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Fix use-after-free in Collator::sort() with a mutating comparator #22467

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Fix use-after-free in Collator::sort() with a mutating comparator #22467

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23 changes: 19 additions & 4 deletions ext/intl/collator/collator_sort.c
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Original file line number Diff line number Diff line change
Expand Up @@ -259,12 +259,13 @@ static void collator_sort_internal( int renumber, INTERNAL_FUNCTION_PARAMETERS )
UCollator* saved_collator;
zval* array = NULL;
HashTable* hash = NULL;
zend_array* sorted = NULL;
zend_long sort_flags = COLLATOR_SORT_REGULAR;

COLLATOR_METHOD_INIT_VARS

/* Parse parameters. */
if( zend_parse_method_parameters( ZEND_NUM_ARGS(), getThis(), "Oa/|l",
if( zend_parse_method_parameters( ZEND_NUM_ARGS(), getThis(), "Oa|l",
&object, Collator_ce_ptr, &array, &sort_flags ) == FAILURE )
{
RETURN_THROWS();
Expand All @@ -283,24 +284,38 @@ static void collator_sort_internal( int renumber, INTERNAL_FUNCTION_PARAMETERS )

hash = Z_ARRVAL_P( array );

/* Copy array, so the in-place modifications will not be visible to the callback function */
sorted = zend_array_dup( hash );

/* Convert strings in the specified array from UTF-8 to UTF-16. */
collator_convert_hash_from_utf8_to_utf16( hash, COLLATOR_ERROR_CODE_P( co ) );
collator_convert_hash_from_utf8_to_utf16( sorted, COLLATOR_ERROR_CODE_P( co ) );
if( U_FAILURE( COLLATOR_ERROR_CODE( co ) ) ) {
zend_array_destroy( sorted );
}
COLLATOR_CHECK_STATUS( co, "Error converting hash from UTF-8 to UTF-16" );

/* Save specified collator in the request-global (?) variable. */
saved_collator = INTL_G( current_collator );
INTL_G( current_collator ) = co->ucoll;

/* Sort specified array. */
zend_hash_sort(hash, collator_compare_func, renumber);
zend_hash_sort( sorted, collator_compare_func, renumber );
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/* Restore saved collator. */
INTL_G( current_collator ) = saved_collator;

/* Convert strings in the specified array back to UTF-8. */
collator_convert_hash_from_utf16_to_utf8( hash, COLLATOR_ERROR_CODE_P( co ) );
collator_convert_hash_from_utf16_to_utf8( sorted, COLLATOR_ERROR_CODE_P( co ) );
if( U_FAILURE( COLLATOR_ERROR_CODE( co ) ) ) {
zend_array_destroy( sorted );
}
COLLATOR_CHECK_STATUS( co, "Error converting hash from UTF-16 to UTF-8" );

zval garbage;
ZVAL_COPY_VALUE( &garbage, array );
ZVAL_ARR( array, sorted );
zval_ptr_dtor( &garbage );

RETURN_TRUE;
}
/* }}} */
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36 changes: 36 additions & 0 deletions ext/intl/tests/collator_sort_modify_during_compare.phpt
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@@ -0,0 +1,36 @@
--TEST--
Collator::sort(): mutating the array from __toString() during comparison must not corrupt the sort
--EXTENSIONS--
intl
--FILE--
<?php
$c = new Collator('en_US');

class Grow {
public static array $ref;
public function __toString(): string {
for ($i = 0; $i < 2000; $i++) {
self::$ref[] = "x$i";
}
return "m";
}
}

$arr = ["z", new Grow(), "a", "b"];
Grow::$ref = &$arr;
var_dump($c->sort($arr));
var_dump($arr);
?>
--EXPECT--
bool(true)
array(4) {
[0]=>
string(1) "a"
[1]=>
string(1) "b"
[2]=>
object(Grow)#2 (0) {
}
[3]=>
string(1) "z"
}
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