On Fri, Mar 28, 2014 at 09:41:53AM -0700, Junio C Hamano wrote:
> Offhand, the three possible failure modes this thread identified
> sounds to me like the only plausible ones, and I think the best way
> forward might be to
>
> - teach the "is the result sane, even though we may have got a
> non-NULL from gmtime? otherwise let's signal a failure by
> replacing it with a known sentinel value" codepath the new
> failure mode Charles's report suggests---if we feed a positive
> timestamp and gmtime gave us back a tm_year+1900 < 0, that is
> certainly an overflow; and
I don't think we can analyze the output from gmtime. If it wraps the
year at N, then won't N+2014 look like a valid value?
If we are going to do something trustworthy I think it has to be before
we hand off to gmtime. Like:
diff --git a/date.c b/date.c
index e1a2cee..e0c43c4 100644
--- a/date.c
+++ b/date.c
@@ -57,6 +57,8 @@ static time_t gm_time_t(unsigned long time, int tz)
static struct tm *time_to_tm(unsigned long time, int tz)
{
time_t t = gm_time_t(time, tz);
+ if (t > 9999999999999999)
+ return NULL;
return gmtime(&t);
}
I suspect that would handle the FreeBSD case, as well.
By the way, I have a suspicion that the gm_time_t above can overflow if
you specially craft a value at the edge of what time_t can handle (we
check that our value will not overflow time_t earlier, but now we might
be adding up to 86400 seconds to it). <sigh>
-Peff
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