phpbugs代码审计基础详解

 $value) { 
$value = trim($value);//trim — 去除字符串首尾处的空白字符（或者其他字符）
is_string($value) && $req[$key] = addslashes($value); // is_string — 检测变量是否是字符串，addslashes — 使用反斜线引用字符串
} 
} 
function is_palindrome_number($number) { 
$number = strval($number); //strval — 获取变量的字符串值
$i = 0; 
$j = strlen($number) - 1; //strlen — 获取字符串长度
while($i < $j) { 
if($number[$i] !== $number[$j]) { 
return false; 
} 
$i++; 
$j--; 
} 
return true; 
} 
if(is_numeric($_REQUEST['number'])) //is_numeric — 检测变量是否为数字或数字字符串 
{
 $info="sorry, you cann't input a number!";
}
elseif($req['number']!=strval(intval($req['number']))) //intval — 获取变量的整数值
{
 $info = "number must be equal to it's integer!! ";
}
else
{
 $value1 = intval($req["number"]);
 $value2 = intval(strrev($req["number"]));
 if($value1!=$value2){
$info="no, this is not a palindrome number!";
 }
 else
 {
if(is_palindrome_number($req["number"])){
$info = "nice! {$value1} is a palindrome number!"; 
}
else
{
 $info=$flag;
}
 }
}
echo $info;

根据代码判断，它需要满足多个条件才可以执行$info=$flag;之后echo出来的才是flag。

if(is_numeric($_REQUEST['number'])) //is_numeric — 检测变量是否为数字或数字字符串 
{
 $info="sorry, you cann't input a number!";
}

elseif($req['number']!=strval(intval($req['number']))) //intval — 获取变量的整数值
{
 $info = "number must be equal to it's integer!! ";
} 

$value1 = intval($req["number"]);
$value2 = intval(strrev($req["number"]));
if($value1!=$value2){
$info="no, this is not a palindrome number!";
 }