timothy
e132c422bb
`ImageElementBase.LoadImage` fetched http(s) images with a throwaway `new HttpClient()` + `GetStreamAsync`: no timeout override (the 100s default), no size cap, unbounded redirects, no pooling — all inside stream startup, while ffmpeg waits on the pipe. #502 routed ordinary channel-logo watermarks onto that path, widening a pre-existing weakness. Introduce `IRemoteImageFetcher` / `HttpRemoteImageFetcher`, modelled on the neighbouring `IRemoteStreamProber`: - deadline covers headers AND body (linked CTS + `CancelAfter`, client `Timeout = InfiniteTimeSpan`) — under `ResponseHeadersRead` the body read falls outside `HttpClient.Timeout` (the #289 lesson) - 10 MiB cap enforced during the copy; `Content-Length` is only a cheap early reject, since it can be absent or a lie - permissive content-type check (rejects an HTML error page, allows a missing type and octet-stream) - pooled via `IHttpClientFactory`; redirects capped at 3, not 50 A byte cap does NOT bound decoding, so `DecodeRemoteImage` additionally reads declared dimensions + frame count from the header and rejects before `Image.LoadAsync` allocates (50 MP / 600 frames). A 4 KB PNG declaring 30000x30000 costs ~3.6 GB to decode and passes every wire-size check — caught by adversarial review of the first version of this change, which capped bytes and wrongly claimed that was decode-bomb protection. Not cached and SSRF not mitigated — both deliberate, with the reasoning recorded in docs/decisions.md. fixes #511
88 lines
3.0 KiB
C#
88 lines
3.0 KiB
C#
using ErsatzTV.Core.Graphics;
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using ErsatzTV.Core.Interfaces.Streaming;
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using Microsoft.Extensions.Logging;
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using NCalc;
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using SkiaSharp;
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namespace ErsatzTV.Infrastructure.Streaming.Graphics;
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public class ImageElement(
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ImageGraphicsElement imageGraphicsElement,
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IRemoteImageFetcher remoteImageFetcher,
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ILogger logger) : ImageElementBase(remoteImageFetcher)
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{
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private Option<Expression> _maybeOpacityExpression;
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private float _opacity;
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public override int ZIndex { get; } = imageGraphicsElement.ZIndex ?? 0;
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public override string DebugKey { get; } = $"Image {imageGraphicsElement.DebugName()}";
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public override async Task InitializeAsync(GraphicsEngineContext context, CancellationToken cancellationToken)
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{
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try
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{
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if (!string.IsNullOrWhiteSpace(imageGraphicsElement.OpacityExpression))
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{
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var expression = new Expression(imageGraphicsElement.OpacityExpression);
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expression.EvaluateFunction += OpacityExpressionHelper.EvaluateFunction;
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_maybeOpacityExpression = expression;
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}
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else
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{
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_opacity = (imageGraphicsElement.OpacityPercent ?? 100) / 100.0f;
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}
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foreach (Expression expression in _maybeOpacityExpression)
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{
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expression.EvaluateFunction += OpacityExpressionHelper.EvaluateFunction;
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}
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await LoadImage(
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context.SquarePixelFrameSize,
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context.FrameSize,
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imageGraphicsElement.Image,
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imageGraphicsElement.Location,
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imageGraphicsElement.Scale,
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imageGraphicsElement.ScaleWidthPercent,
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imageGraphicsElement.HorizontalMarginPercent,
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imageGraphicsElement.VerticalMarginPercent,
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imageGraphicsElement.PlaceWithinSourceContent,
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cancellationToken);
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}
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catch (Exception ex)
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{
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IsFinished = true;
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logger.LogWarning(ex, "Failed to initialize image element; will disable for this content");
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}
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}
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public override ValueTask<Option<PreparedElementImage>> PrepareImage(
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TimeSpan timeOfDay,
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TimeSpan contentTime,
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TimeSpan contentTotalTime,
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TimeSpan channelTime,
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CancellationToken cancellationToken)
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{
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float opacity = _opacity;
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foreach (Expression expression in _maybeOpacityExpression)
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{
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opacity = OpacityExpressionHelper.GetOpacity(
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expression,
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timeOfDay,
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contentTime,
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contentTotalTime,
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channelTime);
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}
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if (opacity == 0)
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{
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return ValueTask.FromResult(Option<PreparedElementImage>.None);
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}
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SKBitmap frameForTimestamp = GetFrameForTimestamp(contentTime);
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return ValueTask.FromResult(
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Optional(new PreparedElementImage(frameForTimestamp, Location, opacity, ZIndex, false)));
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}
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}
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