19f4cf8232
- deferred_bindings migration set under summercms.deferred with backend_user_id - lagoon.DeferredBind/Unbind/Bindings/Forget/Slaves scoped by DeferredKey - lagoon.PurgeDeferred with SKIP LOCKED batches and after-commit blob deletes - attach.Store with the ported image guard, extension and MIME limits - attach.Relation, attach.HasRelations, attach.BlobKeys, File.ThumbKey - lagoon README and attachments docs
48 lines
1.5 KiB
Go
48 lines
1.5 KiB
Go
package attach
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import (
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"bytes"
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"image"
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"net/http"
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"slices"
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)
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// AllowedImageMIMEs are the content types IsAllowedImage accepts, as
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// sniffed from the bytes: JPEG, PNG, GIF and WebP, the formats the
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// thumbnailer decodes.
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var AllowedImageMIMEs = []string{"image/jpeg", "image/png", "image/gif", "image/webp"}
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// MaxImagePixels is the largest image (width times height) IsAllowedImage
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// accepts, the same ceiling File.Thumb applies before decoding, so every
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// accepted image can be thumbnailed.
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const MaxImagePixels = maxThumbSourcePixels
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// IsAllowedImage reports whether data is a JPEG, PNG, GIF or WebP image:
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// the bytes must sniff as one of AllowedImageMIMEs (http.DetectContentType,
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// independent of any file name or client header), the header must decode
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// through image.DecodeConfig as that format with a positive width and
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// height, and the image must not exceed MaxImagePixels. Decoding the header
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// rejects a polyglot whose first bytes alone look right. It fails closed:
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// empty or unreadable content is refused. data may be a prefix of the file
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// as long as it holds the image header.
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func IsAllowedImage(data []byte) bool {
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if len(data) == 0 {
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return false
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}
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if !slices.Contains(AllowedImageMIMEs, http.DetectContentType(data)) {
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return false
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}
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cfg, format, err := image.DecodeConfig(bytes.NewReader(data))
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if err != nil || cfg.Width <= 0 || cfg.Height <= 0 {
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return false
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}
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if int64(cfg.Width)*int64(cfg.Height) > MaxImagePixels {
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return false
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}
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switch format {
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case "jpeg", "png", "gif", "webp":
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return true
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}
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return false
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}
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