Add share attributes + prevent download permission

[PVince81]

Close #16413

• brings in share attributes column in oc_share
• store download permission in extended share attributes
• enforces download restriction

• backend
• frontend, add "hide download" permission
• extension points for secure view ? not for now
• BUG: share view-only file with link, open link then download => this should be blocked on backend level and in UI
• BUG: share view-only folder with link, open link then download any entry => this should be blocked on backend level and in UI
• BUG: reshare with public link should automatically tick "hide download"
• BUG: reshare with public link should not allow to tick "hide download"
• BUG: viewer app still opens (optional)
• TEST: try increasing attribute permissions in reshare create
• TEST: try increasing attribute permissions in reshare update
• TODO: make sure versions endpoint also doesn't allow download past versions

[PVince81]

to test:

1. Share a folder "test" with another local user
2. Upload some files into "test", for example and a file "test.odt"
3. Find share id in the network console
4. Run curl with the share id:

curl -u admin:admin 'https://domain.tld/ocs/v2.php/apps/files_sharing/api/v1/shares/$shareId` \
  -X 'PUT' \
  -H 'OCS-APIRequest: true' \
-H 'Accept: application/json, text/plain, */*' \
  -H 'Content-Type: application/json' \
  --data-raw '{"attributes":[{"scope": "permissions", "key": "download", "enabled": "false"}]}'

5. Login as the share recipient
6. Try downloading the file

=> "Access denied".

Note: this PR doesn't adjust the frontend yet, so the download action is still visible

[PVince81]

• consider renaming "enabled" to "value" as we likely want more than a boolean there for flexibility ? (also change the method interfaces then)
  • need to consider what happens when merging shares (aka super shares / when receiving the same file/folder through multiple shares). with bools, true would have precedence

=> no, keep booleans due to prioritization

[PVince81]

I've fixed more tests, hope they all pass now (minus the node one that is broken on master)

[PVince81]

sqlite only not reproducible locally 😮

1) Test\Share20\DefaultShareProviderTest::testGetShareByIdUserShare
Invalid argument supplied for foreach()

/drone/src/lib/private/Share20/DefaultShareProvider.php:1563
/drone/src/lib/private/Share20/DefaultShareProvider.php:1082
/drone/src/lib/private/Share20/DefaultShareProvider.php:814
/drone/src/tests/lib/Share20/DefaultShareProviderTest.php:221

[PVince81]

rebased for CI, hopefully everything green after that!

[PVince81]

• simplify permissions in DB ?

  • ex: ["permissions","download",false] or even: {'permissions': {'download': false}}
  • => seems it's already stored

  JSON / HTTP: [{scope:'', permission: 'download': 'enabled': true}, {...}]
  DB `` [$scope, $permission, $enabled]```

=> let's keep this as is

[PVince81]

I've added a "Allow download" checkbox now in the frontend and also the logic to read and save it.
Additionally, the share attributes are now available in a "nc:share-attributes" DAV property for clients and is also used by the web UI.

More work needed to:

• make sure resharing cannot increase download perms

• make sure public link page doesn't show download action when resharing a received share that has no download perm

• see if possible to have JS tests for the new bits (at first look it seems we don't have any)

[PVince81]

would be good to have a first pass review already.
I'll fix conflicts/CI in my next pass

[PVince81]

optional: check if we can also skip "permissions"

[CarlSchwan]

ci issue unrelated

[PVince81]

/backport to stable24

[elhananjair]

Hello, @PVince81
I was waiting for this commit for so long, I tested it recently, and didn't work well with PDF files 😢. It works fine with other files I tested such as .docx .md.

[PVince81]

@elhananjair yes, the different apps also need to be adjusted to properly recognize the permission and act accordingly.
for apps that don't support view only, they should simply not view the document at all

[juliusknorr]

I filed nextcloud/files_pdfviewer#649 about this

[iMoshi]

So, I've finally tried the feature, and unchecked "Allow download" when sharing a folder with an internal user, and the user would get "Access forbidden" with basically any document including .pdf.

Is there something I'm missing inside the Administration Settings?

Also, can we have the option to "Allow download" when sharing a single file with an internal user?