Converting hex string to an integer

[Peter Hansen]

Michael Hudson wrote:

> Peter Hansen <peter at engcorp.com> writes:
> 
> 
>>Rick Holbert wrote:
>>
>>>Derek Fountain wrote:
>>>
>>>>Given the character string "0x00A1B2C3" arriving at sys.argv[1] how do I
>>>>convert that to an integer which I can do some math on?
>>>
>>>i = eval(sys.argv[1])
>>
>>That's dangerous advice to a newbie if not qualified carefully.
>>
>>Derek, "eval" could be the source of serious security problems
>>if you don't understand its power.  Specifically it should
>>almost never be used for input that comes from a user or
>>via the command line.  There is pretty much always another
>>and much better way to do the simple stuff like conversions
>>than to use eval.
>>
>>For example, imagine if a malicious could feed your program this:
>>
>>(on the Linux command line)
>>
>>   $ myscript "__import_('os').system('rm -rf /')"
> 
> Well, in this situation, he could just type
> 
> $ rm -rf /
> 
> But, yes.

He could if he were on the same system, but it's quite possible
that sys.argv[1] in this particular program is actually coming
from a remote system in some manner (web?).  But, yes.  :-)

-Peter