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Fix GH-20319: Prevent ASSIGN_OP / ASSIGN_DIM_OP lvalue from being invalidated during assignment #20326

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Fix GH-20319: Prevent ASSIGN_OP / ASSIGN_DIM_OP lvalue from being invalidated during assignment #20326

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32 changes: 32 additions & 0 deletions Zend/tests/gh20319-001.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,32 @@
--TEST--
GH-20319 001: ASSIGN_OP: Ref lvalue may be released by __toString()
--ENV--
LEN=10
--FILE--
<?php

$b = &$c;
var_dump($b .= new class {
function __toString() {
unset($GLOBALS['b'], $GLOBALS['c']);
return str_repeat('d', (int)getenv('LEN'));
}
});

var_dump(isset($b));

$b = &$c;
$b .= new class {
function __toString() {
unset($GLOBALS['b'], $GLOBALS['c']);
return str_repeat('d', (int)getenv('LEN'));
}
};

var_dump(isset($b));

?>
--EXPECT--
string(10) "dddddddddd"
bool(false)
bool(false)
33 changes: 33 additions & 0 deletions Zend/tests/gh20319-002.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,33 @@
--TEST--
GH-20319 002: ASSIGN_OP: var-var ref lvalue may be released by __toString()
--ENV--
LEN=10
--FILE--
<?php

$b = &$c;
$v = 'b';
var_dump($$v .= new class {
function __toString() {
unset($GLOBALS['b'], $GLOBALS['c']);
return str_repeat('d', (int)getenv('LEN'));
}
});

var_dump(isset($b));

$b = &$c;
$$v .= new class {
function __toString() {
unset($GLOBALS['b'], $GLOBALS['c']);
return str_repeat('d', (int)getenv('LEN'));
}
};

var_dump(isset($b));

?>
--EXPECT--
string(10) "dddddddddd"
bool(false)
bool(false)
36 changes: 36 additions & 0 deletions Zend/tests/gh20319-003.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,36 @@
--TEST--
GH-20319 003: ASSIGN_DIM_OP: Array lvalue may be released by __toString()
--ENV--
LEN=10
--FILE--
<?php

$b = ['test'];

var_dump($b[0] .= new class {
function __toString() {
unset($GLOBALS['b']);
return str_repeat('d', (int)getenv('LEN'));
}
});

var_dump(isset($b));

unset($b);

$b = ['test'];

$b[0] .= new class {
function __toString() {
unset($GLOBALS['b']);
return str_repeat('d', (int)getenv('LEN'));
}
};

var_dump(isset($b));

?>
--EXPECT--
string(14) "testdddddddddd"
bool(false)
bool(false)
41 changes: 41 additions & 0 deletions Zend/tests/gh20319-004.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,41 @@
--TEST--
GH-20319 004: ASSIGN_DIM_OP: Array dim lvalue may be released by __toString()
--FILE--
<?php

$t = 'test';
$b = [&$t];

var_dump($b[0] .= new class {
function __toString() {
global $b;
unset($b[0]);
return str_repeat('d', (int)getenv('LEN'));
}
});

var_dump($b);

unset($b);
unset($t);

$t = 'test';
$b = [&$t];

$b[0] .= new class {
function __toString() {
global $b;
unset($b[0]);
return str_repeat('d', (int)getenv('LEN'));
}
};

var_dump($b);

?>
--EXPECT--
string(4) "test"
array(0) {
}
array(0) {
}
35 changes: 35 additions & 0 deletions Zend/tests/gh20319-005.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,35 @@
--TEST--
GH-20319 005: ASSIGN_OP: var-var slot may be invalidated by __toString()
--ENV--
LEN=10
--FILE--
<?php

$v = 'b';

$$v = 'test';
var_dump($$v .= new class {
function __toString() {
for ($i = 0; $i < 128; $i++) {
$GLOBALS['_' . $i] = 0;
}
return str_repeat('a', (int)getenv('LEN'));
}
});

$$v = 'test';
$$v .= new class {
function __toString() {
for ($i = 128; $i < 512; $i++) {
$GLOBALS['_' . $i] = 0;
}
return str_repeat('a', (int)getenv('LEN'));
}
};

var_dump($$v);

?>
--EXPECT--
string(14) "testaaaaaaaaaa"
string(14) "testaaaaaaaaaa"
44 changes: 36 additions & 8 deletions Zend/zend_vm_def.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1188,6 +1188,9 @@ ZEND_VM_C_LABEL(assign_dim_op_new_array):

value = get_op_data_zval_ptr_r((opline+1)->op1_type, (opline+1)->op1);

/* Prevents array from being released or updated during binary_op */
GC_ADDREF(ht);

do {
if (OP2_TYPE != IS_UNUSED && UNEXPECTED(Z_ISREF_P(var_ptr))) {
zend_reference *ref = Z_REF_P(var_ptr);
Expand All @@ -1203,6 +1206,9 @@ ZEND_VM_C_LABEL(assign_dim_op_new_array):
if (UNEXPECTED(RETURN_VALUE_USED(opline))) {
ZVAL_COPY(EX_VAR(opline->result.var), var_ptr);
}

GC_DTOR(ht);

FREE_OP((opline+1)->op1_type, (opline+1)->op1.var);
} else {
if (EXPECTED(Z_ISREF_P(container))) {
Expand Down Expand Up @@ -1264,22 +1270,44 @@ ZEND_VM_HANDLER(26, ZEND_ASSIGN_OP, VAR|CV, CONST|TMPVAR|CV, OP)
value = GET_OP2_ZVAL_PTR(BP_VAR_R);
var_ptr = GET_OP1_ZVAL_PTR_PTR(BP_VAR_RW);

do {
if (UNEXPECTED(Z_TYPE_P(var_ptr) == IS_REFERENCE)) {
zend_reference *ref = Z_REF_P(var_ptr);
var_ptr = Z_REFVAL_P(var_ptr);
if (UNEXPECTED(ZEND_REF_HAS_TYPE_SOURCES(ref))) {
zend_binary_assign_op_typed_ref(ref, value OPLINE_CC EXECUTE_DATA_CC);
break;
if (UNEXPECTED(Z_TYPE_P(var_ptr) == IS_REFERENCE)) {
ZEND_VM_C_LABEL(assign_op_ref):;
zend_reference *ref = Z_REF_P(var_ptr);
GC_ADDREF(ref);

var_ptr = Z_REFVAL_P(var_ptr);
if (UNEXPECTED(ZEND_REF_HAS_TYPE_SOURCES(ref))) {
zend_binary_assign_op_typed_ref(ref, value OPLINE_CC EXECUTE_DATA_CC);
} else {
zend_binary_op(var_ptr, var_ptr, value OPLINE_CC);
}

if (UNEXPECTED(GC_DELREF(ref) == 0)) {
if (RETURN_VALUE_USED(opline)) {
ZVAL_COPY_VALUE(EX_VAR(opline->result.var), var_ptr);
} else {
zval_ptr_dtor(var_ptr);
}
efree_size(ref, sizeof(zend_reference));
ZEND_VM_C_GOTO(assign_op_end);
}
} else {
if (OP1_TYPE == IS_VAR) {
ZEND_ASSERT(Z_TYPE_P(EX_VAR(opline->op1.num)) == IS_INDIRECT);
/* op1 is a var-var, var_ptr is a symbol table slot which may be
* invalidated by the binary operation. Turn it into a ref so we
* control the lifetime of the zval slot. */
ZVAL_MAKE_REF(var_ptr);
ZEND_VM_C_GOTO(assign_op_ref);
}
zend_binary_op(var_ptr, var_ptr, value OPLINE_CC);
} while (0);
}

if (UNEXPECTED(RETURN_VALUE_USED(opline))) {
ZVAL_COPY(EX_VAR(opline->result.var), var_ptr);
}

ZEND_VM_C_LABEL(assign_op_end):
FREE_OP2();
FREE_OP1();
ZEND_VM_NEXT_OPCODE_CHECK_EXCEPTION();
Expand Down
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