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Prevent UB when computing days with extreme timestamps #20955

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Prevent UB when computing days with extreme timestamps #20955

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7 changes: 6 additions & 1 deletion ext/date/lib/interval.c
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Original file line number Diff line number Diff line change
Expand Up @@ -201,7 +201,12 @@ int timelib_diff_days(timelib_time *one, timelib_time *two)
days--;
}
} else {
days = fabs(floor(one->sse - two->sse) / 86400);
double diff = fabs(floor(one->sse - two->sse) / 86400);
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@ndossche ndossche Jan 17, 2026

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Note that I'm not so sure silently capping the number is the right way to go about this.
This is also a bundled library, the fix should go into the upstream library at https://github.com/derickr/timelib

if (diff > INT_MAX) {
days = INT_MAX;
} else {
days = (int) diff;
}
}

return days;
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14 changes: 14 additions & 0 deletions ext/date/tests/bug19894.phpt
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@@ -0,0 +1,14 @@
--TEST--
DateTime::diff() with PHP_INT_MIN timestamp and timezone should not crash
--FILE--
<?php
$nowTime = new DateTime();
$nowTime->setTimestamp(PHP_INT_MIN);

$dateTime = new DateTime();
$dateTime->setTimezone(new DateTimeZone('America/New_York'));

echo $dateTime->diff($nowTime)->format('%R %a %H %I %S'), "\n";
?>
--EXPECTREGEX--
^[+-] [0-9]+ [0-9]+ [0-9]+ [0-9]+$
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