Re: Defect in XSH asctime()

["H. Peter Anvin" <yyy@xxxxxxxxx>]

Clive D.W. Feather wrote:
> yyyyyyyyyyyyyyy@xxxxxxx said:
> 
>>If asctime() is called with a tm structure whose tm_year field results
>>in a year > 9999 (which is possible with 64-bit time_t), the current
>>specification of asctime() would result in asctime() to overrunning a
>>26-character buffer;  the specification says the sprintf() format
>>for printing the year is "%d", and (eg) a 5-digit number would print
>>5 characters, overrunning the buffer.
> 
> WG14 examined this issue quite a long time ago. We decided that the
> behaviour was simply undefined. There is no requirement that a particular
> string appear in the buffer, or even that the function call returns in a
> sensible state (or at all). It's *UNDEFINED*.
> 

I would classify that as a security hazard.  Dates are almost
definitional of something that is user-entered, and for it to neither
fail correctly or produce sensible output sounds like a really dangerous
proposition.

Sorry,

        -hpa