54 lines
2.6 KiB
Markdown
54 lines
2.6 KiB
Markdown
# MSC4189: Allowing guests to access uploaded media
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[MSC3916](https://github.com/matrix-org/matrix-spec-proposals/blob/main/proposals/3916-authentication-for-media.md)
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introduced new endpoints which require clients to provide a valid access token in order to access
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media. The MSC failed to specify [guest access](https://spec.matrix.org/v1.11/client-server-api/#guest-access)
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requirements for the new endpoints.
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This MSC specifies the missing guest access requirements on the new endpoints.
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## Proposal
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The following endpoints explicitly permit guest access, joining the
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[list of other endpoints](https://spec.matrix.org/v1.11/client-server-api/#client-behaviour-13)
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already in the specification:
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* [`GET /_matrix/client/v1/media/download/{serverName}/{mediaId}`](https://spec.matrix.org/v1.11/client-server-api/#get_matrixclientv1mediadownloadservernamemediaid)
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* [`GET /_matrix/client/v1/media/download/{serverName}/{mediaId}/{fileName}`](https://spec.matrix.org/v1.11/client-server-api/#get_matrixclientv1mediadownloadservernamemediaidfilename)
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* [`GET /_matrix/client/v1/media/thumbnail/{serverName}/{mediaId}`](https://spec.matrix.org/v1.11/client-server-api/#get_matrixclientv1mediathumbnailservernamemediaid)
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The rationale for the above endpoints is that being able to see events without the associated media
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isn't very useful.
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For clarity, the following endpoints are *not* added to the guest access list, as their prior (now
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deprecated) versions are not already included. A future MSC may change this with sufficient rationale.
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Note that guests cannot currently *upload* files, but can send messages/events.
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* [`GET /_matrix/client/v1/media/config`](https://spec.matrix.org/v1.11/client-server-api/#get_matrixclientv1mediaconfig)
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* [`GET /_matrix/client/v1/media/preview_url`](https://spec.matrix.org/v1.11/client-server-api/#get_matrixclientv1mediapreview_url)
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## Potential issues
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This MSC fixes an issue where guests cannot download images/files.
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## Alternatives
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None applicable.
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## Security considerations
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This MSC does not materially increase the threat profile for guests: guests could already download
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media using the unauthenticated endpoints.
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## Unstable prefix
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Prefixed endpoints are excessive for this MSC. Implementations can enable guest access on the existing
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endpoints safely, or continue to respond with "guest access forbidden" errors. No `/versions` flag
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is specified for feature detection: clients with guest access tokens should expect failure until a
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server advertises a specification version containing this MSC. Clients should continue trying to make
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requests for the best user experience.
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## Dependencies
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This MSC has no dependencies.
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