RFC 5487): */
+    case TLS_PSK_WITH_AES_128_GCM_SHA256:
+      return "TLS_PSK_WITH_AES_128_GCM_SHA256";
+      break;
+    case TLS_PSK_WITH_AES_256_GCM_SHA384:
+      return "TLS_PSK_WITH_AES_256_GCM_SHA384";
+      break;
+    case TLS_DHE_PSK_WITH_AES_128_GCM_SHA256:
+      return "TLS_DHE_PSK_WITH_AES_128_GCM_SHA256";
+      break;
+    case TLS_DHE_PSK_WITH_AES_256_GCM_SHA384:
+      return "TLS_DHE_PSK_WITH_AES_256_GCM_SHA384";
+      break;
+    case TLS_RSA_PSK_WITH_AES_128_GCM_SHA256:
+      return "TLS_RSA_PSK_WITH_AES_128_GCM_SHA256";
+      break;
+    case TLS_RSA_PSK_WITH_AES_256_GCM_SHA384:
+      return "TLS_PSK_WITH_AES_256_GCM_SHA384";
+      break;
+    case TLS_PSK_WITH_AES_128_CBC_SHA256:
+      return "TLS_PSK_WITH_AES_128_CBC_SHA256";
+      break;
+    case TLS_PSK_WITH_AES_256_CBC_SHA384:
+      return "TLS_PSK_WITH_AES_256_CBC_SHA384";
+      break;
+    case TLS_PSK_WITH_NULL_SHA256:
+      return "TLS_PSK_WITH_NULL_SHA256";
+      break;
+    case TLS_PSK_WITH_NULL_SHA384:
+      return "TLS_PSK_WITH_NULL_SHA384";
+      break;
+    case TLS_DHE_PSK_WITH_AES_128_CBC_SHA256:
+      return "TLS_DHE_PSK_WITH_AES_128_CBC_SHA256";
+      break;
+    case TLS_DHE_PSK_WITH_AES_256_CBC_SHA384:
+      return "TLS_DHE_PSK_WITH_AES_256_CBC_SHA384";
+      break;
+    case TLS_DHE_PSK_WITH_NULL_SHA256:
+      return "TLS_DHE_PSK_WITH_NULL_SHA256";
+      break;
+    case TLS_DHE_PSK_WITH_NULL_SHA384:
+      return "TLS_RSA_PSK_WITH_NULL_SHA384";
+      break;
+    case TLS_RSA_PSK_WITH_AES_128_CBC_SHA256:
+      return "TLS_RSA_PSK_WITH_AES_128_CBC_SHA256";
+      break;
+    case TLS_RSA_PSK_WITH_AES_256_CBC_SHA384:
+      return "TLS_RSA_PSK_WITH_AES_256_CBC_SHA384";
+      break;
+    case TLS_RSA_PSK_WITH_NULL_SHA256:
+      return "TLS_RSA_PSK_WITH_NULL_SHA256";
+      break;
+    case TLS_RSA_PSK_WITH_NULL_SHA384:
+      return "TLS_RSA_PSK_WITH_NULL_SHA384";
+      break;
+#endif /* CURL_BUILD_MAC_10_9 || CURL_BUILD_IOS_7 */
+#if CURL_BUILD_MAC_10_13 || CURL_BUILD_IOS_11
+    /* New ChaCha20+Poly1305 cipher-suites used by TLS 1.3: */
+    case TLS_AES_128_GCM_SHA256:
+      return "TLS_AES_128_GCM_SHA256";
+      break;
+    case TLS_AES_256_GCM_SHA384:
+      return "TLS_AES_256_GCM_SHA384";
+      break;
+    case TLS_CHACHA20_POLY1305_SHA256:
+      return "TLS_CHACHA20_POLY1305_SHA256";
+      break;
+    case TLS_AES_128_CCM_SHA256:
+      return "TLS_AES_128_CCM_SHA256";
+      break;
+    case TLS_AES_128_CCM_8_SHA256:
+      return "TLS_AES_128_CCM_8_SHA256";
+      break;
+    case TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256:
+      return "TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256";
+      break;
+    case TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256:
+      return "TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256";
+      break;
+#endif /* CURL_BUILD_MAC_10_13 || CURL_BUILD_IOS_11 */
+  }
+  return "TLS_NULL_WITH_NULL_NULL";
+}
+#endif /* !CURL_DISABLE_VERBOSE_STRINGS */
+
+#if CURL_BUILD_MAC
+CF_INLINE void GetDarwinVersionNumber(int *major, int *minor)
+{
+  int mib[2];
+  char *os_version;
+  size_t os_version_len;
+  char *os_version_major, *os_version_minor;
+  char *tok_buf;
+
+  /* Get the Darwin kernel version from the kernel using sysctl(): */
+  mib[0] = CTL_KERN;
+  mib[1] = KERN_OSRELEASE;
+  if(sysctl(mib, 2, NULL, &os_version_len, NULL, 0) == -1)
+    return;
+  os_version = malloc(os_version_len*sizeof(char));
+  if(!os_version)
+    return;
+  if(sysctl(mib, 2, os_version, &os_version_len, NULL, 0) == -1) {
+    free(os_version);
+    return;
+  }
+
+  /* Parse the version: */
+  os_version_major = strtok_r(os_version, ".", &tok_buf);
+  os_version_minor = strtok_r(NULL, ".", &tok_buf);
+  *major = atoi(os_version_major);
+  *minor = atoi(os_version_minor);
+  free(os_version);
+}
+#endif /* CURL_BUILD_MAC */
+
+/* Apple provides a myriad of ways of getting information about a certificate
+   into a string. Some aren't available under iOS or newer cats. So here's
+   a unified function for getting a string describing the certificate that
+   ought to work in all cats starting with Leopard. */
+CF_INLINE CFStringRef getsubject(SecCertificateRef cert)
+{
+  CFStringRef server_cert_summary = CFSTR("(null)");
+
+#if CURL_BUILD_IOS
+  /* iOS: There's only one way to do this. */
+  server_cert_summary = SecCertificateCopySubjectSummary(cert);
+#else
+#if CURL_BUILD_MAC_10_7
+  /* Lion & later: Get the long description if we can. */
+  if(SecCertificateCopyLongDescription != NULL)
+    server_cert_summary =
+      SecCertificateCopyLongDescription(NULL, cert, NULL);
+  else
+#endif /* CURL_BUILD_MAC_10_7 */
+#if CURL_BUILD_MAC_10_6
+  /* Snow Leopard: Get the certificate summary. */
+  if(SecCertificateCopySubjectSummary != NULL)
+    server_cert_summary = SecCertificateCopySubjectSummary(cert);
+  else
+#endif /* CURL_BUILD_MAC_10_6 */
+  /* Leopard is as far back as we go... */
+  (void)SecCertificateCopyCommonName(cert, &server_cert_summary);
+#endif /* CURL_BUILD_IOS */
+  return server_cert_summary;
+}
+
+static CURLcode CopyCertSubject(struct Curl_easy *data,
+                                SecCertificateRef cert, char **certp)
+{
+  CFStringRef c = getsubject(cert);
+  CURLcode result = CURLE_OK;
+  const char *direct;
+  char *cbuf = NULL;
+  *certp = NULL;
+
+  if(!c) {
+    failf(data, "SSL: invalid CA certificate subject");
+    return CURLE_PEER_FAILED_VERIFICATION;
+  }
+
+  /* If the subject is already available as UTF-8 encoded (ie 'direct') then
+     use that, else convert it. */
+  direct = CFStringGetCStringPtr(c, kCFStringEncodingUTF8);
+  if(direct) {
+    *certp = strdup(direct);
+    if(!*certp) {
+      failf(data, "SSL: out of memory");
+      result = CURLE_OUT_OF_MEMORY;
+    }
+  }
+  else {
+    size_t cbuf_size = ((size_t)CFStringGetLength(c) * 4) + 1;
+    cbuf = calloc(cbuf_size, 1);
+    if(cbuf) {
+      if(!CFStringGetCString(c, cbuf, cbuf_size,
+                             kCFStringEncodingUTF8)) {
+        failf(data, "SSL: invalid CA certificate subject");
+        result = CURLE_PEER_FAILED_VERIFICATION;
+      }
+      else
+        /* pass back the buffer */
+        *certp = cbuf;
+    }
+    else {
+      failf(data, "SSL: couldn't allocate %zu bytes of memory", cbuf_size);
+      result = CURLE_OUT_OF_MEMORY;
+    }
+  }
+  if(result)
+    free(cbuf);
+  CFRelease(c);
+  return result;
+}
+
+#if CURL_SUPPORT_MAC_10_6
+/* The SecKeychainSearch API was deprecated in Lion, and using it will raise
+   deprecation warnings, so let's not compile this unless it's necessary: */
+static OSStatus CopyIdentityWithLabelOldSchool(char *label,
+                                               SecIdentityRef *out_c_a_k)
+{
+  OSStatus status = errSecItemNotFound;
+  SecKeychainAttributeList attr_list;
+  SecKeychainAttribute attr;
+  SecKeychainSearchRef search = NULL;
+  SecCertificateRef cert = NULL;
+
+  /* Set up the attribute list: */
+  attr_list.count = 1L;
+  attr_list.attr = &attr;
+
+  /* Set up our lone search criterion: */
+  attr.tag = kSecLabelItemAttr;
+  attr.data = label;
+  attr.length = (UInt32)strlen(label);
+
+  /* Start searching: */
+  status = SecKeychainSearchCreateFromAttributes(NULL,
+                                                 kSecCertificateItemClass,
+                                                 &attr_list,
+                                                 &search);
+  if(status == noErr) {
+    status = SecKeychainSearchCopyNext(search,
+                                       (SecKeychainItemRef *)&cert);
+    if(status == noErr && cert) {
+      /* If we found a certificate, does it have a private key? */
+      status = SecIdentityCreateWithCertificate(NULL, cert, out_c_a_k);
+      CFRelease(cert);
+    }
+  }
+
+  if(search)
+    CFRelease(search);
+  return status;
+}
+#endif /* CURL_SUPPORT_MAC_10_6 */
+
+static OSStatus CopyIdentityWithLabel(char *label,
+                                      SecIdentityRef *out_cert_and_key)
+{
+  OSStatus status = errSecItemNotFound;
+
+#if CURL_BUILD_MAC_10_7 || CURL_BUILD_IOS
+  CFArrayRef keys_list;
+  CFIndex keys_list_count;
+  CFIndex i;
+  CFStringRef common_name;
+
+  /* SecItemCopyMatching() was introduced in iOS and Snow Leopard.
+     kSecClassIdentity was introduced in Lion. If both exist, let's use them
+     to find the certificate. */
+  if(SecItemCopyMatching != NULL && kSecClassIdentity != NULL) {
+    CFTypeRef keys[5];
+    CFTypeRef values[5];
+    CFDictionaryRef query_dict;
+    CFStringRef label_cf = CFStringCreateWithCString(NULL, label,
+      kCFStringEncodingUTF8);
+
+    /* Set up our search criteria and expected results: */
+    values[0] = kSecClassIdentity; /* we want a certificate and a key */
+    keys[0] = kSecClass;
+    values[1] = kCFBooleanTrue;    /* we want a reference */
+    keys[1] = kSecReturnRef;
+    values[2] = kSecMatchLimitAll; /* kSecMatchLimitOne would be better if the
+                                    * label matching below worked correctly */
+    keys[2] = kSecMatchLimit;
+    /* identity searches need a SecPolicyRef in order to work */
+    values[3] = SecPolicyCreateSSL(false, NULL);
+    keys[3] = kSecMatchPolicy;
+    /* match the name of the certificate (doesn't work in macOS 10.12.1) */
+    values[4] = label_cf;
+    keys[4] = kSecAttrLabel;
+    query_dict = CFDictionaryCreate(NULL, (const void **)keys,
+                                    (const void **)values, 5L,
+                                    &kCFCopyStringDictionaryKeyCallBacks,
+                                    &kCFTypeDictionaryValueCallBacks);
+    CFRelease(values[3]);
+
+    /* Do we have a match? */
+    status = SecItemCopyMatching(query_dict, (CFTypeRef *) &keys_list);
+
+    /* Because kSecAttrLabel matching doesn't work with kSecClassIdentity,
+     * we need to find the correct identity ourselves */
+    if(status == noErr) {
+      keys_list_count = CFArrayGetCount(keys_list);
+      *out_cert_and_key = NULL;
+      status = 1;
+      for(i = 0; i<keys_list_count; i++) {
+        OSStatus err = noErr;
+        SecCertificateRef cert = NULL;
+        SecIdentityRef identity =
+          (SecIdentityRef) CFArrayGetValueAtIndex(keys_list, i);
+        err = SecIdentityCopyCertificate(identity, &cert);
+        if(err == noErr) {
+#if CURL_BUILD_IOS
+          common_name = SecCertificateCopySubjectSummary(cert);
+#elif CURL_BUILD_MAC_10_7
+          SecCertificateCopyCommonName(cert, &common_name);
+#endif
+          if(CFStringCompare(common_name, label_cf, 0) == kCFCompareEqualTo) {
+            CFRelease(cert);
+            CFRelease(common_name);
+            CFRetain(identity);
+            *out_cert_and_key = identity;
+            status = noErr;
+            break;
+          }
+          CFRelease(common_name);
+        }
+        CFRelease(cert);
+      }
+    }
+
+    if(keys_list)
+      CFRelease(keys_list);
+    CFRelease(query_dict);
+    CFRelease(label_cf);
+  }
+  else {
+#if CURL_SUPPORT_MAC_10_6
+    /* On Leopard and Snow Leopard, fall back to SecKeychainSearch. */
+    status = CopyIdentityWithLabelOldSchool(label, out_cert_and_key);
+#endif /* CURL_SUPPORT_MAC_10_6 */
+  }
+#elif CURL_SUPPORT_MAC_10_6
+  /* For developers building on older cats, we have no choice but to fall back
+     to SecKeychainSearch. */
+  status = CopyIdentityWithLabelOldSchool(label, out_cert_and_key);
+#endif /* CURL_BUILD_MAC_10_7 || CURL_BUILD_IOS */
+  return status;
+}
+
+static OSStatus CopyIdentityFromPKCS12File(const char *cPath,
+                                           const char *cPassword,
+                                           SecIdentityRef *out_cert_and_key)
+{
+  OSStatus status = errSecItemNotFound;
+  CFURLRef pkcs_url = CFURLCreateFromFileSystemRepresentation(NULL,
+    (const UInt8 *)cPath, strlen(cPath), false);
+  CFStringRef password = cPassword ? CFStringCreateWithCString(NULL,
+    cPassword, kCFStringEncodingUTF8) : NULL;
+  CFDataRef pkcs_data = NULL;
+
+  /* We can import P12 files on iOS or OS X 10.7 or later: */
+  /* These constants are documented as having first appeared in 10.6 but they
+     raise linker errors when used on that cat for some reason. */
+#if CURL_BUILD_MAC_10_7 || CURL_BUILD_IOS
+  if(CFURLCreateDataAndPropertiesFromResource(NULL, pkcs_url, &pkcs_data,
+   NULL, NULL, &status)) {
+    CFArrayRef items = NULL;
+
+  /* On iOS SecPKCS12Import will never add the client certificate to the
+   * Keychain.
+   *
+   * It gives us back a SecIdentityRef that we can use directly. */
+#if CURL_BUILD_IOS
+    const void *cKeys[] = {kSecImportExportPassphrase};
+    const void *cValues[] = {password};
+    CFDictionaryRef options = CFDictionaryCreate(NULL, cKeys, cValues,
+      password ? 1L : 0L, NULL, NULL);
+
+    if(options != NULL) {
+      status = SecPKCS12Import(pkcs_data, options, &items);
+      CFRelease(options);
+    }
+
+
+  /* On macOS SecPKCS12Import will always add the client certificate to
+   * the Keychain.
+   *
+   * As this doesn't match iOS, and apps may not want to see their client
+   * certificate saved in the the user's keychain, we use SecItemImport
+   * with a NULL keychain to avoid importing it.
+   *
+   * This returns a SecCertificateRef from which we can construct a
+   * SecIdentityRef.
+   */
+#elif CURL_BUILD_MAC_10_7
+    SecItemImportExportKeyParameters keyParams;
+    SecExternalFormat inputFormat = kSecFormatPKCS12;
+    SecExternalItemType inputType = kSecItemTypeCertificate;
+
+    memset(&keyParams, 0x00, sizeof(keyParams));
+    keyParams.version    = SEC_KEY_IMPORT_EXPORT_PARAMS_VERSION;
+    keyParams.passphrase = password;
+
+    status = SecItemImport(pkcs_data, NULL, &inputFormat, &inputType,
+                           0, &keyParams, NULL, &items);
+#endif
+
+
+    /* Extract the SecIdentityRef */
+    if(status == errSecSuccess && items && CFArrayGetCount(items)) {
+      CFIndex i, count;
+      count = CFArrayGetCount(items);
+
+      for(i = 0; i < count; i++) {
+        CFTypeRef item = (CFTypeRef) CFArrayGetValueAtIndex(items, i);
+        CFTypeID  itemID = CFGetTypeID(item);
+
+        if(itemID == CFDictionaryGetTypeID()) {
+          CFTypeRef identity = (CFTypeRef) CFDictionaryGetValue(
+                                                 (CFDictionaryRef) item,
+                                                 kSecImportItemIdentity);
+          CFRetain(identity);
+          *out_cert_and_key = (SecIdentityRef) identity;
+          break;
+        }
+#if CURL_BUILD_MAC_10_7
+        else if(itemID == SecCertificateGetTypeID()) {
+          status = SecIdentityCreateWithCertificate(NULL,
+                                                 (SecCertificateRef) item,
+                                                 out_cert_and_key);
+          break;
+        }
+#endif
+      }
+    }
+
+    if(items)
+      CFRelease(items);
+    CFRelease(pkcs_data);
+  }
+#endif /* CURL_BUILD_MAC_10_7 || CURL_BUILD_IOS */
+  if(password)
+    CFRelease(password);
+  CFRelease(pkcs_url);
+  return status;
+}
+
+/* This code was borrowed from nss.c, with some modifications:
+ * Determine whether the nickname passed in is a filename that needs to
+ * be loaded as a PEM or a regular NSS nickname.
+ *
+ * returns 1 for a file
+ * returns 0 for not a file
+ */
+CF_INLINE bool is_file(const char *filename)
+{
+  struct_stat st;
+
+  if(filename == NULL)
+    return false;
+
+  if(stat(filename, &st) == 0)
+    return S_ISREG(st.st_mode);
+  return false;
+}
+
+#if CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS
+static CURLcode sectransp_version_from_curl(SSLProtocol *darwinver,
+                                            long ssl_version)
+{
+  switch(ssl_version) {
+    case CURL_SSLVERSION_TLSv1_0:
+      *darwinver = kTLSProtocol1;
+      return CURLE_OK;
+    case CURL_SSLVERSION_TLSv1_1:
+      *darwinver = kTLSProtocol11;
+      return CURLE_OK;
+    case CURL_SSLVERSION_TLSv1_2:
+      *darwinver = kTLSProtocol12;
+      return CURLE_OK;
+    case CURL_SSLVERSION_TLSv1_3:
+      /* TLS 1.3 support first appeared in iOS 11 and macOS 10.13 */
+#if (CURL_BUILD_MAC_10_13 || CURL_BUILD_IOS_11) && HAVE_BUILTIN_AVAILABLE == 1
+      if(__builtin_available(macOS 10.13, iOS 11.0, *)) {
+        *darwinver = kTLSProtocol13;
+        return CURLE_OK;
+      }
+#endif /* (CURL_BUILD_MAC_10_13 || CURL_BUILD_IOS_11) &&
+          HAVE_BUILTIN_AVAILABLE == 1 */
+      break;
+  }
+  return CURLE_SSL_CONNECT_ERROR;
+}
+#endif
+
+static CURLcode
+set_ssl_version_min_max(struct connectdata *conn, int sockindex)
+{
+  struct Curl_easy *data = conn->data;
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  long ssl_version = SSL_CONN_CONFIG(version);
+  long ssl_version_max = SSL_CONN_CONFIG(version_max);
+  long max_supported_version_by_os;
+
+  /* macOS 10.5-10.7 supported TLS 1.0 only.
+     macOS 10.8 and later, and iOS 5 and later, added TLS 1.1 and 1.2.
+     macOS 10.13 and later, and iOS 11 and later, added TLS 1.3. */
+#if (CURL_BUILD_MAC_10_13 || CURL_BUILD_IOS_11) && HAVE_BUILTIN_AVAILABLE == 1
+  if(__builtin_available(macOS 10.13, iOS 11.0, *)) {
+    max_supported_version_by_os = CURL_SSLVERSION_MAX_TLSv1_3;
+  }
+  else {
+    max_supported_version_by_os = CURL_SSLVERSION_MAX_TLSv1_2;
+  }
+#else
+  max_supported_version_by_os = CURL_SSLVERSION_MAX_TLSv1_2;
+#endif /* (CURL_BUILD_MAC_10_13 || CURL_BUILD_IOS_11) &&
+          HAVE_BUILTIN_AVAILABLE == 1 */
+
+  switch(ssl_version) {
+    case CURL_SSLVERSION_DEFAULT:
+    case CURL_SSLVERSION_TLSv1:
+      ssl_version = CURL_SSLVERSION_TLSv1_0;
+      break;
+  }
+
+  switch(ssl_version_max) {
+    case CURL_SSLVERSION_MAX_NONE:
+    case CURL_SSLVERSION_MAX_DEFAULT:
+      ssl_version_max = max_supported_version_by_os;
+      break;
+  }
+
+#if CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS
+  if(SSLSetProtocolVersionMax != NULL) {
+    SSLProtocol darwin_ver_min = kTLSProtocol1;
+    SSLProtocol darwin_ver_max = kTLSProtocol1;
+    CURLcode result = sectransp_version_from_curl(&darwin_ver_min,
+                                                  ssl_version);
+    if(result) {
+      failf(data, "unsupported min version passed via CURLOPT_SSLVERSION");
+      return result;
+    }
+    result = sectransp_version_from_curl(&darwin_ver_max,
+                                         ssl_version_max >> 16);
+    if(result) {
+      failf(data, "unsupported max version passed via CURLOPT_SSLVERSION");
+      return result;
+    }
+
+    (void)SSLSetProtocolVersionMin(BACKEND->ssl_ctx, darwin_ver_min);
+    (void)SSLSetProtocolVersionMax(BACKEND->ssl_ctx, darwin_ver_max);
+    return result;
+  }
+  else {
+#if CURL_SUPPORT_MAC_10_8
+    long i = ssl_version;
+    (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+                                       kSSLProtocolAll,
+                                       false);
+    for(; i <= (ssl_version_max >> 16); i++) {
+      switch(i) {
+        case CURL_SSLVERSION_TLSv1_0:
+          (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+                                            kTLSProtocol1,
+                                            true);
+          break;
+        case CURL_SSLVERSION_TLSv1_1:
+          (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+                                            kTLSProtocol11,
+                                            true);
+          break;
+        case CURL_SSLVERSION_TLSv1_2:
+          (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+                                            kTLSProtocol12,
+                                            true);
+          break;
+        case CURL_SSLVERSION_TLSv1_3:
+          failf(data, "Your version of the OS does not support TLSv1.3");
+          return CURLE_SSL_CONNECT_ERROR;
+      }
+    }
+    return CURLE_OK;
+#endif  /* CURL_SUPPORT_MAC_10_8 */
+  }
+#endif  /* CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS */
+  failf(data, "Secure Transport: cannot set SSL protocol");
+  return CURLE_SSL_CONNECT_ERROR;
+}
+
+
+static CURLcode sectransp_connect_step1(struct connectdata *conn,
+                                        int sockindex)
+{
+  struct Curl_easy *data = conn->data;
+  curl_socket_t sockfd = conn->sock[sockindex];
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  const char * const ssl_cafile = SSL_CONN_CONFIG(CAfile);
+  const bool verifypeer = SSL_CONN_CONFIG(verifypeer);
+  char * const ssl_cert = SSL_SET_OPTION(cert);
+  const char * const hostname = SSL_IS_PROXY() ? conn->http_proxy.host.name :
+    conn->host.name;
+  const long int port = SSL_IS_PROXY() ? conn->port : conn->remote_port;
+#ifdef ENABLE_IPV6
+  struct in6_addr addr;
+#else
+  struct in_addr addr;
+#endif /* ENABLE_IPV6 */
+  size_t all_ciphers_count = 0UL, allowed_ciphers_count = 0UL, i;
+  SSLCipherSuite *all_ciphers = NULL, *allowed_ciphers = NULL;
+  OSStatus err = noErr;
+#if CURL_BUILD_MAC
+  int darwinver_maj = 0, darwinver_min = 0;
+
+  GetDarwinVersionNumber(&darwinver_maj, &darwinver_min);
+#endif /* CURL_BUILD_MAC */
+
+#if CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS
+  if(SSLCreateContext != NULL) {  /* use the newer API if available */
+    if(BACKEND->ssl_ctx)
+      CFRelease(BACKEND->ssl_ctx);
+    BACKEND->ssl_ctx = SSLCreateContext(NULL, kSSLClientSide, kSSLStreamType);
+    if(!BACKEND->ssl_ctx) {
+      failf(data, "SSL: couldn't create a context!");
+      return CURLE_OUT_OF_MEMORY;
+    }
+  }
+  else {
+  /* The old ST API does not exist under iOS, so don't compile it: */
+#if CURL_SUPPORT_MAC_10_8
+    if(BACKEND->ssl_ctx)
+      (void)SSLDisposeContext(BACKEND->ssl_ctx);
+    err = SSLNewContext(false, &(BACKEND->ssl_ctx));
+    if(err != noErr) {
+      failf(data, "SSL: couldn't create a context: OSStatus %d", err);
+      return CURLE_OUT_OF_MEMORY;
+    }
+#endif /* CURL_SUPPORT_MAC_10_8 */
+  }
+#else
+  if(BACKEND->ssl_ctx)
+    (void)SSLDisposeContext(BACKEND->ssl_ctx);
+  err = SSLNewContext(false, &(BACKEND->ssl_ctx));
+  if(err != noErr) {
+    failf(data, "SSL: couldn't create a context: OSStatus %d", err);
+    return CURLE_OUT_OF_MEMORY;
+  }
+#endif /* CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS */
+  BACKEND->ssl_write_buffered_length = 0UL; /* reset buffered write length */
+
+  /* check to see if we've been told to use an explicit SSL/TLS version */
+#if CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS
+  if(SSLSetProtocolVersionMax != NULL) {
+    switch(conn->ssl_config.version) {
+    case CURL_SSLVERSION_TLSv1:
+      (void)SSLSetProtocolVersionMin(BACKEND->ssl_ctx, kTLSProtocol1);
+#if (CURL_BUILD_MAC_10_13 || CURL_BUILD_IOS_11) && HAVE_BUILTIN_AVAILABLE == 1
+      if(__builtin_available(macOS 10.13, iOS 11.0, *)) {
+        (void)SSLSetProtocolVersionMax(BACKEND->ssl_ctx, kTLSProtocol13);
+      }
+      else {
+        (void)SSLSetProtocolVersionMax(BACKEND->ssl_ctx, kTLSProtocol12);
+      }
+#else
+      (void)SSLSetProtocolVersionMax(BACKEND->ssl_ctx, kTLSProtocol12);
+#endif /* (CURL_BUILD_MAC_10_13 || CURL_BUILD_IOS_11) &&
+          HAVE_BUILTIN_AVAILABLE == 1 */
+      break;
+    case CURL_SSLVERSION_DEFAULT:
+    case CURL_SSLVERSION_TLSv1_0:
+    case CURL_SSLVERSION_TLSv1_1:
+    case CURL_SSLVERSION_TLSv1_2:
+    case CURL_SSLVERSION_TLSv1_3:
+      {
+        CURLcode result = set_ssl_version_min_max(conn, sockindex);
+        if(result != CURLE_OK)
+          return result;
+        break;
+      }
+    case CURL_SSLVERSION_SSLv3:
+      err = SSLSetProtocolVersionMin(BACKEND->ssl_ctx, kSSLProtocol3);
+      if(err != noErr) {
+        failf(data, "Your version of the OS does not support SSLv3");
+        return CURLE_SSL_CONNECT_ERROR;
+      }
+      (void)SSLSetProtocolVersionMax(BACKEND->ssl_ctx, kSSLProtocol3);
+      break;
+    case CURL_SSLVERSION_SSLv2:
+      err = SSLSetProtocolVersionMin(BACKEND->ssl_ctx, kSSLProtocol2);
+      if(err != noErr) {
+        failf(data, "Your version of the OS does not support SSLv2");
+        return CURLE_SSL_CONNECT_ERROR;
+      }
+      (void)SSLSetProtocolVersionMax(BACKEND->ssl_ctx, kSSLProtocol2);
+      break;
+    default:
+      failf(data, "Unrecognized parameter passed via CURLOPT_SSLVERSION");
+      return CURLE_SSL_CONNECT_ERROR;
+    }
+  }
+  else {
+#if CURL_SUPPORT_MAC_10_8
+    (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+                                       kSSLProtocolAll,
+                                       false);
+    switch(conn->ssl_config.version) {
+    case CURL_SSLVERSION_DEFAULT:
+    case CURL_SSLVERSION_TLSv1:
+      (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+                                         kTLSProtocol1,
+                                         true);
+      (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+                                         kTLSProtocol11,
+                                         true);
+      (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+                                         kTLSProtocol12,
+                                         true);
+      break;
+    case CURL_SSLVERSION_TLSv1_0:
+    case CURL_SSLVERSION_TLSv1_1:
+    case CURL_SSLVERSION_TLSv1_2:
+    case CURL_SSLVERSION_TLSv1_3:
+      {
+        CURLcode result = set_ssl_version_min_max(conn, sockindex);
+        if(result != CURLE_OK)
+          return result;
+        break;
+      }
+    case CURL_SSLVERSION_SSLv3:
+      err = SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+                                         kSSLProtocol3,
+                                         true);
+      if(err != noErr) {
+        failf(data, "Your version of the OS does not support SSLv3");
+        return CURLE_SSL_CONNECT_ERROR;
+      }
+      break;
+    case CURL_SSLVERSION_SSLv2:
+      err = SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+                                         kSSLProtocol2,
+                                         true);
+      if(err != noErr) {
+        failf(data, "Your version of the OS does not support SSLv2");
+        return CURLE_SSL_CONNECT_ERROR;
+      }
+      break;
+    default:
+      failf(data, "Unrecognized parameter passed via CURLOPT_SSLVERSION");
+      return CURLE_SSL_CONNECT_ERROR;
+    }
+#endif  /* CURL_SUPPORT_MAC_10_8 */
+  }
+#else
+  if(conn->ssl_config.version_max != CURL_SSLVERSION_MAX_NONE) {
+    failf(data, "Your version of the OS does not support to set maximum"
+                " SSL/TLS version");
+    return CURLE_SSL_CONNECT_ERROR;
+  }
+  (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx, kSSLProtocolAll, false);
+  switch(conn->ssl_config.version) {
+  case CURL_SSLVERSION_DEFAULT:
+  case CURL_SSLVERSION_TLSv1:
+  case CURL_SSLVERSION_TLSv1_0:
+    (void)SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+                                       kTLSProtocol1,
+                                       true);
+    break;
+  case CURL_SSLVERSION_TLSv1_1:
+    failf(data, "Your version of the OS does not support TLSv1.1");
+    return CURLE_SSL_CONNECT_ERROR;
+  case CURL_SSLVERSION_TLSv1_2:
+    failf(data, "Your version of the OS does not support TLSv1.2");
+    return CURLE_SSL_CONNECT_ERROR;
+  case CURL_SSLVERSION_TLSv1_3:
+    failf(data, "Your version of the OS does not support TLSv1.3");
+    return CURLE_SSL_CONNECT_ERROR;
+  case CURL_SSLVERSION_SSLv2:
+    err = SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+                                       kSSLProtocol2,
+                                       true);
+    if(err != noErr) {
+      failf(data, "Your version of the OS does not support SSLv2");
+      return CURLE_SSL_CONNECT_ERROR;
+    }
+    break;
+  case CURL_SSLVERSION_SSLv3:
+    err = SSLSetProtocolVersionEnabled(BACKEND->ssl_ctx,
+                                       kSSLProtocol3,
+                                       true);
+    if(err != noErr) {
+      failf(data, "Your version of the OS does not support SSLv3");
+      return CURLE_SSL_CONNECT_ERROR;
+    }
+    break;
+  default:
+    failf(data, "Unrecognized parameter passed via CURLOPT_SSLVERSION");
+    return CURLE_SSL_CONNECT_ERROR;
+  }
+#endif /* CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS */
+
+#if (CURL_BUILD_MAC_10_13 || CURL_BUILD_IOS_11) && HAVE_BUILTIN_AVAILABLE == 1
+  if(conn->bits.tls_enable_alpn) {
+    if(__builtin_available(macOS 10.13.4, iOS 11, tvOS 11, *)) {
+      CFMutableArrayRef alpnArr = CFArrayCreateMutable(NULL, 0,
+                                                       &kCFTypeArrayCallBacks);
+
+#ifdef USE_NGHTTP2
+      if(data->set.httpversion >= CURL_HTTP_VERSION_2 &&
+         (!SSL_IS_PROXY() || !conn->bits.tunnel_proxy)) {
+        CFArrayAppendValue(alpnArr, CFSTR(NGHTTP2_PROTO_VERSION_ID));
+        infof(data, "ALPN, offering %s\n", NGHTTP2_PROTO_VERSION_ID);
+      }
+#endif
+
+      CFArrayAppendValue(alpnArr, CFSTR(ALPN_HTTP_1_1));
+      infof(data, "ALPN, offering %s\n", ALPN_HTTP_1_1);
+
+      /* expects length prefixed preference ordered list of protocols in wire
+       * format
+       */
+      err = SSLSetALPNProtocols(BACKEND->ssl_ctx, alpnArr);
+      if(err != noErr)
+        infof(data, "WARNING: failed to set ALPN protocols; OSStatus %d\n",
+              err);
+      CFRelease(alpnArr);
+    }
+  }
+#endif
+
+  if(SSL_SET_OPTION(key)) {
+    infof(data, "WARNING: SSL: CURLOPT_SSLKEY is ignored by Secure "
+          "Transport. The private key must be in the Keychain.\n");
+  }
+
+  if(ssl_cert) {
+    SecIdentityRef cert_and_key = NULL;
+    bool is_cert_file = is_file(ssl_cert);
+
+    /* User wants to authenticate with a client cert. Look for it:
+       If we detect that this is a file on disk, then let's load it.
+       Otherwise, assume that the user wants to use an identity loaded
+       from the Keychain. */
+    if(is_cert_file) {
+      if(!SSL_SET_OPTION(cert_type))
+        infof(data, "WARNING: SSL: Certificate type not set, assuming "
+                    "PKCS#12 format.\n");
+      else if(strncmp(SSL_SET_OPTION(cert_type), "P12",
+        strlen(SSL_SET_OPTION(cert_type))) != 0)
+        infof(data, "WARNING: SSL: The Security framework only supports "
+                    "loading identities that are in PKCS#12 format.\n");
+
+      err = CopyIdentityFromPKCS12File(ssl_cert,
+        SSL_SET_OPTION(key_passwd), &cert_and_key);
+    }
+    else
+      err = CopyIdentityWithLabel(ssl_cert, &cert_and_key);
+
+    if(err == noErr && cert_and_key) {
+      SecCertificateRef cert = NULL;
+      CFTypeRef certs_c[1];
+      CFArrayRef certs;
+
+      /* If we found one, print it out: */
+      err = SecIdentityCopyCertificate(cert_and_key, &cert);
+      if(err == noErr) {
+        char *certp;
+        CURLcode result = CopyCertSubject(data, cert, &certp);
+        if(!result) {
+          infof(data, "Client certificate: %s\n", certp);
+          free(certp);
+        }
+
+        CFRelease(cert);
+        if(result == CURLE_PEER_FAILED_VERIFICATION)
+          return CURLE_SSL_CERTPROBLEM;
+        if(result)
+          return result;
+      }
+      certs_c[0] = cert_and_key;
+      certs = CFArrayCreate(NULL, (const void **)certs_c, 1L,
+                            &kCFTypeArrayCallBacks);
+      err = SSLSetCertificate(BACKEND->ssl_ctx, certs);
+      if(certs)
+        CFRelease(certs);
+      if(err != noErr) {
+        failf(data, "SSL: SSLSetCertificate() failed: OSStatus %d", err);
+        return CURLE_SSL_CERTPROBLEM;
+      }
+      CFRelease(cert_and_key);
+    }
+    else {
+      switch(err) {
+      case errSecAuthFailed: case -25264: /* errSecPkcs12VerifyFailure */
+        failf(data, "SSL: Incorrect password for the certificate \"%s\" "
+                    "and its private key.", ssl_cert);
+        break;
+      case -26275: /* errSecDecode */ case -25257: /* errSecUnknownFormat */
+        failf(data, "SSL: Couldn't make sense of the data in the "
+                    "certificate \"%s\" and its private key.",
+                    ssl_cert);
+        break;
+      case -25260: /* errSecPassphraseRequired */
+        failf(data, "SSL The certificate \"%s\" requires a password.",
+                    ssl_cert);
+        break;
+      case errSecItemNotFound:
+        failf(data, "SSL: Can't find the certificate \"%s\" and its private "
+                    "key in the Keychain.", ssl_cert);
+        break;
+      default:
+        failf(data, "SSL: Can't load the certificate \"%s\" and its private "
+                    "key: OSStatus %d", ssl_cert, err);
+        break;
+      }
+      return CURLE_SSL_CERTPROBLEM;
+    }
+  }
+
+  /* SSL always tries to verify the peer, this only says whether it should
+   * fail to connect if the verification fails, or if it should continue
+   * anyway. In the latter case the result of the verification is checked with
+   * SSL_get_verify_result() below. */
+#if CURL_BUILD_MAC_10_6 || CURL_BUILD_IOS
+  /* Snow Leopard introduced the SSLSetSessionOption() function, but due to
+     a library bug with the way the kSSLSessionOptionBreakOnServerAuth flag
+     works, it doesn't work as expected under Snow Leopard, Lion or
+     Mountain Lion.
+     So we need to call SSLSetEnableCertVerify() on those older cats in order
+     to disable certificate validation if the user turned that off.
+     (SecureTransport will always validate the certificate chain by
+     default.)
+  Note:
+  Darwin 11.x.x is Lion (10.7)
+  Darwin 12.x.x is Mountain Lion (10.8)
+  Darwin 13.x.x is Mavericks (10.9)
+  Darwin 14.x.x is Yosemite (10.10)
+  Darwin 15.x.x is El Capitan (10.11)
+  */
+#if CURL_BUILD_MAC
+  if(SSLSetSessionOption != NULL && darwinver_maj >= 13) {
+#else
+  if(SSLSetSessionOption != NULL) {
+#endif /* CURL_BUILD_MAC */
+    bool break_on_auth = !conn->ssl_config.verifypeer || ssl_cafile;
+    err = SSLSetSessionOption(BACKEND->ssl_ctx,
+                              kSSLSessionOptionBreakOnServerAuth,
+                              break_on_auth);
+    if(err != noErr) {
+      failf(data, "SSL: SSLSetSessionOption() failed: OSStatus %d", err);
+      return CURLE_SSL_CONNECT_ERROR;
+    }
+  }
+  else {
+#if CURL_SUPPORT_MAC_10_8
+    err = SSLSetEnableCertVerify(BACKEND->ssl_ctx,
+                                 conn->ssl_config.verifypeer?true:false);
+    if(err != noErr) {
+      failf(data, "SSL: SSLSetEnableCertVerify() failed: OSStatus %d", err);
+      return CURLE_SSL_CONNECT_ERROR;
+    }
+#endif /* CURL_SUPPORT_MAC_10_8 */
+  }
+#else
+  err = SSLSetEnableCertVerify(BACKEND->ssl_ctx,
+                               conn->ssl_config.verifypeer?true:false);
+  if(err != noErr) {
+    failf(data, "SSL: SSLSetEnableCertVerify() failed: OSStatus %d", err);
+    return CURLE_SSL_CONNECT_ERROR;
+  }
+#endif /* CURL_BUILD_MAC_10_6 || CURL_BUILD_IOS */
+
+  if(ssl_cafile && verifypeer) {
+    bool is_cert_file = is_file(ssl_cafile);
+
+    if(!is_cert_file) {
+      failf(data, "SSL: can't load CA certificate file %s", ssl_cafile);
+      return CURLE_SSL_CACERT_BADFILE;
+    }
+  }
+
+  /* Configure hostname check. SNI is used if available.
+   * Both hostname check and SNI require SSLSetPeerDomainName().
+   * Also: the verifyhost setting influences SNI usage */
+  if(conn->ssl_config.verifyhost) {
+    err = SSLSetPeerDomainName(BACKEND->ssl_ctx, hostname,
+    strlen(hostname));
+
+    if(err != noErr) {
+      infof(data, "WARNING: SSL: SSLSetPeerDomainName() failed: OSStatus %d\n",
+            err);
+    }
+
+    if((Curl_inet_pton(AF_INET, hostname, &addr))
+  #ifdef ENABLE_IPV6
+    || (Curl_inet_pton(AF_INET6, hostname, &addr))
+  #endif
+       ) {
+      infof(data, "WARNING: using IP address, SNI is being disabled by "
+            "the OS.\n");
+    }
+  }
+  else {
+    infof(data, "WARNING: disabling hostname validation also disables SNI.\n");
+  }
+
+  /* Disable cipher suites that ST supports but are not safe. These ciphers
+     are unlikely to be used in any case since ST gives other ciphers a much
+     higher priority, but it's probably better that we not connect at all than
+     to give the user a false sense of security if the server only supports
+     insecure ciphers. (Note: We don't care about SSLv2-only ciphers.) */
+  err = SSLGetNumberSupportedCiphers(BACKEND->ssl_ctx, &all_ciphers_count);
+  if(err != noErr) {
+    failf(data, "SSL: SSLGetNumberSupportedCiphers() failed: OSStatus %d",
+          err);
+    return CURLE_SSL_CIPHER;
+  }
+  all_ciphers = malloc(all_ciphers_count*sizeof(SSLCipherSuite));
+  if(!all_ciphers) {
+    failf(data, "SSL: Failed to allocate memory for all ciphers");
+    return CURLE_OUT_OF_MEMORY;
+  }
+  allowed_ciphers = malloc(all_ciphers_count*sizeof(SSLCipherSuite));
+  if(!allowed_ciphers) {
+    Curl_safefree(all_ciphers);
+    failf(data, "SSL: Failed to allocate memory for allowed ciphers");
+    return CURLE_OUT_OF_MEMORY;
+  }
+  err = SSLGetSupportedCiphers(BACKEND->ssl_ctx, all_ciphers,
+                               &all_ciphers_count);
+  if(err != noErr) {
+    Curl_safefree(all_ciphers);
+    Curl_safefree(allowed_ciphers);
+    return CURLE_SSL_CIPHER;
+  }
+  for(i = 0UL ; i < all_ciphers_count ; i++) {
+#if CURL_BUILD_MAC
+   /* There's a known bug in early versions of Mountain Lion where ST's ECC
+      ciphers (cipher suite 0xC001 through 0xC032) simply do not work.
+      Work around the problem here by disabling those ciphers if we are
+      running in an affected version of OS X. */
+    if(darwinver_maj == 12 && darwinver_min <= 3 &&
+       all_ciphers[i] >= 0xC001 && all_ciphers[i] <= 0xC032) {
+      continue;
+    }
+#endif /* CURL_BUILD_MAC */
+    switch(all_ciphers[i]) {
+      /* Disable NULL ciphersuites: */
+      case SSL_NULL_WITH_NULL_NULL:
+      case SSL_RSA_WITH_NULL_MD5:
+      case SSL_RSA_WITH_NULL_SHA:
+      case 0x003B: /* TLS_RSA_WITH_NULL_SHA256 */
+      case SSL_FORTEZZA_DMS_WITH_NULL_SHA:
+      case 0xC001: /* TLS_ECDH_ECDSA_WITH_NULL_SHA */
+      case 0xC006: /* TLS_ECDHE_ECDSA_WITH_NULL_SHA */
+      case 0xC00B: /* TLS_ECDH_RSA_WITH_NULL_SHA */
+      case 0xC010: /* TLS_ECDHE_RSA_WITH_NULL_SHA */
+      case 0x002C: /* TLS_PSK_WITH_NULL_SHA */
+      case 0x002D: /* TLS_DHE_PSK_WITH_NULL_SHA */
+      case 0x002E: /* TLS_RSA_PSK_WITH_NULL_SHA */
+      case 0x00B0: /* TLS_PSK_WITH_NULL_SHA256 */
+      case 0x00B1: /* TLS_PSK_WITH_NULL_SHA384 */
+      case 0x00B4: /* TLS_DHE_PSK_WITH_NULL_SHA256 */
+      case 0x00B5: /* TLS_DHE_PSK_WITH_NULL_SHA384 */
+      case 0x00B8: /* TLS_RSA_PSK_WITH_NULL_SHA256 */
+      case 0x00B9: /* TLS_RSA_PSK_WITH_NULL_SHA384 */
+      /* Disable anonymous ciphersuites: */
+      case SSL_DH_anon_EXPORT_WITH_RC4_40_MD5:
+      case SSL_DH_anon_WITH_RC4_128_MD5:
+      case SSL_DH_anon_EXPORT_WITH_DES40_CBC_SHA:
+      case SSL_DH_anon_WITH_DES_CBC_SHA:
+      case SSL_DH_anon_WITH_3DES_EDE_CBC_SHA:
+      case TLS_DH_anon_WITH_AES_128_CBC_SHA:
+      case TLS_DH_anon_WITH_AES_256_CBC_SHA:
+      case 0xC015: /* TLS_ECDH_anon_WITH_NULL_SHA */
+      case 0xC016: /* TLS_ECDH_anon_WITH_RC4_128_SHA */
+      case 0xC017: /* TLS_ECDH_anon_WITH_3DES_EDE_CBC_SHA */
+      case 0xC018: /* TLS_ECDH_anon_WITH_AES_128_CBC_SHA */
+      case 0xC019: /* TLS_ECDH_anon_WITH_AES_256_CBC_SHA */
+      case 0x006C: /* TLS_DH_anon_WITH_AES_128_CBC_SHA256 */
+      case 0x006D: /* TLS_DH_anon_WITH_AES_256_CBC_SHA256 */
+      case 0x00A6: /* TLS_DH_anon_WITH_AES_128_GCM_SHA256 */
+      case 0x00A7: /* TLS_DH_anon_WITH_AES_256_GCM_SHA384 */
+      /* Disable weak key ciphersuites: */
+      case SSL_RSA_EXPORT_WITH_RC4_40_MD5:
+      case SSL_RSA_EXPORT_WITH_RC2_CBC_40_MD5:
+      case SSL_RSA_EXPORT_WITH_DES40_CBC_SHA:
+      case SSL_DH_DSS_EXPORT_WITH_DES40_CBC_SHA:
+      case SSL_DH_RSA_EXPORT_WITH_DES40_CBC_SHA:
+      case SSL_DHE_DSS_EXPORT_WITH_DES40_CBC_SHA:
+      case SSL_DHE_RSA_EXPORT_WITH_DES40_CBC_SHA:
+      case SSL_RSA_WITH_DES_CBC_SHA:
+      case SSL_DH_DSS_WITH_DES_CBC_SHA:
+      case SSL_DH_RSA_WITH_DES_CBC_SHA:
+      case SSL_DHE_DSS_WITH_DES_CBC_SHA:
+      case SSL_DHE_RSA_WITH_DES_CBC_SHA:
+      /* Disable IDEA: */
+      case SSL_RSA_WITH_IDEA_CBC_SHA:
+      case SSL_RSA_WITH_IDEA_CBC_MD5:
+      /* Disable RC4: */
+      case SSL_RSA_WITH_RC4_128_MD5:
+      case SSL_RSA_WITH_RC4_128_SHA:
+      case 0xC002: /* TLS_ECDH_ECDSA_WITH_RC4_128_SHA */
+      case 0xC007: /* TLS_ECDHE_ECDSA_WITH_RC4_128_SHA*/
+      case 0xC00C: /* TLS_ECDH_RSA_WITH_RC4_128_SHA */
+      case 0xC011: /* TLS_ECDHE_RSA_WITH_RC4_128_SHA */
+      case 0x008A: /* TLS_PSK_WITH_RC4_128_SHA */
+      case 0x008E: /* TLS_DHE_PSK_WITH_RC4_128_SHA */
+      case 0x0092: /* TLS_RSA_PSK_WITH_RC4_128_SHA */
+        break;
+      default: /* enable everything else */
+        allowed_ciphers[allowed_ciphers_count++] = all_ciphers[i];
+        break;
+    }
+  }
+  err = SSLSetEnabledCiphers(BACKEND->ssl_ctx, allowed_ciphers,
+                             allowed_ciphers_count);
+  Curl_safefree(all_ciphers);
+  Curl_safefree(allowed_ciphers);
+  if(err != noErr) {
+    failf(data, "SSL: SSLSetEnabledCiphers() failed: OSStatus %d", err);
+    return CURLE_SSL_CIPHER;
+  }
+
+#if CURL_BUILD_MAC_10_9 || CURL_BUILD_IOS_7
+  /* We want to enable 1/n-1 when using a CBC cipher unless the user
+     specifically doesn't want us doing that: */
+  if(SSLSetSessionOption != NULL) {
+    SSLSetSessionOption(BACKEND->ssl_ctx, kSSLSessionOptionSendOneByteRecord,
+                      !data->set.ssl.enable_beast);
+    SSLSetSessionOption(BACKEND->ssl_ctx, kSSLSessionOptionFalseStart,
+                      data->set.ssl.falsestart); /* false start support */
+  }
+#endif /* CURL_BUILD_MAC_10_9 || CURL_BUILD_IOS_7 */
+
+  /* Check if there's a cached ID we can/should use here! */
+  if(SSL_SET_OPTION(primary.sessionid)) {
+    char *ssl_sessionid;
+    size_t ssl_sessionid_len;
+
+    Curl_ssl_sessionid_lock(conn);
+    if(!Curl_ssl_getsessionid(conn, (void **)&ssl_sessionid,
+                              &ssl_sessionid_len, sockindex)) {
+      /* we got a session id, use it! */
+      err = SSLSetPeerID(BACKEND->ssl_ctx, ssl_sessionid, ssl_sessionid_len);
+      Curl_ssl_sessionid_unlock(conn);
+      if(err != noErr) {
+        failf(data, "SSL: SSLSetPeerID() failed: OSStatus %d", err);
+        return CURLE_SSL_CONNECT_ERROR;
+      }
+      /* Informational message */
+      infof(data, "SSL re-using session ID\n");
+    }
+    /* If there isn't one, then let's make one up! This has to be done prior
+       to starting the handshake. */
+    else {
+      CURLcode result;
+      ssl_sessionid =
+        aprintf("%s:%d:%d:%s:%hu", ssl_cafile,
+                verifypeer, SSL_CONN_CONFIG(verifyhost), hostname, port);
+      ssl_sessionid_len = strlen(ssl_sessionid);
+
+      err = SSLSetPeerID(BACKEND->ssl_ctx, ssl_sessionid, ssl_sessionid_len);
+      if(err != noErr) {
+        Curl_ssl_sessionid_unlock(conn);
+        failf(data, "SSL: SSLSetPeerID() failed: OSStatus %d", err);
+        return CURLE_SSL_CONNECT_ERROR;
+      }
+
+      result = Curl_ssl_addsessionid(conn, ssl_sessionid, ssl_sessionid_len,
+                                     sockindex);
+      Curl_ssl_sessionid_unlock(conn);
+      if(result) {
+        failf(data, "failed to store ssl session");
+        return result;
+      }
+    }
+  }
+
+  err = SSLSetIOFuncs(BACKEND->ssl_ctx, SocketRead, SocketWrite);
+  if(err != noErr) {
+    failf(data, "SSL: SSLSetIOFuncs() failed: OSStatus %d", err);
+    return CURLE_SSL_CONNECT_ERROR;
+  }
+
+  /* pass the raw socket into the SSL layers */
+  /* We need to store the FD in a constant memory address, because
+   * SSLSetConnection() will not copy that address. I've found that
+   * conn->sock[sockindex] may change on its own. */
+  BACKEND->ssl_sockfd = sockfd;
+  err = SSLSetConnection(BACKEND->ssl_ctx, connssl);
+  if(err != noErr) {
+    failf(data, "SSL: SSLSetConnection() failed: %d", err);
+    return CURLE_SSL_CONNECT_ERROR;
+  }
+
+  connssl->connecting_state = ssl_connect_2;
+  return CURLE_OK;
+}
+
+static long pem_to_der(const char *in, unsigned char **out, size_t *outlen)
+{
+  char *sep_start, *sep_end, *cert_start, *cert_end;
+  size_t i, j, err;
+  size_t len;
+  unsigned char *b64;
+
+  /* Jump through the separators at the beginning of the certificate. */
+  sep_start = strstr(in, "-----");
+  if(sep_start == NULL)
+    return 0;
+  cert_start = strstr(sep_start + 1, "-----");
+  if(cert_start == NULL)
+    return -1;
+
+  cert_start += 5;
+
+  /* Find separator after the end of the certificate. */
+  cert_end = strstr(cert_start, "-----");
+  if(cert_end == NULL)
+    return -1;
+
+  sep_end = strstr(cert_end + 1, "-----");
+  if(sep_end == NULL)
+    return -1;
+  sep_end += 5;
+
+  len = cert_end - cert_start;
+  b64 = malloc(len + 1);
+  if(!b64)
+    return -1;
+
+  /* Create base64 string without linefeeds. */
+  for(i = 0, j = 0; i < len; i++) {
+    if(cert_start[i] != '\r' && cert_start[i] != '\n')
+      b64[j++] = cert_start[i];
+  }
+  b64[j] = '\0';
+
+  err = Curl_base64_decode((const char *)b64, out, outlen);
+  free(b64);
+  if(err) {
+    free(*out);
+    return -1;
+  }
+
+  return sep_end - in;
+}
+
+static int read_cert(const char *file, unsigned char **out, size_t *outlen)
+{
+  int fd;
+  ssize_t n, len = 0, cap = 512;
+  unsigned char buf[512], *data;
+
+  fd = open(file, 0);
+  if(fd < 0)
+    return -1;
+
+  data = malloc(cap);
+  if(!data) {
+    close(fd);
+    return -1;
+  }
+
+  for(;;) {
+    n = read(fd, buf, sizeof(buf));
+    if(n < 0) {
+      close(fd);
+      free(data);
+      return -1;
+    }
+    else if(n == 0) {
+      close(fd);
+      break;
+    }
+
+    if(len + n >= cap) {
+      cap *= 2;
+      data = Curl_saferealloc(data, cap);
+      if(!data) {
+        close(fd);
+        return -1;
+      }
+    }
+
+    memcpy(data + len, buf, n);
+    len += n;
+  }
+  data[len] = '\0';
+
+  *out = data;
+  *outlen = len;
+
+  return 0;
+}
+
+static int append_cert_to_array(struct Curl_easy *data,
+                                unsigned char *buf, size_t buflen,
+                                CFMutableArrayRef array)
+{
+    CFDataRef certdata = CFDataCreate(kCFAllocatorDefault, buf, buflen);
+    char *certp;
+    CURLcode result;
+    if(!certdata) {
+      failf(data, "SSL: failed to allocate array for CA certificate");
+      return CURLE_OUT_OF_MEMORY;
+    }
+
+    SecCertificateRef cacert =
+      SecCertificateCreateWithData(kCFAllocatorDefault, certdata);
+    CFRelease(certdata);
+    if(!cacert) {
+      failf(data, "SSL: failed to create SecCertificate from CA certificate");
+      return CURLE_SSL_CACERT_BADFILE;
+    }
+
+    /* Check if cacert is valid. */
+    result = CopyCertSubject(data, cacert, &certp);
+    switch(result) {
+      case CURLE_OK:
+        break;
+      case CURLE_PEER_FAILED_VERIFICATION:
+        return CURLE_SSL_CACERT_BADFILE;
+      case CURLE_OUT_OF_MEMORY:
+      default:
+        return result;
+    }
+    free(certp);
+
+    CFArrayAppendValue(array, cacert);
+    CFRelease(cacert);
+
+    return CURLE_OK;
+}
+
+static CURLcode verify_cert(const char *cafile, struct Curl_easy *data,
+                            SSLContextRef ctx)
+{
+  int n = 0, rc;
+  long res;
+  unsigned char *certbuf, *der;
+  size_t buflen, derlen, offset = 0;
+
+  if(read_cert(cafile, &certbuf, &buflen) < 0) {
+    failf(data, "SSL: failed to read or invalid CA certificate");
+    return CURLE_SSL_CACERT_BADFILE;
+  }
+
+  /*
+   * Certbuf now contains the contents of the certificate file, which can be
+   * - a single DER certificate,
+   * - a single PEM certificate or
+   * - a bunch of PEM certificates (certificate bundle).
+   *
+   * Go through certbuf, and convert any PEM certificate in it into DER
+   * format.
+   */
+  CFMutableArrayRef array = CFArrayCreateMutable(kCFAllocatorDefault, 0,
+                                                 &kCFTypeArrayCallBacks);
+  if(array == NULL) {
+    free(certbuf);
+    failf(data, "SSL: out of memory creating CA certificate array");
+    return CURLE_OUT_OF_MEMORY;
+  }
+
+  while(offset < buflen) {
+    n++;
+
+    /*
+     * Check if the certificate is in PEM format, and convert it to DER. If
+     * this fails, we assume the certificate is in DER format.
+     */
+    res = pem_to_der((const char *)certbuf + offset, &der, &derlen);
+    if(res < 0) {
+      free(certbuf);
+      CFRelease(array);
+      failf(data, "SSL: invalid CA certificate #%d (offset %d) in bundle",
+            n, offset);
+      return CURLE_SSL_CACERT_BADFILE;
+    }
+    offset += res;
+
+    if(res == 0 && offset == 0) {
+      /* This is not a PEM file, probably a certificate in DER format. */
+      rc = append_cert_to_array(data, certbuf, buflen, array);
+      free(certbuf);
+      if(rc != CURLE_OK) {
+        CFRelease(array);
+        return rc;
+      }
+      break;
+    }
+    else if(res == 0) {
+      /* No more certificates in the bundle. */
+      free(certbuf);
+      break;
+    }
+
+    rc = append_cert_to_array(data, der, derlen, array);
+    free(der);
+    if(rc != CURLE_OK) {
+      free(certbuf);
+      CFRelease(array);
+      return rc;
+    }
+  }
+
+  SecTrustRef trust;
+  OSStatus ret = SSLCopyPeerTrust(ctx, &trust);
+  if(trust == NULL) {
+    failf(data, "SSL: error getting certificate chain");
+    CFRelease(array);
+    return CURLE_PEER_FAILED_VERIFICATION;
+  }
+  else if(ret != noErr) {
+    CFRelease(array);
+    failf(data, "SSLCopyPeerTrust() returned error %d", ret);
+    return CURLE_PEER_FAILED_VERIFICATION;
+  }
+
+  ret = SecTrustSetAnchorCertificates(trust, array);
+  if(ret != noErr) {
+    CFRelease(array);
+    CFRelease(trust);
+    failf(data, "SecTrustSetAnchorCertificates() returned error %d", ret);
+    return CURLE_PEER_FAILED_VERIFICATION;
+  }
+  ret = SecTrustSetAnchorCertificatesOnly(trust, true);
+  if(ret != noErr) {
+    CFRelease(array);
+    CFRelease(trust);
+    failf(data, "SecTrustSetAnchorCertificatesOnly() returned error %d", ret);
+    return CURLE_PEER_FAILED_VERIFICATION;
+  }
+
+  SecTrustResultType trust_eval = 0;
+  ret = SecTrustEvaluate(trust, &trust_eval);
+  CFRelease(array);
+  CFRelease(trust);
+  if(ret != noErr) {
+    failf(data, "SecTrustEvaluate() returned error %d", ret);
+    return CURLE_PEER_FAILED_VERIFICATION;
+  }
+
+  switch(trust_eval) {
+    case kSecTrustResultUnspecified:
+    case kSecTrustResultProceed:
+      return CURLE_OK;
+
+    case kSecTrustResultRecoverableTrustFailure:
+    case kSecTrustResultDeny:
+    default:
+      failf(data, "SSL: certificate verification failed (result: %d)",
+            trust_eval);
+      return CURLE_PEER_FAILED_VERIFICATION;
+  }
+}
+
+#ifdef SECTRANSP_PINNEDPUBKEY
+static CURLcode pkp_pin_peer_pubkey(struct Curl_easy *data,
+                                    SSLContextRef ctx,
+                                    const char *pinnedpubkey)
+{  /* Scratch */
+  size_t pubkeylen, realpubkeylen, spkiHeaderLength = 24;
+  unsigned char *pubkey = NULL, *realpubkey = NULL;
+  const unsigned char *spkiHeader = NULL;
+  CFDataRef publicKeyBits = NULL;
+
+  /* Result is returned to caller */
+  CURLcode result = CURLE_SSL_PINNEDPUBKEYNOTMATCH;
+
+  /* if a path wasn't specified, don't pin */
+  if(!pinnedpubkey)
+    return CURLE_OK;
+
+
+  if(!ctx)
+    return result;
+
+  do {
+    SecTrustRef trust;
+    OSStatus ret = SSLCopyPeerTrust(ctx, &trust);
+    if(ret != noErr || trust == NULL)
+      break;
+
+    SecKeyRef keyRef = SecTrustCopyPublicKey(trust);
+    CFRelease(trust);
+    if(keyRef == NULL)
+      break;
+
+#ifdef SECTRANSP_PINNEDPUBKEY_V1
+
+    publicKeyBits = SecKeyCopyExternalRepresentation(keyRef, NULL);
+    CFRelease(keyRef);
+    if(publicKeyBits == NULL)
+      break;
+
+#elif SECTRANSP_PINNEDPUBKEY_V2
+
+    OSStatus success = SecItemExport(keyRef, kSecFormatOpenSSL, 0, NULL,
+                                     &publicKeyBits);
+    CFRelease(keyRef);
+    if(success != errSecSuccess || publicKeyBits == NULL)
+      break;
+
+#endif /* SECTRANSP_PINNEDPUBKEY_V2 */
+
+    pubkeylen = CFDataGetLength(publicKeyBits);
+    pubkey = (unsigned char *)CFDataGetBytePtr(publicKeyBits);
+
+    switch(pubkeylen) {
+      case 526:
+        /* 4096 bit RSA pubkeylen == 526 */
+        spkiHeader = rsa4096SpkiHeader;
+        break;
+      case 270:
+        /* 2048 bit RSA pubkeylen == 270 */
+        spkiHeader = rsa2048SpkiHeader;
+        break;
+#ifdef SECTRANSP_PINNEDPUBKEY_V1
+      case 65:
+        /* ecDSA secp256r1 pubkeylen == 65 */
+        spkiHeader = ecDsaSecp256r1SpkiHeader;
+        spkiHeaderLength = 26;
+        break;
+      case 97:
+        /* ecDSA secp384r1 pubkeylen == 97 */
+        spkiHeader = ecDsaSecp384r1SpkiHeader;
+        spkiHeaderLength = 23;
+        break;
+      default:
+        infof(data, "SSL: unhandled public key length: %d\n", pubkeylen);
+#elif SECTRANSP_PINNEDPUBKEY_V2
+      default:
+        /* ecDSA secp256r1 pubkeylen == 91 header already included?
+         * ecDSA secp384r1 header already included too
+         * we assume rest of algorithms do same, so do nothing
+         */
+        result = Curl_pin_peer_pubkey(data, pinnedpubkey, pubkey,
+                                    pubkeylen);
+#endif /* SECTRANSP_PINNEDPUBKEY_V2 */
+        continue; /* break from loop */
+    }
+
+    realpubkeylen = pubkeylen + spkiHeaderLength;
+    realpubkey = malloc(realpubkeylen);
+    if(!realpubkey)
+      break;
+
+    memcpy(realpubkey, spkiHeader, spkiHeaderLength);
+    memcpy(realpubkey + spkiHeaderLength, pubkey, pubkeylen);
+
+    result = Curl_pin_peer_pubkey(data, pinnedpubkey, realpubkey,
+                                  realpubkeylen);
+
+  } while(0);
+
+  Curl_safefree(realpubkey);
+  if(publicKeyBits != NULL)
+    CFRelease(publicKeyBits);
+
+  return result;
+}
+#endif /* SECTRANSP_PINNEDPUBKEY */
+
+static CURLcode
+sectransp_connect_step2(struct connectdata *conn, int sockindex)
+{
+  struct Curl_easy *data = conn->data;
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  OSStatus err;
+  SSLCipherSuite cipher;
+  SSLProtocol protocol = 0;
+  const char * const hostname = SSL_IS_PROXY() ? conn->http_proxy.host.name :
+    conn->host.name;
+
+  DEBUGASSERT(ssl_connect_2 == connssl->connecting_state
+              || ssl_connect_2_reading == connssl->connecting_state
+              || ssl_connect_2_writing == connssl->connecting_state);
+
+  /* Here goes nothing: */
+  err = SSLHandshake(BACKEND->ssl_ctx);
+
+  if(err != noErr) {
+    switch(err) {
+      case errSSLWouldBlock:  /* they're not done with us yet */
+        connssl->connecting_state = BACKEND->ssl_direction ?
+            ssl_connect_2_writing : ssl_connect_2_reading;
+        return CURLE_OK;
+
+      /* The below is errSSLServerAuthCompleted; it's not defined in
+        Leopard's headers */
+      case -9841:
+        if(SSL_CONN_CONFIG(CAfile) && SSL_CONN_CONFIG(verifypeer)) {
+          CURLcode result = verify_cert(SSL_CONN_CONFIG(CAfile), data,
+                                        BACKEND->ssl_ctx);
+          if(result)
+            return result;
+        }
+        /* the documentation says we need to call SSLHandshake() again */
+        return sectransp_connect_step2(conn, sockindex);
+
+      /* Problem with encrypt / decrypt */
+      case errSSLPeerDecodeError:
+        failf(data, "Decode failed");
+        break;
+      case errSSLDecryptionFail:
+      case errSSLPeerDecryptionFail:
+        failf(data, "Decryption failed");
+        break;
+      case errSSLPeerDecryptError:
+        failf(data, "A decryption error occurred");
+        break;
+      case errSSLBadCipherSuite:
+        failf(data, "A bad SSL cipher suite was encountered");
+        break;
+      case errSSLCrypto:
+        failf(data, "An underlying cryptographic error was encountered");
+        break;
+#if CURL_BUILD_MAC_10_11 || CURL_BUILD_IOS_9
+      case errSSLWeakPeerEphemeralDHKey:
+        failf(data, "Indicates a weak ephemeral Diffie-Hellman key");
+        break;
+#endif
+
+      /* Problem with the message record validation */
+      case errSSLBadRecordMac:
+      case errSSLPeerBadRecordMac:
+        failf(data, "A record with a bad message authentication code (MAC) "
+                    "was encountered");
+        break;
+      case errSSLRecordOverflow:
+      case errSSLPeerRecordOverflow:
+        failf(data, "A record overflow occurred");
+        break;
+
+      /* Problem with zlib decompression */
+      case errSSLPeerDecompressFail:
+        failf(data, "Decompression failed");
+        break;
+
+      /* Problem with access */
+      case errSSLPeerAccessDenied:
+        failf(data, "Access was denied");
+        break;
+      case errSSLPeerInsufficientSecurity:
+        failf(data, "There is insufficient security for this operation");
+        break;
+
+      /* These are all certificate problems with the server: */
+      case errSSLXCertChainInvalid:
+        failf(data, "SSL certificate problem: Invalid certificate chain");
+        return CURLE_PEER_FAILED_VERIFICATION;
+      case errSSLUnknownRootCert:
+        failf(data, "SSL certificate problem: Untrusted root certificate");
+        return CURLE_PEER_FAILED_VERIFICATION;
+      case errSSLNoRootCert:
+        failf(data, "SSL certificate problem: No root certificate");
+        return CURLE_PEER_FAILED_VERIFICATION;
+      case errSSLCertNotYetValid:
+        failf(data, "SSL certificate problem: The certificate chain had a "
+                    "certificate that is not yet valid");
+        return CURLE_PEER_FAILED_VERIFICATION;
+      case errSSLCertExpired:
+      case errSSLPeerCertExpired:
+        failf(data, "SSL certificate problem: Certificate chain had an "
+              "expired certificate");
+        return CURLE_PEER_FAILED_VERIFICATION;
+      case errSSLBadCert:
+      case errSSLPeerBadCert:
+        failf(data, "SSL certificate problem: Couldn't understand the server "
+              "certificate format");
+        return CURLE_PEER_FAILED_VERIFICATION;
+      case errSSLPeerUnsupportedCert:
+        failf(data, "SSL certificate problem: An unsupported certificate "
+                    "format was encountered");
+        return CURLE_PEER_FAILED_VERIFICATION;
+      case errSSLPeerCertRevoked:
+        failf(data, "SSL certificate problem: The certificate was revoked");
+        return CURLE_PEER_FAILED_VERIFICATION;
+      case errSSLPeerCertUnknown:
+        failf(data, "SSL certificate problem: The certificate is unknown");
+        return CURLE_PEER_FAILED_VERIFICATION;
+
+      /* These are all certificate problems with the client: */
+      case errSecAuthFailed:
+        failf(data, "SSL authentication failed");
+        break;
+      case errSSLPeerHandshakeFail:
+        failf(data, "SSL peer handshake failed, the server most likely "
+              "requires a client certificate to connect");
+        break;
+      case errSSLPeerUnknownCA:
+        failf(data, "SSL server rejected the client certificate due to "
+              "the certificate being signed by an unknown certificate "
+              "authority");
+        break;
+
+      /* This error is raised if the server's cert didn't match the server's
+         host name: */
+      case errSSLHostNameMismatch:
+        failf(data, "SSL certificate peer verification failed, the "
+              "certificate did not match \"%s\"\n", conn->host.dispname);
+        return CURLE_PEER_FAILED_VERIFICATION;
+
+      /* Problem with SSL / TLS negotiation */
+      case errSSLNegotiation:
+        failf(data, "Could not negotiate an SSL cipher suite with the server");
+        break;
+      case errSSLBadConfiguration:
+        failf(data, "A configuration error occurred");
+        break;
+      case errSSLProtocol:
+        failf(data, "SSL protocol error");
+        break;
+      case errSSLPeerProtocolVersion:
+        failf(data, "A bad protocol version was encountered");
+        break;
+      case errSSLPeerNoRenegotiation:
+        failf(data, "No renegotiation is allowed");
+        break;
+
+      /* Generic handshake errors: */
+      case errSSLConnectionRefused:
+        failf(data, "Server dropped the connection during the SSL handshake");
+        break;
+      case errSSLClosedAbort:
+        failf(data, "Server aborted the SSL handshake");
+        break;
+      case errSSLClosedGraceful:
+        failf(data, "The connection closed gracefully");
+        break;
+      case errSSLClosedNoNotify:
+        failf(data, "The server closed the session with no notification");
+        break;
+      /* Sometimes paramErr happens with buggy ciphers: */
+      case paramErr:
+      case errSSLInternal:
+      case errSSLPeerInternalError:
+        failf(data, "Internal SSL engine error encountered during the "
+              "SSL handshake");
+        break;
+      case errSSLFatalAlert:
+        failf(data, "Fatal SSL engine error encountered during the SSL "
+              "handshake");
+        break;
+      /* Unclassified error */
+      case errSSLBufferOverflow:
+        failf(data, "An insufficient buffer was provided");
+        break;
+      case errSSLIllegalParam:
+        failf(data, "An illegal parameter was encountered");
+        break;
+      case errSSLModuleAttach:
+        failf(data, "Module attach failure");
+        break;
+      case errSSLSessionNotFound:
+        failf(data, "An attempt to restore an unknown session failed");
+        break;
+      case errSSLPeerExportRestriction:
+        failf(data, "An export restriction occurred");
+        break;
+      case errSSLPeerUserCancelled:
+        failf(data, "The user canceled the operation");
+        break;
+      case errSSLPeerUnexpectedMsg:
+        failf(data, "Peer rejected unexpected message");
+        break;
+#if CURL_BUILD_MAC_10_11 || CURL_BUILD_IOS_9
+      /* Treaing non-fatal error as fatal like before */
+      case errSSLClientHelloReceived:
+        failf(data, "A non-fatal result for providing a server name "
+                    "indication");
+        break;
+#endif
+
+      /* Error codes defined in the enum but should never be returned.
+         We list them here just in case. */
+#if CURL_BUILD_MAC_10_6
+      /* Only returned when kSSLSessionOptionBreakOnCertRequested is set */
+      case errSSLClientCertRequested:
+        failf(data, "The server has requested a client certificate");
+        break;
+#endif
+#if CURL_BUILD_MAC_10_9
+      /* Alias for errSSLLast, end of error range */
+      case errSSLUnexpectedRecord:
+        failf(data, "Unexpected (skipped) record in DTLS");
+        break;
+#endif
+      default:
+        /* May also return codes listed in Security Framework Result Codes */
+        failf(data, "Unknown SSL protocol error in connection to %s:%d",
+              hostname, err);
+        break;
+    }
+    return CURLE_SSL_CONNECT_ERROR;
+  }
+  else {
+    /* we have been connected fine, we're not waiting for anything else. */
+    connssl->connecting_state = ssl_connect_3;
+
+#ifdef SECTRANSP_PINNEDPUBKEY
+    if(data->set.str[STRING_SSL_PINNEDPUBLICKEY_ORIG]) {
+      CURLcode result = pkp_pin_peer_pubkey(data, BACKEND->ssl_ctx,
+                            data->set.str[STRING_SSL_PINNEDPUBLICKEY_ORIG]);
+      if(result) {
+        failf(data, "SSL: public key does not match pinned public key!");
+        return result;
+      }
+    }
+#endif /* SECTRANSP_PINNEDPUBKEY */
+
+    /* Informational message */
+    (void)SSLGetNegotiatedCipher(BACKEND->ssl_ctx, &cipher);
+    (void)SSLGetNegotiatedProtocolVersion(BACKEND->ssl_ctx, &protocol);
+    switch(protocol) {
+      case kSSLProtocol2:
+        infof(data, "SSL 2.0 connection using %s\n",
+              SSLCipherNameForNumber(cipher));
+        break;
+      case kSSLProtocol3:
+        infof(data, "SSL 3.0 connection using %s\n",
+              SSLCipherNameForNumber(cipher));
+        break;
+      case kTLSProtocol1:
+        infof(data, "TLS 1.0 connection using %s\n",
+              TLSCipherNameForNumber(cipher));
+        break;
+#if CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS
+      case kTLSProtocol11:
+        infof(data, "TLS 1.1 connection using %s\n",
+              TLSCipherNameForNumber(cipher));
+        break;
+      case kTLSProtocol12:
+        infof(data, "TLS 1.2 connection using %s\n",
+              TLSCipherNameForNumber(cipher));
+        break;
+#endif /* CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS */
+#if CURL_BUILD_MAC_10_13 || CURL_BUILD_IOS_11
+      case kTLSProtocol13:
+        infof(data, "TLS 1.3 connection using %s\n",
+              TLSCipherNameForNumber(cipher));
+        break;
+#endif /* CURL_BUILD_MAC_10_13 || CURL_BUILD_IOS_11 */
+      default:
+        infof(data, "Unknown protocol connection\n");
+        break;
+    }
+
+#if(CURL_BUILD_MAC_10_13 || CURL_BUILD_IOS_11) && HAVE_BUILTIN_AVAILABLE == 1
+    if(conn->bits.tls_enable_alpn) {
+      if(__builtin_available(macOS 10.13.4, iOS 11, tvOS 11, *)) {
+        CFArrayRef alpnArr = NULL;
+        CFStringRef chosenProtocol = NULL;
+        err = SSLCopyALPNProtocols(BACKEND->ssl_ctx, &alpnArr);
+
+        if(err == noErr && alpnArr && CFArrayGetCount(alpnArr) >= 1)
+          chosenProtocol = CFArrayGetValueAtIndex(alpnArr, 0);
+
+#ifdef USE_NGHTTP2
+        if(chosenProtocol &&
+           !CFStringCompare(chosenProtocol, CFSTR(NGHTTP2_PROTO_VERSION_ID),
+                            0)) {
+          conn->negnpn = CURL_HTTP_VERSION_2;
+        }
+        else
+#endif
+        if(chosenProtocol &&
+           !CFStringCompare(chosenProtocol, CFSTR(ALPN_HTTP_1_1), 0)) {
+          conn->negnpn = CURL_HTTP_VERSION_1_1;
+        }
+        else
+          infof(data, "ALPN, server did not agree to a protocol\n");
+
+        Curl_multiuse_state(conn, conn->negnpn == CURL_HTTP_VERSION_2 ?
+                            BUNDLE_MULTIPLEX : BUNDLE_NO_MULTIUSE);
+
+        /* chosenProtocol is a reference to the string within alpnArr
+           and doesn't need to be freed separately */
+        if(alpnArr)
+          CFRelease(alpnArr);
+      }
+    }
+#endif
+
+    return CURLE_OK;
+  }
+}
+
+#ifndef CURL_DISABLE_VERBOSE_STRINGS
+/* This should be called during step3 of the connection at the earliest */
+static void
+show_verbose_server_cert(struct connectdata *conn,
+                         int sockindex)
+{
+  struct Curl_easy *data = conn->data;
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  CFArrayRef server_certs = NULL;
+  SecCertificateRef server_cert;
+  OSStatus err;
+  CFIndex i, count;
+  SecTrustRef trust = NULL;
+
+  if(!BACKEND->ssl_ctx)
+    return;
+
+#if CURL_BUILD_MAC_10_7 || CURL_BUILD_IOS
+#if CURL_BUILD_IOS
+#pragma unused(server_certs)
+  err = SSLCopyPeerTrust(BACKEND->ssl_ctx, &trust);
+  /* For some reason, SSLCopyPeerTrust() can return noErr and yet return
+     a null trust, so be on guard for that: */
+  if(err == noErr && trust) {
+    count = SecTrustGetCertificateCount(trust);
+    for(i = 0L ; i < count ; i++) {
+      CURLcode result;
+      char *certp;
+      server_cert = SecTrustGetCertificateAtIndex(trust, i);
+      result = CopyCertSubject(data, server_cert, &certp);
+      if(!result) {
+        infof(data, "Server certificate: %s\n", certp);
+        free(certp);
+      }
+    }
+    CFRelease(trust);
+  }
+#else
+  /* SSLCopyPeerCertificates() is deprecated as of Mountain Lion.
+     The function SecTrustGetCertificateAtIndex() is officially present
+     in Lion, but it is unfortunately also present in Snow Leopard as
+     private API and doesn't work as expected. So we have to look for
+     a different symbol to make sure this code is only executed under
+     Lion or later. */
+  if(SecTrustEvaluateAsync != NULL) {
+#pragma unused(server_certs)
+    err = SSLCopyPeerTrust(BACKEND->ssl_ctx, &trust);
+    /* For some reason, SSLCopyPeerTrust() can return noErr and yet return
+       a null trust, so be on guard for that: */
+    if(err == noErr && trust) {
+      count = SecTrustGetCertificateCount(trust);
+      for(i = 0L ; i < count ; i++) {
+        char *certp;
+        CURLcode result;
+        server_cert = SecTrustGetCertificateAtIndex(trust, i);
+        result = CopyCertSubject(data, server_cert, &certp);
+        if(!result) {
+          infof(data, "Server certificate: %s\n", certp);
+          free(certp);
+        }
+      }
+      CFRelease(trust);
+    }
+  }
+  else {
+#if CURL_SUPPORT_MAC_10_8
+    err = SSLCopyPeerCertificates(BACKEND->ssl_ctx, &server_certs);
+    /* Just in case SSLCopyPeerCertificates() returns null too... */
+    if(err == noErr && server_certs) {
+      count = CFArrayGetCount(server_certs);
+      for(i = 0L ; i < count ; i++) {
+        char *certp;
+        CURLcode result;
+        server_cert = (SecCertificateRef)CFArrayGetValueAtIndex(server_certs,
+                                                                i);
+        result = CopyCertSubject(data, server_cert, &certp);
+        if(!result) {
+          infof(data, "Server certificate: %s\n", certp);
+          free(certp);
+        }
+      }
+      CFRelease(server_certs);
+    }
+#endif /* CURL_SUPPORT_MAC_10_8 */
+  }
+#endif /* CURL_BUILD_IOS */
+#else
+#pragma unused(trust)
+  err = SSLCopyPeerCertificates(BACKEND->ssl_ctx, &server_certs);
+  if(err == noErr) {
+    count = CFArrayGetCount(server_certs);
+    for(i = 0L ; i < count ; i++) {
+      CURLcode result;
+      char *certp;
+      server_cert = (SecCertificateRef)CFArrayGetValueAtIndex(server_certs, i);
+      result = CopyCertSubject(data, server_cert, &certp);
+      if(!result) {
+        infof(data, "Server certificate: %s\n", certp);
+        free(certp);
+      }
+    }
+    CFRelease(server_certs);
+  }
+#endif /* CURL_BUILD_MAC_10_7 || CURL_BUILD_IOS */
+}
+#endif /* !CURL_DISABLE_VERBOSE_STRINGS */
+
+static CURLcode
+sectransp_connect_step3(struct connectdata *conn,
+                        int sockindex)
+{
+  struct Curl_easy *data = conn->data;
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+
+  /* There is no step 3!
+   * Well, okay, if verbose mode is on, let's print the details of the
+   * server certificates. */
+#ifndef CURL_DISABLE_VERBOSE_STRINGS
+  if(data->set.verbose)
+    show_verbose_server_cert(conn, sockindex);
+#endif
+
+  connssl->connecting_state = ssl_connect_done;
+  return CURLE_OK;
+}
+
+static Curl_recv sectransp_recv;
+static Curl_send sectransp_send;
+
+static CURLcode
+sectransp_connect_common(struct connectdata *conn,
+                         int sockindex,
+                         bool nonblocking,
+                         bool *done)
+{
+  CURLcode result;
+  struct Curl_easy *data = conn->data;
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  curl_socket_t sockfd = conn->sock[sockindex];
+  long timeout_ms;
+  int what;
+
+  /* check if the connection has already been established */
+  if(ssl_connection_complete == connssl->state) {
+    *done = TRUE;
+    return CURLE_OK;
+  }
+
+  if(ssl_connect_1 == connssl->connecting_state) {
+    /* Find out how much more time we're allowed */
+    timeout_ms = Curl_timeleft(data, NULL, TRUE);
+
+    if(timeout_ms < 0) {
+      /* no need to continue if time already is up */
+      failf(data, "SSL connection timeout");
+      return CURLE_OPERATION_TIMEDOUT;
+    }
+
+    result = sectransp_connect_step1(conn, sockindex);
+    if(result)
+      return result;
+  }
+
+  while(ssl_connect_2 == connssl->connecting_state ||
+        ssl_connect_2_reading == connssl->connecting_state ||
+        ssl_connect_2_writing == connssl->connecting_state) {
+
+    /* check allowed time left */
+    timeout_ms = Curl_timeleft(data, NULL, TRUE);
+
+    if(timeout_ms < 0) {
+      /* no need to continue if time already is up */
+      failf(data, "SSL connection timeout");
+      return CURLE_OPERATION_TIMEDOUT;
+    }
+
+    /* if ssl is expecting something, check if it's available. */
+    if(connssl->connecting_state == ssl_connect_2_reading ||
+       connssl->connecting_state == ssl_connect_2_writing) {
+
+      curl_socket_t writefd = ssl_connect_2_writing ==
+      connssl->connecting_state?sockfd:CURL_SOCKET_BAD;
+      curl_socket_t readfd = ssl_connect_2_reading ==
+      connssl->connecting_state?sockfd:CURL_SOCKET_BAD;
+
+      what = Curl_socket_check(readfd, CURL_SOCKET_BAD, writefd,
+                               nonblocking?0:timeout_ms);
+      if(what < 0) {
+        /* fatal error */
+        failf(data, "select/poll on SSL socket, errno: %d", SOCKERRNO);
+        return CURLE_SSL_CONNECT_ERROR;
+      }
+      else if(0 == what) {
+        if(nonblocking) {
+          *done = FALSE;
+          return CURLE_OK;
+        }
+        else {
+          /* timeout */
+          failf(data, "SSL connection timeout");
+          return CURLE_OPERATION_TIMEDOUT;
+        }
+      }
+      /* socket is readable or writable */
+    }
+
+    /* Run transaction, and return to the caller if it failed or if this
+     * connection is done nonblocking and this loop would execute again. This
+     * permits the owner of a multi handle to abort a connection attempt
+     * before step2 has completed while ensuring that a client using select()
+     * or epoll() will always have a valid fdset to wait on.
+     */
+    result = sectransp_connect_step2(conn, sockindex);
+    if(result || (nonblocking &&
+                  (ssl_connect_2 == connssl->connecting_state ||
+                   ssl_connect_2_reading == connssl->connecting_state ||
+                   ssl_connect_2_writing == connssl->connecting_state)))
+      return result;
+
+  } /* repeat step2 until all transactions are done. */
+
+
+  if(ssl_connect_3 == connssl->connecting_state) {
+    result = sectransp_connect_step3(conn, sockindex);
+    if(result)
+      return result;
+  }
+
+  if(ssl_connect_done == connssl->connecting_state) {
+    connssl->state = ssl_connection_complete;
+    conn->recv[sockindex] = sectransp_recv;
+    conn->send[sockindex] = sectransp_send;
+    *done = TRUE;
+  }
+  else
+    *done = FALSE;
+
+  /* Reset our connect state machine */
+  connssl->connecting_state = ssl_connect_1;
+
+  return CURLE_OK;
+}
+
+static CURLcode Curl_sectransp_connect_nonblocking(struct connectdata *conn,
+                                                   int sockindex, bool *done)
+{
+  return sectransp_connect_common(conn, sockindex, TRUE, done);
+}
+
+static CURLcode Curl_sectransp_connect(struct connectdata *conn, int sockindex)
+{
+  CURLcode result;
+  bool done = FALSE;
+
+  result = sectransp_connect_common(conn, sockindex, FALSE, &done);
+
+  if(result)
+    return result;
+
+  DEBUGASSERT(done);
+
+  return CURLE_OK;
+}
+
+static void Curl_sectransp_close(struct connectdata *conn, int sockindex)
+{
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+
+  if(BACKEND->ssl_ctx) {
+    (void)SSLClose(BACKEND->ssl_ctx);
+#if CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS
+    if(SSLCreateContext != NULL)
+      CFRelease(BACKEND->ssl_ctx);
+#if CURL_SUPPORT_MAC_10_8
+    else
+      (void)SSLDisposeContext(BACKEND->ssl_ctx);
+#endif  /* CURL_SUPPORT_MAC_10_8 */
+#else
+    (void)SSLDisposeContext(BACKEND->ssl_ctx);
+#endif /* CURL_BUILD_MAC_10_8 || CURL_BUILD_IOS */
+    BACKEND->ssl_ctx = NULL;
+  }
+  BACKEND->ssl_sockfd = 0;
+}
+
+static int Curl_sectransp_shutdown(struct connectdata *conn, int sockindex)
+{
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  struct Curl_easy *data = conn->data;
+  ssize_t nread;
+  int what;
+  int rc;
+  char buf[120];
+
+  if(!BACKEND->ssl_ctx)
+    return 0;
+
+#ifndef CURL_DISABLE_FTP
+  if(data->set.ftp_ccc != CURLFTPSSL_CCC_ACTIVE)
+    return 0;
+#endif
+
+  Curl_sectransp_close(conn, sockindex);
+
+  rc = 0;
+
+  what = SOCKET_READABLE(conn->sock[sockindex], SSL_SHUTDOWN_TIMEOUT);
+
+  for(;;) {
+    if(what < 0) {
+      /* anything that gets here is fatally bad */
+      failf(data, "select/poll on SSL socket, errno: %d", SOCKERRNO);
+      rc = -1;
+      break;
+    }
+
+    if(!what) {                                /* timeout */
+      failf(data, "SSL shutdown timeout");
+      break;
+    }
+
+    /* Something to read, let's do it and hope that it is the close
+     notify alert from the server. No way to SSL_Read now, so use read(). */
+
+    nread = read(conn->sock[sockindex], buf, sizeof(buf));
+
+    if(nread < 0) {
+      failf(data, "read: %s", strerror(errno));
+      rc = -1;
+    }
+
+    if(nread <= 0)
+      break;
+
+    what = SOCKET_READABLE(conn->sock[sockindex], 0);
+  }
+
+  return rc;
+}
+
+static void Curl_sectransp_session_free(void *ptr)
+{
+  /* ST, as of iOS 5 and Mountain Lion, has no public method of deleting a
+     cached session ID inside the Security framework. There is a private
+     function that does this, but I don't want to have to explain to you why I
+     got your application rejected from the App Store due to the use of a
+     private API, so the best we can do is free up our own char array that we
+     created way back in sectransp_connect_step1... */
+  Curl_safefree(ptr);
+}
+
+static size_t Curl_sectransp_version(char *buffer, size_t size)
+{
+  return msnprintf(buffer, size, "SecureTransport");
+}
+
+/*
+ * This function uses SSLGetSessionState to determine connection status.
+ *
+ * Return codes:
+ *     1 means the connection is still in place
+ *     0 means the connection has been closed
+ *    -1 means the connection status is unknown
+ */
+static int Curl_sectransp_check_cxn(struct connectdata *conn)
+{
+  struct ssl_connect_data *connssl = &conn->ssl[FIRSTSOCKET];
+  OSStatus err;
+  SSLSessionState state;
+
+  if(BACKEND->ssl_ctx) {
+    err = SSLGetSessionState(BACKEND->ssl_ctx, &state);
+    if(err == noErr)
+      return state == kSSLConnected || state == kSSLHandshake;
+    return -1;
+  }
+  return 0;
+}
+
+static bool Curl_sectransp_data_pending(const struct connectdata *conn,
+                                        int connindex)
+{
+  const struct ssl_connect_data *connssl = &conn->ssl[connindex];
+  OSStatus err;
+  size_t buffer;
+
+  if(BACKEND->ssl_ctx) {  /* SSL is in use */
+    err = SSLGetBufferedReadSize(BACKEND->ssl_ctx, &buffer);
+    if(err == noErr)
+      return buffer > 0UL;
+    return false;
+  }
+  else
+    return false;
+}
+
+static CURLcode Curl_sectransp_random(struct Curl_easy *data UNUSED_PARAM,
+                                      unsigned char *entropy, size_t length)
+{
+  /* arc4random_buf() isn't available on cats older than Lion, so let's
+     do this manually for the benefit of the older cats. */
+  size_t i;
+  u_int32_t random_number = 0;
+
+  (void)data;
+
+  for(i = 0 ; i < length ; i++) {
+    if(i % sizeof(u_int32_t) == 0)
+      random_number = arc4random();
+    entropy[i] = random_number & 0xFF;
+    random_number >>= 8;
+  }
+  i = random_number = 0;
+  return CURLE_OK;
+}
+
+static CURLcode Curl_sectransp_md5sum(unsigned char *tmp, /* input */
+                                      size_t tmplen,
+                                      unsigned char *md5sum, /* output */
+                                      size_t md5len)
+{
+  (void)md5len;
+  (void)CC_MD5(tmp, (CC_LONG)tmplen, md5sum);
+  return CURLE_OK;
+}
+
+static CURLcode Curl_sectransp_sha256sum(const unsigned char *tmp, /* input */
+                                     size_t tmplen,
+                                     unsigned char *sha256sum, /* output */
+                                     size_t sha256len)
+{
+  assert(sha256len >= CURL_SHA256_DIGEST_LENGTH);
+  (void)CC_SHA256(tmp, (CC_LONG)tmplen, sha256sum);
+  return CURLE_OK;
+}
+
+static bool Curl_sectransp_false_start(void)
+{
+#if CURL_BUILD_MAC_10_9 || CURL_BUILD_IOS_7
+  if(SSLSetSessionOption != NULL)
+    return TRUE;
+#endif
+  return FALSE;
+}
+
+static ssize_t sectransp_send(struct connectdata *conn,
+                              int sockindex,
+                              const void *mem,
+                              size_t len,
+                              CURLcode *curlcode)
+{
+  /*struct Curl_easy *data = conn->data;*/
+  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
+  size_t processed = 0UL;
+  OSStatus err;
+
+  /* The SSLWrite() function works a little differently than expected. The
+     fourth argument (processed) is currently documented in Apple's
+     documentation as: "On return, the length, in bytes, of the data actually
+     written."
+
+     Now, one could interpret that as "written to the socket," but actually,
+     it returns the amount of data that was written to a buffer internal to
+     the SSLContextRef instead. So it's possible for SSLWrite() to return
+     errSSLWouldBlock and a number of bytes "written" because those bytes were
+     encrypted and written to a buffer, not to the socket.
+
+     So if this happens, then we need to keep calling SSLWrite() over and
+     over again with no new data until it quits returning errSSLWouldBlock. */
+
+  /* Do we have buffered data to write from the last time we were called? */
+  if(BACKEND->ssl_write_buffered_length) {
+    /* Write the buffered data: */
+    err = SSLWrite(BACKEND->ssl_ctx, NULL, 0UL, &processed);
+    switch(err) {
+      case noErr:
+        /* processed is always going to be 0 because we didn't write to
+           the buffer, so return how much was written to the socket */
+        processed = BACKEND->ssl_write_buffered_length;
+        BACKEND->ssl_write_buffered_length = 0UL;
+        break;
+      case errSSLWouldBlock: /* argh, try again */
+        *curlcode = CURLE_AGAIN;
+        return -1L;
+      default:
+        failf(conn->data, "SSLWrite() returned error %d", err);
+        *curlcode = CURLE_SEND_ERROR;
+        return -1L;
+    }
+  }
+  else {
+    /* We've got new data to write: */
+    err = SSLWrite(BACKEND->ssl_ctx, mem, len, &processed);
+    if(err != noErr) {
+      switch(err) {
+        case errSSLWouldBlock:
+          /* Data was buffered but not sent, we have to tell the caller
+             to try sending again, and remember how much was buffered */
+          BACKEND->ssl_write_buffered_length = len;
+          *curlcode = CURLE_AGAIN;
+          return -1L;
+        default:
+          failf(conn->data, "SSLWrite() returned error %d", err);
+          *curlcode = CURLE_SEND_ERROR;
+          return -1L;
+      }
+    }
+  }
+  return (ssize_t)processed;
+}
+
+static ssize_t sectransp_recv(struct connectdata *conn,
+                              int num,
+                              char *buf,
+                              size_t buffersize,
+                              CURLcode *curlcode)
+{
+  /*struct Curl_easy *data = conn->data;*/
+  struct ssl_connect_data *connssl = &conn->ssl[num];
+  size_t processed = 0UL;
+  OSStatus err;
+
+  again:
+  err = SSLRead(BACKEND->ssl_ctx, buf, buffersize, &processed);
+
+  if(err != noErr) {
+    switch(err) {
+      case errSSLWouldBlock:  /* return how much we read (if anything) */
+        if(processed)
+          return (ssize_t)processed;
+        *curlcode = CURLE_AGAIN;
+        return -1L;
+        break;
+
+      /* errSSLClosedGraceful - server gracefully shut down the SSL session
+         errSSLClosedNoNotify - server hung up on us instead of sending a
+           closure alert notice, read() is returning 0
+         Either way, inform the caller that the server disconnected. */
+      case errSSLClosedGraceful:
+      case errSSLClosedNoNotify:
+        *curlcode = CURLE_OK;
+        return -1L;
+        break;
+
+        /* The below is errSSLPeerAuthCompleted; it's not defined in
+           Leopard's headers */
+      case -9841:
+        if(SSL_CONN_CONFIG(CAfile) && SSL_CONN_CONFIG(verifypeer)) {
+          CURLcode result = verify_cert(SSL_CONN_CONFIG(CAfile), conn->data,
+                                        BACKEND->ssl_ctx);
+          if(result)
+            return result;
+        }
+        goto again;
+      default:
+        failf(conn->data, "SSLRead() return error %d", err);
+        *curlcode = CURLE_RECV_ERROR;
+        return -1L;
+        break;
+    }
+  }
+  return (ssize_t)processed;
+}
+
+static void *Curl_sectransp_get_internals(struct ssl_connect_data *connssl,
+                                          CURLINFO info UNUSED_PARAM)
+{
+  (void)info;
+  return BACKEND->ssl_ctx;
+}
+
+const struct Curl_ssl Curl_ssl_sectransp = {
+  { CURLSSLBACKEND_SECURETRANSPORT, "secure-transport" }, /* info */
+
+#ifdef SECTRANSP_PINNEDPUBKEY
+  SSLSUPP_PINNEDPUBKEY,
+#else
+  0,
+#endif /* SECTRANSP_PINNEDPUBKEY */
+
+  sizeof(struct ssl_backend_data),
+
+  Curl_none_init,                     /* init */
+  Curl_none_cleanup,                  /* cleanup */
+  Curl_sectransp_version,             /* version */
+  Curl_sectransp_check_cxn,           /* check_cxn */
+  Curl_sectransp_shutdown,            /* shutdown */
+  Curl_sectransp_data_pending,        /* data_pending */
+  Curl_sectransp_random,              /* random */
+  Curl_none_cert_status_request,      /* cert_status_request */
+  Curl_sectransp_connect,             /* connect */
+  Curl_sectransp_connect_nonblocking, /* connect_nonblocking */
+  Curl_sectransp_get_internals,       /* get_internals */
+  Curl_sectransp_close,               /* close_one */
+  Curl_none_close_all,                /* close_all */
+  Curl_sectransp_session_free,        /* session_free */
+  Curl_none_set_engine,               /* set_engine */
+  Curl_none_set_engine_default,       /* set_engine_default */
+  Curl_none_engines_list,             /* engines_list */
+  Curl_sectransp_false_start,         /* false_start */
+  Curl_sectransp_md5sum,              /* md5sum */
+  Curl_sectransp_sha256sum            /* sha256sum */
+};
+
+#ifdef __clang__
+#pragma clang diagnostic pop
+#endif
+
+#endif /* USE_SECTRANSP */