base64_*功能已禁用,现在该怎么办？

Question

当我尝试使用base64_decode()函数时,我收到以下警告

"Warning: base64_decode() has been disabled for security reasons"

看起来我的主机已禁用base64_*功能.

我几乎没有问题

1. 我认为默认情况下可以在php中启用base64_*函数,对吗？
2. 是否有任何安全原因导致base64_*功能未启用？任何安全漏洞？
3. base64_*函数的替代方法,默认情况下可用？
4. 我在哪里可以找到base64_*实现的自定义类/函数,以便我可以将它们放在我的PHP文件中,如果PHP的base64_*函数不可用则使用它们？

帮助赞赏.

Answer 1

我已经为所有base64目的编写了替代函数.

看这里:

function base64_decode($input) {
    $keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
    $chr1 = $chr2 = $chr3 = "";
    $enc1 = $enc2 = $enc3 = $enc4 = "";
    $i = 0;
    $output = "";

    // remove all characters that are not A-Z, a-z, 0-9, +, /, or =
    $filter = $input;
    $input = preg_replace("[^A-Za-z0-9\+\/\=]", "", $input);
    if ($filter != $input) {
        return false;
    }

    do {
        $enc1 = strpos($keyStr, substr($input, $i++, 1));
        $enc2 = strpos($keyStr, substr($input, $i++, 1));
        $enc3 = strpos($keyStr, substr($input, $i++, 1));
        $enc4 = strpos($keyStr, substr($input, $i++, 1));
        $chr1 = ($enc1 << 2) | ($enc2 >> 4);
        $chr2 = (($enc2 & 15) << 4) | ($enc3 >> 2);
        $chr3 = (($enc3 & 3) << 6) | $enc4;
        $output = $output . chr((int) $chr1);
        if ($enc3 != 64) {
            $output = $output . chr((int) $chr2);
        }
        if ($enc4 != 64) {
            $output = $output . chr((int) $chr3);
        }
        $chr1 = $chr2 = $chr3 = "";
        $enc1 = $enc2 = $enc3 = $enc4 = "";
    } while ($i < strlen($input));
    return urldecode($output);
}

function base64_encode($data) {
    $b64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';
    $o1 = $o2 = $o3 = $h1 = $h2 = $h3 = $h4 = $bits = $i = 0;
    $ac = 0;
    $enc = '';
    $tmp_arr = array();
    if (!$data) {
        return data;
    }
    do {
    // pack three octets into four hexets
    $o1 = charCodeAt($data, $i++);
    $o2 = charCodeAt($data, $i++);
    $o3 = charCodeAt($data, $i++);
    $bits = $o1 << 16 | $o2 << 8 | $o3;
    $h1 = $bits >> 18 & 0x3f;
    $h2 = $bits >> 12 & 0x3f;
    $h3 = $bits >> 6 & 0x3f;
    $h4 = $bits & 0x3f;
    // use hexets to index into b64, and append result to encoded string
    $tmp_arr[$ac++] = charAt($b64, $h1).charAt($b64, $h2).charAt($b64, $h3).charAt($b64, $h4);
    } while ($i < strlen($data));
    $enc = implode($tmp_arr, '');
    $r = (strlen($data) % 3);
    return ($r ? substr($enc, 0, ($r - 3)) . substr('===', $r) : $enc);
}

function charCodeAt($data, $char) {
    return ord(substr($data, $char, 1));
}

function charAt($data, $char) {
    return substr($data, $char, 1);
}

但不要忘记charCodeAt和charAt功能.他们都是必要的base64_encode.这两个函数都base64_encode和base64_decode内置的PHP函数一样工作.但是只使用它们,如果内置的那些不可用,因为它们没有内置的那么快.

希望能帮助到你!

Answer 2

这是托管问题。

请更改您的主机或要求他们消除此安全问题