/*
 * Copyright (c) 1997 - 2001, 2003 - 2004 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "hdb_locl.h"

/*
 * free all the memory used by (len, keys)
 */

void
hdb_free_keys(krb5_context context, int len, Key *keys)
{
    int i;

    for (i = 0; i < len; i++) {
        free(keys[i].mkvno);
        keys[i].mkvno = NULL;
        if (keys[i].salt != NULL) {
            free_Salt(keys[i].salt);
            free(keys[i].salt);
            keys[i].salt = NULL;
        }
        krb5_free_keyblock_contents(context, &keys[i].key);
    }
    free (keys);
}

void
hdb_free_keysets(krb5_context context, int len, hdb_keyset *keysets)
{
    int i;

    for (i = 0; i < len; i++) {
        hdb_free_keys(context, keysets[i].keys.len, keysets[i].keys.val);
        keysets[i].keys.val = NULL;
        keysets[i].keys.len = 0;
    }
    free (keysets);
}

/*
 * for each entry in `default_keys' try to parse it as a sequence
 * of etype:salttype:salt, syntax of this if something like:
 * [(des|des3|etype):](pw-salt|afs3)[:string], if etype is omitted it
 *      means all etypes, and if string is omitted is means the default
 * string (for that principal). Additional special values:
 *      v5 == pw-salt, and
 *      v4 == des:pw-salt:
 *      afs or afs3 == des:afs3-salt
 */

static const krb5_enctype des_etypes[] = {
    ETYPE_DES_CBC_MD5,
    ETYPE_DES_CBC_MD4,
    ETYPE_DES_CBC_CRC
};

static const krb5_enctype all_etypes[] = {
    ETYPE_AES256_CTS_HMAC_SHA1_96,
    ETYPE_ARCFOUR_HMAC_MD5,
    ETYPE_DES3_CBC_SHA1
};

static krb5_error_code
parse_key_set(krb5_context context, const char *key,
              krb5_enctype **ret_enctypes, size_t *ret_num_enctypes,
              krb5_salt *salt, krb5_principal principal)
{
    const char *p;
    char buf[3][256];
    int num_buf = 0;
    int i, num_enctypes = 0;
    krb5_enctype e;
    const krb5_enctype *enctypes = NULL;
    krb5_error_code ret;

    p = key;

    *ret_enctypes = NULL;
    *ret_num_enctypes = 0;

    /* split p in a list of :-separated strings */
    for(num_buf = 0; num_buf < 3; num_buf++)
        if(strsep_copy(&p, ":", buf[num_buf], sizeof(buf[num_buf])) == -1)
            break;

    salt->saltvalue.data = NULL;
    salt->saltvalue.length = 0;

    for(i = 0; i < num_buf; i++) {
        if(enctypes == NULL && num_buf > 1) {
            /* this might be a etype specifier */
            /* XXX there should be a string_to_etypes handling
               special cases like `des' and `all' */
            if(strcmp(buf[i], "des") == 0) {
                enctypes = des_etypes;
                num_enctypes = sizeof(des_etypes)/sizeof(des_etypes[0]);
            } else if(strcmp(buf[i], "des3") == 0) {
                e = ETYPE_DES3_CBC_SHA1;
                enctypes = &e;
                num_enctypes = 1;
            } else {
                ret = krb5_string_to_enctype(context, buf[i], &e);
                if (ret == 0) {
                    enctypes = &e;
                    num_enctypes = 1;
                } else
                    return ret;
            }
            continue;
        }
        if(salt->salttype == 0) {
            /* interpret string as a salt specifier, if no etype
               is set, this sets default values */
            /* XXX should perhaps use string_to_salttype, but that
               interface sucks */
            if(strcmp(buf[i], "pw-salt") == 0) {
                if(enctypes == NULL) {
                    enctypes = all_etypes;
                    num_enctypes = sizeof(all_etypes)/sizeof(all_etypes[0]);
                }
                salt->salttype = KRB5_PW_SALT;
            } else if(strcmp(buf[i], "afs3-salt") == 0) {
                if(enctypes == NULL) {
                    enctypes = des_etypes;
                    num_enctypes = sizeof(des_etypes)/sizeof(des_etypes[0]);
                }
                salt->salttype = KRB5_AFS3_SALT;
            }
            continue;
        }

        {
            /* if there is a final string, use it as the string to
               salt with, this is mostly useful with null salt for
               v4 compat, and a cell name for afs compat */
            salt->saltvalue.data = strdup(buf[i]);
            if (salt->saltvalue.data == NULL) {
                krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
                return ENOMEM;
            }
            salt->saltvalue.length = strlen(buf[i]);
        }
    }

    if(enctypes == NULL || salt->salttype == 0) {
        krb5_set_error_message(context, EINVAL, "bad value for default_keys `%s'", key);
        return EINVAL;
    }

    /* if no salt was specified make up default salt */
    if(salt->saltvalue.data == NULL) {
        if(salt->salttype == KRB5_PW_SALT)
            ret = krb5_get_pw_salt(context, principal, salt);
        else if(salt->salttype == KRB5_AFS3_SALT) {
            krb5_const_realm realm = krb5_principal_get_realm(context, principal);
            salt->saltvalue.data = strdup(realm);
            if(salt->saltvalue.data == NULL) {
                krb5_set_error_message(context, ENOMEM,
                                       "out of memory while "
                                       "parsing salt specifiers");
                return ENOMEM;
            }
            strlwr(salt->saltvalue.data);
            salt->saltvalue.length = strlen(realm);
        }
    }

    *ret_enctypes = malloc(sizeof(enctypes[0]) * num_enctypes);
    if (*ret_enctypes == NULL) {
        krb5_free_salt(context, *salt);
        krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
        return ENOMEM;
    }
    memcpy(*ret_enctypes, enctypes, sizeof(enctypes[0]) * num_enctypes);
    *ret_num_enctypes = num_enctypes;

    return 0;
}


krb5_error_code
hdb_add_current_keys_to_history(krb5_context context, hdb_entry *entry)
{
    krb5_error_code ret;
    HDB_extension *ext;
    HDB_Ext_KeySet *hist_keys;
    hdb_keyset *tmp_keysets;
    int add = 0;

    ext = hdb_find_extension(entry, choice_HDB_extension_data_hist_keys);
    if (ext != NULL) {
        hist_keys = &ext->data.u.hist_keys;
        tmp_keysets = realloc(hist_keys->val,
                              sizeof (*hist_keys->val) * (hist_keys->len + 1));
        if (tmp_keysets == NULL)
            return ENOMEM;
        hist_keys->val = tmp_keysets;
        memmove(&hist_keys->val[1], hist_keys->val,
                sizeof (*hist_keys->val) * hist_keys->len++);
    } else {
        add = 1;
        ext = calloc(1, sizeof (*ext));
        if (ext == NULL)
            return ENOMEM;
        ext->data.element = choice_HDB_extension_data_hist_keys;
        hist_keys = &ext->data.u.hist_keys;
        hist_keys->val = calloc(1, sizeof (*hist_keys->val));
        if (hist_keys->val == NULL) {
            free(ext);
            return ENOMEM;
        }
        hist_keys->len = 1;
    }

    hist_keys->val[0].keys.val = entry->keys.val;
    hist_keys->val[0].keys.len = entry->keys.len;
    hist_keys->val[0].kvno = entry->kvno;
    hist_keys->val[0].replace_time = time(NULL);

    if (add) {
        ret = hdb_replace_extension(context, entry, ext);
        if (ret) {
            free_HDB_extension(ext);
            return ret;
        }
    }

    /* hdb_replace_extension() copies ext, so we have to free it */
    free_HDB_extension(ext);
    return 0;
}


static krb5_error_code
add_enctype_to_key_set(Key **key_set, size_t *nkeyset,
                       krb5_enctype enctype, krb5_salt *salt)
{
    krb5_error_code ret;
    Key key, *tmp;

    memset(&key, 0, sizeof(key));

    tmp = realloc(*key_set, (*nkeyset + 1) * sizeof((*key_set)[0]));
    if (tmp == NULL)
        return ENOMEM;

    *key_set = tmp;

    key.key.keytype = enctype;
    key.key.keyvalue.length = 0;
    key.key.keyvalue.data = NULL;

    if (salt) {
        key.salt = calloc(1, sizeof(*key.salt));
        if (key.salt == NULL) {
            free_Key(&key);
            return ENOMEM;
        }

        key.salt->type = salt->salttype;
        krb5_data_zero (&key.salt->salt);

        ret = krb5_data_copy(&key.salt->salt,
                             salt->saltvalue.data,
                             salt->saltvalue.length);
        if (ret) {
            free_Key(&key);
            return ret;
        }
    } else
        key.salt = NULL;

    (*key_set)[*nkeyset] = key;

    *nkeyset += 1;

    return 0;
}


/*
 * Generate the `key_set' from the [kadmin]default_keys statement. If
 * `no_salt' is set, salt is not important (and will not be set) since
 * it's random keys that is going to be created.
 */

krb5_error_code
hdb_generate_key_set(krb5_context context, krb5_principal principal,
                     Key **ret_key_set, size_t *nkeyset, int no_salt)
{
    char **ktypes, **kp;
    krb5_error_code ret;
    Key *k, *key_set;
    size_t i, j;
    static const char *default_keytypes[] = {
        "aes256-cts-hmac-sha1-96:pw-salt",
        "des3-cbc-sha1:pw-salt",
        "arcfour-hmac-md5:pw-salt",
        NULL
    };

    ktypes = krb5_config_get_strings(context, NULL, "kadmin",
                                     "default_keys", NULL);
    if (ktypes == NULL)
        ktypes = (char **)(intptr_t)default_keytypes;

    *ret_key_set = key_set = NULL;
    *nkeyset = 0;

    ret = 0;

    for(kp = ktypes; kp && *kp; kp++) {
        const char *p;
        krb5_salt salt;
        krb5_enctype *enctypes;
        size_t num_enctypes;

        p = *kp;
        /* check alias */
        if(strcmp(p, "v5") == 0)
            p = "pw-salt";
        else if(strcmp(p, "v4") == 0)
            p = "des:pw-salt:";
        else if(strcmp(p, "afs") == 0 || strcmp(p, "afs3") == 0)
            p = "des:afs3-salt";
        else if (strcmp(p, "arcfour-hmac-md5") == 0)
            p = "arcfour-hmac-md5:pw-salt";

        memset(&salt, 0, sizeof(salt));

        ret = parse_key_set(context, p,
                            &enctypes, &num_enctypes, &salt, principal);
        if (ret) {
            krb5_warn(context, ret, "bad value for default_keys `%s'", *kp);
            ret = 0;
            continue;
        }

        for (i = 0; i < num_enctypes; i++) {
            /* find duplicates */
            for (j = 0; j < *nkeyset; j++) {

                k = &key_set[j];

                if (k->key.keytype == enctypes[i]) {
                    if (no_salt)
                        break;
                    if (k->salt == NULL && salt.salttype == KRB5_PW_SALT)
                        break;
                    if (k->salt->type == salt.salttype &&
                        k->salt->salt.length == salt.saltvalue.length &&
                        memcmp(k->salt->salt.data, salt.saltvalue.data,
                               salt.saltvalue.length) == 0)
                        break;
                }
            }
            /* not a duplicate, lets add it */
            if (j == *nkeyset) {
                ret = add_enctype_to_key_set(&key_set, nkeyset, enctypes[i],
                                             no_salt ? NULL : &salt);
                if (ret) {
                    free(enctypes);
                    krb5_free_salt(context, salt);
                    goto out;
                }
            }
        }
        free(enctypes);
        krb5_free_salt(context, salt);
    }

    *ret_key_set = key_set;

 out:
    if (ktypes != (char **)(intptr_t)default_keytypes)
        krb5_config_free_strings(ktypes);

    if (ret) {
        krb5_warn(context, ret,
                  "failed to parse the [kadmin]default_keys values");

        for (i = 0; i < *nkeyset; i++)
            free_Key(&key_set[i]);
        free(key_set);
    } else if (*nkeyset == 0) {
        krb5_warnx(context,
                   "failed to parse any of the [kadmin]default_keys values");
        ret = EINVAL; /* XXX */
    }

    return ret;
}


krb5_error_code
hdb_generate_key_set_password(krb5_context context,
                              krb5_principal principal,
                              const char *password,
                              Key **keys, size_t *num_keys)
{
    krb5_error_code ret;
    size_t i;

    ret = hdb_generate_key_set(context, principal,
                                keys, num_keys, 0);
    if (ret)
        return ret;

    for (i = 0; i < (*num_keys); i++) {
        krb5_salt salt;

        salt.salttype = (*keys)[i].salt->type;
        salt.saltvalue.length = (*keys)[i].salt->salt.length;
        salt.saltvalue.data = (*keys)[i].salt->salt.data;

        ret = krb5_string_to_key_salt (context,
                                       (*keys)[i].key.keytype,
                                       password,
                                       salt,
                                       &(*keys)[i].key);

        if(ret)
            break;
    }

    if(ret) {
        hdb_free_keys (context, *num_keys, *keys);
        return ret;
    }
    return ret;
}