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Fix fatal error during sccp shift eval #19972

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Fix fatal error during sccp shift eval #19972

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13 changes: 13 additions & 0 deletions Zend/tests/oss_fuzz_447521098.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,13 @@
--TEST--
OSS-Fuzz #447521098: Fatal error during sccp shift eval
--FILE--
<?php
function test() {
$x = 0;
$y = -1;
$x >> $y;
}
?>
===DONE===
--EXPECT--
===DONE===
8 changes: 6 additions & 2 deletions Zend/zend_compile.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9998,7 +9998,9 @@ ZEND_API bool zend_binary_op_produces_error(uint32_t opcode, const zval *op1, co
/* Operation which cast float/float-strings to integers might produce incompatible float to int errors */
if (opcode == ZEND_SL || opcode == ZEND_SR || opcode == ZEND_BW_OR
|| opcode == ZEND_BW_AND || opcode == ZEND_BW_XOR) {
return !zend_is_op_long_compatible(op1) || !zend_is_op_long_compatible(op2);
if (!zend_is_op_long_compatible(op1) || !zend_is_op_long_compatible(op2)) {
return 1;
}
Comment on lines 9999 to +10003
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Other thing you could do, is move the:

	if ((opcode == ZEND_SL || opcode == ZEND_SR) && zval_get_long(op2) < 0) {
		/* Shift by negative number throws an error. */
		return 1;
	}

code check above this one or move this back to be last check as it was previously. This shouldn't be a problem now that ZEND_MOD is dealt separately.

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I don't think it's great to mix early returns for positive and negative results (or conditional results), as checks become order-dependent. I'll keep this simple change for now, but if you feel strongly you can still adjust on master.

}

if (opcode == ZEND_DIV && zval_get_double(op2) == 0.0) {
Expand All @@ -10009,7 +10011,9 @@ ZEND_API bool zend_binary_op_produces_error(uint32_t opcode, const zval *op1, co
/* Mod is an operation that will cast float/float-strings to integers which might
produce float to int incompatible errors, and also cannot be divided by 0 */
if (opcode == ZEND_MOD) {
return !zend_is_op_long_compatible(op1) || !zend_is_op_long_compatible(op2) || zval_get_long(op2) == 0;
if (!zend_is_op_long_compatible(op1) || !zend_is_op_long_compatible(op2) || zval_get_long(op2) == 0) {
return 1;
}
}

if ((opcode == ZEND_POW) && zval_get_double(op1) == 0 && zval_get_double(op2) < 0) {
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