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Fix stack overflow in count() with COUNT_RECURSIVE and deep arrays #23197

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Merged
arnaud-lb merged 2 commits into from
Aug 11, 2026
Merged

Fix stack overflow in count() with COUNT_RECURSIVE and deep arrays #23197

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4e0de1b
Add a stack limit check in php_count_recursive
lazerg Aug 10, 2026
a11b59f
Signal stack overflow through the return value of php_count_recursive
lazerg Aug 11, 2026
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Signal stack overflow through the return value of php_count_recursive
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@lazerg
lazerg committed Aug 11, 2026
commit a11b59fee3faac7b4e9d078c58c8d6f4021c9f70
6 changes: 5 additions & 1 deletion ext/spl/spl_observer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -679,7 +679,11 @@ PHP_METHOD(SplObjectStorage, count)
}

if (mode == PHP_COUNT_RECURSIVE) {
RETURN_LONG(php_count_recursive(&intern->storage));
zend_long count = php_count_recursive(&intern->storage);
if (UNEXPECTED(count < 0)) {
RETURN_THROWS();
}
RETURN_LONG(count);
}

RETURN_LONG(zend_hash_num_elements(&intern->storage));
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13 changes: 8 additions & 5 deletions ext/standard/array.c
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Expand Up @@ -614,14 +614,15 @@ PHPAPI zend_long php_count_recursive(HashTable *ht) /* {{{ */
#ifdef ZEND_CHECK_STACK_LIMIT
if (UNEXPECTED(zend_call_stack_overflowed(EG(stack_limit)))) {
zend_call_stack_size_error();
return 0;
return -1;
}
#endif

if (!(GC_FLAGS(ht) & GC_IMMUTABLE)) {
if (GC_IS_RECURSIVE(ht)) {
php_error_docref(NULL, E_WARNING, "Recursion detected");
return 0;
/* A user error handler may have thrown. */
return EG(exception) ? -1 : 0;
}
GC_PROTECT_RECURSION(ht);
}
Expand All @@ -630,10 +631,12 @@ PHPAPI zend_long php_count_recursive(HashTable *ht) /* {{{ */
ZEND_HASH_FOREACH_VAL(ht, element) {
ZVAL_DEREF(element);
if (Z_TYPE_P(element) == IS_ARRAY) {
cnt += php_count_recursive(Z_ARRVAL_P(element));
if (UNEXPECTED(EG(exception))) {
zend_long sub_cnt = php_count_recursive(Z_ARRVAL_P(element));
if (UNEXPECTED(sub_cnt < 0)) {
cnt = -1;
break;
}
cnt += sub_cnt;
}
} ZEND_HASH_FOREACH_END();

Expand Down Expand Up @@ -666,7 +669,7 @@ PHP_FUNCTION(count)
cnt = zend_hash_num_elements(Z_ARRVAL_P(array));
} else {
cnt = php_count_recursive(Z_ARRVAL_P(array));
if (UNEXPECTED(EG(exception))) {
if (UNEXPECTED(cnt < 0)) {
RETURN_THROWS();
}
}
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1 change: 1 addition & 0 deletions ext/standard/php_array.h
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Expand Up @@ -29,6 +29,7 @@ PHPAPI int php_array_merge(HashTable *dest, HashTable *src);
PHPAPI int php_array_merge_recursive(HashTable *dest, HashTable *src);
PHPAPI int php_array_replace_recursive(HashTable *dest, HashTable *src);
PHPAPI int php_multisort_compare(const void *a, const void *b);
/* Returns -1 and throws if the array is nested too deeply. */
PHPAPI zend_long php_count_recursive(HashTable *ht);

PHPAPI bool php_array_data_shuffle(php_random_algo_with_state engine, zval *array);
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