'get_current_user_id' in 'gettext' filter causing memory error

[adityaarora010196]

I am trying to 'get_current_user_id' in 'gettext' filter and causing memory error.

Here is log of error:

2022/11/15 22:18:30 [error] 667958#667958: *8577 FastCGI sent in stderr: "PHP message: PHP Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 20480 bytes) in /var/www/server/htdocs/wp-includes/class-wp-user.php on line 521

I am not sure but this code is working on WP 5.8.6

Let me know if i can help in anything...

[SergeyBiryukov]

Hi there, welcome to WordPress Trac! Thanks for the report.

I was able to reproduce the issue with this code:

add_filter( 'gettext', function( $translation ) {
	static $call_count = 0;

	if ( $call_count++ > 500 ) {
		echo implode( '<br />', array_reverse( wp_debug_backtrace_summary( null, 0, false ) ) );
		die();
	}

	$user_id = get_current_user_id();

	return $translation;
});

which displays the following call stack:

require_once('wp-admin/admin.php')
require_once('wp-load.php')
require_once('S:/home/wordpress.test/develop/wp-config.php')
require_once('wp-settings.php')
do_action('setup_theme')
WP_Hook->do_action
WP_Hook->apply_filters
create_initial_theme_features
__
translate
apply_filters('gettext')
WP_Hook->apply_filters
{closure}
get_current_user_id
wp_get_current_user
_wp_get_current_user
apply_filters('determine_current_user')
WP_Hook->apply_filters
wp_validate_auth_cookie
wp_hash
wp_salt
__
translate
apply_filters('gettext')
WP_Hook->apply_filters
{closure}
get_current_user_id
wp_get_current_user
_wp_get_current_user
apply_filters('determine_current_user')
WP_Hook->apply_filters
wp_validate_auth_cookie
wp_hash
wp_salt
__
translate
apply_filters('gettext')
...

This appears to be introduced in [54249] / #55937, where a __() function call was added to wp_salt().

get_current_user_id() calls the determine_current_user filter, which calls wp_validate_auth_cookie(), which eventually calls wp_salt(), leading to an infinite loop.

Moving to 6.1.2 to investigate potential options to fix this.

[SergeyBiryukov]

57121.diff​ appears to work, because it succeeds in setting the static $duplicated_keys array once and no longer goes into this code section on subsequent calls.

As a workaround until a fix is released, this can also be resolved by removing the filter before calling get_current_user_id() and readding it after:

function my_gettext_callback( $translation ) {
	remove_filter( 'gettext', __FUNCTION__ );
	$user_id = get_current_user_id();
	add_filter( 'gettext', __FUNCTION__ );

	return $translation;
}
add_filter( 'gettext', 'my_gettext_callback' );

[SergeyBiryukov]

Writing a test for this is tricky, as wp_salt() is called via wp_create_nonce() in wp_default_scripts() and wp_default_packages_inline_scripts() as part of the general bootstrap routine before test suite initialization, so the $duplicated_keys static variable is already set and the loop cannot be triggered by a test.

[SergeyBiryukov]

In 55433:

Users: Adjust the initialization of the $duplicated_keys array in wp_salt().

This avoids an endless loop if get_current_user_id() is used in a callback attached to the gettext filter.

With the translated phrase moved into a separate assignment, the function succeeds in setting the static $duplicated_keys array once and no longer goes into this code section on subsequent calls.

Follow-up to [54249].

Props adityaarora010196, SergeyBiryukov.
Fixes #57121.

[SergeyBiryukov]

Reopening for 6.1.2 consideration.

[SergeyBiryukov]

Moving to 6.2.1, as there are no plans for 6.1.2 at this time.

[SergeyBiryukov]

This is already included in the 6.2 branch as of [55504], no backport needed.