Infinite loop in wp_mkdir_p with open_basedir restrictions

[1265578519]

Cause the head exceeds the 4M limit.

/wwwroot/wp-includes/functions.php 1618

modify is_dir front @ cpu 100%.

[soulseekah]

It's an infinite loop :D to reproduce:

ini_set( 'open_basedir', '/tmp/' );
wp_mkdir_p( '/hello/world/' );

[soulseekah]

Initial fix attempt

[soulseekah]

The test is tough to write, once ini_set is called the whole test suite breaks. Plus the test can't fail, because it's in an infinite loop, it can only pass.

<?php
        /**
         * @ticket 43417
         */
        public function test_wp_mkdir_p_loop() {
                ini_set( 'open_basedir', '/no/exists/ever' );

                // suppress open_basedir restriction errors
                @wp_mkdir_p( '/tmp/try/his' );

                ini_restore( 'open_basedir' );
        }

[1265578519]

Thanks, 43417.diff successfully solved the problem .

[soulseekah]

Didn't think I'd ever encounter this, but I just saw this happen on a migrated client site via a call to wp_upload_dir from Divi theme, where the et_images_temp_folder option was not replaced correctly.

An incorrect/badly formed upload_path would also get into an infinite loop. So this is not a theoretical scenario, this actually happens :(

Patch got rid of infinite loop in wp_mkdir_p call.

Any ideas on how to automate test for this? Or can this be merged without unit tests due to it being so dangerous to test?

[SergeyBiryukov]

Introduced in [25047].

[SergeyBiryukov]

In 42801:

Filesystem API: Avoid an infinite loop in wp_mkdir_p() when trying to determine the parent folder with open_basedir restriction in effect.

Props soulseekah, 1265578519-1.
Fixes #43417.

[SergeyBiryukov]

Reopening for 4.9.5 consideration.

[SergeyBiryukov]

In 42804:

Filesystem API: Avoid an infinite loop in wp_mkdir_p() when trying to determine the parent folder with open_basedir restriction in effect.

Props soulseekah, 1265578519-1.
Merges [42801] to the 4.9 branch.
Fixes #43417.

[costdev]

#36184 was marked as a duplicate.