text: /***************************************************************************
   *                                  _   _ ____  _
   *  Project                     ___| | | |  _ \| |
   *                             / __| | | | |_) | |
   *                            | (__| |_| |  _ <| |___
   *                             \___|\___/|_| \_\_____|
   *
   * Copyright (C) 1998 - 2016, 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.
   *
   ***************************************************************************/
  
  /* This file is for implementing all "generic" SSL functions that all libcurl
     internals should use. It is then responsible for calling the proper
     "backend" function.
  
     SSL-functions in libcurl should call functions in this source file, and not
     to any specific SSL-layer.
  
     Curl_ssl_ - prefix for generic ones
     Curl_ossl_ - prefix for OpenSSL ones
     Curl_gtls_ - prefix for GnuTLS ones
     Curl_nss_ - prefix for NSS ones
     Curl_gskit_ - prefix for GSKit ones
     Curl_polarssl_ - prefix for PolarSSL ones
     Curl_cyassl_ - prefix for CyaSSL ones
     Curl_schannel_ - prefix for Schannel SSPI ones
     Curl_darwinssl_ - prefix for SecureTransport (Darwin) ones
  
     Note that this source code uses curlssl_* functions, and they are all
     defines/macros #defined by the lib-specific header files.
  
     "SSL/TLS Strong Encryption: An Introduction"
     https://httpd.apache.org/docs/2.0/ssl/ssl_intro.html
  */
  
  #include "curl_setup.h"
  
  #ifdef HAVE_SYS_TYPES_H
  #include <sys/types.h>
  #endif
  #ifdef HAVE_SYS_STAT_H
  #include <sys/stat.h>
  #endif
  #ifdef HAVE_FCNTL_H
  #include <fcntl.h>
  #endif
  
  #include "urldata.h"
  
  #include "vtls.h" /* generic SSL protos etc */
  #include "slist.h"
  #include "sendf.h"
  #include "rawstr.h"
  #include "url.h"
  #include "progress.h"
  #include "share.h"
  #include "timeval.h"
  #include "curl_md5.h"
  #include "warnless.h"
  #include "curl_base64.h"
  #include "curl_printf.h"
  
  /* The last #include files should be: */
  #include "curl_memory.h"
  #include "memdebug.h"
  
  /* convenience macro to check if this handle is using a shared SSL session */
  #define SSLSESSION_SHARED(data) (data->share &&                        \
                                   (data->share->specifier &             \
                                    (1<<CURL_LOCK_DATA_SSL_SESSION)))
  
  static bool safe_strequal(char* str1, char* str2)
  {
    if(str1 && str2)
      /* both pointers point to something then compare them */
      return (0 != Curl_raw_equal(str1, str2)) ? TRUE : FALSE;
    else
      /* if both pointers are NULL then treat them as equal */
      return (!str1 && !str2) ? TRUE : FALSE;
  }
  
  bool
  Curl_ssl_config_matches(struct ssl_config_data* data,
                          struct ssl_config_data* needle)
  {
    if((data->version == needle->version) &&
       (data->verifypeer == needle->verifypeer) &&
       (data->verifyhost == needle->verifyhost) &&
       safe_strequal(data->CApath, needle->CApath) &&
       safe_strequal(data->CAfile, needle->CAfile) &&
       safe_strequal(data->clientcert, needle->clientcert) &&
       safe_strequal(data->cipher_list, needle->cipher_list))
      return TRUE;
  
    return FALSE;
  }
  
  bool
  Curl_clone_ssl_config(struct ssl_config_data *source,
                        struct ssl_config_data *dest)
  {
    dest->sessionid = source->sessionid;
    dest->verifyhost = source->verifyhost;
    dest->verifypeer = source->verifypeer;
    dest->version = source->version;
  
    if(source->CAfile) {
      dest->CAfile = strdup(source->CAfile);
      if(!dest->CAfile)
        return FALSE;
    }
    else
      dest->CAfile = NULL;
  
    if(source->CApath) {
      dest->CApath = strdup(source->CApath);
      if(!dest->CApath)
        return FALSE;
    }
    else
      dest->CApath = NULL;
  
    if(source->cipher_list) {
      dest->cipher_list = strdup(source->cipher_list);
      if(!dest->cipher_list)
        return FALSE;
    }
    else
      dest->cipher_list = NULL;
  
    if(source->egdsocket) {
      dest->egdsocket = strdup(source->egdsocket);
      if(!dest->egdsocket)
        return FALSE;
    }
    else
      dest->egdsocket = NULL;
  
    if(source->random_file) {
      dest->random_file = strdup(source->random_file);
      if(!dest->random_file)
        return FALSE;
    }
    else
      dest->random_file = NULL;
  
    if(source->clientcert) {
      dest->clientcert = strdup(source->clientcert);
      if(!dest->clientcert)
        return FALSE;
      dest->sessionid = FALSE;
    }
    else
      dest->clientcert = NULL;
  
    return TRUE;
  }
  
  void Curl_free_ssl_config(struct ssl_config_data* sslc)
  {
    Curl_safefree(sslc->CAfile);
    Curl_safefree(sslc->CApath);
    Curl_safefree(sslc->cipher_list);
    Curl_safefree(sslc->egdsocket);
    Curl_safefree(sslc->random_file);
    Curl_safefree(sslc->clientcert);
  }
  
  
  /*
   * Curl_rand() returns a random unsigned integer, 32bit.
   *
   * This non-SSL function is put here only because this file is the only one
   * with knowledge of what the underlying SSL libraries provide in terms of
   * randomizers.
   *
   * NOTE: 'data' may be passed in as NULL when coming from external API without
   * easy handle!
   *
   */
  
  unsigned int Curl_rand(struct Curl_easy *data)
  {
    unsigned int r = 0;
    static unsigned int randseed;
    static bool seeded = FALSE;
  
  #ifdef CURLDEBUG
    char *force_entropy = getenv("CURL_ENTROPY");
    if(force_entropy) {
      if(!seeded) {
        size_t elen = strlen(force_entropy);
        size_t clen = sizeof(randseed);
        size_t min = elen < clen ? elen : clen;
        memcpy((char *)&randseed, force_entropy, min);
        seeded = TRUE;
      }
      else
        randseed++;
      return randseed;
    }
  #endif
  
    /* data may be NULL! */
    if(!Curl_ssl_random(data, (unsigned char *)&r, sizeof(r)))
      return r;
  
    /* If Curl_ssl_random() returns non-zero it couldn't offer randomness and we
       instead perform a "best effort" */
  
  #ifdef RANDOM_FILE
    if(!seeded) {
      /* if there's a random file to read a seed from, use it */
      int fd = open(RANDOM_FILE, O_RDONLY);
      if(fd > -1) {
        /* read random data into the randseed variable */
        ssize_t nread = read(fd, &randseed, sizeof(randseed));
        if(nread == sizeof(randseed))
          seeded = TRUE;
        close(fd);
      }
    }
  #endif
  
    if(!seeded) {
      struct timeval now = curlx_tvnow();
      infof(data, "WARNING: Using weak random seed\n");
      randseed += (unsigned int)now.tv_usec + (unsigned int)now.tv_sec;
      randseed = randseed * 1103515245 + 12345;
      randseed = randseed * 1103515245 + 12345;
      randseed = randseed * 1103515245 + 12345;
      seeded = TRUE;
    }
  
    /* Return an unsigned 32-bit pseudo-random number. */
    r = randseed = randseed * 1103515245 + 12345;
    return (r << 16) | ((r >> 16) & 0xFFFF);
  }
  
  int Curl_ssl_backend(void)
  {
    return (int)CURL_SSL_BACKEND;
  }
  
  #ifdef USE_SSL
  
  /* "global" init done? */
  static bool init_ssl=FALSE;
  
  /**
   * Global SSL init
   *
   * @retval 0 error initializing SSL
   * @retval 1 SSL initialized successfully
   */
  int Curl_ssl_init(void)
  {
    /* make sure this is only done once */
    if(init_ssl)
      return 1;
    init_ssl = TRUE; /* never again */
  
    return curlssl_init();
  }
  
  
  /* Global cleanup */
  void Curl_ssl_cleanup(void)
  {
    if(init_ssl) {
      /* only cleanup if we did a previous init */
      curlssl_cleanup();
      init_ssl = FALSE;
    }
  }
  
  static bool ssl_prefs_check(struct Curl_easy *data)
  {
    /* check for CURLOPT_SSLVERSION invalid parameter value */
    if((data->set.ssl.version < 0)
       || (data->set.ssl.version >= CURL_SSLVERSION_LAST)) {
      failf(data, "Unrecognized parameter value passed via CURLOPT_SSLVERSION");
      return FALSE;
    }
    return TRUE;
  }
  
  CURLcode
  Curl_ssl_connect(struct connectdata *conn, int sockindex)
  {
    CURLcode result;
  
    if(!ssl_prefs_check(conn->data))
      return CURLE_SSL_CONNECT_ERROR;
  
    /* mark this is being ssl-enabled from here on. */
    conn->ssl[sockindex].use = TRUE;
    conn->ssl[sockindex].state = ssl_connection_negotiating;
  
    result = curlssl_connect(conn, sockindex);
  
    if(!result)
      Curl_pgrsTime(conn->data, TIMER_APPCONNECT); /* SSL is connected */
  
    return result;
  }
  
  CURLcode
  Curl_ssl_connect_nonblocking(struct connectdata *conn, int sockindex,
                               bool *done)
  {
    CURLcode result;
  
    if(!ssl_prefs_check(conn->data))
      return CURLE_SSL_CONNECT_ERROR;
  
    /* mark this is being ssl requested from here on. */
    conn->ssl[sockindex].use = TRUE;
  #ifdef curlssl_connect_nonblocking
    result = curlssl_connect_nonblocking(conn, sockindex, done);
  #else
    *done = TRUE; /* fallback to BLOCKING */
    result = curlssl_connect(conn, sockindex);
  #endif /* non-blocking connect support */
    if(!result && *done)
      Curl_pgrsTime(conn->data, TIMER_APPCONNECT); /* SSL is connected */
    return result;
  }
  
  /*
   * Lock shared SSL session data
   */
  void Curl_ssl_sessionid_lock(struct connectdata *conn)
  {
    if(SSLSESSION_SHARED(conn->data))
      Curl_share_lock(conn->data,
                      CURL_LOCK_DATA_SSL_SESSION, CURL_LOCK_ACCESS_SINGLE);
  }
  
  /*
   * Unlock shared SSL session data
   */
  void Curl_ssl_sessionid_unlock(struct connectdata *conn)
  {
    if(SSLSESSION_SHARED(conn->data))
      Curl_share_unlock(conn->data, CURL_LOCK_DATA_SSL_SESSION);
  }
  
  /*
   * Check if there's a session ID for the given connection in the cache, and if
   * there's one suitable, it is provided. Returns TRUE when no entry matched.
   */
  bool Curl_ssl_getsessionid(struct connectdata *conn,
                             void **ssl_sessionid,
                             size_t *idsize) /* set 0 if unknown */
  {
    struct curl_ssl_session *check;
    struct Curl_easy *data = conn->data;
    size_t i;
    long *general_age;
    bool no_match = TRUE;
  
    *ssl_sessionid = NULL;
  
    DEBUGASSERT(conn->ssl_config.sessionid);
  
    if(!conn->ssl_config.sessionid)
      /* session ID re-use is disabled */
      return TRUE;
  
    /* Lock if shared */
    if(SSLSESSION_SHARED(data))
      general_age = &data->share->sessionage;
    else
      general_age = &data->state.sessionage;
  
    for(i = 0; i < data->set.ssl.max_ssl_sessions; i++) {
      check = &data->state.session[i];
      if(!check->sessionid)
        /* not session ID means blank entry */
        continue;
      if(Curl_raw_equal(conn->host.name, check->name) &&
         ((!conn->bits.conn_to_host && !check->conn_to_host) ||
           (conn->bits.conn_to_host && check->conn_to_host &&
             Curl_raw_equal(conn->conn_to_host.name, check->conn_to_host))) &&
         ((!conn->bits.conn_to_port && check->conn_to_port == -1) ||
           (conn->bits.conn_to_port && check->conn_to_port != -1 &&
             conn->conn_to_port == check->conn_to_port)) &&
         (conn->remote_port == check->remote_port) &&
         Curl_raw_equal(conn->handler->scheme, check->scheme) &&
         Curl_ssl_config_matches(&conn->ssl_config, &check->ssl_config)) {
        /* yes, we have a session ID! */
        (*general_age)++;          /* increase general age */
        check->age = *general_age; /* set this as used in this age */
        *ssl_sessionid = check->sessionid;
        if(idsize)
          *idsize = check->idsize;
        no_match = FALSE;
        break;
      }
    }
  
    return no_match;
  }
  
  /*
   * Kill a single session ID entry in the cache.
   */
  void Curl_ssl_kill_session(struct curl_ssl_session *session)
  {
    if(session->sessionid) {
      /* defensive check */
  
      /* free the ID the SSL-layer specific way */
      curlssl_session_free(session->sessionid);
  
      session->sessionid = NULL;
      session->age = 0; /* fresh */
  
      Curl_free_ssl_config(&session->ssl_config);
  
      Curl_safefree(session->name);
      Curl_safefree(session->conn_to_host);
    }
  }
  
  /*
   * Delete the given session ID from the cache.
   */
  void Curl_ssl_delsessionid(struct connectdata *conn, void *ssl_sessionid)
  {
    size_t i;
    struct Curl_easy *data=conn->data;
  
    for(i = 0; i < data->set.ssl.max_ssl_sessions; i++) {
      struct curl_ssl_session *check = &data->state.session[i];
  
      if(check->sessionid == ssl_sessionid) {
        Curl_ssl_kill_session(check);
        break;
      }
    }
  }
  
  /*
   * Store session id in the session cache. The ID passed on to this function
   * must already have been extracted and allocated the proper way for the SSL
   * layer. Curl_XXXX_session_free() will be called to free/kill the session ID
   * later on.
   */
  CURLcode Curl_ssl_addsessionid(struct connectdata *conn,
                                 void *ssl_sessionid,
                                 size_t idsize)
  {
    size_t i;
    struct Curl_easy *data=conn->data; /* the mother of all structs */
    struct curl_ssl_session *store = &data->state.session[0];
    long oldest_age=data->state.session[0].age; /* zero if unused */
    char *clone_host;
    char *clone_conn_to_host;
    int conn_to_port;
    long *general_age;
  
    DEBUGASSERT(conn->ssl_config.sessionid);
  
    clone_host = strdup(conn->host.name);
    if(!clone_host)
      return CURLE_OUT_OF_MEMORY; /* bail out */
  
    if(conn->bits.conn_to_host) {
      clone_conn_to_host = strdup(conn->conn_to_host.name);
      if(!clone_conn_to_host) {
        free(clone_host);
        return CURLE_OUT_OF_MEMORY; /* bail out */
      }
    }
    else
      clone_conn_to_host = NULL;
  
    if(conn->bits.conn_to_port)
      conn_to_port = conn->conn_to_port;
    else
      conn_to_port = -1;
  
    /* Now we should add the session ID and the host name to the cache, (remove
       the oldest if necessary) */
  
    /* If using shared SSL session, lock! */
    if(SSLSESSION_SHARED(data)) {
      general_age = &data->share->sessionage;
    }
    else {
      general_age = &data->state.sessionage;
    }
  
    /* find an empty slot for us, or find the oldest */
    for(i = 1; (i < data->set.ssl.max_ssl_sessions) &&
          data->state.session[i].sessionid; i++) {
      if(data->state.session[i].age < oldest_age) {
        oldest_age = data->state.session[i].age;
        store = &data->state.session[i];
      }
    }
    if(i == data->set.ssl.max_ssl_sessions)
      /* cache is full, we must "kill" the oldest entry! */
      Curl_ssl_kill_session(store);
    else
      store = &data->state.session[i]; /* use this slot */
  
    /* now init the session struct wisely */
    store->sessionid = ssl_sessionid;
    store->idsize = idsize;
    store->age = *general_age;    /* set current age */
      /* free it if there's one already present */
    free(store->name);
    free(store->conn_to_host);
    store->name = clone_host;               /* clone host name */
    store->conn_to_host = clone_conn_to_host; /* clone connect to host name */
    store->conn_to_port = conn_to_port; /* connect to port number */
    store->remote_port = conn->remote_port; /* port number */
    store->scheme = conn->handler->scheme;
  
    if(!Curl_clone_ssl_config(&conn->ssl_config, &store->ssl_config)) {
      store->sessionid = NULL; /* let caller free sessionid */
      free(clone_host);
      free(clone_conn_to_host);
      return CURLE_OUT_OF_MEMORY;
    }
  
    return CURLE_OK;
  }
  
  
  void Curl_ssl_close_all(struct Curl_easy *data)
  {
    size_t i;
    /* kill the session ID cache if not shared */
    if(data->state.session && !SSLSESSION_SHARED(data)) {
      for(i = 0; i < data->set.ssl.max_ssl_sessions; i++)
        /* the single-killer function handles empty table slots */
        Curl_ssl_kill_session(&data->state.session[i]);
  
      /* free the cache data */
      Curl_safefree(data->state.session);
    }
  
    curlssl_close_all(data);
  }
  
  void Curl_ssl_close(struct connectdata *conn, int sockindex)
  {
    DEBUGASSERT((sockindex <= 1) && (sockindex >= -1));
    curlssl_close(conn, sockindex);
  }
  
  CURLcode Curl_ssl_shutdown(struct connectdata *conn, int sockindex)
  {
    if(curlssl_shutdown(conn, sockindex))
      return CURLE_SSL_SHUTDOWN_FAILED;
  
    conn->ssl[sockindex].use = FALSE; /* get back to ordinary socket usage */
    conn->ssl[sockindex].state = ssl_connection_none;
  
    conn->recv[sockindex] = Curl_recv_plain;
    conn->send[sockindex] = Curl_send_plain;
  
    return CURLE_OK;
  }
  
  /* Selects an SSL crypto engine
   */
  CURLcode Curl_ssl_set_engine(struct Curl_easy *data, const char *engine)
  {
    return curlssl_set_engine(data, engine);
  }
  
  /* Selects the default SSL crypto engine
   */
  CURLcode Curl_ssl_set_engine_default(struct Curl_easy *data)
  {
    return curlssl_set_engine_default(data);
  }
  
  /* Return list of OpenSSL crypto engine names. */
  struct curl_slist *Curl_ssl_engines_list(struct Curl_easy *data)
  {
    return curlssl_engines_list(data);
  }
  
  /*
   * This sets up a session ID cache to the specified size. Make sure this code
   * is agnostic to what underlying SSL technology we use.
   */
  CURLcode Curl_ssl_initsessions(struct Curl_easy *data, size_t amount)
  {
    struct curl_ssl_session *session;
  
    if(data->state.session)
      /* this is just a precaution to prevent multiple inits */
      return CURLE_OK;
  
    session = calloc(amount, sizeof(struct curl_ssl_session));
    if(!session)
      return CURLE_OUT_OF_MEMORY;
  
    /* store the info in the SSL section */
    data->set.ssl.max_ssl_sessions = amount;
    data->state.session = session;
    data->state.sessionage = 1; /* this is brand new */
    return CURLE_OK;
  }
  
  size_t Curl_ssl_version(char *buffer, size_t size)
  {
    return curlssl_version(buffer, size);
  }
  
  /*
   * This function tries 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
   */
  int Curl_ssl_check_cxn(struct connectdata *conn)
  {
    return curlssl_check_cxn(conn);
  }
  
  bool Curl_ssl_data_pending(const struct connectdata *conn,
                             int connindex)
  {
    return curlssl_data_pending(conn, connindex);
  }
  
  void Curl_ssl_free_certinfo(struct Curl_easy *data)
  {
    int i;
    struct curl_certinfo *ci = &data->info.certs;
  
    if(ci->num_of_certs) {
      /* free all individual lists used */
      for(i=0; i<ci->num_of_certs; i++) {
        curl_slist_free_all(ci->certinfo[i]);
        ci->certinfo[i] = NULL;
      }
  
      free(ci->certinfo); /* free the actual array too */
      ci->certinfo = NULL;
      ci->num_of_certs = 0;
    }
  }
  
  CURLcode Curl_ssl_init_certinfo(struct Curl_easy *data, int num)
  {
    struct curl_certinfo *ci = &data->info.certs;
    struct curl_slist **table;
  
    /* Free any previous certificate information structures */
    Curl_ssl_free_certinfo(data);
  
    /* Allocate the required certificate information structures */
    table = calloc((size_t) num, sizeof(struct curl_slist *));
    if(!table)
      return CURLE_OUT_OF_MEMORY;
  
    ci->num_of_certs = num;
    ci->certinfo = table;
  
    return CURLE_OK;
  }
  
  /*
   * 'value' is NOT a zero terminated string
   */
  CURLcode Curl_ssl_push_certinfo_len(struct Curl_easy *data,
                                      int certnum,
                                      const char *label,
                                      const char *value,
                                      size_t valuelen)
  {
    struct curl_certinfo * ci = &data->info.certs;
    char * output;
    struct curl_slist * nl;
    CURLcode result = CURLE_OK;
    size_t labellen = strlen(label);
    size_t outlen = labellen + 1 + valuelen + 1; /* label:value\0 */
  
    output = malloc(outlen);
    if(!output)
      return CURLE_OUT_OF_MEMORY;
  
    /* sprintf the label and colon */
    snprintf(output, outlen, "%s:", label);
  
    /* memcpy the value (it might not be zero terminated) */
    memcpy(&output[labellen+1], value, valuelen);
  
    /* zero terminate the output */
    output[labellen + 1 + valuelen] = 0;
  
    nl = Curl_slist_append_nodup(ci->certinfo[certnum], output);
    if(!nl) {
      free(output);
      curl_slist_free_all(ci->certinfo[certnum]);
      result = CURLE_OUT_OF_MEMORY;
    }
  
    ci->certinfo[certnum] = nl;
    return result;
  }
  
  /*
   * This is a convenience function for push_certinfo_len that takes a zero
   * terminated value.
   */
  CURLcode Curl_ssl_push_certinfo(struct Curl_easy *data,
                                  int certnum,
                                  const char *label,
                                  const char *value)
  {
    size_t valuelen = strlen(value);
  
    return Curl_ssl_push_certinfo_len(data, certnum, label, value, valuelen);
  }
  
  int Curl_ssl_random(struct Curl_easy *data,
                       unsigned char *entropy,
                       size_t length)
  {
    return curlssl_random(data, entropy, length);
  }
  
  /*
   * Public key pem to der conversion
   */
  
  static CURLcode pubkey_pem_to_der(const char *pem,
                                    unsigned char **der, size_t *der_len)
  {
    char *stripped_pem, *begin_pos, *end_pos;
    size_t pem_count, stripped_pem_count = 0, pem_len;
    CURLcode result;
  
    /* if no pem, exit. */
    if(!pem)
      return CURLE_BAD_CONTENT_ENCODING;
  
    begin_pos = strstr(pem, "-----BEGIN PUBLIC KEY-----");
    if(!begin_pos)
      return CURLE_BAD_CONTENT_ENCODING;
  
    pem_count = begin_pos - pem;
    /* Invalid if not at beginning AND not directly following \n */
    if(0 != pem_count && '\n' != pem[pem_count - 1])
      return CURLE_BAD_CONTENT_ENCODING;
  
    /* 26 is length of "-----BEGIN PUBLIC KEY-----" */
    pem_count += 26;
  
    /* Invalid if not directly following \n */
    end_pos = strstr(pem + pem_count, "\n-----END PUBLIC KEY-----");
    if(!end_pos)
      return CURLE_BAD_CONTENT_ENCODING;
  
    pem_len = end_pos - pem;
  
    stripped_pem = malloc(pem_len - pem_count + 1);
    if(!stripped_pem)
      return CURLE_OUT_OF_MEMORY;
  
    /*
     * Here we loop through the pem array one character at a time between the
     * correct indices, and place each character that is not '\n' or '\r'
     * into the stripped_pem array, which should represent the raw base64 string
     */
    while(pem_count < pem_len) {
      if('\n' != pem[pem_count] && '\r' != pem[pem_count])
        stripped_pem[stripped_pem_count++] = pem[pem_count];
      ++pem_count;
    }
    /* Place the null terminator in the correct place */
    stripped_pem[stripped_pem_count] = '\0';
  
    result = Curl_base64_decode(stripped_pem, der, der_len);
  
    Curl_safefree(stripped_pem);
  
    return result;
  }
  
  /*
   * Generic pinned public key check.
   */
  
  CURLcode Curl_pin_peer_pubkey(struct Curl_easy *data,
                                const char *pinnedpubkey,
                                const unsigned char *pubkey, size_t pubkeylen)
  {
    FILE *fp;
    unsigned char *buf = NULL, *pem_ptr = NULL;
    long filesize;
    size_t size, pem_len;
    CURLcode pem_read;
    CURLcode result = CURLE_SSL_PINNEDPUBKEYNOTMATCH;
  #ifdef curlssl_sha256sum
    CURLcode encode;
    size_t encodedlen, pinkeylen;
    char *encoded, *pinkeycopy, *begin_pos, *end_pos;
    unsigned char *sha256sumdigest = NULL;
  #endif
  
    /* if a path wasn't specified, don't pin */
    if(!pinnedpubkey)
      return CURLE_OK;
    if(!pubkey || !pubkeylen)
      return result;
  
    /* only do this if pinnedpubkey starts with "sha256//", length 8 */
    if(strncmp(pinnedpubkey, "sha256//", 8) == 0) {
  #ifdef curlssl_sha256sum
      /* compute sha256sum of public key */
      sha256sumdigest = malloc(SHA256_DIGEST_LENGTH);
      if(!sha256sumdigest)
        return CURLE_OUT_OF_MEMORY;
      curlssl_sha256sum(pubkey, pubkeylen,
                        sha256sumdigest, SHA256_DIGEST_LENGTH);
      encode = Curl_base64_encode(data, (char *)sha256sumdigest,
                                  SHA256_DIGEST_LENGTH, &encoded, &encodedlen);
      Curl_safefree(sha256sumdigest);
  
      if(encode)
        return encode;
  
      infof(data, "\t public key hash: sha256//%s\n", encoded);
  
      /* it starts with sha256//, copy so we can modify it */
      pinkeylen = strlen(pinnedpubkey) + 1;
      pinkeycopy = malloc(pinkeylen);
      if(!pinkeycopy) {
        Curl_safefree(encoded);
        return CURLE_OUT_OF_MEMORY;
      }
      memcpy(pinkeycopy, pinnedpubkey, pinkeylen);
      /* point begin_pos to the copy, and start extracting keys */
      begin_pos = pinkeycopy;
      do {
        end_pos = strstr(begin_pos, ";sha256//");
        /*
         * if there is an end_pos, null terminate,
         * otherwise it'll go to the end of the original string
         */
        if(end_pos)
          end_pos[0] = '\0';
  
        /* compare base64 sha256 digests, 8 is the length of "sha256//" */
        if(encodedlen == strlen(begin_pos + 8) &&
           !memcmp(encoded, begin_pos + 8, encodedlen)) {
          result = CURLE_OK;
          break;
        }
  
        /*
         * change back the null-terminator we changed earlier,
         * and look for next begin
         */
        if(end_pos) {
          end_pos[0] = ';';
          begin_pos = strstr(end_pos, "sha256//");
        }
      } while(end_pos && begin_pos);
      Curl_safefree(encoded);
      Curl_safefree(pinkeycopy);
  #else
      /* without sha256 support, this cannot match */
      (void)data;
  #endif
      return result;
    }
  
    fp = fopen(pinnedpubkey, "rb");
    if(!fp)
      return result;
  
    do {
      /* Determine the file's size */
      if(fseek(fp, 0, SEEK_END))
        break;
      filesize = ftell(fp);
      if(fseek(fp, 0, SEEK_SET))
        break;
      if(filesize < 0 || filesize > MAX_PINNED_PUBKEY_SIZE)
        break;
  
      /*
       * if the size of our certificate is bigger than the file
       * size then it can't match
       */
      size = curlx_sotouz((curl_off_t) filesize);
      if(pubkeylen > size)
        break;
  
      /*
       * Allocate buffer for the pinned key
       * With 1 additional byte for null terminator in case of PEM key
       */
      buf = malloc(size + 1);
      if(!buf)
        break;
  
      /* Returns number of elements read, which should be 1 */
      if((int) fread(buf, size, 1, fp) != 1)
        break;
  
      /* If the sizes are the same, it can't be base64 encoded, must be der */
      if(pubkeylen == size) {
        if(!memcmp(pubkey, buf, pubkeylen))
          result = CURLE_OK;
        break;
      }
  
      /*
       * Otherwise we will assume it's PEM and try to decode it
       * after placing null terminator
       */
      buf[size] = '\0';
      pem_read = pubkey_pem_to_der((const char *)buf, &pem_ptr, &pem_len);
      /* if it wasn't read successfully, exit */
      if(pem_read)
        break;
  
      /*
       * if the size of our certificate doesn't match the size of
       * the decoded file, they can't be the same, otherwise compare
       */
      if(pubkeylen == pem_len && !memcmp(pubkey, pem_ptr, pubkeylen))
        result = CURLE_OK;
    } while(0);
  
    Curl_safefree(buf);
    Curl_safefree(pem_ptr);
    fclose(fp);
  
    return result;
  }
  
  #ifndef CURL_DISABLE_CRYPTO_AUTH
  CURLcode Curl_ssl_md5sum(unsigned char *tmp, /* input */
                           size_t tmplen,
                           unsigned char *md5sum, /* output */
                           size_t md5len)
  {
  #ifdef curlssl_md5sum
    curlssl_md5sum(tmp, tmplen, md5sum, md5len);
  #else
    MD5_context *MD5pw;
  
    (void) md5len;
  
    MD5pw = Curl_MD5_init(Curl_DIGEST_MD5);
    if(!MD5pw)
      return CURLE_OUT_OF_MEMORY;
    Curl_MD5_update(MD5pw, tmp, curlx_uztoui(tmplen));
    Curl_MD5_final(MD5pw, md5sum);
  #endif
    return CURLE_OK;
  }
  #endif
  
  /*
   * Check whether the SSL backend supports the status_request extension.
   */
  bool Curl_ssl_cert_status_request(void)
  {
  #ifdef curlssl_cert_status_request
    return curlssl_cert_status_request();
  #else
    return FALSE;
  #endif
  }
  
  /*
   * Check whether the SSL backend supports false start.
   */
  bool Curl_ssl_false_start(void)
  {
  #ifdef curlssl_false_start
    return curlssl_false_start();
  #else
    return FALSE;
  #endif
  }
  
  #endif /* USE_SSL */
  