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Opened 4 years ago

Last modified 18 months ago

#19856 new defect (bug)

wp_get_referer() doesn't return false when the referer URL is the same as the current URL

Reported by: garyc40 Owned by:
Milestone: Future Release Priority: normal
Severity: normal Version: 3.3.1
Component: Bootstrap/Load Keywords: needs-patch
Focuses: Cc:

Description

Inside wp_get_referer(), there's this conditional statement:

if ( $ref && $ref !== $_SERVER['REQUEST_URI'] )

It is there to ensure that wp_get_referer() doesn't return the same page I'm on. This is useful when redirecting because I can detect and avoid infinite redirection.

According to PHP documentation, $_SERVER['REQUEST_URI'] is only the URI on the host. As a result, the conditional statement above fails in this case:

Let's say I was redirected from http://example.com/sample-uri to itself (either by clicking a link or a form submission). Then:

$ref = 'http://example.com/sample-uri';
$_SERVER['REQUEST_URI'] = '/sample-uri';

So technically, the referrer is the same page, but wp_get_referer() doesn't return false as expected, because $ref !== $_SERVER['REQUEST_URI'].

A better conditional statement would be:

if ( $ref && parse_url( $ref, PHP_URL_PATH ) !== $_SERVER['REQUEST_URI'] )

Patch attached.

I'm using PHP 5.3.6, Apache 2.2.20.

Attachments (4)

19856.diff (488 bytes) - added by garyc40 4 years ago.
19856-2.patch (455 bytes) - added by bpetty 3 years ago.
use get_site_url() in wp_get_referer() checks
19856-tests.patch (2.1 KB) - added by bpetty 3 years ago.
unit tests
ticket-19856-referer.3.patch (3.9 KB) - added by bpetty 18 months ago.

Download all attachments as: .zip

Change History (14)

@garyc404 years ago

comment:1 @SergeyBiryukov3 years ago

  • Milestone changed from Awaiting Review to 3.4

comment:2 @nacin3 years ago

  • Keywords needs-unit-tests added
  • Milestone changed from 3.4 to Future Release

@bpetty3 years ago

use get_site_url() in wp_get_referer() checks

@bpetty3 years ago

unit tests

comment:3 @bpetty3 years ago

  • Keywords needs-unit-tests removed

The original patch here breaks referer URLs from different query variables, and also doesn't account for URLs from the different servers, but (coincidentally) the same resource.

If we use get_site_url() in wp_get_referer() for comparison instead, it fixes this and accounts for query variables and different servers.

I've also attached unit tests for this.

comment:4 @bpetty3 years ago

  • Cc bpetty added

comment:5 @bpetty3 years ago

  • Milestone changed from Future Release to 3.6

comment:6 @mordauk2 years ago

  • Cc pippin@… added

comment:7 @ryan2 years ago

  • Milestone changed from 3.6 to Future Release

comment:8 @nacin19 months ago

  • Component changed from General to Bootstrap/Load
  • Keywords needs-patch needs-unit-tests added; has-patch removed

The patch would break if WordPress was not at the root of a domain.

comment:9 @nacinbot18 months ago

  • Milestone changed from Future Release to 3.9

comment:10 @bpetty18 months ago

  • Keywords needs-unit-tests removed
  • Milestone changed from 3.9 to Future Release

I've refreshed the patch, and added subfolder unit tests, however, this patch does not actually fix the broken subfolder detection from the previous patch. It can at least now be confirmed by explicitly running the unit tests for this ticket.

I was hoping to avoid using anything complex like parse_url(), but it's looking like it would be necessary for properly handling subfolder installations unless someone else has a better suggestion for retrieving just the path from site_url without using parse_url() (maybe I'm not aware of such a method in WP already).

I'm punting this back out of 3.9 milestone for now.

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