text: /* Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  /*                      _             _
   *  _ __ ___   ___   __| |    ___ ___| |  mod_ssl
   * | '_ ` _ \ / _ \ / _` |   / __/ __| |  Apache Interface to OpenSSL
   * | | | | | | (_) | (_| |   \__ \__ \ |
   * |_| |_| |_|\___/ \__,_|___|___/___/_|
   *                      |_____|
   *  ssl_util_ssl.c
   *  Additional Utility Functions for OpenSSL
   */
  
  #include "ssl_private.h"
  
  /*  _________________________________________________________________
  **
  **  Additional High-Level Functions for OpenSSL
  **  _________________________________________________________________
  */
  
  /* we initialize this index at startup time
   * and never write to it at request time,
   * so this static is thread safe.
   * also note that OpenSSL increments at static variable when
   * SSL_get_ex_new_index() is called, so we _must_ do this at startup.
   */
  static int app_data2_idx = -1;
  
  void modssl_init_app_data2_idx(void)
  {
      int i;
  
      if (app_data2_idx > -1) {
          return;
      }
  
      /* we _do_ need to call this twice */
      for (i = 0; i <= 1; i++) {
          app_data2_idx =
              SSL_get_ex_new_index(0,
                                   "Second Application Data for SSL",
                                   NULL, NULL, NULL);
      }
  }
  
  void *modssl_get_app_data2(SSL *ssl)
  {
      return (void *)SSL_get_ex_data(ssl, app_data2_idx);
  }
  
  void modssl_set_app_data2(SSL *ssl, void *arg)
  {
      SSL_set_ex_data(ssl, app_data2_idx, (char *)arg);
      return;
  }
  
  /*  _________________________________________________________________
  **
  **  High-Level Private Key Loading
  **  _________________________________________________________________
  */
  
  EVP_PKEY *modssl_read_privatekey(const char* filename, EVP_PKEY **key, pem_password_cb *cb, void *s)
  {
      EVP_PKEY *rc;
      BIO *bioS;
      BIO *bioF;
  
      /* 1. try PEM (= DER+Base64+headers) */
      if ((bioS=BIO_new_file(filename, "r")) == NULL)
          return NULL;
      rc = PEM_read_bio_PrivateKey(bioS, key, cb, s);
      BIO_free(bioS);
  
      if (rc == NULL) {
          /* 2. try DER+Base64 */
          if ((bioS = BIO_new_file(filename, "r")) == NULL)
              return NULL;
  
          if ((bioF = BIO_new(BIO_f_base64())) == NULL) {
              BIO_free(bioS);
              return NULL;
          }
          bioS = BIO_push(bioF, bioS);
          rc = d2i_PrivateKey_bio(bioS, NULL);
          BIO_free_all(bioS);
  
          if (rc == NULL) {
              /* 3. try plain DER */
              if ((bioS = BIO_new_file(filename, "r")) == NULL)
                  return NULL;
              rc = d2i_PrivateKey_bio(bioS, NULL);
              BIO_free(bioS);
          }
      }
      if (rc != NULL && key != NULL) {
          if (*key != NULL)
              EVP_PKEY_free(*key);
          *key = rc;
      }
      return rc;
  }
  
  typedef struct {
      const char *pass;
      int pass_len;
  } pass_ctx;
  
  static int provide_pass(char *buf, int size, int rwflag, void *baton)
  {
      pass_ctx *ctx = baton;
      if (ctx->pass_len > 0) {
          if (ctx->pass_len < size) {
              size = (int)ctx->pass_len;
          }
          memcpy(buf, ctx->pass, size);
      }
      return ctx->pass_len;
  }
  
  EVP_PKEY   *modssl_read_encrypted_pkey(const char *filename, EVP_PKEY **key, 
                                         const char *pass, apr_size_t pass_len)
  {
      pass_ctx ctx;
      
      ctx.pass = pass;
      ctx.pass_len = pass_len;
      return modssl_read_privatekey(filename, key, provide_pass, &ctx);
  }
  
  /*  _________________________________________________________________
  **
  **  Smart shutdown
  **  _________________________________________________________________
  */
  
  int modssl_smart_shutdown(SSL *ssl)
  {
      int i;
      int rc;
      int flush;
  
      /*
       * Repeat the calls, because SSL_shutdown internally dispatches through a
       * little state machine. Usually only one or two interation should be
       * needed, so we restrict the total number of restrictions in order to
       * avoid process hangs in case the client played bad with the socket
       * connection and OpenSSL cannot recognize it.
       */
      rc = 0;
      flush = !(SSL_get_shutdown(ssl) & SSL_SENT_SHUTDOWN);
      for (i = 0; i < 4 /* max 2x pending + 2x data = 4 */; i++) {
          rc = SSL_shutdown(ssl);
          if (rc >= 0 && flush && (SSL_get_shutdown(ssl) & SSL_SENT_SHUTDOWN)) {
              /* Once the close notity is sent through the output filters,
               * ensure it is flushed through the socket.
               */
              if (BIO_flush(SSL_get_wbio(ssl)) <= 0) {
                  rc = -1;
                  break;
              }
              flush = 0;
          }
          if (rc != 0)
              break;
      }
      return rc;
  }
  
  /*  _________________________________________________________________
  **
  **  Certificate Checks
  **  _________________________________________________________________
  */
  
  /* retrieve basic constraints ingredients */
  BOOL modssl_X509_getBC(X509 *cert, int *ca, int *pathlen)
  {
      BASIC_CONSTRAINTS *bc;
      BIGNUM *bn = NULL;
      char *cp;
  
      bc = X509_get_ext_d2i(cert, NID_basic_constraints, NULL, NULL);
      if (bc == NULL)
          return FALSE;
      *ca = bc->ca;
      *pathlen = -1 /* unlimited */;
      if (bc->pathlen != NULL) {
          if ((bn = ASN1_INTEGER_to_BN(bc->pathlen, NULL)) == NULL) {
              BASIC_CONSTRAINTS_free(bc);
              return FALSE;
          }
          if ((cp = BN_bn2dec(bn)) == NULL) {
              BN_free(bn);
              BASIC_CONSTRAINTS_free(bc);
              return FALSE;
          }
          *pathlen = atoi(cp);
          OPENSSL_free(cp);
          BN_free(bn);
      }
      BASIC_CONSTRAINTS_free(bc);
      return TRUE;
  }
  
  /* Convert ASN.1 string to a pool-allocated char * string, escaping
   * control characters.  If raw is zero, convert to UTF-8, otherwise
   * unchanged from the character set. */
  static char *asn1_string_convert(apr_pool_t *p, ASN1_STRING *asn1str, int raw)
  {
      char *result = NULL;
      BIO *bio;
      int len, flags = ASN1_STRFLGS_ESC_CTRL;
  
      if ((bio = BIO_new(BIO_s_mem())) == NULL)
          return NULL;
  
      if (!raw) flags |= ASN1_STRFLGS_UTF8_CONVERT;
      
      ASN1_STRING_print_ex(bio, asn1str, flags);
      len = BIO_pending(bio);
      if (len > 0) {
          result = apr_palloc(p, len+1);
          len = BIO_read(bio, result, len);
          result[len] = NUL;
      }
      BIO_free(bio);
      return result;
  }
  
  #define asn1_string_to_utf8(p, a) asn1_string_convert(p, a, 0)
  
  /* convert a NAME_ENTRY to UTF8 string */
  char *modssl_X509_NAME_ENTRY_to_string(apr_pool_t *p, X509_NAME_ENTRY *xsne,
                                         int raw)
  {
      char *result = asn1_string_convert(p, X509_NAME_ENTRY_get_data(xsne), raw);
      ap_xlate_proto_from_ascii(result, len);
      return result;
  }
  
  /*
   * convert an X509_NAME to an RFC 2253 formatted string, optionally truncated
   * to maxlen characters (specify a maxlen of 0 for no length limit)
   */
  char *modssl_X509_NAME_to_string(apr_pool_t *p, X509_NAME *dn, int maxlen)
  {
      char *result = NULL;
      BIO *bio;
      int len;
  
      if ((bio = BIO_new(BIO_s_mem())) == NULL)
          return NULL;
      X509_NAME_print_ex(bio, dn, 0, XN_FLAG_RFC2253);
      len = BIO_pending(bio);
      if (len > 0) {
          result = apr_palloc(p, (maxlen > 0) ? maxlen+1 : len+1);
          if (maxlen > 0 && maxlen < len) {
              len = BIO_read(bio, result, maxlen);
              if (maxlen > 2) {
                  /* insert trailing ellipsis if there's enough space */
                  apr_snprintf(result + maxlen - 3, 4, "...");
              }
          } else {
              len = BIO_read(bio, result, len);
          }
          result[len] = NUL;
      }
      BIO_free(bio);
  
      return result;
  }
  
  static void parse_otherName_value(apr_pool_t *p, ASN1_TYPE *value,
                                    const char *onf, apr_array_header_t **entries)
  {
      const char *str;
      int nid = onf ? OBJ_txt2nid(onf) : NID_undef;
  
      if (!value || (nid == NID_undef) || !*entries)
         return;
  
      /* 
       * Currently supported otherName forms (values for "onf"):
       * "msUPN" (1.3.6.1.4.1.311.20.2.3): Microsoft User Principal Name
       * "id-on-dnsSRV" (1.3.6.1.5.5.7.8.7): SRVName, as specified in RFC 4985
       */
      if ((nid == NID_ms_upn) && (value->type == V_ASN1_UTF8STRING) &&
          (str = asn1_string_to_utf8(p, value->value.utf8string))) {
          APR_ARRAY_PUSH(*entries, const char *) = str;
      } else if (strEQ(onf, "id-on-dnsSRV") &&
                 (value->type == V_ASN1_IA5STRING) &&
                 (str = asn1_string_to_utf8(p, value->value.ia5string))) {
          APR_ARRAY_PUSH(*entries, const char *) = str;
      }
  }
  
  /* 
   * Return an array of subjectAltName entries of type "type". If idx is -1,
   * return all entries of the given type, otherwise return an array consisting
   * of the n-th occurrence of that type only. Currently supported types:
   * GEN_EMAIL (rfc822Name)
   * GEN_DNS (dNSName)
   * GEN_OTHERNAME (requires the otherName form ["onf"] argument to be supplied,
   *                see parse_otherName_value for the currently supported forms)
   */
  BOOL modssl_X509_getSAN(apr_pool_t *p, X509 *x509, int type, const char *onf,
                          int idx, apr_array_header_t **entries)
  {
      STACK_OF(GENERAL_NAME) *names;
      int nid = onf ? OBJ_txt2nid(onf) : NID_undef;
  
      if (!x509 || (type < GEN_OTHERNAME) ||
          ((type == GEN_OTHERNAME) && (nid == NID_undef)) ||
          (type > GEN_RID) || (idx < -1) ||
          !(*entries = apr_array_make(p, 0, sizeof(char *)))) {
          *entries = NULL;
          return FALSE;
      }
  
      if ((names = X509_get_ext_d2i(x509, NID_subject_alt_name, NULL, NULL))) {
          int i, n = 0;
          GENERAL_NAME *name;
          const char *utf8str;
  
          for (i = 0; i < sk_GENERAL_NAME_num(names); i++) {
              name = sk_GENERAL_NAME_value(names, i);
  
              if (name->type != type)
                  continue;
  
              switch (type) {
              case GEN_EMAIL:
              case GEN_DNS:
                  if (((idx == -1) || (n == idx)) &&
                      (utf8str = asn1_string_to_utf8(p, name->d.ia5))) {
                      APR_ARRAY_PUSH(*entries, const char *) = utf8str;
                  }
                  n++;
                  break;
              case GEN_OTHERNAME:
                  if (OBJ_obj2nid(name->d.otherName->type_id) == nid) {
                      if (((idx == -1) || (n == idx))) {
                          parse_otherName_value(p, name->d.otherName->value,
                                                onf, entries);
                      }
                      n++;
                  }
                  break;
              default:
                  /*
                   * Not implemented right now:
                   * GEN_X400 (x400Address)
                   * GEN_DIRNAME (directoryName)
                   * GEN_EDIPARTY (ediPartyName)
                   * GEN_URI (uniformResourceIdentifier)
                   * GEN_IPADD (iPAddress)
                   * GEN_RID (registeredID)
                   */
                  break;
              }
  
              if ((idx != -1) && (n > idx))
                 break;
          }
  
          sk_GENERAL_NAME_pop_free(names, GENERAL_NAME_free);
      }
  
      return apr_is_empty_array(*entries) ? FALSE : TRUE;
  }
  
  /* return an array of (RFC 6125 coined) DNS-IDs and CN-IDs in a certificate */
  static BOOL getIDs(apr_pool_t *p, X509 *x509, apr_array_header_t **ids)
  {
      X509_NAME *subj;
      int i = -1;
  
      /* First, the DNS-IDs (dNSName entries in the subjectAltName extension) */
      if (!x509 ||
          (modssl_X509_getSAN(p, x509, GEN_DNS, NULL, -1, ids) == FALSE && !*ids)) {
          *ids = NULL;
          return FALSE;
      }
  
      /* Second, the CN-IDs (commonName attributes in the subject DN) */
      subj = X509_get_subject_name(x509);
      while ((i = X509_NAME_get_index_by_NID(subj, NID_commonName, i)) != -1) {
          APR_ARRAY_PUSH(*ids, const char *) = 
              modssl_X509_NAME_ENTRY_to_string(p, X509_NAME_get_entry(subj, i), 0);
      }
  
      return apr_is_empty_array(*ids) ? FALSE : TRUE;
  }
  
  /* 
   * Check if a certificate matches for a particular name, by iterating over its
   * DNS-IDs and CN-IDs (RFC 6125), optionally with basic wildcard matching.
   * If server_rec is non-NULL, some (debug/trace) logging is enabled.
   */
  BOOL modssl_X509_match_name(apr_pool_t *p, X509 *x509, const char *name,
                              BOOL allow_wildcard, server_rec *s)
  {
      BOOL matched = FALSE;
      apr_array_header_t *ids;
  
      /*
       * At some day in the future, this might be replaced with X509_check_host()
       * (available in OpenSSL 1.0.2 and later), but two points should be noted:
       * 1) wildcard matching in X509_check_host() might yield different
       *    results (by default, it supports a broader set of patterns, e.g.
       *    wildcards in non-initial positions);
       * 2) we lose the option of logging each DNS- and CN-ID (until a match
       *    is found).
       */
  
      if (getIDs(p, x509, &ids)) {
          const char *cp;
          int i;
          char **id = (char **)ids->elts;
          BOOL is_wildcard;
  
          for (i = 0; i < ids->nelts; i++) {
              if (!id[i])
                  continue;
  
              /*
               * Determine if it is a wildcard ID - we're restrictive
               * in the sense that we require the wildcard character to be
               * THE left-most label (i.e., the ID must start with "*.")
               */
              is_wildcard = (*id[i] == '*' && *(id[i]+1) == '.') ? TRUE : FALSE;
  
              /*
               * If the ID includes a wildcard character (and the caller is
               * allowing wildcards), check if it matches for the left-most
               * DNS label - i.e., the wildcard character is not allowed
               * to match a dot. Otherwise, try a simple string compare.
               */
              if ((allow_wildcard == TRUE && is_wildcard == TRUE &&
                   (cp = ap_strchr_c(name, '.')) && !strcasecmp(id[i]+1, cp)) ||
                  !strcasecmp(id[i], name)) {
                  matched = TRUE;
              }
  
              if (s) {
                  ap_log_error(APLOG_MARK, APLOG_TRACE3, 0, s,
                               "[%s] modssl_X509_match_name: expecting name '%s', "
                               "%smatched by ID '%s'",
                               (mySrvConfig(s))->vhost_id, name,
                               matched == TRUE ? "" : "NOT ", id[i]);
              }
  
              if (matched == TRUE) {
                  break;
              }
          }
  
      }
  
      if (s) {
          ssl_log_xerror(SSLLOG_MARK, APLOG_DEBUG, 0, p, s, x509,
                         APLOGNO(02412) "[%s] Cert %s for name '%s'",
                         (mySrvConfig(s))->vhost_id,
                         matched == TRUE ? "matches" : "does not match",
                         name);
      }
  
      return matched;
  }
  
  /*  _________________________________________________________________
  **
  **  Custom (EC)DH parameter support
  **  _________________________________________________________________
  */
  
  DH *ssl_dh_GetParamFromFile(const char *file)
  {
      DH *dh = NULL;
      BIO *bio;
  
      if ((bio = BIO_new_file(file, "r")) == NULL)
          return NULL;
      dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
      BIO_free(bio);
      return (dh);
  }
  
  #ifdef HAVE_ECC
  EC_GROUP *ssl_ec_GetParamFromFile(const char *file)
  {
      EC_GROUP *group = NULL;
      BIO *bio;
  
      if ((bio = BIO_new_file(file, "r")) == NULL)
          return NULL;
      group = PEM_read_bio_ECPKParameters(bio, NULL, NULL, NULL);
      BIO_free(bio);
      return (group);
  }
  #endif
  
  /*  _________________________________________________________________
  **
  **  Session Stuff
  **  _________________________________________________________________
  */
  
  char *modssl_SSL_SESSION_id2sz(IDCONST unsigned char *id, int idlen,
                                 char *str, int strsize)
  {
      if (idlen > SSL_MAX_SSL_SESSION_ID_LENGTH)
          idlen = SSL_MAX_SSL_SESSION_ID_LENGTH;
          
      /* We must ensure not to process more than what would fit in the
       * destination buffer, including terminating NULL */
      if (idlen > (strsize-1) / 2)
          idlen = (strsize-1) / 2;
  
      ap_bin2hex(id, idlen, str);
  
      return str;
  }
  