Uploading file to folder a few levels up - PHP

Question

Sorry I wasn't able to be a lot more descriptive in my question title, I'm struggling to word the issue correctly. I have a script add-new-post.php that adds a new blog post to the database. I'm struggling with the file upload process as the upload file is a few levels away from the script that's doing the uploading.

File locations:

public_html/content/uploads/imgs 
public_html/content/themes/admin-cm/post/add-new-post.php

So, the script is attempting to upload files to the first directory. Below is the relevant snippet concerning the file upload, at the moment I'm just getting it to echo some info to the page so I can see what's happening:

        if ( !empty( $_FILES[ "featured_image" ][ "name" ] ) ) {

            $target_dir = '/content/uploads/imgs/';
            $target_file = dirname(__FILES__, 4 ) . $target_dir . basename( $_FILES[ "featured_image" ][ "name" ] );
            $upload_ok = 1;
            $image_file_type = strtolower( pathinfo( $target_file, PATHINFO_EXTENSION ) );

            $check = getimagesize( $_FILES[ "featured_image" ][ "tmp_name" ] );

            if ( $check !== false ) {

                echo "File is an image - " . $check[ "mime" ] . ".";
                echo "<br>" . $target_file;
                $upload_ok = 1;

            } else {

                $errors[] = "The uploaded file is not an image.";
                $upload_ok = 0;

            }

            if ( file_exists( $target_file ) ) {

                echo "Sorry, this file already exists.";
                $upload_ok = 0;

            } else {

                echo "<br>This image doesn't exist already.";

            }

            if ( $_FILES[ "featured_image" ][ "size" ] > 500000 ) {

                echo "Sorry, your file is too large.";
                $upload_ok = 0;

            }

            if ( $upload_ok ) {

                if ( move_uploaded_file( $_FILES[ "featured_image" ][ "name" ], $target_file ) ) {

                    echo "<br>Successfully uploaded the image.";

                } else {

                    echo "<br>Couldn't upload the image.";

                }

            }

        }

I'm guessing my issue is the directory, I've tried a few different ways of inputting the target directory and none seem to work (such as initially entering the $target_file variable as a string ie. "../../../../content/uploads/imgs). I am testing this out by attempting to upload a file that DOES currently exist in the uploads directory and the following is what is printed to the page:

File is an image - image/jpeg.
./content/uploads/imgs/post-img-8.jpg
This image doesn't exist already.
Couldn't upload the image.

To me the target directory looks correct.. I've also tried substr() to lose the dot and tried it to lose the ./. Any ideas what I'm doing wrong?

SOLVED (thanks to Martin in the comments):

I replaced the following:

$target_dir = '/content/uploads/imgs/';
$target_file = dirname(__FILES__, 4 ) . $target_dir . basename( $_FILES[ "featured_image" ][ "name" ] );

with:

$target_dir ="content/uploads/imgs/";
$target_file = $_SERVER[ "DOCUMENT_ROOT" ] . $target_dir . basename( $_FILES[ "featured_image" ][ "name" ] );

`$target_dir = '/content/uploads/imgs/';` – that is an absolute path referring to the root of the server’s file system. I doubt you actually have `content` at the root level …? You are probably confusing URLs with file system paths here, I suppose? — CBroe, Mar 05 '20 at 10:59

Martin · Accepted Answer · 2020-03-05T11:47:34.017

You should use $_SERVER['DOCUMENT_ROOT'] to set an absolute filepath to save the files to your server's filesystem.

$_SERVER['DOCUMENT_ROOT'] typically is /user/domain/public_html and inside this folder is the world-accessible website;

https://www.mywebsite.co.uk/somefolder/somefile.php

Is the same as :

$_SERVER['DOCUMENT_ROOT']."/somefolder/somefile.php";

Therefore to save your file to: www.mywebsite.org/content/uploads/imgs/post-img-8.jpg you would save it to $_SERVER['DOCUMENT_ROOT']."/content/uploads/imgs/post-img-8.jpg";

This is universal no matter what part of your website this code is run from.

Security Notes:

DO NOT save files with the given $_FILES[ "featured_image" ][ "name" ] value, this value can be easily compromised and should be at least Regex escaped to remove any invalid characters.
- Example: $name = preg_replace('/[^a-z0-9_-]/i','',$_FILES['featured_image']['name']);
DO NOT trust upload MIME types. Even getimagesize can be compromised. Best suggestion is to use PHP fileinfo functions.
- The best way of handling images is to load the image into PHP (imagecreatefromjpeg or similar) and resave the loaded image data, this can strip out the nasty meta-data that JPG images especially can contain.

Uploading file to folder a few levels up - PHP

1 Answers1

Security Notes:

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