PDO ist not supported in target system I'm working on and though I seek a solution for preventing SQL-Injection using PHP 5.1.x on a PostGres-DB 8.2+. There is at the moment no chance of switching to PDO.
My solution at the moment is pg_prepare-prepared statement:
// Trying to prevent SQL-Injection
$query = 'SELECT * FROM user WHERE login=$1 and password=md5($2)';
$result = pg_prepare($dbconn, "", $query);
$result = pg_execute($dbconn, "", array($_POST["user"], $_POST["password"]));
if (pg_num_rows($result) < 1) {
die ("failure");
}
But pg_prepare-documentation lacks about an important information:
it tells about "later usage"
pg_prepare() creates a prepared statement for later execution with pg_execute() or pg_send_execute().[...]
it tells about "named/anonymous statements"
The function creates a prepared statement named stmtname from the query string, which must contain a single SQL command. stmtname may be "" to create an unnamed statement, in which case any pre-existing unnamed statement is automatically replaced;[...]
it tells about "typecasting"
Prepared statements for use with pg_prepare() can also be created by executing SQL PREPARE statements. (But pg_prepare() is more flexible since it does not require parameter types to be pre-specified.) Also, although there is no PHP function for deleting a prepared statement, the SQL DEALLOCATE statement can be used for that purpose.
but it does not tell, if this implementation of prepared statements is safe from SQL-injection
*Nearly all comments by this security question refers to the PDO-solution, where in documentation is noticed that the driver prevents SQL-injection. But if an easy solution may be pg_prepare, I would use pg_prepare at the moment.*
Thanks for this important information of maybe a best practice solution.
EDIT (after marked as solution): Thanks for very enlightening answers!
- I marked the solution of Frank Heikens as best answer, cause it explains an important point in SQL-injection. A programmer may use prepared statemtents, but the SQL-injection-lack may still be there by mistake!
- Aside from Frank Heikens answer, hoppa shows that the SQL-injection is prevented using pg_prepare/pg_query_params. Thanks though.
- Will now use an optimized code with
pg_query_params(thanks to Milen A. Radev) - And
pg_escape_string()as alternative when it comes to it (thanks to halfer)
All answers are helpfully :)
// Trying to prevent SQL-Injection (**updated**)
$sql_query = 'SELECT * FROM user WHERE login=$1 and password=md5($2);';
$result = pg_query_params($dbconn_login, $sql_query, array($_POST["user"], $_POST["password"]));
if (pg_num_rows($result) < 1) {
die('failure');
}
