Java integer overflows (was: a really long topic)

I'm not talking arbitrary code execution, I'm talking about odd code
paths, bizarre outcomes, and DoS.

For example (found via 19 Sins, Viega, Howard and LeBlanc):
http://seclists.org/lists/bugtraq/2004/Nov/0097.html

I know Michael reads webappsec, he may have more examples.

In my own code testing, I look for silly behaviors if a user can
insert a large or negative number. You'd be surprised how often it
occurs. There is no excuse not to include basic range checks when
performing data validation.

thanks,
Andrew

On 29/03/2006, at 2:30 PM, michaelslists_at_gmail.com wrote:

> No you dont.
>
> Arrays are all bounds checked; ..., that is, the following code will
> throw an exception:
>
> ================================
> class Foo {
> static {
> int[] m = new int[2];
> System.out.println(m[34]);
> }
> }
> ================================
>
>
> What do you mean by "overflow"? Do you mean this?
>
> ================================
> class Foo {
> static {
> int m = Integer.MAX_VALUE;
> int k = Integer.MAX_VALUE + Integer.MAX_VALUE;
> System.out.println(m);
> System.out.println(k);
> System.exit(0);
> }
> }
> ================================
>
> if so, I don't see how that is an issue.
>
> -- Michael
>
>
>
> On 3/29/06, Andrew van der Stock <vanderaj_at_greebo.net> wrote:
>> This is not quite true.
>>
>> Java does not prevent integer overflows (it will not throw an
>> exception). So you still have to be careful about array indexes.
>>
>> Andrew