Zabbix

/*

** Copyright (C) 2001-2025 Zabbix SIA

**

** This program is free software: you can redistribute it and/or modify it under the terms of

** the GNU Affero General Public License as published by the Free Software Foundation, version 3.

**

** This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;

** without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

** See the GNU Affero General Public License for more details.

**

** You should have received a copy of the GNU Affero General Public License along with this program.

** If not, see <https://www.gnu.org/licenses/>.

**/

​

#include "zbxcrypto.h"

​

#include <assert.h>

#include "zbxcommon.h"

​

/**********************************************************************

 *  Purpose: Check if supplied character is a valid base64 character. *

 *           Not a complete check, since it ignores equal sign '='    *

 *       as it depends on the context where this is placed.       *

 *       Corresponds to the [A-Za-z0-9+\\/] block validation from *

 *       zbx_base64_validate() function below.                    *

 **********************************************************************/

static int  is_valid_base64_char(const char c)

{

    if (('A' <= c && 'Z' >= c) ||

        ('a' <= c && 'z' >= c) ||

        ('/' <= c && '9' >= c) ||

        '+' == c)

    {

        return SUCCEED;

    }

​

    return FAIL;

}

​

/*************************************************************************************************

 *                                                                                               *

 * Purpose: Checks if the string is a valid Base64 encoded string.                               *

 *          Check is based on RFC 4648, based on the following regexp:                           *

 *   "^(?:[A-Za-z0-9+\\/]{4})*(?:[A-Za-z0-9+\\/]{2}==|[A-Za-z0-9+\\/]{3}=|[A-Za-z0-9+\\/]{4})$"  *

 *                                                                                               *

 *          Note, that pcre regexp matching cannot be used, because it would exceed max          *

 *          stack frame limit when recursively checking long strings,                            *

 *          (check compute_recursion_limit() for more details).                                  *

 *                                                                                               *

 * Parameters: p_str - [IN] string to validate                                                   *

 *                                                                                               *

 * Return value: SUCCEED - string is a valid Base64 encoded string                               *

 *               FAIL    - otherwise                                                             *

 *                                                                                               *

 *************************************************************************************************/

int zbx_base64_validate(const char *p_str)

{

    size_t  i;

​

    /* consider empty strings - valid Base64 encodings */

    if ('\0' == p_str[0])

        return SUCCEED;

​