[php-src] PHP-8.4: Add a stack limit check in php_array_walk() (#23125)

Author: Lazizbek Ergashev (lazerg) Committer: GitHub (web-flow) Pusher: arnaud-lb Date: 2026-08-10T11:57:00+02:00 Commit: https://github.com/php/php-src/commit/69d5f1b5d20b160cdd80ea65ef7d8e7548fd9935 Raw diff: https://github.com/php/php-src/commit/69d5f1b5d20b160cdd80ea65ef7d8e7548fd9935.diff Add a stack limit check in php_array_walk() (#23125) php_array_walk() recurses once per nesting level with no stack check, so array_walk_recursive() on a deeply nested array exhausts the native stack and the process dies with a segfault. This adds the same stack limit check ext/standard already uses in var.c and http.c, so the call throws an Error instead of crashing. The existing GC_IS_RECURSIVE guard only covers self-referential arrays, not plain deep nesting. Fixes GH-23111 Changed paths: A ext/standard/tests/array/gh23111.phpt M NEWS M ext/standard/array.c Diff: diff --git a/NEWS b/NEWS index 7a93e72de06f..01eb4160a20a 100644 --- a/NEWS +++ b/NEWS @@ -69,6 +69,10 @@ PHP NEWS - SQLite: . Fix leak when trying to close db if blob stream is still open. (ndossche) +- Standard: + . Fixed bug GH-23111 (Stack overflow in array_walk_recursive() with deeply + nested arrays). (Lazizbek Ergashev) + - Streams: . Fixed bug GH-15836 (Use-after-free when a user stream filter accesses $this->stream during the close flush). (iliaal) diff --git a/ext/standard/array.c b/ext/standard/array.c index 4527d9a80df8..6863586c81ff 100644 --- a/ext/standard/array.c +++ b/ext/standard/array.c @@ -1465,6 +1465,13 @@ static zend_result php_array_walk( * levels of recursion. */ zend_fcall_info fci = context->fci; +#ifdef ZEND_CHECK_STACK_LIMIT + if (UNEXPECTED(zend_call_stack_overflowed(EG(stack_limit)))) { + zend_call_stack_size_error(); + return FAILURE; + } +#endif + if (zend_hash_num_elements(target_hash) == 0) { return result; } diff --git a/ext/standard/tests/array/gh23111.phpt b/ext/standard/tests/array/gh23111.phpt new file mode 100644 index 000000000000..21db33a2fc75 --- /dev/null +++ b/ext/standard/tests/array/gh23111.phpt @@ -0,0 +1,27 @@ +--TEST-- +GH-23111 (Stack overflow in array_walk_recursive with deeply nested arrays) +--SKIPIF-- +<?php +if (ini_get('zend.max_allowed_stack_size') === false) { + die('skip No stack limit support'); +} +if (getenv('SKIP_ASAN')) { + die('skip ASAN needs different stack limit setting due to more stack space usage'); +} +?> +--INI-- +zend.max_allowed_stack_size=256K +--FILE-- +<?php +$a = []; +for ($i = 0; $i < 30000; $i++) { + $a = [$a]; +} +try { + array_walk_recursive($a, function ($v) {}); +} catch (Throwable $e) { + echo $e::class, ": ", $e->getMessage(), "\n"; +} +?> +--EXPECTF-- +Error: Maximum call stack size of %d bytes (zend.max_allowed_stack_size - zend.reserved_stack_size) reached. Infinite recursion?