/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2009, 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 http://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.
 *
 * $Id: nss.c,v 1.62 2009-10-28 20:30:24 bagder Exp $
 ***************************************************************************/

/*
 * Source file for all NSS-specific code for the TLS/SSL layer. No code
 * but sslgen.c should ever call or use these functions.
 */

#include "setup.h"

#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif

#include "urldata.h"
#include "sendf.h"
#include "formdata.h" /* for the boundary function */
#include "url.h" /* for the ssl config check function */
#include "connect.h"
#include "strequal.h"
#include "select.h"
#include "sslgen.h"

#define _MPRINTF_REPLACE /* use the internal *printf() functions */
#include <curl/mprintf.h>

#ifdef USE_NSS

#include "nssg.h"
#include <nspr.h>
#include <nss.h>
#include <ssl.h>
#include <sslerr.h>
#include <secerr.h>
#include <secmod.h>
#include <sslproto.h>
#include <prtypes.h>
#include <pk11pub.h>
#include <prio.h>
#include <secitem.h>
#include <secport.h>
#include <certdb.h>
#include <base64.h>

#include "curl_memory.h"
#include "rawstr.h"
#include "easyif.h" /* for Curl_convert_from_utf8 prototype */

/* The last #include file should be: */
#include "memdebug.h"

#define SSL_DIR "/etc/pki/nssdb"

/* enough to fit the string "PEM Token #[0|1]" */
#define SLOTSIZE 13

PRFileDesc *PR_ImportTCPSocket(PRInt32 osfd);

PRLock * nss_initlock = NULL;

volatile int initialized = 0;

#define HANDSHAKE_TIMEOUT 30

typedef struct {
  const char *name;
  int num;
  PRInt32 version; /* protocol version valid for this cipher */
} cipher_s;

#define PK11_SETATTRS(x,id,v,l) (x)->type = (id); \
                     (x)->pValue=(v); (x)->ulValueLen = (l)

#define CERT_NewTempCertificate __CERT_NewTempCertificate

enum sslversion { SSL2 = 1, SSL3 = 2, TLS = 4 };

#define NUM_OF_CIPHERS sizeof(cipherlist)/sizeof(cipherlist[0])
static const cipher_s cipherlist[] = {
  /* SSL2 cipher suites */
  {"rc4", SSL_EN_RC4_128_WITH_MD5, SSL2},
  {"rc4-md5", SSL_EN_RC4_128_WITH_MD5, SSL2},
  {"rc4export", SSL_EN_RC4_128_EXPORT40_WITH_MD5, SSL2},
  {"rc2", SSL_EN_RC2_128_CBC_WITH_MD5, SSL2},
  {"rc2export", SSL_EN_RC2_128_CBC_EXPORT40_WITH_MD5, SSL2},
  {"des", SSL_EN_DES_64_CBC_WITH_MD5, SSL2},
  {"desede3", SSL_EN_DES_192_EDE3_CBC_WITH_MD5, SSL2},
  /* SSL3/TLS cipher suites */
  {"rsa_rc4_128_md5", SSL_RSA_WITH_RC4_128_MD5, SSL3 | TLS},
  {"rsa_rc4_128_sha", SSL_RSA_WITH_RC4_128_SHA, SSL3 | TLS},
  {"rsa_3des_sha", SSL_RSA_WITH_3DES_EDE_CBC_SHA, SSL3 | TLS},
  {"rsa_des_sha", SSL_RSA_WITH_DES_CBC_SHA, SSL3 | TLS},
  {"rsa_rc4_40_md5", SSL_RSA_EXPORT_WITH_RC4_40_MD5, SSL3 | TLS},
  {"rsa_rc2_40_md5", SSL_RSA_EXPORT_WITH_RC2_CBC_40_MD5, SSL3 | TLS},
  {"rsa_null_md5", SSL_RSA_WITH_NULL_MD5, SSL3 | TLS},
  {"rsa_null_sha", SSL_RSA_WITH_NULL_SHA, SSL3 | TLS},
  {"fips_3des_sha", SSL_RSA_FIPS_WITH_3DES_EDE_CBC_SHA, SSL3 | TLS},
  {"fips_des_sha", SSL_RSA_FIPS_WITH_DES_CBC_SHA, SSL3 | TLS},
  {"fortezza", SSL_FORTEZZA_DMS_WITH_FORTEZZA_CBC_SHA, SSL3 | TLS},
  {"fortezza_rc4_128_sha", SSL_FORTEZZA_DMS_WITH_RC4_128_SHA, SSL3 | TLS},
  {"fortezza_null", SSL_FORTEZZA_DMS_WITH_NULL_SHA, SSL3 | TLS},
  /* TLS 1.0: Exportable 56-bit Cipher Suites. */
  {"rsa_des_56_sha", TLS_RSA_EXPORT1024_WITH_DES_CBC_SHA, SSL3 | TLS},
  {"rsa_rc4_56_sha", TLS_RSA_EXPORT1024_WITH_RC4_56_SHA, SSL3 | TLS},
  /* AES ciphers. */
  {"rsa_aes_128_sha", TLS_RSA_WITH_AES_128_CBC_SHA, SSL3 | TLS},
  {"rsa_aes_256_sha", TLS_RSA_WITH_AES_256_CBC_SHA, SSL3 | TLS},
#ifdef NSS_ENABLE_ECC
  /* ECC ciphers. */
  {"ecdh_ecdsa_null_sha", TLS_ECDH_ECDSA_WITH_NULL_SHA, TLS},
  {"ecdh_ecdsa_rc4_128_sha", TLS_ECDH_ECDSA_WITH_RC4_128_SHA, TLS},
  {"ecdh_ecdsa_3des_sha", TLS_ECDH_ECDSA_WITH_3DES_EDE_CBC_SHA, TLS},
  {"ecdh_ecdsa_aes_128_sha", TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA, TLS},
  {"ecdh_ecdsa_aes_256_sha", TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA, TLS},
  {"ecdhe_ecdsa_null_sha", TLS_ECDHE_ECDSA_WITH_NULL_SHA, TLS},
  {"ecdhe_ecdsa_rc4_128_sha", TLS_ECDHE_ECDSA_WITH_RC4_128_SHA, TLS},
  {"ecdhe_ecdsa_3des_sha", TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA, TLS},
  {"ecdhe_ecdsa_aes_128_sha", TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA, TLS},
  {"ecdhe_ecdsa_aes_256_sha", TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA, TLS},
  {"ecdh_rsa_null_sha", TLS_ECDH_RSA_WITH_NULL_SHA, TLS},
  {"ecdh_rsa_128_sha", TLS_ECDH_RSA_WITH_RC4_128_SHA, TLS},
  {"ecdh_rsa_3des_sha", TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA, TLS},
  {"ecdh_rsa_aes_128_sha", TLS_ECDH_RSA_WITH_AES_128_CBC_SHA, TLS},
  {"ecdh_rsa_aes_256_sha", TLS_ECDH_RSA_WITH_AES_256_CBC_SHA, TLS},
  {"echde_rsa_null", TLS_ECDHE_RSA_WITH_NULL_SHA, TLS},
  {"ecdhe_rsa_rc4_128_sha", TLS_ECDHE_RSA_WITH_RC4_128_SHA, TLS},
  {"ecdhe_rsa_3des_sha", TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA, TLS},
  {"ecdhe_rsa_aes_128_sha", TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA, TLS},
  {"ecdhe_rsa_aes_256_sha", TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, TLS},
  {"ecdh_anon_null_sha", TLS_ECDH_anon_WITH_NULL_SHA, TLS},
  {"ecdh_anon_rc4_128sha", TLS_ECDH_anon_WITH_RC4_128_SHA, TLS},
  {"ecdh_anon_3des_sha", TLS_ECDH_anon_WITH_3DES_EDE_CBC_SHA, TLS},
  {"ecdh_anon_aes_128_sha", TLS_ECDH_anon_WITH_AES_128_CBC_SHA, TLS},
  {"ecdh_anon_aes_256_sha", TLS_ECDH_anon_WITH_AES_256_CBC_SHA, TLS},
#endif
};

/* following ciphers are new in NSS 3.4 and not enabled by default, therefore
   they are enabled explicitly */
static const int enable_ciphers_by_default[] = {
  TLS_DHE_DSS_WITH_AES_128_CBC_SHA,
  TLS_DHE_DSS_WITH_AES_256_CBC_SHA,
  TLS_DHE_RSA_WITH_AES_128_CBC_SHA,
  TLS_DHE_RSA_WITH_AES_256_CBC_SHA,
  TLS_RSA_WITH_AES_128_CBC_SHA,
  TLS_RSA_WITH_AES_256_CBC_SHA,
  SSL_NULL_WITH_NULL_NULL
};

#ifdef HAVE_PK11_CREATEGENERICOBJECT
static const char* pem_library = "libnsspem.so";
#endif
SECMODModule* mod = NULL;

static SECStatus set_ciphers(struct SessionHandle *data, PRFileDesc * model,
                             char *cipher_list)
{
  unsigned int i;
  PRBool cipher_state[NUM_OF_CIPHERS];
  PRBool found;
  char *cipher;
  SECStatus rv;

  /* First disable all ciphers. This uses a different max value in case
   * NSS adds more ciphers later we don't want them available by
   * accident
   */
  for(i=0; i<SSL_NumImplementedCiphers; i++) {
    SSL_CipherPrefSet(model, SSL_ImplementedCiphers[i], SSL_NOT_ALLOWED);
  }

  /* Set every entry in our list to false */
  for(i=0; i<NUM_OF_CIPHERS; i++) {
    cipher_state[i] = PR_FALSE;
  }

  cipher = cipher_list;

  while(cipher_list && (cipher_list[0])) {
    while((*cipher) && (ISSPACE(*cipher)))
      ++cipher;

    if((cipher_list = strchr(cipher, ','))) {
      *cipher_list++ = '\0';
    }

    found = PR_FALSE;

    for(i=0; i<NUM_OF_CIPHERS; i++) {
      if(Curl_raw_equal(cipher, cipherlist[i].name)) {
        cipher_state[i] = PR_TRUE;
        found = PR_TRUE;
        break;
      }
    }

    if(found == PR_FALSE) {
      failf(data, "Unknown cipher in list: %s", cipher);
      return SECFailure;
    }

    if(cipher_list) {
      cipher = cipher_list;
    }
  }

  /* Finally actually enable the selected ciphers */
  for(i=0; i<NUM_OF_CIPHERS; i++) {
    rv = SSL_CipherPrefSet(model, cipherlist[i].num, cipher_state[i]);
    if(rv != SECSuccess) {
      failf(data, "Unknown cipher in cipher list");
      return SECFailure;
    }
  }

  return SECSuccess;
}

/*
 * Get the number of ciphers that are enabled. We use this to determine
 * if we need to call NSS_SetDomesticPolicy() to enable the default ciphers.
 */
static int num_enabled_ciphers(void)
{
  PRInt32 policy = 0;
  int count = 0;
  unsigned int i;

  for(i=0; i<NUM_OF_CIPHERS; i++) {
    SSL_CipherPolicyGet(cipherlist[i].num, &policy);
    if(policy)
      count++;
  }
  return count;
}

/*
 * 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 (NSS nickname)
 */
static int is_file(const char *filename)
{
  struct_stat st;

  if(filename == NULL)
    return 0;

  if(stat(filename, &st) == 0)
    if(S_ISREG(st.st_mode))
      return 1;

  return 0;
}

static char *fmt_nickname(char *str, bool *nickname_alloc)
{
    char *nickname = NULL;
    *nickname_alloc = FALSE;

    if(is_file(str)) {
      char *n = strrchr(str, '/');
      if(n) {
        *nickname_alloc = TRUE;
        n++; /* skip last slash */
        nickname = aprintf("PEM Token #%d:%s", 1, n);
      }
      return nickname;
    }

    return str;
}

static int nss_load_cert(struct ssl_connect_data *ssl,
                         const char *filename, PRBool cacert)
{
#ifdef HAVE_PK11_CREATEGENERICOBJECT
  CK_SLOT_ID slotID;
  PK11SlotInfo * slot = NULL;
  CK_ATTRIBUTE *attrs;
  CK_ATTRIBUTE theTemplate[20];
  CK_BBOOL cktrue = CK_TRUE;
  CK_BBOOL ckfalse = CK_FALSE;
  CK_OBJECT_CLASS objClass = CKO_CERTIFICATE;
  char slotname[SLOTSIZE];
#endif
  CERTCertificate *cert;
  char *nickname = NULL;
  char *n = NULL;

  /* If there is no slash in the filename it is assumed to be a regular
   * NSS nickname.
   */
  if(is_file(filename)) {
    n = strrchr(filename, '/');
    if(n)
      n++;
    if(!mod)
      return 1;
  }
  else {
    /* A nickname from the NSS internal database */
    if(cacert)
      return 0; /* You can't specify an NSS CA nickname this way */
    nickname = strdup(filename);
    if(!nickname)
      return 0;
    goto done;
  }

#ifdef HAVE_PK11_CREATEGENERICOBJECT
  attrs = theTemplate;

  /* All CA and trust objects go into slot 0. Other slots are used
   * for storing certificates. With each new user certificate we increment
   * the slot count. We only support 1 user certificate right now.
   */
  if(cacert)
    slotID = 0;
  else
    slotID = 1;

  snprintf(slotname, SLOTSIZE, "PEM Token #%ld", slotID);

  nickname = aprintf("PEM Token #%ld:%s", slotID, n);
  if(!nickname)
    return 0;

  slot = PK11_FindSlotByName(slotname);

  if(!slot) {
    free(nickname);
    return 0;
  }

  PK11_SETATTRS(attrs, CKA_CLASS, &objClass, sizeof(objClass) );
  attrs++;
  PK11_SETATTRS(attrs, CKA_TOKEN, &cktrue, sizeof(CK_BBOOL) );
  attrs++;
  PK11_SETATTRS(attrs, CKA_LABEL, (unsigned char *)filename,
                strlen(filename)+1);
  attrs++;
  if(cacert) {
    PK11_SETATTRS(attrs, CKA_TRUST, &cktrue, sizeof(CK_BBOOL) );
  }
  else {
    PK11_SETATTRS(attrs, CKA_TRUST, &ckfalse, sizeof(CK_BBOOL) );
  }
  attrs++;

  /* This load the certificate in our PEM module into the appropriate
   * slot.
   */
  ssl->cacert[slotID] = PK11_CreateGenericObject(slot, theTemplate, 4,
                                         PR_FALSE /* isPerm */);

  PK11_FreeSlot(slot);

  if(ssl->cacert[slotID] == NULL) {
    free(nickname);
    return 0;
  }
#else
  /* We don't have PK11_CreateGenericObject but a file-based cert was passed
   * in. We need to fail.
   */
  return 0;
#endif

done:
  /* Double-check that the certificate or nickname requested exists in
   * either the token or the NSS certificate database.
   */
  if(!cacert) {
    cert = PK11_FindCertFromNickname((char *)nickname, NULL);

    /* An invalid nickname was passed in */
    if(cert == NULL) {
      free(nickname);
      PR_SetError(SEC_ERROR_UNKNOWN_CERT, 0);
      return 0;
    }

    CERT_DestroyCertificate(cert);
  }

  free(nickname);

  return 1;
}

static int nss_load_crl(const char* crlfilename, PRBool ascii)
{
  PRFileDesc *infile;
  PRStatus    prstat;
  PRFileInfo  info;
  PRInt32     nb;
  int rv;
  SECItem crlDER;
  CERTSignedCrl *crl=NULL;
  PK11SlotInfo *slot=NULL;

  infile = PR_Open(crlfilename,PR_RDONLY,0);
  if (!infile) {
    return 0;
  }
  crlDER.data = NULL;
  prstat = PR_GetOpenFileInfo(infile,&info);
  if (prstat!=PR_SUCCESS)
    return 0;
  if (ascii) {
    SECItem filedata;
    char *asc,*body;
    filedata.data = NULL;
    if (!SECITEM_AllocItem(NULL,&filedata,info.size))
      return 0;
    nb = PR_Read(infile,filedata.data,info.size);
    if (nb!=info.size)
      return 0;
    asc = (char*)filedata.data;
    if (!asc)
      return 0;

    body=strstr(asc,"-----BEGIN");
    if (body != NULL) {
      char *trailer=NULL;
      asc = body;
      body = PORT_Strchr(asc,'\n');
      if (!body)
        body = PORT_Strchr(asc,'\r');
      if (body)
        trailer = strstr(++body,"-----END");
      if (trailer!=NULL)
        *trailer='\0';
      else
        return 0;
    }
    else {
      body = asc;
    }
    rv = ATOB_ConvertAsciiToItem(&crlDER,body);
    PORT_Free(filedata.data);
    if (rv)
      return 0;
  }
  else {
    if (!SECITEM_AllocItem(NULL,&crlDER,info.size))
      return 0;
    nb = PR_Read(infile,crlDER.data,info.size);
    if (nb!=info.size)
      return 0;
  }

  slot = PK11_GetInternalKeySlot();
  crl  = PK11_ImportCRL(slot,&crlDER,
                        NULL,SEC_CRL_TYPE,
                        NULL,CRL_IMPORT_DEFAULT_OPTIONS,
                        NULL,(CRL_DECODE_DEFAULT_OPTIONS|
                              CRL_DECODE_DONT_COPY_DER));
  if (slot) PK11_FreeSlot(slot);
  if (!crl) return 0;
  SEC_DestroyCrl(crl);
  return 1;
}

static int nss_load_key(struct connectdata *conn, int sockindex, char *key_file)
{
#ifdef HAVE_PK11_CREATEGENERICOBJECT
  PK11SlotInfo * slot = NULL;
  CK_ATTRIBUTE *attrs;
  CK_ATTRIBUTE theTemplate[20];
  CK_BBOOL cktrue = CK_TRUE;
  CK_OBJECT_CLASS objClass = CKO_PRIVATE_KEY;
  CK_SLOT_ID slotID;
  char slotname[SLOTSIZE];
  struct ssl_connect_data *sslconn = &conn->ssl[sockindex];

  attrs = theTemplate;

  /* FIXME: grok the various file types */

  slotID = 1; /* hardcoded for now */

  snprintf(slotname, sizeof(slotname), "PEM Token #%ld", slotID);
  slot = PK11_FindSlotByName(slotname);

  if(!slot)
    return 0;

  PK11_SETATTRS(attrs, CKA_CLASS, &objClass, sizeof(objClass) ); attrs++;
  PK11_SETATTRS(attrs, CKA_TOKEN, &cktrue, sizeof(CK_BBOOL) ); attrs++;
  PK11_SETATTRS(attrs, CKA_LABEL, (unsigned char *)key_file,
                strlen(key_file)+1); attrs++;

  /* When adding an encrypted key the PKCS#11 will be set as removed */
  sslconn->key = PK11_CreateGenericObject(slot, theTemplate, 3,
                                          PR_FALSE /* isPerm */);
  if(sslconn->key == NULL) {
    PR_SetError(SEC_ERROR_BAD_KEY, 0);
    return 0;
  }

  /* This will force the token to be seen as re-inserted */
  SECMOD_WaitForAnyTokenEvent(mod, 0, 0);
  PK11_IsPresent(slot);

  /* parg is initialized in nss_Init_Tokens() */
  if(PK11_Authenticate(slot, PR_TRUE,
                       conn->data->set.str[STRING_KEY_PASSWD]) != SECSuccess) {

    PK11_FreeSlot(slot);
    return 0;
  }
  PK11_FreeSlot(slot);

  return 1;
#else
  /* If we don't have PK11_CreateGenericObject then we can't load a file-based
   * key.
   */
  (void)conn; /* unused */
  (void)key_file; /* unused */
  return 0;
#endif
}

static int display_error(struct connectdata *conn, PRInt32 err,
                         const char *filename)
{
  switch(err) {
  case SEC_ERROR_BAD_PASSWORD:
    failf(conn->data, "Unable to load client key: Incorrect password");
    return 1;
  case SEC_ERROR_UNKNOWN_CERT:
    failf(conn->data, "Unable to load certificate %s", filename);
    return 1;
  default:
    break;
  }
  return 0; /* The caller will print a generic error */
}

static int cert_stuff(struct connectdata *conn,
                      int sockindex, char *cert_file, char *key_file)
{
  struct SessionHandle *data = conn->data;
  int rv = 0;

  if(cert_file) {
    rv = nss_load_cert(&conn->ssl[sockindex], cert_file, PR_FALSE);
    if(!rv) {
      if(!display_error(conn, PR_GetError(), cert_file))
        failf(data, "Unable to load client cert %d.", PR_GetError());
      return 0;
    }
  }
  if(key_file || (is_file(cert_file))) {
    if(key_file)
      rv = nss_load_key(conn, sockindex, key_file);
    else
      /* In case the cert file also has the key */
      rv = nss_load_key(conn, sockindex, cert_file);
    if(!rv) {
      if(!display_error(conn, PR_GetError(), key_file))
        failf(data, "Unable to load client key %d.", PR_GetError());

      return 0;
    }
  }
  return 1;
}

static char * nss_get_password(PK11SlotInfo * slot, PRBool retry, void *arg)
{
  (void)slot; /* unused */
  if(retry || NULL == arg)
    return NULL;
  else
    return (char *)PORT_Strdup((char *)arg);
}

static SECStatus BadCertHandler(void *arg, PRFileDesc *sock)
{
  SECStatus success = SECSuccess;
  struct connectdata *conn = (struct connectdata *)arg;
  PRErrorCode err = PR_GetError();
  CERTCertificate *cert = NULL;
  char *subject, *subject_cn, *issuer;

  if(conn->data->set.ssl.certverifyresult!=0)
    return success;

  conn->data->set.ssl.certverifyresult=err;
  cert = SSL_PeerCertificate(sock);
  subject = CERT_NameToAscii(&cert->subject);
  subject_cn = CERT_GetCommonName(&cert->subject);
  issuer = CERT_NameToAscii(&cert->issuer);
  CERT_DestroyCertificate(cert);

  switch(err) {
  case SEC_ERROR_CA_CERT_INVALID:
    infof(conn->data, "Issuer certificate is invalid: '%s'\n", issuer);
    if(conn->data->set.ssl.verifypeer)
      success = SECFailure;
    break;
  case SEC_ERROR_UNTRUSTED_ISSUER:
    if(conn->data->set.ssl.verifypeer)
      success = SECFailure;
    infof(conn->data, "Certificate is signed by an untrusted issuer: '%s'\n",
          issuer);
    break;
  case SSL_ERROR_BAD_CERT_DOMAIN:
    if(conn->data->set.ssl.verifyhost) {
      failf(conn->data, "SSL: certificate subject name '%s' does not match "
            "target host name '%s'", subject_cn, conn->host.dispname);
      success = SECFailure;
    } else {
      infof(conn->data, "warning: SSL: certificate subject name '%s' does not "
            "match target host name '%s'\n", subject_cn, conn->host.dispname);
    }
    break;
  case SEC_ERROR_EXPIRED_CERTIFICATE:
    if(conn->data->set.ssl.verifypeer)
      success = SECFailure;
    infof(conn->data, "Remote Certificate has expired.\n");
    break;
  case SEC_ERROR_UNKNOWN_ISSUER:
    if(conn->data->set.ssl.verifypeer)
      success = SECFailure;
    infof(conn->data, "Peer's certificate issuer is not recognized: '%s'\n",
          issuer);
    break;
  default:
    if(conn->data->set.ssl.verifypeer)
      success = SECFailure;
    infof(conn->data, "Bad certificate received. Subject = '%s', "
          "Issuer = '%s'\n", subject, issuer);
    break;
  }
  if(success == SECSuccess)
    infof(conn->data, "SSL certificate verify ok.\n");
  PR_Free(subject);
  PR_Free(subject_cn);
  PR_Free(issuer);

  return success;
}

/**
 * Inform the application that the handshake is complete.
 */
static SECStatus HandshakeCallback(PRFileDesc *sock, void *arg)
{
  (void)sock;
  (void)arg;
  return SECSuccess;
}

static void display_cert_info(struct SessionHandle *data, CERTCertificate *cert) {
    char *subject, *issuer, *common_name;
    PRExplodedTime printableTime;
    char timeString[256];
    PRTime notBefore, notAfter;

    subject = CERT_NameToAscii(&cert->subject);
    issuer = CERT_NameToAscii(&cert->issuer);
    common_name = CERT_GetCommonName(&cert->subject);
    infof(data, "\tsubject: %s\n", subject);

    CERT_GetCertTimes(cert, &notBefore, &notAfter);
    PR_ExplodeTime(notBefore, PR_GMTParameters, &printableTime);
    PR_FormatTime(timeString, 256, "%b %d %H:%M:%S %Y GMT", &printableTime);
    infof(data, "\tstart date: %s\n", timeString);
    PR_ExplodeTime(notAfter, PR_GMTParameters, &printableTime);
    PR_FormatTime(timeString, 256, "%b %d %H:%M:%S %Y GMT", &printableTime);
    infof(data, "\texpire date: %s\n", timeString);
    infof(data, "\tcommon name: %s\n", common_name);
    infof(data, "\tissuer: %s\n", issuer);

    PR_Free(subject);
    PR_Free(issuer);
    PR_Free(common_name);
}

static void display_conn_info(struct connectdata *conn, PRFileDesc *sock)
{
  SSLChannelInfo channel;
  SSLCipherSuiteInfo suite;
  CERTCertificate *cert;

  if(SSL_GetChannelInfo(sock, &channel, sizeof channel) ==
     SECSuccess && channel.length == sizeof channel &&
     channel.cipherSuite) {
    if(SSL_GetCipherSuiteInfo(channel.cipherSuite,
                              &suite, sizeof suite) == SECSuccess) {
      infof(conn->data, "SSL connection using %s\n", suite.cipherSuiteName);
    }
  }

  infof(conn->data, "Server certificate:\n");

  cert = SSL_PeerCertificate(sock);
  display_cert_info(conn->data, cert);
  CERT_DestroyCertificate(cert);

  return;
}

/**
 *
 * Check that the Peer certificate's issuer certificate matches the one found
 * by issuer_nickname.  This is not exactly the way OpenSSL and GNU TLS do the
 * issuer check, so we provide comments that mimic the OpenSSL
 * X509_check_issued function (in x509v3/v3_purp.c)
 */
static SECStatus check_issuer_cert(PRFileDesc *sock,
                                   char *issuer_nickname)
{
  CERTCertificate *cert,*cert_issuer,*issuer;
  SECStatus res=SECSuccess;
  void *proto_win = NULL;

  /*
  PRArenaPool   *tmpArena = NULL;
  CERTAuthKeyID *authorityKeyID = NULL;
  SECITEM       *caname = NULL;
  */

  cert = SSL_PeerCertificate(sock);
  cert_issuer = CERT_FindCertIssuer(cert,PR_Now(),certUsageObjectSigner);

  proto_win = SSL_RevealPinArg(sock);
  issuer = NULL;
  issuer = PK11_FindCertFromNickname(issuer_nickname, proto_win);

  if ((!cert_issuer) || (!issuer))
    res = SECFailure;
  else if (SECITEM_CompareItem(&cert_issuer->derCert,
                               &issuer->derCert)!=SECEqual)
    res = SECFailure;

  CERT_DestroyCertificate(cert);
  CERT_DestroyCertificate(issuer);
  CERT_DestroyCertificate(cert_issuer);
  return res;
}

/**
 *
 * Callback to pick the SSL client certificate.
 */
static SECStatus SelectClientCert(void *arg, PRFileDesc *sock,
                                  struct CERTDistNamesStr *caNames,
                                  struct CERTCertificateStr **pRetCert,
                                  struct SECKEYPrivateKeyStr **pRetKey)
{
  static const char pem_nickname[] = "PEM Token #1";
  const char *pem_slotname = pem_nickname;

  struct ssl_connect_data *connssl = (struct ssl_connect_data *)arg;
  struct SessionHandle *data = connssl->data;
  const char *nickname = connssl->client_nickname;

  if (mod && nickname &&
      0 == strncmp(nickname, pem_nickname, /* length of "PEM Token" */ 9)) {

    /* use the cert/key provided by PEM reader */
    PK11SlotInfo *slot;
    void *proto_win = SSL_RevealPinArg(sock);
    *pRetKey = NULL;

    *pRetCert = PK11_FindCertFromNickname(nickname, proto_win);
    if (NULL == *pRetCert) {
      failf(data, "NSS: client certificate not found: %s", nickname);
      return SECFailure;
    }

    slot = PK11_FindSlotByName(pem_slotname);
    if (NULL == slot) {
      failf(data, "NSS: PK11 slot not found: %s", pem_slotname);
      return SECFailure;
    }

    *pRetKey = PK11_FindPrivateKeyFromCert(slot, *pRetCert, NULL);
    PK11_FreeSlot(slot);
    if (NULL == *pRetKey) {
      failf(data, "NSS: private key not found for certificate: %s", nickname);
      return SECFailure;
    }

    infof(data, "NSS: client certificate: %s\n", nickname);
    display_cert_info(data, *pRetCert);
    return SECSuccess;
  }

  /* use the default NSS hook */
  if (SECSuccess != NSS_GetClientAuthData((void *)nickname, sock, caNames,
                                          pRetCert, pRetKey)
      || NULL == *pRetCert) {

    if (NULL == nickname)
      failf(data, "NSS: client certificate not found (nickname not specified)");
    else
      failf(data, "NSS: client certificate not found: %s", nickname);

    return SECFailure;
  }

  /* get certificate nickname if any */
  nickname = (*pRetCert)->nickname;
  if (NULL == nickname)
    nickname = "[unknown]";

  if (NULL == *pRetKey) {
    failf(data, "NSS: private key not found for certificate: %s", nickname);
    return SECFailure;
  }

  infof(data, "NSS: using client certificate: %s\n", nickname);
  display_cert_info(data, *pRetCert);
  return SECSuccess;
}

/**
 * Global SSL init
 *
 * @retval 0 error initializing SSL
 * @retval 1 SSL initialized successfully
 */
int Curl_nss_init(void)
{
  /* curl_global_init() is not thread-safe so this test is ok */
  if (nss_initlock == NULL) {
    PR_Init(PR_USER_THREAD, PR_PRIORITY_NORMAL, 256);
    nss_initlock = PR_NewLock();
  }

  /* We will actually initialize NSS later */

  return 1;
}

/* Global cleanup */
void Curl_nss_cleanup(void)
{
  /* This function isn't required to be threadsafe and this is only done
   * as a safety feature.
   */
  PR_Lock(nss_initlock);
  if (initialized) {
    /* Free references to client certificates held in the SSL session cache.
     * Omitting this hampers destruction of the security module owning
     * the certificates. */
    SSL_ClearSessionCache();

    if(mod && SECSuccess == SECMOD_UnloadUserModule(mod)) {
      SECMOD_DestroyModule(mod);
      mod = NULL;
    }
    NSS_Shutdown();
  }
  PR_Unlock(nss_initlock);

  PR_DestroyLock(nss_initlock);
  nss_initlock = NULL;

  initialized = 0;
}

/*
 * This function uses SSL_peek 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_nss_check_cxn(struct connectdata *conn)
{
  int rc;
  char buf;

  rc =
    PR_Recv(conn->ssl[FIRSTSOCKET].handle, (void *)&buf, 1, PR_MSG_PEEK,
            PR_SecondsToInterval(1));
  if(rc > 0)
    return 1; /* connection still in place */

  if(rc == 0)
    return 0; /* connection has been closed */

  return -1;  /* connection status unknown */
}

/*
 * This function is called when an SSL connection is closed.
 */
void Curl_nss_close(struct connectdata *conn, int sockindex)
{
  struct ssl_connect_data *connssl = &conn->ssl[sockindex];

  if(connssl->handle) {
    PR_Close(connssl->handle);

    /* NSS closes the socket we previously handed to it, so we must mark it
       as closed to avoid double close */
    fake_sclose(conn->sock[sockindex]);
    conn->sock[sockindex] = CURL_SOCKET_BAD;
    if(connssl->client_nickname != NULL) {
      free(connssl->client_nickname);
      connssl->client_nickname = NULL;
    }
#ifdef HAVE_PK11_CREATEGENERICOBJECT
    if(connssl->key)
      (void)PK11_DestroyGenericObject(connssl->key);
    if(connssl->cacert[1])
      (void)PK11_DestroyGenericObject(connssl->cacert[1]);
    if(connssl->cacert[0])
      (void)PK11_DestroyGenericObject(connssl->cacert[0]);
#endif
    connssl->handle = NULL;
  }
}

/*
 * This function is called when the 'data' struct is going away. Close
 * down everything and free all resources!
 */
int Curl_nss_close_all(struct SessionHandle *data)
{
  (void)data;
  return 0;
}

CURLcode Curl_nss_connect(struct connectdata *conn, int sockindex)
{
  PRInt32 err;
  PRFileDesc *model = NULL;
  PRBool ssl2, ssl3, tlsv1;
  struct SessionHandle *data = conn->data;
  curl_socket_t sockfd = conn->sock[sockindex];
  struct ssl_connect_data *connssl = &conn->ssl[sockindex];
  SECStatus rv;
  char *certDir = NULL;
  int curlerr;
  const int *cipher_to_enable;

  curlerr = CURLE_SSL_CONNECT_ERROR;

  if (connssl->state == ssl_connection_complete)
    return CURLE_OK;

  connssl->data = data;

#ifdef HAVE_PK11_CREATEGENERICOBJECT
  connssl->cacert[0] = NULL;
  connssl->cacert[1] = NULL;
  connssl->key = NULL;
#endif

  /* FIXME. NSS doesn't support multiple databases open at the same time. */
  PR_Lock(nss_initlock);
  if(!initialized) {
    struct_stat st;

    /* First we check if $SSL_DIR points to a valid dir */
    certDir = getenv("SSL_DIR");
    if(certDir) {
      if((stat(certDir, &st) != 0) ||
              (!S_ISDIR(st.st_mode))) {
        certDir = NULL;
      }
    }

    /* Now we check if the default location is a valid dir */
    if(!certDir) {
      if((stat(SSL_DIR, &st) == 0) &&
              (S_ISDIR(st.st_mode))) {
        certDir = (char *)SSL_DIR;
      }
    }

    if (!NSS_IsInitialized()) {
      initialized = 1;
      infof(conn->data, "Initializing NSS with certpath: %s\n",
            certDir ? certDir : "none");
      if(!certDir) {
        rv = NSS_NoDB_Init(NULL);
      }
      else {
        char *certpath = PR_smprintf("%s%s",
                         NSS_VersionCheck("3.12.0") ? "sql:" : "",
                         certDir);
        rv = NSS_Initialize(certpath, "", "", "", NSS_INIT_READONLY);
        PR_smprintf_free(certpath);
      }
      if(rv != SECSuccess) {
        infof(conn->data, "Unable to initialize NSS database\n");
        curlerr = CURLE_SSL_CACERT_BADFILE;
        initialized = 0;
        PR_Unlock(nss_initlock);
        goto error;
      }
    }

    if(num_enabled_ciphers() == 0)
      NSS_SetDomesticPolicy();

#ifdef HAVE_PK11_CREATEGENERICOBJECT
    if(!mod) {
      char *configstring = aprintf("library=%s name=PEM", pem_library);
      if(!configstring) {
        PR_Unlock(nss_initlock);
        goto error;
      }
      mod = SECMOD_LoadUserModule(configstring, NULL, PR_FALSE);
      free(configstring);

      if(!mod || !mod->loaded) {
        if(mod) {
          SECMOD_DestroyModule(mod);
          mod = NULL;
        }
        infof(data, "WARNING: failed to load NSS PEM library %s. Using OpenSSL "
              "PEM certificates will not work.\n", pem_library);
      }
    }
#endif

    PK11_SetPasswordFunc(nss_get_password);

  }
  PR_Unlock(nss_initlock);

  model = PR_NewTCPSocket();
  if(!model)
    goto error;
  model = SSL_ImportFD(NULL, model);

  if(SSL_OptionSet(model, SSL_SECURITY, PR_TRUE) != SECSuccess)
    goto error;
  if(SSL_OptionSet(model, SSL_HANDSHAKE_AS_SERVER, PR_FALSE) != SECSuccess)
    goto error;
  if(SSL_OptionSet(model, SSL_HANDSHAKE_AS_CLIENT, PR_TRUE) != SECSuccess)
    goto error;

  ssl2 = ssl3 = tlsv1 = PR_FALSE;

  switch (data->set.ssl.version) {
  default:
  case CURL_SSLVERSION_DEFAULT:
    ssl3 = tlsv1 = PR_TRUE;
    break;
  case CURL_SSLVERSION_TLSv1:
    tlsv1 = PR_TRUE;
    break;
  case CURL_SSLVERSION_SSLv2:
    ssl2 = PR_TRUE;
    break;
  case CURL_SSLVERSION_SSLv3:
    ssl3 = PR_TRUE;
    break;
  }

  if(SSL_OptionSet(model, SSL_ENABLE_SSL2, ssl2) != SECSuccess)
    goto error;
  if(SSL_OptionSet(model, SSL_ENABLE_SSL3, ssl3) != SECSuccess)
    goto error;
  if(SSL_OptionSet(model, SSL_ENABLE_TLS, tlsv1) != SECSuccess)
    goto error;

  if(SSL_OptionSet(model, SSL_V2_COMPATIBLE_HELLO, ssl2) != SECSuccess)
    goto error;

  /* enable all ciphers from enable_ciphers_by_default */
  cipher_to_enable = enable_ciphers_by_default;
  while (SSL_NULL_WITH_NULL_NULL != *cipher_to_enable) {
    if (SSL_CipherPrefSet(model, *cipher_to_enable, PR_TRUE) != SECSuccess) {
      curlerr = CURLE_SSL_CIPHER;
      goto error;
    }
    cipher_to_enable++;
  }

  if(data->set.ssl.cipher_list) {
    if(set_ciphers(data, model, data->set.ssl.cipher_list) != SECSuccess) {
      curlerr = CURLE_SSL_CIPHER;
      goto error;
    }
  }

  if(data->set.ssl.verifyhost == 1)
    infof(data, "warning: ignoring unsupported value (1) of ssl.verifyhost\n");

  data->set.ssl.certverifyresult=0; /* not checked yet */
  if(SSL_BadCertHook(model, (SSLBadCertHandler) BadCertHandler, conn)
     != SECSuccess) {
    goto error;
  }
  if(SSL_HandshakeCallback(model, (SSLHandshakeCallback) HandshakeCallback,
                           NULL) != SECSuccess)
    goto error;

  if(!data->set.ssl.verifypeer)
    /* skip the verifying of the peer */
    ;
  else if(data->set.ssl.CAfile) {
    int rc = nss_load_cert(&conn->ssl[sockindex], data->set.ssl.CAfile,
                           PR_TRUE);
    if(!rc) {
      curlerr = CURLE_SSL_CACERT_BADFILE;
      goto error;
    }
  }
  else if(data->set.ssl.CApath) {
    struct_stat st;
    PRDir      *dir;
    PRDirEntry *entry;

    if(stat(data->set.ssl.CApath, &st) == -1) {
      curlerr = CURLE_SSL_CACERT_BADFILE;
      goto error;
    }

    if(S_ISDIR(st.st_mode)) {
      int rc;

      dir = PR_OpenDir(data->set.ssl.CApath);
      do {
        entry = PR_ReadDir(dir, PR_SKIP_BOTH | PR_SKIP_HIDDEN);

        if(entry) {
          char fullpath[PATH_MAX];

          snprintf(fullpath, sizeof(fullpath), "%s/%s", data->set.ssl.CApath,
                   entry->name);
          rc = nss_load_cert(&conn->ssl[sockindex], fullpath, PR_TRUE);
          /* FIXME: check this return value! */
        }
        /* This is purposefully tolerant of errors so non-PEM files
         * can be in the same directory */
      } while(entry != NULL);
      PR_CloseDir(dir);
    }
  }
  infof(data,
        "  CAfile: %s\n"
        "  CApath: %s\n",
        data->set.ssl.CAfile ? data->set.ssl.CAfile : "none",
        data->set.ssl.CApath ? data->set.ssl.CApath : "none");

  if (data->set.ssl.CRLfile) {
    int rc = nss_load_crl(data->set.ssl.CRLfile, PR_FALSE);
    if (!rc) {
      curlerr = CURLE_SSL_CRL_BADFILE;
      goto error;
    }
    infof(data,
          "  CRLfile: %s\n",
          data->set.ssl.CRLfile ? data->set.ssl.CRLfile : "none");
  }

  if(data->set.str[STRING_CERT]) {
    bool nickname_alloc = FALSE;
    char *nickname = fmt_nickname(data->set.str[STRING_CERT], &nickname_alloc);
    if(!nickname)
      return CURLE_OUT_OF_MEMORY;

    if(!cert_stuff(conn, sockindex, data->set.str[STRING_CERT],
                    data->set.str[STRING_KEY])) {
      /* failf() is already done in cert_stuff() */
      if(nickname_alloc)
        free(nickname);
      return CURLE_SSL_CERTPROBLEM;
    }

    /* this "takes over" the pointer to the allocated name or makes a
       dup of it */
    connssl->client_nickname = nickname_alloc?nickname:strdup(nickname);
    if(!connssl->client_nickname)
      return CURLE_OUT_OF_MEMORY;

  }
  else
    connssl->client_nickname = NULL;

  if(SSL_GetClientAuthDataHook(model, SelectClientCert,
                               (void *)connssl) != SECSuccess) {
    curlerr = CURLE_SSL_CERTPROBLEM;
    goto error;
  }

  /* Import our model socket  onto the existing file descriptor */
  connssl->handle = PR_ImportTCPSocket(sockfd);
  connssl->handle = SSL_ImportFD(model, connssl->handle);
  if(!connssl->handle)
    goto error;
  PR_Close(model); /* We don't need this any more */

  /* This is the password associated with the cert that we're using */
  if (data->set.str[STRING_KEY_PASSWD]) {
      SSL_SetPKCS11PinArg(connssl->handle, data->set.str[STRING_KEY_PASSWD]);
  }

  /* Force handshake on next I/O */
  SSL_ResetHandshake(connssl->handle, /* asServer */ PR_FALSE);

  SSL_SetURL(connssl->handle, conn->host.name);

  /* Force the handshake now */
  if(SSL_ForceHandshakeWithTimeout(connssl->handle,
                                    PR_SecondsToInterval(HANDSHAKE_TIMEOUT))
      != SECSuccess) {
    if(conn->data->set.ssl.certverifyresult == SSL_ERROR_BAD_CERT_DOMAIN)
      curlerr = CURLE_PEER_FAILED_VERIFICATION;
    else if(conn->data->set.ssl.certverifyresult!=0)
      curlerr = CURLE_SSL_CACERT;
    goto error;
  }

  connssl->state = ssl_connection_complete;

  display_conn_info(conn, connssl->handle);

  if (data->set.str[STRING_SSL_ISSUERCERT]) {
    SECStatus ret;
    bool nickname_alloc = FALSE;
    char *nickname = fmt_nickname(data->set.str[STRING_SSL_ISSUERCERT],
                                  &nickname_alloc);

    if(!nickname)
      return CURLE_OUT_OF_MEMORY;

    ret = check_issuer_cert(connssl->handle, nickname);

    if(nickname_alloc)
      free(nickname);

    if(SECFailure == ret) {
      infof(data,"SSL certificate issuer check failed\n");
      curlerr = CURLE_SSL_ISSUER_ERROR;
      goto error;
    }
    else {
      infof(data, "SSL certificate issuer check ok\n");
    }
  }

  return CURLE_OK;

error:
  err = PR_GetError();
  infof(data, "NSS error %d\n", err);
  if(model)
    PR_Close(model);
  return curlerr;
}

/* return number of sent (non-SSL) bytes */
int Curl_nss_send(struct connectdata *conn,  /* connection data */
                  int sockindex,             /* socketindex */
                  const void *mem,           /* send this data */
                  size_t len)                /* amount to write */
{
  PRInt32 err;
  struct SessionHandle *data = conn->data;
  PRInt32 timeout;
  int rc;

  if(data->set.timeout)
    timeout = PR_MillisecondsToInterval((PRUint32)data->set.timeout);
  else
    timeout = PR_MillisecondsToInterval(DEFAULT_CONNECT_TIMEOUT);

  rc = PR_Send(conn->ssl[sockindex].handle, mem, (int)len, 0, timeout);

  if(rc < 0) {
    err = PR_GetError();

    if(err == PR_IO_TIMEOUT_ERROR) {
      failf(data, "SSL connection timeout");
      return CURLE_OPERATION_TIMEDOUT;
    }

    failf(conn->data, "SSL write: error %d", err);
    return -1;
  }
  return rc; /* number of bytes */
}

/*
 * If the read would block we return -1 and set 'wouldblock' to TRUE.
 * Otherwise we return the amount of data read. Other errors should return -1
 * and set 'wouldblock' to FALSE.
 */
ssize_t Curl_nss_recv(struct connectdata * conn, /* connection data */
                      int num,                   /* socketindex */
                      char *buf,                 /* store read data here */
                      size_t buffersize,         /* max amount to read */
                      bool * wouldblock)
{
  ssize_t nread;
  struct SessionHandle *data = conn->data;
  PRInt32 timeout;

  if(data->set.timeout)
    timeout = PR_SecondsToInterval((PRUint32)data->set.timeout);
  else
    timeout = PR_MillisecondsToInterval(DEFAULT_CONNECT_TIMEOUT);

  nread = PR_Recv(conn->ssl[num].handle, buf, (int)buffersize, 0, timeout);
  *wouldblock = FALSE;
  if(nread < 0) {
    /* failed SSL read */
    PRInt32 err = PR_GetError();

    if(err == PR_WOULD_BLOCK_ERROR) {
      *wouldblock = TRUE;
      return -1; /* basically EWOULDBLOCK */
    }
    if(err == PR_IO_TIMEOUT_ERROR) {
      failf(data, "SSL connection timeout");
      return CURLE_OPERATION_TIMEDOUT;
    }
    failf(conn->data, "SSL read: errno %d", err);
    return -1;
  }
  return nread;
}

size_t Curl_nss_version(char *buffer, size_t size)
{
  return snprintf(buffer, size, "NSS/%s", NSS_VERSION);
}
#endif /* USE_NSS */