[Cryptography] GCC bug 30475

[Nemo]

Bear <bear at sonic.net> writes:

> There are in fact conformant checks for signed overflow. 
>
> For example, you can say 
>
> if (MAXINT - al >= be) halt(2); // overflow check - not using assert()

What does that do if al is -1?

The usual approaches are more complex. See:

  http://stackoverflow.com/questions/6856227/

...and everything it references, especially:

  https://www.securecoding.cert.org/confluence/display/seccode/INT32-C.+Ensure+that+operations+on+signed+integers+do+not+result+in+overflow

On the bright side, you only have to solve this problem once.

 - Nemo
   https://self-evident.org/