S4 stored-XSS + S9 upload-size DoS from the #197 cold API review.
The artwork path trusted client-supplied content types at both ends: upload
validated only the declared multipart Content-Type (never decoded the bytes),
and serving reflected a client `?contentType=` straight into the response
Content-Type on unauthenticated GET sinks (/iptv/logos, /artwork/watermarks).
Chain: upload <script> bytes as image/png -> GET ...?contentType=text/html
serves them as HTML in-origin. nosniff (#279) does not help because the server
explicitly declares text/html.
- Upload: derive the content type from the bytes via SkiaSharp SKCodec
(header-only, no decode -> no decompression-bomb path); reject non-images 422.
New ErsatzTV.Core/Images/ImageContentTypes as the single allow-list source.
Dropped the untrusted declared Content-Type from the UploadArtwork command.
- Serve: removed the ?contentType= reflection structurally -- dropped ContentType
from GetCachedImagePath and the [FromQuery] binding on GetImage/GetWatermark;
the handler always sniffs the file, defaulting application/octet-stream.
ArtworkContentTypeModel.UrlWithContentType is now the bare path; SPA previews
no longer append the query.
- Defense-in-depth: channel-logo / watermark {path, contentType} DTOs run through
ArtworkContentTypeModel.Sanitized(), blanking non-allow-listed types on write.
- S9: Kestrel MaxRequestBodySize from ETV_MAXIMUM_UPLOAD_MB rejects oversized
bodies during read (controller file.Length check kept as friendly-error backstop).
Both serve sinks are IgnoreApi, so no OpenAPI change. Tests: byte-sniff accept/
reject, Sanitized() allow-list, Location no longer carries ?contentType=.
Docs: api-conventions §4a + decisions.md 2026-07-12.
Refs #283#197#66
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
First slice of the REST API (ersatztv#2). Idiomatic REST over existing MediatR handlers; design in docs/rest-api.md.
Foundation: NotFoundError : BaseError (Core) to split 404 from 422; ApiResults mapping helpers (Either/Option -> 201+Location / 200 / 204 / 404 / 422), additive (existing *ToActionResult untouched); ApiKeyAuthorizationFilter (optional X-Api-Key on mutating actions, gated by Api:WriteKey, no-op when unset) — independent of the IPTV JWT toggle so Jellyfin/Dispatcharr reads are unaffected, applied at controller-class level so every mutating action incl. ResetPlayout is covered fail-safe.
Channels: POST /api/channels (201+Location), PUT/{id} (200/404), DELETE/{id} (204/404), GET/{id} (200/404). Request DTOs -> existing commands; responses reuse ChannelViewModel. Ported page-only validations into handlers (ShowInEpg-when-disabled, external-logo-URL, Group NotEmpty) + FFmpegProfile/Watermark/Filler existence on update for create-parity. Fixed a latent 500: the .Filter(c>0) existence pattern threw TaskCanceledException on not-found; rewritten to AnyAsync.
Tests (NUnit, TZ=UTC): handler success/404/422, ApiResults mapping, API-key filter, controller status/Location/mapping, a controller-security regression net, and a create->read->delete EF integration test on a new in-memory SQLite harness. ErsatzTV.Tests 46/46, Architecture 5/5.
Refs #34
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
timothy
