/* 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, 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, NULL, 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);

        }

    }

    return rc;

}

/*  _________________________________________________________________

**

**  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;

}