Avoid UB in timelib_diff_days() #162
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We clamp the calculated days to properly fit in an `int`. See <php/php-src#17504>.
derickr
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Jan 20, 2025
| @@ -201,7 +201,8 @@ int timelib_diff_days(timelib_time *one, timelib_time *two) | |||
| days--; | |||
| } | |||
| } else { | |||
| days = fabs(floor(one->sse - two->sse) / 86400); | |||
| double ddays = fabs(floor(one->sse - two->sse) / 86400); | |||
| days = ddays <= INT_MAX ? ddays : INT_MAX; | |||
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I'm not so sure whether truncating the value is a good idea either. Ideally, it should return with a failure. But then again, the APIs for most timelib functions have currently no such capability.
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Right. This is not meant to be a clean solution, but merely to avoid UB; and for practical purposes, a difference of almost 6 million years might just be good enough (for now).
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We clamp the calculated days to properly fit in an
int.See php/php-src#17504.