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Fix GH-20006: Power of 0 of BcMath number causes UB #20007

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Fix GH-20006: Power of 0 of BcMath number causes UB #20007

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7 changes: 6 additions & 1 deletion ext/bcmath/libbcmath/src/raise.c
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Original file line number Diff line number Diff line change
Expand Up @@ -193,7 +193,12 @@ bc_raise_status bc_raise(bc_num base, long exponent, bc_num *result, size_t scal

if (bc_is_zero(base)) {
/* If the exponent is negative, it divides by 0 */
return is_neg ? BC_RAISE_STATUS_DIVIDE_BY_ZERO : BC_RAISE_STATUS_OK;
if (is_neg) {
return BC_RAISE_STATUS_DIVIDE_BY_ZERO;
}
bc_free_num (result);
*result = bc_copy_num(BCG(_zero_));
return BC_RAISE_STATUS_OK;
}

/* check overflow */
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16 changes: 16 additions & 0 deletions ext/bcmath/tests/gh20006.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,16 @@
--TEST--
GH-20006 (Power of 0 of BcMath number causes crash)
--EXTENSIONS--
bcmath
--FILE--
<?php
$n = new BcMath\Number("0");
var_dump(pow($n, 2));
?>
--EXPECTF--
object(BcMath\Number)#%d (2) {
["value"]=>
string(1) "0"
["scale"]=>
int(0)
}