Is this a secure method to insert form data into a MySQL database? [duplicate]
Possible Duplicate:
How can I prevent SQL injection in PHP?
This is the example on w3schools.org:
HTML form:
<html>
<body>
<form action="insert.php" method="post">
Firstname: <input type="text" name="firstname" />
Lastname: <input type="text" name="lastname" />
Age: <input type="text" name="age" />
<input type="submit" />
</form>
</body>
</html>
File insert.php:
<?php
$con = mysql_connect("localhost","peter","abc123");
if (!$con)
{
die('Could not connect: ' . mysql_error());
}
mysql_select_db("my_db", $con);
$sql="INSERT INTO Persons (FirstName, LastName, Age)
VALUES
('$_POST[firstname]','$_POST[lastname]','$_POST[age]')";
if (!mysql_query($sql,$con))
{
die('Error: ' . mysql_error());
}
echo "1 record added";
mysql_close($con)
?>
I've read through other questions on here, but I couldn't find a direct answer, as most were much more complicated.
I looked at How can I prevent SQL injection in PHP?, but I'm a bit confused on how to modify this:
$preparedStatement = $db->prepare('INSERT INTO table (column) VALUES (:column)');
$preparedStatement->execute(array(':column' => $unsafeValue));
Assuming I used the HTML form above and wanted to insert the data from field 'firstname' into the database, should it look like this? Or am I supposed to modify column?:
$preparedStatement = $db->prepare('INSERT INTO table (column) VALUES (:column)');
$preparedStatement->execute(array(':column' => $firstname));
Solution 1:
The example you provided inserts the post vars into the database without first analyzing them for evil user input. Use type casting, escaping/filter functions, prepared statements etc. before using them to interact with your DB.
A general rule to go by is to never trust user input. EVER!
Check out: Best way to stop SQL Injection in PHP
In response to your question, here is how you'd handle the entire form using PDO prepared statements.
$stmt = $db->prepare('INSERT INTO Persons (FirstName, LastName, Age) VALUES (:first_name, :last_name, :age)');
$stmt->execute(array(':first_name' => $first_name,':last_name' => $last_name, ':age' => $age));
If you just want to insert one column in the record like you asked, the syntax would be:
$stmt = $db->prepare('INSERT INTO Persons (FirstName) VALUES (:first_name)');
$stmt->execute(':first_name', $first_name);
Solution 2:
NO.
That is HIGHLY vulnerable to sql injection attacks.
Instead of using mysql_real_escape_string, I suggest using prepared statements.
Solution 3:
Use mysql_real_escape_string.