fix permissions for share jail

[micbar]

Description

The shared jail should not be writable.

closes owncloud/ocis#2322

@aduffeck @refs @ishank011 This will only be temporary, until we remove all "Share" awareness and logic from the storage.

[ishank011]

It should already be handled, no? https://github.com/cs3org/reva/blob/master/internal/grpc/services/gateway/storageprovider.go#L531-L657

[micbar]

It should already be handled, no? https://github.com/cs3org/reva/blob/master/internal/grpc/services/gateway/storageprovider.go#L531-L657

yes, this is already forbidden.

But to get the information to the Client, the webDAV permissions should not indicate write possibilities.

So we need to return the permissions also from the decomposedfs

See Example WebDAV response after the fix

<?xml version="1.0" encoding="utf-8"?>
<d:multistatus xmlns:d="DAV:" xmlns:s="http://sabredav.org/ns" xmlns:oc="http://owncloud.org/ns">
    <d:response>
        <d:href>/dav/files/einstein/Shares/</d:href>
        <d:propstat>
            <d:prop>
                <oc:id>MTI4NGQyMzgtYWE5Mi00MmNlLWJkYzQtMGIwMDAwMDA5MTU3OmY0MjQ4MDBmLTc5YjItNDZhNi05NzQ2LTFmM2I4MmEwYjViYw==</oc:id>
                <oc:fileid>MTI4NGQyMzgtYWE5Mi00MmNlLWJkYzQtMGIwMDAwMDA5MTU3OmY0MjQ4MDBmLTc5YjItNDZhNi05NzQ2LTFmM2I4MmEwYjViYw==</oc:fileid>
                <d:getetag>&#34;05e827b715f0da007b7adc800703bb1e&#34;</d:getetag>
                <oc:permissions></oc:permissions>
                <d:resourcetype>
                    <d:collection/>
                </d:resourcetype>
                <oc:size>0</oc:size>
                <d:getlastmodified>Tue, 27 Jul 2021 14:38:25 GMT</d:getlastmodified>
                <oc:favorite>0</oc:favorite>
            </d:prop>
            <d:status>HTTP/1.1 200 OK</d:status>
        </d:propstat>
    </d:response>
    <d:response>
        <d:href>/dav/files/einstein/Shares/NewFolder/</d:href>
        <d:propstat>
            <d:prop>
                <oc:id>MTI4NGQyMzgtYWE5Mi00MmNlLWJkYzQtMGIwMDAwMDA5MTU3OjNjY2RhNzUyLWFiMWQtNGEzMS05YWFkLWVjNjA2ZmY4MDZkYw==</oc:id>
                <oc:fileid>MTI4NGQyMzgtYWE5Mi00MmNlLWJkYzQtMGIwMDAwMDA5MTU3OjNjY2RhNzUyLWFiMWQtNGEzMS05YWFkLWVjNjA2ZmY4MDZkYw==</oc:fileid>
                <d:getetag>&#34;74d129b6a9a38d48976c1dee64a9bd53&#34;</d:getetag>
                <oc:permissions>S</oc:permissions>
                <d:resourcetype>
                    <d:collection/>
                </d:resourcetype>
                <oc:size>0</oc:size>
                <d:getlastmodified>Tue, 27 Jul 2021 14:37:49 GMT</d:getlastmodified>
                <oc:favorite>0</oc:favorite>
            </d:prop>
            <d:status>HTTP/1.1 200 OK</d:status>
        </d:propstat>
    </d:response>
</d:multistatus>

[micbar]

@aduffeck @butonic It turned into a small refactoring. Happy to discuss this in general how we work with pointer variables.

@dragotin FYI