[bug] Sharing w/ S3 + direct middleware produces 403

[Haarolean]

Description of the bug

When using S3 as a backend and direct middleware sharing doesn't work, every link has 403 as a result. Looks like this: Oops! AccessDenied: Access Denied. status code: 403, request id: 174757DA33D49990, host id: Request: http://host/api/files/ls?path=%2F&share=Imr5jVL gives 500 with this response body: {"status":"error","message":"AccessDenied: Access Denied.\n\tstatus code: 403, request id: 174757DA33D49990, host id: "}

Step by step instructions to reproduce the bug

1. Set up S3
2. Set up direct middleware
3. Share a link

Logs (DEBUG level):

filestash    | 2023/02/26 10:31:13 HTTP 200 POST    1.6ms /api/share/e9CkP4k/proof
filestash    | 2023/02/26 10:31:13 HTTP 200 GET    0.2ms /admin/api/session
filestash    | 2023/02/26 10:31:14 SYST DEBUG ls::backend 'AccessDenied: Access Denied.
filestash    | 	status code: 403, request id: 17475935D8185F41, host id: '
filestash    | 2023/02/26 10:31:14 HTTP 500 GET    6.1ms /api/files/ls?path=%2F&share=e9CkP4k
filestash    | 2023/02/26 10:31:15 HTTP 304 GET    0.2ms /sw_cache.js

[Haarolean]

Welp, I figured this out. That required some network debugging, s3 tracing, and reading the code of the app. It turns out, you have to put a slash at the end of the path in your middleware if it's not empty. I wanted to give access to root w/ bucket "public", so I did put "/public" as the path, that was the cause of the issue, all the paths became "publicactualfilename", without a slash. That's absolutely not obvious behavior, can we do something with it?

[mickael-kerjean]

I can't replicate this on my own. If you can reproduce this from the demo.filestash.app and publish all the steps in here, I'll make up a fix for it

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.