Fix directory traversal issue

[kanarip]

This pull request also brings the used terminology of "public_path" in line with Swoole upstream's "document_root".

Reproduce and validate with, repeating ../ as many times as is necessary to get to your / top level directory:

$ curl --path-as-is http://127.0.0.1:1215/js/../etc/hosts

[Arkanius]

Thanks for yout PR!

Well, we could add this at next major version of package, but this is Albert's decision.

I wouldn't go with it for now

[kanarip]

Thanks for yout PR!

Well, we could add this at next major version of package, but this is Albert's decision.

I wouldn't go with it for now

Is it the transition from 'public_path' to 'document_root' standing in the way of accepting the fix to the security issue?

[alecpl]

"Low priority" for a security issue?

[Arkanius]

Is it the transition from 'public_path' to 'document_root' standing in the way of accepting the fix to the security issue?

yes, that way we had a BC that would force us to release the fix in a major version

[kanarip]

Is it the transition from 'public_path' to 'document_root' standing in the way of accepting the fix to the security issue?

yes, that way we had a BC that would force us to release the fix in a major version

Fair enough, it's now removed.

This should be included in a release as soon as possible, if the proposed solution is indeed acceptable. Thank you.

[Arkanius]

Thanks @kanarip . I'll prepare the release this week. Good job

[Arkanius]

I couldn't reproduce this behavior. When doing a curl to my swoole server Laravel's route handler tried to go to the mentioned route:

The json format is my default Route exception handler acting.

Am I missing something?

[kanarip]

I couldn't reproduce this behavior. When doing a curl to my swoole server Laravel's route handler tried to go to the mentioned route:

The json format is my default Route exception handler acting.

Am I missing something?

We are definitely not using a custom route exception handler, albeit we are using a fallback route, but another project that doesn't use such a fallback route is used to reproduce below;

Prepare the verification as follows;

0. Set handle_static_files to true in config/swoole_http.php,

   • Without handle_static_files, this exploit does not work,

1. Chose a directory that exists in public/, such as js/, or css/, or images/themes/default/,

2. Append repetitions of ../ as many times as it takes to, from that existing public/js/ directory on your filesystem, get to the top-level / directory of your filesystem, i.e. if you are in /var/www/app/, then public/js/ is /var/www/app/public/js/, meaning you'll need to append ../../../../../,

   • To validate the path you can, cd public/js/ and simply ls -l ../../../../../etc/hosts to see if you have the right amount of ../,

3. Add a path to an existing file, such as `/etc/hosts';

$ pwd
/home/kanarip/devel/src/projects/laravel.git/src/
$ ls -l public/js/
total 596
-rw-rw-r--. 1 kanarip kanarip 608663  2. Jan 12:57 app.js
$ cd public/js/
$ ls -l ../../../../../../../../../etc/hosts
-rw-r--r--. 1 root root 158 23. Jun 2020  ../../../../../../../../../etc/hosts
$ curl -v --path-as-is http://127.0.0.1:1215/js/../../../../../../../../../etc/hosts
*   Trying 127.0.0.1:1215...
* TCP_NODELAY set
* Connected to 127.0.0.1 (127.0.0.1) port 1215 (#0)
> GET /js/../../../../../../../../../etc/hosts HTTP/1.1
> Host: 127.0.0.1:1215
> User-Agent: curl/7.66.0
> Accept: */*
> 
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Content-Type: application/octet-stream
< Server: swoole-http-server
< Connection: keep-alive
< Date: Mon, 18 Jan 2021 06:45:52 GMT
< Content-Length: 158
< 
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
* Connection #0 to host 127.0.0.1 left intact

[Arkanius]

Oh I see. You're not using nginx in front of swoole, are you?

[kanarip]

Oh I see. You're not using nginx in front of swoole, are you?

No. Neither NGINX nor Apache nor any other "proxying" engine that secretly does more than just proxy.