Fix GH-16235 jdtogregorian overflow

[devnexen]

No description provided.

[cmb69]

See also php/pecl-database-dbase@06121a5#diff-267845cccb1065a0819b505e5acbccaed653de3f6304d53e82b106b91f60f4adR139 (I don't know if that patch was correct, though).

[devnexen]

sure let's truncate, will give it a try

[devnexen]

See also php/pecl-database-dbase@06121a5#diff-267845cccb1065a0819b505e5acbccaed653de3f6304d53e82b106b91f60f4adR139 (I don't know if that patch was correct, though).

So I gave a try locally 2 existing tests fail, jdtofrench.phpt and jdtomonthname.phpt.

[cmb69]

So I gave a try locally 2 existing tests fail, jdtofrench.phpt and jdtomonthname.phpt.

Indeed, that patch is actually not meant for general consumption, but only for DBase date fields (limited range).

Anyhow, I do not understand the bug. Passing very large integers to SdnToGregorian() is supposed to fail early

php-src/ext/calendar/gregor.c

Lines 150 to 153 in 4b855eb

	if (sdn <= 0 ||
	sdn > (LONG_MAX - 4 * GREGOR_SDN_OFFSET) / 4) {
	goto fail;
	}

Ah, that is Windows! I suggest to use INT_MAX instead of LONG_MAX there. That should do.

PS: or use ZEND_LONG_MAX there, and apply the additional check. In any way, LONG_MAX makes no sense there, since there are no longs involved.

[cmb69]

Yeah, that should catch all overflows. Thank you!