curl/lib/ssluse.c

/*****************************************************************************
 *                                  _   _ ____  _     
 *  Project                     ___| | | |  _ \| |    
 *                             / __| | | | |_) | |    
 *                            | (__| |_| |  _ <| |___ 
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 2000, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * In order to be useful for every potential user, curl and libcurl are
 * dual-licensed under the MPL and the MIT/X-derivate licenses.
 *
 * 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 MPL or the MIT/X-derivate
 * licenses. You may pick one of these licenses.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 * $Id$
 *****************************************************************************/

/*
 * The original SSL code was written by
 * Linas Vepstas <linas@linas.org> and Sampo Kellomaki <sampo@iki.fi>
 */

#include "setup.h"
#include <string.h>
#include <stdlib.h>

#include "urldata.h"
#include "sendf.h"
#include "formdata.h" /* for the boundary function */

#ifdef USE_SSLEAY

static char global_passwd[64];

static int passwd_callback(char *buf, int num, int verify
#if OPENSSL_VERSION_NUMBER >= 0x00904100L
                           /* This was introduced in 0.9.4, we can set this
                              using SSL_CTX_set_default_passwd_cb_userdata()
                              */
                           , void *userdata
#endif
                           )
{
  if(verify)
    fprintf(stderr, "%s\n", buf);
  else {
    if(num > strlen(global_passwd)) {
      strcpy(buf, global_passwd);
      return strlen(buf);
    }
  }  
  return 0;
}

/* This function is *highly* inspired by (and parts are directly stolen
 * from) source from the SSLeay package written by Eric Young
 * (eay@cryptsoft.com).  */

static
int cert_stuff(struct UrlData *data, 
               char *cert_file,
               char *key_file)
{
  if (cert_file != NULL) {
    SSL *ssl;
    X509 *x509;

    if(data->cert_passwd) {
      /*
       * If password has been given, we store that in the global
       * area (*shudder*) for a while:
       */
      strcpy(global_passwd, data->cert_passwd);
      /* Set passwd callback: */
      SSL_CTX_set_default_passwd_cb(data->ssl.ctx, passwd_callback);
    }

    if (SSL_CTX_use_certificate_file(data->ssl.ctx,
				     cert_file,
				     SSL_FILETYPE_PEM) <= 0) {
      failf(data, "unable to set certificate file (wrong password?)\n");
      return(0);
    }
    if (key_file == NULL)
      key_file=cert_file;

    if (SSL_CTX_use_PrivateKey_file(data->ssl.ctx,
				    key_file,
				    SSL_FILETYPE_PEM) <= 0) {
      failf(data, "unable to set public key file\n");
      return(0);
    }
    
    ssl=SSL_new(data->ssl.ctx);
    x509=SSL_get_certificate(ssl);
    
    if (x509 != NULL)
      EVP_PKEY_copy_parameters(X509_get_pubkey(x509),
			       SSL_get_privatekey(ssl));
    SSL_free(ssl);

    /* If we are using DSA, we can copy the parameters from
     * the private key */
		
    
    /* Now we know that a key and cert have been set against
     * the SSL context */
    if (!SSL_CTX_check_private_key(data->ssl.ctx)) {
      failf(data, "Private key does not match the certificate public key\n");
      return(0);
    }
    
    /* erase it now */
    memset(global_passwd, 0, sizeof(global_passwd));
  }
  return(1);
}

#endif

#ifdef USE_SSLEAY
static
int cert_verify_callback(int ok, X509_STORE_CTX *ctx)
{
  X509 *err_cert;
  char buf[256];

  err_cert=X509_STORE_CTX_get_current_cert(ctx);
  X509_NAME_oneline(X509_get_subject_name(err_cert),buf,256);

  return 1;
}

#endif

/* ====================================================== */
int
Curl_SSLConnect (struct UrlData *data)
{
#ifdef USE_SSLEAY
    int err;
    char * str;
    SSL_METHOD *req_method;

    /* mark this is being ssl enabled from here on out. */
    data->ssl.use = TRUE;

    /* Lets get nice error messages */
    SSL_load_error_strings();

#ifdef HAVE_RAND_STATUS
    /* RAND_status() was introduced in OpenSSL 0.9.5 */
    if(0 == RAND_status())
#endif
    {
      /* We need to seed the PRNG properly! */
#ifdef HAVE_RAND_SCREEN
      /* This one gets a random value by reading the currently shown screen */
      RAND_screen();
#else
      int len;
      char *area = Curl_FormBoundary();
      if(!area)
	return 3; /* out of memory */
	
      len = strlen(area);

      RAND_seed(area, len);

      free(area); /* now remove the random junk */
#endif
    }
    
    /* Setup all the global SSL stuff */
    SSLeay_add_ssl_algorithms();

    switch(data->ssl.version) {
    default:
      req_method = SSLv23_client_method();
      break;
    case 2:
      req_method = SSLv2_client_method();
      break;
    case 3:
      req_method = SSLv3_client_method();
      break;
    }
    
    data->ssl.ctx = SSL_CTX_new(req_method);

    if(!data->ssl.ctx) {
      failf(data, "SSL: couldn't create a context!");
      return 1;
    }
    
    if(data->cert) {
      if (!cert_stuff(data, data->cert, data->cert)) {
	failf(data, "couldn't use certificate!\n");
	return 2;
      }
    }

    if(data->ssl.verifypeer){
      SSL_CTX_set_verify(data->ssl.ctx,
                         SSL_VERIFY_PEER|SSL_VERIFY_FAIL_IF_NO_PEER_CERT|
                         SSL_VERIFY_CLIENT_ONCE,
                         cert_verify_callback);
      if (!SSL_CTX_load_verify_locations(data->ssl.ctx,
                                         data->ssl.CAfile,
                                         data->ssl.CApath)) {
        failf(data,"error setting cerficate verify locations\n");
        return 2;
      }
    }
    else
      SSL_CTX_set_verify(data->ssl.ctx, SSL_VERIFY_NONE, cert_verify_callback);


    /* Lets make an SSL structure */
    data->ssl.handle = SSL_new (data->ssl.ctx);
    SSL_set_connect_state (data->ssl.handle);

    data->ssl.server_cert = 0x0;

    /* pass the raw socket into the SSL layers */
    SSL_set_fd (data->ssl.handle, data->firstsocket);
    err = SSL_connect (data->ssl.handle);

    if (-1 == err) {
      err = ERR_get_error(); 
      failf(data, "SSL: %s", ERR_error_string(err, NULL));
      return 10;
    }

    /* Informational message */
    infof (data, "SSL connection using %s\n",
           SSL_get_cipher(data->ssl.handle));
  
    /* Get server's certificate (note: beware of dynamic allocation) - opt */
    /* major serious hack alert -- we should check certificates
     * to authenticate the server; otherwise we risk man-in-the-middle
     * attack
     */

    data->ssl.server_cert = SSL_get_peer_certificate (data->ssl.handle);
    if(!data->ssl.server_cert) {
      failf(data, "SSL: couldn't get peer certificate!");
      return 3;
    }
    infof (data, "Server certificate:\n");
  
    str = X509_NAME_oneline (X509_get_subject_name (data->ssl.server_cert),
                             NULL, 0);
    if(!str) {
      failf(data, "SSL: couldn't get X509-subject!");
      return 4;
    }
    infof(data, "\t subject: %s\n", str);
    CRYPTO_free(str);

    str = X509_NAME_oneline (X509_get_issuer_name  (data->ssl.server_cert),
                             NULL, 0);
    if(!str) {
      failf(data, "SSL: couldn't get X509-issuer name!");
      return 5;
    }
    infof(data, "\t issuer: %s\n", str);
    CRYPTO_free(str);

    /* We could do all sorts of certificate verification stuff here before
       deallocating the certificate. */

    if(data->ssl.verifypeer) {
      data->ssl.certverifyresult=SSL_get_verify_result(data->ssl.handle);
      infof(data, "Verify result: %d\n", data->ssl.certverifyresult);
    }
    else
      data->ssl.certverifyresult=0;

    X509_free(data->ssl.server_cert);
#else /* USE_SSLEAY */
    /* this is for "-ansi -Wall -pedantic" to stop complaining!   (rabe) */
    (void) data;
#endif
    return 0;
}