Re: a stored procedure ..with integer as the parameter

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От Alex Turner
Тема Re: a stored procedure ..with integer as the parameter
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Msg-id 33c6269f0510241421p2802061dhe79b3d99495b8087@mail.gmail.com
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Ответ на Re: a stored procedure ..with integer as the parameter  (Harald Fuchs <hf0923x@protecting.net>)
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On 24 Oct 2005 22:00:55 +0200, Harald Fuchs <hf0923x@protecting.net> wrote:
In article <33c6269f0510241144s680be862pfdc0c59dcba06eee@mail.gmail.com>,
Alex Turner <armtuk@gmail.com > writes:

> 1.  ( ) text/plain          (*) text/html
> As sort of a side discussion - I have postulated that quoting all incomming
> numbers as string would be an effective defense against SQL Injection style
> attacks, as magic quotes would destory any end-quote type syntax:
> in_value=1
> select * from table where my_id='$in_value';
> as an example for PHP - Postgres will silenty perform an atoi on the string to
> make it a number, but it would prevent:
> in_value=1; delete * from user;
> select * from table where my_id=$in_value
> Am I just smoking crack here, or does this approach have some merit?

The former :-)
The correct defense against SQL injection is proper escaping, not quoting.
How about $in_value = '1''; delete from user'?


This would be escaped by magic_quotes resulting in:
select * from table where my_id='\'1\'\'; delete from user \'', which would result in an error, and a failed attack would it not, which would be a good thing?

I tried to create this scenario, but in a trasactional environment, it executes, but blew the transation so the data never committed as the select query generated an error with the insert on the end because the return type was no longer a result set, but a status in PyGresql:
AttributeError: 'long' object has no attribute 'ntuples'
So maybe there isn't an easy way to create a SQL injection attack in a xactional environment that will actualy work?

Alex

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