[Snort-devel] Potential for division by zero in file 'util.c' function TimeStop:

Bill Parker wp02855 at ...2499...
Mon Oct 12 12:53:01 EDT 2015


Hello All,

    In running Snort 2.9.8.0 Beta/RC through clang-analyzer, it
returned a potential for a division by zero at lines 1071-1073
in file 'util.c', function 'TimeStop'.  The issue could occur where
mins is 1, hrs is 0, days = 0, and the value for total_secs is 60
and SECONDS_PER_MIN is 60, which 60/60 = 0, which would result in
a division by zero error.

if ( mins > 0 || hrs > 0 || days > 0 )
{
uint64_t n = (pc.total_from_daq / (total_secs / SECONDS_PER_MIN));
I know this is unlikely to occur, as snort would have to be started
and stopped in exactly 60 seconds, but perhaps it should be written
as this:

    if ( mins > 0 || hrs > 0 || days > 0 )
{
if (total_secs != SECONDS_PER_MIN)
{
uint64_t n = (pc.total_from_daq / (total_secs / SECONDS_PER_MIN));
}
else /* total_secs and SECONDS_PER_MIN are 60 */
{
uint64_t n = (pc.total_from_daq / SECONDS_PER_MIN);
}
}
This would elininate the potential for the division by zero occuring at
all, would it not?

The same issue could occur in TimeStop where total_secs is equal to
SECONDS_PER_HOUR at lines 1065-1069, and where total_secs is equal to
SECONDS_PER_DAY at lines 1059-1063.

Bill
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